Federal Lands Highway

Field Materials Manual 

March 2021

Commitment to Excellence

Federal Highway Administration 

U.S. Department of Transportation 
Field Materials Manual

Introduction i

(This page intentionally left blank.)
Field Materials Manual

ii Introduction

INTRODUCTION

This manual has been developed to provide construction project personnel with information and 

guidance for field activities relating to materials. This manual complements the Standard 

Specifications for Construction of Roads and Bridges on Federal Highway Projects (FP). When 

the guidelines or directions set forth in this manual conflict with an FLH contract, the contract shall 

govern. 

This manual is intended as general guidance. It sets forth procedures and best practices for 

testing and verifying materials on a contract. The application of this manual to any particular 

situation is to be guided by sound engineering principles. This manual does not create 

enforceable rights. However, a contract may adopt or incorporate by reference any portion of this

manual and thereby establish that portion as binding on the parties. 

The manual is divided into five chapters: 

Chapter 1 – Division 100: Acceptance and Verification Procedures

Chapter 2 – Division 200: Earthwork Testing and Evaluation

Chapter 3 – Division 300: Aggregate Base, Subbase, Aggregate-Topsoil, and 

Base Stabilization

Chapter 4 – Division 400: Asphalt Pavements and Surface Treatments

Chapter 5 – Division 500: Concrete 

Chapter 1 processes and procedures are generally applicable to the categories of materials 

addressed in Chapters 2 through 5. Chapters 2 through 5 set forth the processes needed to 

address the categories of materials specifically addressed in each particular chapter. 

In this manual, the term “Project Engineer” applies to both FHWA Project Engineers and 

contracted Construction Managers. The Construction Managers role, however, is limited as 

identified in the specific contract with FHWA and the Delegation of Authority letter.
Field Materials Manual

Table of Contents iii

TABLE OF CONTENTS

Section Page

Contents

Contents........................................................................................................................ iii

Chapter 1.....................................................................................................................1-1

Division 100: Acceptance and Verification Procedures..........................................1-1

1.1 GENERAL GUIDANCE ............................................................................................1-1

1.2 ACCEPTANCE.........................................................................................................1-2

1.2.1 Visual Inspection .......................................................................................1-2

1.2.2 Certification................................................................................................1-2

1.2.3 Measured or Tested Conformance............................................................1-3

1.2.4 Statistical Evaluation of Work and Determination of Pay Factor 

(Value of Work)..........................................................................................1-4

1.3 VERIFICATION PROCESSES.................................................................................1-5

1.3.1 Verification of Material Quality...................................................................1-5

1.3.2 Visual Inspection and Certification ............................................................1-5

1.3.3 Measured or Tested for Conformance.......................................................1-5

1.3.4 Statistical Evaluation of Work and Determination of Pay Factor 

(Value of Work)..........................................................................................1-6

1.4 VALIDATION OF TEST RESULTS AND PAY FACTORS .......................................1-7

1.4.1 Validation of Contractor Test Results ........................................................1-7

1.4.1.1 Validation Conditions ............................................................1-7

1.4.1.2 Test Results Verification .......................................................1-7

1.4.2 Test Results Review..................................................................................1-9

1.4.3 Dispute Resolution Guidelines ................................................................1-10

1.5 ACCEPTANCE OF WORK AND VALUE DETERMINATION ................................1-11

1.6 MATERIAL PROJECT REQUIREMENTS..............................................................1-13

1.6.1 Personnel ................................................................................................1-13

1.6.1.1 Qualification Documentation ...............................................1-13

1.6.1.2 Subcontracted Sampling and Testing .................................1-13

1.6.2 Equipment and Testing Laboratories.......................................................1-14

1.6.2.1 Contractor-furnished Laboratories ......................................1-14

1.6.2.2 Government-furnished Laboratories ...................................1-14

1.6.2.3 Equipment Calibration.........................................................1-15

1.6.2.4 Equipment Calibration Documentation................................1-16

1.6.3 Sampling..................................................................................................1-16

1.6.3.1 Sampling Responsibilities ...................................................1-17
Field Materials Manual

TABLE OF CONTENTS

(Continued)

Section Page

iv Table of Contents

1.6.3.2 Sampling Procedures..........................................................1-18

1.6.3.3 Sampling Methodologies.....................................................1-18

1.6.3.4 Sample Handling.................................................................1-19

1.6.3.5 Request for laboratory testing.............................................1-20

1.7 FORM REFERENCES .............................................................................................1-1

Chapter 2.....................................................................................................................2-3

Division 200: Earthwork Testing and Evaluation....................................................2-3

2.1 SUMMARY AND DESCRIPTION.............................................................................2-3

2.2 MATERIAL PROPERTIES AND TEST METHODS .................................................2-4

2.2.1 Classification .............................................................................................2-4

2.2.1.1 Particle Size Distribution .......................................................2-5

2.2.1.2 Consistency and Plasticity (Atterberg Limits)........................2-5

2.2.2 Moisture – Density Relations.....................................................................2-6

2.2.2.1 Moisture content ...................................................................2-6

2.2.2.2 Density ..................................................................................2-7

2.2.3 Soil Strength ..............................................................................................2-8

2.3 IMPORTED SUBGRADE AND BACKFILL MATERIALS .........................................2-9

2.4 ROLES AND RESPONSIBILITIES.........................................................................2-12

2.4.1 Contractor’s Responsibilities ...................................................................2-12

2.4.2 Government’s Responsibilities ................................................................2-12

2.5 MATERIAL CERTIFICATIONS ..............................................................................2-14

2.6 FORM REFERENCES ...........................................................................................2-15

Chapter 3.....................................................................................................................3-1

Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base 

Stabilization...........................................................................................................3-1

3.1 SUMMARY AND DESCRIPTION.............................................................................3-1

3.2 AGGREGATE BASE PROPERTIES AND TEST METHODS..................................3-2

3.2.1 Aggregate Quality Properties ....................................................................3-2

3.2.2 Processed Aggregate Properties...............................................................3-3

3.2.2.1 Moisture Density Relationship ..............................................3-4

3.2.3 Aggregate Sampling and Splitting .............................................................3-4

3.2.3.1 Sampling from Stockpiles .....................................................3-4

3.2.3.2 Sampling from Flowing Aggregate Stream ...........................3-6

3.2.3.3 Sampling from Conveyor Belt ...............................................3-7
Field Materials Manual

TABLE OF CONTENTS

(Continued)

Section Page

Table of Contents v

3.2.3.4 Sampling from Roadbed or Windrow ....................................3-9

3.2.3.5 Splitting Samples ..................................................................3-9

3.2.4 Typical Aggregate Base Treatments .......................................................3-10

3.2.5 Other Associated Aggregate Products ....................................................3-11

3.2.5.1 Minor Crushed Aggregate...................................................3-11

3.2.5.2 Recycled Aggregate Base and Road Reconditioning .........3-11

3.2.5.3 Aggregate-Topsoil...............................................................3-11

3.2.5.4 Dust Palliatives and Stabilization Admixtures .....................3-11

3.2.6 Field Testing Requirements.....................................................................3-12

3.3 RECYCLING TECHNIQUES..................................................................................3-14

3.3.1 Cold Recycling.........................................................................................3-14

3.3.2 Full Depth Reclamation (FDR) Techniques.............................................3-14

3.4 ROLES AND RESPONSIBILITES..........................................................................3-16

3.4.1 Contractor’s Responsibilities ...................................................................3-16

3.4.2 Government’s Responsibilities ................................................................3-16

3.5 MATERIAL CERTIFICATIONS ..............................................................................3-18

3.6 FORM REFERENCES ...........................................................................................3-19

Chapter 4.....................................................................................................................4-1

Division 400: Asphalt Pavements and Surface Treatments ..................................4-1

4.1 SUMMARY AND DESCRIPTION.............................................................................4-1

4.2 SUPERPAVE HOT ASPHALT CONCRETE AGGREGATE AND MIX 

DESIGN....................................................................................................................4-2

4.2.1 Aggregate Quality and Gradation ..............................................................4-2

4.2.2 Superpave Mix Design Process ................................................................4-2

4.2.2.1 Hveem and Marshall Mix Design Methods............................4-3

4.2.3 Asphalt Binder ...........................................................................................4-4

4.2.4 Additives ....................................................................................................4-5

4.3 CONSTRUCTION PROCESS..................................................................................4-6

4.3.1 Equipment for Production and Placement .................................................4-6

4.3.2 Production Start-Up Procedures................................................................4-6

4.3.3 Full Production Operations ........................................................................4-7

4.3.4 Pavement Smoothness ...........................................................................4-13

4.3.5 Other Types of Asphalt Mixtures .............................................................4-14

4.4 SURFACE TREATMENTS.....................................................................................4-15

4.4.1 Single or Multiple-Course Chip Seals......................................................4-15
Field Materials Manual

TABLE OF CONTENTS

(Continued)

Section Page

vi Table of Contents

4.4.2 Fog Seal ..................................................................................................4-16

4.4.3 Slurry Seal and Micro-Surfacing..............................................................4-17

4.4.4 Prime Coat...............................................................................................4-17

4.5 ROLES AND RESPONSIBILITIES.........................................................................4-18

4.5.1 Contractor’s Responsibilities ...................................................................4-18

4.5.2 Government’s Responsibilities ................................................................4-19

4.6 MATERIAL CERTIFICATIONS ..............................................................................4-21

4.7 FORM REFERENCES .............................................................................................4-1

Chapter 5.....................................................................................................................5-2

Division 500 – Concrete.............................................................................................5-2

5.1 SUMMARY AND DESCRIPTION.............................................................................5-2

5.2 CONCRETE MATERIALS SPECIFICATIONS.........................................................5-3

5.2.1 Hydraulic Cement ......................................................................................5-4

5.2.1.1 Portland Cement ...................................................................5-4

5.2.1.2 Blended Cement ...................................................................5-4

5.2.1.3 Hydraulic Cement Constructability Issues.............................5-6

5.2.2 Mineral Admixtures / Pozzolans ................................................................5-6

5.2.2.1 Fly Ash ..................................................................................5-7

5.2.2.2 Ground Granulated Blast-furnace Slag (GGBFS).................5-8

5.2.2.3 Silica Fume ...........................................................................5-9

5.2.2.4 Collective Mineral Admixture Limitation ..............................5-11

5.2.3 Water.......................................................................................................5-12

5.2.4 Concrete Aggregates...............................................................................5-13

5.2.4.1 Concrete Aggregate Gradation ...........................................5-13

5.2.4.2 Concrete Fine Aggregate....................................................5-13

5.2.4.3 Concrete Coarse Aggregate ...............................................5-15

5.2.4.4 Aggregate Tests Used During Concrete Mixture 

Proportioning.................................................................5-16

5.2.5 Chemical Admixtures...............................................................................5-17

5.2.5.1 Air-entraining Admixtures....................................................5-17

5.2.5.2 Water-reducing and Set-controlling Admixtures .................5-18

5.2.5.3 Concrete Coloring Admixtures ............................................5-19

5.2.5.4 Miscellaneous Admixtures ..................................................5-19

5.2.6 Fibers.......................................................................................................5-19

5.3 CONCRETE MATERIALS ACCEPTANCE REQUIREMENTS ..............................5-21

5.3.1 Materials Certification Acceptance ..........................................................5-21

5.3.2 Water Acceptance ...................................................................................5-23

5.3.3 Aggregate Acceptance ............................................................................5-23
Field Materials Manual

TABLE OF CONTENTS

(Continued)

Section Page

Table of Contents vii

5.4 CONCRETE MIXTURE PROPORTIONING AND APPROVAL 

REQUIREMENTS ..................................................................................................5-25

5.4.1 Concrete Mixture Composition and Proportioning Requirements ...........5-25

5.4.1.1 ACI 211.1 Standard Practice for Selecting Proportions 

for Normal, Heavyweight and Mass Concrete...............5-25

5.4.1.2 ACI 211.2 Standard Practice for Selecting Proportions 

for Structural Lightweight Concrete...............................5-25

5.4.1.3 ACI 211.3 Guide for Selecting Proportions for NoSlump Concrete ............................................................5-26

5.4.1.4 ACI 211.4 Guide for Selecting Proportions for HighStrength Concrete using Portland Cement and 

other Cementitious Materials ........................................5-26

5.4.2 Concrete Mixture Durability Requirements..............................................5-27

5.4.2.1 Exposure Category F (Freezing and thawing) ....................5-28

5.4.2.2 Exposure Category S (Sulfates) .........................................5-29

5.4.2.3 Exposure Category C (Corrosion).......................................5-30

5.4.2.4 Delayed Ettringite Formation (DEF)....................................5-31

5.4.2.5 Alkali-Silica Reactivity (ASR) ..............................................5-31

5.4.3 Concrete Mixture Strength Requirements ...............................................5-35

5.4.3.1 Determine a Sample Standard Deviation from Suitable 

Test Records (Strength Tests)......................................5-35

5.4.3.2 Determine a Required Average Strength (f’cr)....................5-37

5.4.3.3 Select Mixture Proportions..................................................5-40

5.4.4 Concrete Mix Design Submittal ...............................................................5-40

5.4.5 Concrete Mix Design Approval ................................................................5-40

5.5 CONCRETE CONSTRUCTION REQUIREMENTS ...............................................5-41

5.5.1 Aggregate Testing for Uniformity and Water Content Adjustment of 

Concrete Mixtures ...................................................................................5-42

5.5.2 Fresh Concrete Properties ......................................................................5-43

5.5.2.1 Sampling .............................................................................5-44

5.5.2.2 Concrete Slump ..................................................................5-44

5.5.2.3 Air Content ..........................................................................5-44

5.5.2.4 Concrete Temperature........................................................5-45

5.5.2.5 Concrete Unit Weight..........................................................5-45

5.5.3 Hardened Concrete Properties................................................................5-45

5.6 SHOTCRETE .........................................................................................................5-48

5.6.1 Shotcrete Material Specifications ............................................................5-48

5.6.2 Shotcrete Mixture Proportioning and Preconstruction Requirements......5-49

5.6.2.1 Fresh Shotcrete Properties Sampling and Testing .............5-49

5.6.2.2 Making and Curing Shotcrete Test Panels..........................5-49

5.6.2.3 Hardened Shotcrete Properties Testing..............................5-50

5.6.3 Shotcrete Mixture Approval Requirements..............................................5-51

5.6.4 Shotcrete Construction Requirements.....................................................5-51
Field Materials Manual

TABLE OF CONTENTS

(Continued)

Section Page

viii Table of Contents

5.7 DRIVEN PILES.......................................................................................................5-53

5.7.1 Steel H-piles ............................................................................................5-53

5.7.2 Concrete-filled Steel Shell Piles ..............................................................5-53

5.7.3 Concrete-filled Pipe Piles ........................................................................5-53

5.7.4 Precast / Prestressed Concrete Piles......................................................5-54

5.7.5 Sheet Piles ..............................................................................................5-54

5.7.6 Timber Piles.............................................................................................5-54

5.7.7 Driven Piles Materials Acceptance ..........................................................5-54

5.7.8 Driven Pile Materials Sampling and Testing............................................5-54

5.8 PAINTING ..............................................................................................................5-55

5.8.1 Coating System Components..................................................................5-55

5.8.2 Coating Types .........................................................................................5-55

5.8.2.1 Alkyd ...................................................................................5-55

5.8.2.2 Epoxy ..................................................................................5-56

5.8.2.3 Urethane .............................................................................5-56

5.8.2.4 Moisture-cured Urethane ....................................................5-56

5.8.2.5 Zinc-rich ..............................................................................5-56

5.8.2.6 Acrylic Latex........................................................................5-56

5.8.2.7 Vinyl ....................................................................................5-57

5.8.3 Curing ......................................................................................................5-57

5.8.4 Surface Preparation.................................................................................5-57

5.8.5 Application ...............................................................................................5-57

5.8.6 Inspection ................................................................................................5-58

5.8.7 Safety ......................................................................................................5-58

5.8.8 Painting Materials Acceptance ................................................................5-59

5.9 DRILLED SHAFTS.................................................................................................5-60

5.9.1 Casings....................................................................................................5-60

5.9.2 Mineral Slurry ..........................................................................................5-60

5.9.3 Integrity Testing .......................................................................................5-61

5.9.4 Concrete and Reinforcing Steel for Drilled Shafts ...................................5-61

5.9.5 Drilled Shaft Materials Acceptance..........................................................5-61

5.9.6 Drilled Shaft Materials Sampling and Testing..........................................5-61

5.10 ROLES AND RESPONSIBILITIES.........................................................................5-62

5.10.1 Contractor’s Responsibilities ...................................................................5-62

5.10.2 Government’s Responsibilities ................................................................5-63

5.11 FORM REFERENCES ...........................................................................................5-65

5.11.1 Fineness Modulus of Fine Aggregate Calculation ...................................5-66
Field Materials Manual

TABLE OF CONTENTS

(Continued)

Section Page

Table of Contents ix

Appendix.................................................................................................................... A-1

APPENDIX A: FORMS........................................................................................................ A-1

APPENDIX B: FLH TEST METHODS AND ADDENDUMS................................................ B-1

APPENDIX C: SAMPLE QUANTITIES GUIDE................................................................... C-1

APPENDIX D: PRE-CONSTRUCTION MEETING AGENDAS........................................... D-1

APPENDIX D.1: PRE-PAVING MEETING AGENDA.......................................................... D-1

APPENDIX D.2: PRE-CONCRETING MEETING AGENDA............................................... D-5

APPENDIX D.3: PRE-DRILLED SHAFT MEETING AGENDA ........................................... D-7
Field Materials Manual

List of Exhibits x

LIST OF EXHIBITS

Exhibit Page

Exhibit 1-1 Common Sample Containers .....................................................................1-20

Exhibit 2-2 Soil Test Methods.........................................................................................2-4

Exhibit 2-3 Classification of Soil Material from AASHTO M 145.....................................2-4

Exhibit 2-4 Particle Sizes................................................................................................2-5

Exhibit 2-5 Relationship of Atterberg Limits....................................................................2-6

Exhibit 2-6 Five Point Moisture Density Curve ...............................................................2-7

Exhibit 2-7 Guidance for Sample Sizes for Transmitting to FLH Laboratory ................2-10

Exhibit 2-8 AASHTO Soil Test Procedures ..................................................................2-11

Exhibit 2-9 Materials Certification.................................................................................2-14

Exhibit 3-10 Aggregate Quality Test Methods ..................................................................3-2

Exhibit 3-11 Gradation Classification................................................................................3-3

Exhibit 3-12 Supplemental Aggregate Base Tests ...........................................................3-3

Exhibit 3-13 Proper Sampling of Coarse Aggregate.........................................................3-5

Exhibit 3-14 Proper Use of Shield for Sampling ...............................................................3-5

Exhibit 3-15 Proper Sampling of Fine Aggregate Stockpile..............................................3-6

Exhibit 3-16 Sampling Device Cutting Across Flowing Stream ........................................3-7

Exhibit 3-17 Sampling from Conveyor Belt.......................................................................3-7

Exhibit 3-18 Proper Device for Belt Sampling ..................................................................3-8

Exhibit 3-19 Schematic of Belt Sampling Device..............................................................3-8

Exhibit 3-20 Schematic of Sampling from a Windrow.......................................................3-9

Exhibit 3-21 Guidance for Sample Sizes for Transmitting to FLH Laboratory ................3-10

Exhibit 3-22 AASHTO, ASTM and FLH Aggregate Test Procedures .............................3-13

Exhibit 3-23 Materials Certifications ...............................................................................3-18

Exhibit 4-24 Superpave Aggregate Quality Test Methods................................................4-2

Exhibit 4-25 Mix Design Test Methods .............................................................................4-3

Exhibit 4-26 Sampling Asphalt Binder ..............................................................................4-8

Exhibit 4-27 Placing Separator for Obtaining Mixture Sample .........................................4-9

Exhibit 4-28 Obtaining Mixture Sample Prior to Compaction ...........................................4-9

Exhibit 4-29 Splitting the Uncompacted Mixture Sample................................................4-10
Division 100: Acceptance and Verification Procedures January 2020

General Guidance xi

Exhibit 4-30 Quartering the Mixture Sample to Obtain the Proper Split .........................4-11

Exhibit 4-31 Reducing Mixture Sample to Testing Size..................................................4-12

Exhibit 4-32 Cutting Core ...............................................................................................4-12

Exhibit 4-33 Proper Core Removal Device.....................................................................4-13

Exhibit 4-34 Sawing to Separate Pavement Layers .......................................................4-13

Exhibit 4-35 Chip Seal Aggregate Placement ................................................................4-15

Exhibit 4-36 Close-up of Placement ...............................................................................4-15

Exhibit 4-37 Completed Chip Seal Surface ....................................................................4-16

Exhibit 4-38 Fog Seal Application...................................................................................4-17

Exhibit 4-39 Materials Certifications ...............................................................................4-21

Exhibit 5-40 Concrete Material Specifications ..................................................................5-3

Exhibit 5-41 Portland and Blended Hydraulic Cement Comparison .................................5-6

Exhibit 5-42 Maximum Cementitious Material Requirements.........................................5-12

Exhibit 5-43 Water and Mortar Requirements for Questionable Water Source..............5-13

Exhibit 5-44 Fine Aggregate Source Quality Characteristics..........................................5-15

Exhibit 5-45 Coarse Aggregate Source Quality Characteristics .....................................5-16

Exhibit 5-46 Aggregate Tests Used During Concrete Mixture Proportioning .................5-17

Exhibit 5-47 Required Concrete Material Certifications..................................................5-21

Exhibit 5-48 Material Sampling Specifications and Sample Sizes..................................5-22

Exhibit 5-49 Concrete freeze-thaw damage (1) on the surface in the form of deicer 

scaling; (2) throughout the thickness in the form of cracks in paste 

around aggregate; and (3) at pavement joints in the form of Dcracking. .....................................................................................................5-28

Exhibit 5-50 At the microstructure level, salt deposits (i.e. the formation of 

ettringite) are shown on a hardened concrete sample as well as 

cracking in the paste due to the formation and expansion of ettringite. .....5-29

Exhibit 5-51 At the microstructure level, the characteristic ASR gel is shown within 

cracks that have formed through and around aggregate and into the 

surrounding paste. At the macrostructure level, an advanced and 

characteristic ASR cracking pattern known as map or pattern cracking 

is shown......................................................................................................5-32

Exhibit 5-52 FLH Accepted ASR Testing........................................................................5-34

Exhibit 5-53 Required Average Compressive Strength with Test Records of 30 or 

More Consecutive Tests.............................................................................5-37

Exhibit 5-54 Required Average Compressive Strength with Test Records of 15 to 

29 Consecutive Tests .................................................................................5-38
Division 100: Acceptance and Verification Procedures January 2020

xii General Guidance

Exhibit 5-55 Required Average Compressive Strength with Test Records less than 

15 Consecutive Tests .................................................................................5-39

Exhibit 5-56 Example of Concrete Batch Ticket .............................................................5-41

Exhibit 5-57 The four moisture conditions of an aggregate particle ...............................5-42

Exhibit 5-58 Fresh Concrete Test Methods ....................................................................5-44

Exhibit 5-59 Fineness Modulus Calculation....................................................................5-66
Division 100: Acceptance and Verification Procedures January 2020

General Guidance xiii

(This page intentionally left blank.)

Division 100: Acceptance and Verification Procedures January 2020

General Guidance 1-1

CHAPTER 1

DIVISION 100: ACCEPTANCE AND VERIFICATION 

PROCEDURES

1.1 GENERAL GUIDANCE

Quality assurance and quality control (see Construction Manual for details on Contractor Quality 

Control Plans) as they relate to the construction process, are continuous and ongoing project

activities for both the contractor and the Government. Documentation and record keeping are an 

important part of this process. The process has its beginning with the approval of the contractor’s 

Quality Control Plan; includes the completion and acceptance of the project work, and ends with 

the signing of the materials certification.
Division 100: Acceptance and Verification Procedures January 2020

1-2 Acceptance

1.2 ACCEPTANCE

Material is to be inspected and/or tested by the Project Engineer before final acceptance of the 

work. There are four methods for accepting material each having varying degrees of involvement 

by the Project Engineer; visual inspection, certification, measured or tested for conformance, and 

statistical evaluation. The contract defines these methods for any particular item of work. The 

contract also defines the primary acceptance procedure applicable to each item of work in the 

Acceptance Subsection under each Section of work in the FP. Where there is a conflict between 

the contract and this Manual, the contract will control. A brief discussion of each method follows.

1.2.1 Visual Inspection

This is the simplest method of acceptance and allows material to be accepted without certification

or test results. The Project Engineer accepts or rejects the material based solely on visual 

inspection of the material. The Project Engineer relies on experience and engineering judgment 

to determine the acceptability of the material. When accepting material based on visual inspection 

the Project Engineer should ascertain if the material will perform as intended. Visual acceptance 

still requires documentation in writing. This can be as simple as a notation in the pay estimate, 

materials record book, or project files. See Subsection 106.02 of the FP.

1.2.2 Certification

The next method of acceptance is based on the receipt of a certification. A certification should 

accompany the material to document that the material meets the specifications. The contractor 

shall provide a commercial certification for items requiring a certification, unless the acceptance 

subsection for the item specifically calls for a production certification. 

A commercial certification is a manufacturer’s or Contractor’s representation that the material 

complies with all contract requirements. It typically consists of a supplier’s certification indicating 

the material has been produced to a specific specification and is often accompanied by product 

catalog data. Commercial certifications are routinely required for products purchased off the shelf, 

such as paint, sign hardware, mortar, grout, fencing materials, etc. Only one commercial 

certification is required for all similar materials. 

A production certification requires a supplier’s certification that the material has been produced 

to a specific standard, accompanying test data and more. When production certification is 

required, a production certification is required for each separate shipment of material and must 

include the following:

• Date and place of manufacture

• Lot number or other means of cross-referencing to the manufacturer’s inspection and 

testing system; and 

• Substantiating evidence that the material conforms to the contract quality requirements of 

FAR 46.105(a)(4). Such evidence includes:
Division 100: Acceptance and Verification Procedures January 2020

Acceptance 1-3

+ Test results on material from the same lot and documentation of the inspection 

and testing system

+ A statement from the manufacturer that the material complies with all contract 

requirements; and 

+ Manufacturer’s signature or other means of demonstrating accountability for the 

certification.

A production certification covers materials that are specifically manufactured or fabricated for a 

specific project. Examples might include culvert pipes, structural elements, bridge hand rails, 

asphalt binder, etc. The Project Engineer should check the certification prior to allowing the 

material to be incorporated into the work, although this may not always be possible. The 

certification should identify the project and reference the appropriate specification requirements 

(e.g., AASHTO or ASTM standard).

The certification generally must specify that it conforms to “FLH specifications” or specific 

AASHTO, ASTM or other recognized testing standards. The applicable standards will be stated 

in the contract.

Sometimes certifications are provided that give test results for individual parameters and do not 

reference the applicable specification. These are acceptable; however, the Project Engineer 

needs to verify that the values and individual parameters are those listed in the project 

specification and that the values are all within acceptable limits. The Project Engineer should 

discuss the content of certifications with the contractor or supplier ahead of time. Early 

discussions can help avoid delay in receiving certifications.

Material accepted by certification may be sampled and tested at any time to verify the quality of 

the materials being supplied. If such material is found not to be in conformance with the contract, 

it should be rejected whether in place or not.

Certifications should be kept as part of the final documentation for the project and should be 

included in the project files. See Subsection 106.03 of the FP.

1.2.3 Measured or Tested Conformance

A third method of acceptance is based on measuring or testing material for conformance to the 

specifications stated in the contract. The contractor may perform tests on the material and provide 

the results to the Project Engineer to demonstrate that the product meets the contract 

requirements. In the event of small quantities, testing may be performed ahead of the actual 

delivery of the product; however, the contractor may elect to provide these results at the time the 

material is delivered and/or placed (e.g., structural steel, prefabricated concrete units). 

The Project Engineer may accept the results provided by the contractor or arrange for sampling 

and testing once the material has arrived on-site. Sampling should normally be performed by the 

contractor and witnessed by Government personnel. Upon the completion of the sampling, the 

Project Engineer should take possession of the sampled material and arrange for testing. Testing 

will usually be performed by the FLH Laboratory; however, with concurrence of the FLH Division 
Division 100: Acceptance and Verification Procedures January 2020

1-4 Acceptance

Materials Engineer, arrangements may be made for testing by a third-party laboratory. The thirdparty laboratory should not be under contract to or otherwise affiliated with the contractor.

If the test results indicate that the material meets the contract requirements, the material will be

accepted. If the test results indicate that the material does not conform to the contract 

specifications, the material should be removed and replaced with conforming material at no cost 

to the Government. As an alternative to removal and replacement, the contractor may request 

acceptance at a reduced price or be given permission to correct any deficiencies. A decision to 

accept material at a reduced price will be made by the Contracting Officer generally after review 

by the Division Materials Engineer.

Material used in highway construction projects may be fabricated or manufactured at plants or 

locations off site. Materials fabricated off-site (such as prestressed concrete girders, steel bridge 

girders, etc.) require inspection, sampling, and testing arrangements. This off-site inspection and 

testing must be arranged for at least 30 days before fabrication begins. Contact the Division 

Materials Engineer for coordination of inspection and testing requirements. See Subsection 

106.04 of the FP.

1.2.4 Statistical Evaluation of Work and Determination of Pay Factor (Value of Work)

The fourth and final method of acceptance is based on making an evaluation of the value of the 

work and is often called “Statistical Acceptance”. The Project Engineer determines the random 

sampling locations using QL-PAY. Typically, the contractor will be sampling and testing the 

materials and will have a portable testing laboratory on site. The random sampling locations 

should not be divulged to the contractor until moments before a sample is to be taken. The Project 

Engineer must witness the actual sampling and splitting of each sample. Once the material is 

sampled and split, the Project Engineer must take immediate possession of the Government’s 

portion (split).

After obtaining the sample, the Project Engineer will test the material. This means sending the 

material to the FLH Laboratory. Upon receiving test results, the Project Engineer should 

immediately enter all the test results (those tested by the contractor as well as those tested by 

the Government) into QL-PAY to determine the value of the work. QL-PAY files should be 

transmitted to the Division Materials Engineer at least weekly. If no additional test results are 

added during the next 7-day reporting period, the current QL-PAY files do not need to be 

resubmitted.

Where contractor testing is part of the contract, in addition to determining the value of the work, it 

is necessary to verify the validity of the contractor’s results. This is also done within QL-PAY. Only 

after the contractor’s test results are validated may they be used to determine the amount of pay 

due the contractor. See Subsection 106.05 of the FP.
Division 100: Acceptance and Verification Procedures January 2020

Verification Processes 1-5

1.3 VERIFICATION PROCESSES

1.3.1 Verification of Material Quality

Regardless of which acceptance method is used, it is always necessary to verify the quality of 

materials incorporated into the work. The responsibility for final acceptance of all materials rests 

with the Contracting Officer. Therefore, the Project Engineer must be confident that the results 

obtained on which the acceptance decision is based are valid. Using qualified laboratories and 

qualified technicians facilitates achieving a quality project and having reliable test results on which 

to base acceptance decisions.

Whenever there are at least three samples tested by both the contractor and the Government, 

comparison of the results should be performed by entering them into QL-PAY. QL-PAY uses 

statistical procedures to analyze the data and determine if there are significant differences 

between the contractor’s and Government’s results or if the results are within what would be 

considered normal limits of variability. If the results are within normal variability limits, the 

contractor’s results would be considered valid. If the results are not within normal variability limits, 

QL-PAY will issue an alert. It is essential that the Division Materials Engineer be contacted 

immediately and review the data before any action is taken. A final determination as to the validity 

of the contractor’s results must be made by an individual having a background in both statistical 

analysis and materials in order to avoid making an incorrect decision.

When there are fewer than three samples tested by either party, the comparison cannot be done 

in QL-PAY. In those instances, the results of samples should be compared using the multilaboratory precision limit specified in the applicable test method. This provides an acceptable 

range for two results obtained from different laboratories by different operators. If the results are 

within the multi-laboratory precision limit, the contractor’s results would be considered valid. 

1.3.2 Visual Inspection and Certification

Acceptance verification of material quality may be by visually inspecting the material and verifying 

the certification. If the Project Engineer has any doubts regarding material quality, he has the right 

to obtain a sample and have it tested and should do so. Normally, if a sample is desired, it should 

be obtained by the contractor in the presence of the Project Engineer with the Project Engineer 

determining the location of the sample. The Project Engineer should take immediate possession 

of the sample after it is obtained (and split if desired). The sample is usually obtained by using 

random numbers; however, the Project Engineer may elect to test in a specific location to verify

the quality of the material.

1.3.3 Measured or Tested for Conformance

The Project Engineer should normally obtain and test a minimum of three random samples; 

however, for small quantities fewer samples may be appropriate. In the case where the Project 

Engineer has suspicions concerning the quality of the material, the Project Engineer may direct 

the contractor to obtain one or more samples from the suspect area rather than use random 

samples. The Project Engineer should take immediate possession of the sample after it is 

obtained (and split if desired) by the contractor.
Division 100: Acceptance and Verification Procedures January 2020

1-6 Verification Processes

1.3.4 Statistical Evaluation of Work and Determination of Pay Factor (Value of Work)

For this type of material acceptance, the contract specifies the sampling frequency and the Project 

Engineer determines the random location of all the samples. All samples intended for use in the 

acceptance decision must be obtained by the contractor in the presence of the Project Engineer.

The sample location should not be revealed to the contractor until moments before the sample is 

to be obtained. The Project Engineer should take immediate possession of the sample after it is 

obtained and split. All comparisons of results should be made in QL-PAY.
Division 100: Acceptance and Verification Procedures January 2020

Validation of Test Results and Pay Factors 1-7

1.4 VALIDATION OF TEST RESULTS AND PAY FACTORS

1.4.1 Validation of Contractor Test Results

When a contract provides for contractor testing, the Government has the option of using the 

contractor’s tests results in the acceptance decision. The contractor’s results can only be used if 

the materials quality is verified and the contractor’s tests results are validated. This is done by 

entering the data into QL-PAY. QL-PAY uses various statistical techniques to analyze the test 

results obtained by the contractor compared to those obtained by the Government.

1.4.1.1 Validation Conditions

In order to be able to verify the quality of the material and validate the contractor’s test results the 

following conditions must be met:

1. All the samples must be obtained based on random locations determined by the 

Project Engineer. Random numbers and locations can be generated within QLPAY.

2. Sampling locations must not be divulged to the contractor until moments before 

the sample is to be taken.

3. All samples must be obtained by the contractor in the presence of the Project 

Engineer.

4. The Project Engineer must take immediate possession of the material after it is 

sampled and split.

5. The Project Engineer must remain in control of the Government’s sample. The 

contractor is not to handle or have further contact with the sample once the Project 

Engineer takes possession.

6. The Project Engineer should obtain a split sample of all material and submit the 

first three to five samples obtained to the FLH Laboratory for testing. After 

submitting these samples, a minimum of 10 percent of the remaining split samples 

should be selected and sent to the FLH Laboratory for testing. Split samples should 

be submitted as work progresses. Do not wait until all the work is completed before 

sending the split samples in for testing.

7. All split samples not submitted for testing must be properly stored until final 

acceptance of the material. In the event the contractor’s test results are not verified 

it may become necessary for the government to test all the split samples.

1.4.1.2 Test Results Verification

With the conditions in Section 1.4.1.1 satisfied, the Project Engineer enters all the test results 

obtained by the contractor and the Government into QL-PAY and determines the appropriate pay 

factor (value of work). Before the computed pay factor can be used however, it is necessary to 

verify the quality of the material and validate the contractor’s test result. In order to verify the 
Division 100: Acceptance and Verification Procedures January 2020

1-8 Validation of Test Results and Pay Factors

quality of the material and validate the contractor’s results, QL-PAY performs the following 

functions:

1. Determines the Degree of Normality and Skewness Coefficients for each quality 

characteristic. These computations determine the appropriateness of running the 

pay factor computations, which are based on the assumption of normality. If the 

assumptions are not true, it may still be possible to analyze the data. For example, 

when data does not approximate a normal distribution, the data can be 

mathematically transformed to a normal distribution. A warning is issued if the 

results fall outside acceptable limits and further analysis by the Division Materials 

Engineer is required.

2. Determines the pay factor for each quality characteristic and uses the lowest single 

pay factor to determine the lot pay factor. The program calculates the current pay 

factor based on available test results and a projected pay factor based on the total 

number of test results expected, assuming no change in quality level from that 

calculated for the current number of samples. This provides the contractor with an 

early indication of what to expect for a pay factor when the work is completed if 

there is no change in the quality level of the material provided.

3. Performs an F-test for each quality characteristic based on independent data. The 

F-test compares the sample variance of all the not-paired split sample test results 

obtained by the contractor to the sample variance of all the Government’s test 

results. For example, 100 samples are obtained and split. The contractor tests all 

100 samples. The Government tests 20 split samples. The 80 sample test results 

obtained by the contractor, which are not paired splits, are compared to the 20 

sample test results of the Government. The sample variances should be equal 

within acceptable limits. A warning is issued if the results fall outside acceptable 

limits and further analysis by the Division Materials Engineer is required.

4. Performs an Independent t-test for each quality characteristic. The Independent ttest compares the mean of all the non-paired split sample test results obtained by 

the contractor to the mean of all Government’s test results. For example, 100 

samples are obtained and split. The contractor tests all 100 samples. The 

Government tests 20 split samples. The 80 sample test results obtained by the 

contractor, which are not paired splits, are compared to the 20 sample test results 

of the Government. The means should be equal or comparable within acceptable 

limits. Testing the means of the independent samples verifies the quality of the 

material. A warning is issued if the results fall outside acceptable limits and further 

analysis by the Division Materials Engineer is required.

5. Performs an F-test for each quality characteristic based on paired data. The F-test 

compares the sample variance of all the matching split samples tested by the 

contractor to the variance of all Government’s test results. For example, 100 

samples are obtained and split. The contractor tests all 100 samples. The 

Government tests 20 split samples. The 20 sample test results obtained by the 

contractor that are paired splits are then compared to the 20 sample test results of 

the Government. The sample variances should be equal within acceptable limits.
Division 100: Acceptance and Verification Procedures January 2020

Validation of Test Results and Pay Factors 1-9

A warning is issued if the results fall outside acceptable limits and further analysis 

by the Division Materials Engineer is required.

6. Performs a Paired t-test for each paired quality characteristic. The Paired t-test 

compares the mean of all the matching split samples tested by the contractor to 

the mean of all the Government’s test results. For example, 100 samples are 

obtained and split. The contractor tests all 100 samples. The Government tests 20 

split samples. The 20 sample test results obtained by the contractor that are paired 

splits are compared to the 20 sample test results of the Government. The sample 

variances should be equal within acceptable limits. This validates the contractor’s 

testing procedures. A warning is issued if the results fall outside acceptable limits 

and further analysis by the Division Materials Engineer is required.

7. Plots control charts. Control charts showing the contractor’s test results and the 

Government’s test results are plotted for each quality characteristic. This allows 

the user to perform an analysis of test results, look for bias in test procedures that 

may not be apparent from the Paired t-test or Independent t-test, and to assist in 

identifying production problems. Review and analysis of the control charts by the 

Division Materials Engineer can provide early identification of production problems.

1.4.2 Test Results Review

All test results should be reviewed and evaluated by the Division Materials Engineer to confirm 

the assumptions of normality, verify the quality of the material, and to validate the contractor’s 

testing procedures. All QL-PAY files should be e-mailed to the Division Materials Engineer. The 

files should be transmitted at least weekly if additional test results were added during the 

preceding 7 days.

Sometimes the initial statistical analysis performed by QL-PAY will indicate a problem, which after 

further analysis is not substantiated. Statistical comparison is only a tool to be used in analysis of 

the test results. It takes a combined knowledge of material, material variances, and statistics to 

make a proper analysis of the data and reach an appropriate decision concerning the validity of 

the data.

It is imperative that consultation regarding the final decision to accept the contractor’s test results 

is made with an individual with a background in both materials and statistics and that sound 

engineering judgment be applied so as not to affect adversely the contractor or compromise the 

Government's position. Although the final decision resides with the Construction Branch, it should 

be done with the concurrence of the Division Materials Engineer.

If the contractor’s test results are rejected, the Project Engineer will be requested to submit the 

Government’s entire remaining split samples for that work item to the FLH Laboratory. In such 

cases, the Project Engineer should notify the contractor in writing and afford the contractor the 

opportunity to witness the testing of the remaining split samples. After testing is completed, the 

Project Engineer should enter all of the results into QL-PAY and e-mail a copy to the Division 

Materials Engineer for final analysis.

If the final analysis substantiates the decision to reject the contractor’s test results, the final 

acceptance and pay factor determination will be based on the Government’s test results. In such 
Division 100: Acceptance and Verification Procedures January 2020

1-10 Validation of Test Results and Pay Factors

cases, the contractor will be responsible for the cost for all additional Government materials 

testing. The Division Materials Engineer will provide the Project Engineer with an itemized list of 

the increased testing costs. The costs should be deducted from the contractor’s monthly estimate.

If the final analysis does not substantiate the decision to reject the contractor’s test result, the final 

acceptance and pay factor determination will be based on the contractor’s test results, and the 

Government will absorb the additional costs associated with the increased testing.

1.4.3 Dispute Resolution Guidelines

If the contractor refutes and provides persuasive evidence that Government test results do not 

accurately reflect the property(s) of material or work tested, and reasonable steps have been 

taken to resolve disputes, the contractor may request further evaluation of the Government’s test 

results. The request must be in writing and contain a justification for making the request. The 

contractor should submit for approval a proposed resolution protocol that addresses the following:

sampling method, number of samples, sample transport, test procedures, testing laboratory(s), 

reporting, estimated time and costs, and the validation process (i.e., how results will be used).

If the evaluation requires that additional sampling and/or testing be performed, the Government 

and contractor must mutually agree on witnessing procedures and the use of a third-party

laboratory to conduct the sampling and/or testing. The third-party laboratory must be accredited 

by AASHTO for the procedures to be used, except in the case where AASHTO accreditation for 

the procedure is not offered. The laboratory must not have been used by the contractor or 

Government in producing the test results in dispute or used as a basis to establish just cause that 

Government testing does not accurately reflect the property of the material or work.

The Project Engineer should notify the Construction Operations Engineer and the Division 

Materials Engineer immediately if a contractor submits a request for additional sampling and/or 

testing. Upon receipt of the proposed resolution protocol, it will be evaluated for merit, accepted 

if appropriate, modified if necessary, or rejected. At that time, the Project Engineer will be given 

guidance on how to proceed with the resolution process proposed.

The approved resolution protocol test results will be used to validate disputed testing. Validation 

will be determined by the Government in accordance with procedures established in the approved 

resolution protocol. If the Government test results are validated as acceptable, the contractor will 

be responsible for all costs derived from the additional sampling, testing, and evaluation. If the 

Government test results are not validated as acceptable, the Government will be responsible for 

all costs derived from the additional sampling, testing, and evaluation. If the validity of the 

Government test results cannot be determined, the contractor and Government will equally share 

all costs associated with the additional sampling, testing, and evaluation.
Division 100: Acceptance and Verification Procedures January 2020

Acceptance of Work and Value Determination 1-11

1.5 ACCEPTANCE OF WORK AND VALUE DETERMINATION

Acceptable work conforming to the contract should be paid for at the contract unit bid price. When 

material or work fails to meet the established specification, the material or work shall be removed 

and replaced unless in the public interest the Government consents to accept the work with an 

appropriate adjustment in price or corrective action. If the contractor requests to have the work 

accepted at a reduced price or requests permission to perform corrective measures, the request 

will be evaluated based on the public interest. It is the contractor’s responsibility to submit a 

proposal outlining any action that will be taken in lieu of removal and replacement. The contractor 

may submit a written request to:

1. Have the work accepted at a reduced price; or

2. Be given permission to perform corrective measures to bring the work into 

conformity.

A written request must contain supporting rationale and documentation. This would include 

references or data justifying the proposal based on an evaluation of test results, effect on service 

life, value of material or work, quality, aesthetics, and other tangible engineering basis.

If the contractor submits a written request, the following process outline provides guidance for 

addressing the request to accept work at a reduced price:

1. Meet to discuss the non-compliance material or workmanship. The meeting should 

include the Project Engineer, Construction Operations Engineer, and Technical 

Services Branch representative with expertise in or responsibility for the area of 

concern (i.e., bridge, hydraulics, materials).

2. Review test data to determine the significance of non-compliance.

3. Evaluate the degree of deviation from contract requirements. Such evaluation is a 

subjective process and must take into account the criticality of the material or work, 

the risk associated with any deviation from the contract requirements, and the 

degree of deviation from contract requirements.

4. Reduce the contract unit price for the item in question depending on the 

significance of the noncompliance. The percent reduction in the unit price are 

based on the following guidelines:

0 to 5% Material substantially meets the contract requirements with minor deviations from the 

specifications.

6 to 15% Material fails to meet contract requirements and results in the use of an inferior 

product. Generally, this material will result in a reduction in the usable life of the item in 

question. 

16 to 75% Material fails to meet contract requirements by a significant amount and is clearly 

and inferior product. Use of this material may meet the intended purpose; however, the quality 

is well below that specified. The criticality of this material may be low and does not warrant 

removal or other corrective action.
Division 100: Acceptance and Verification Procedures January 2020

1-12 Acceptance of Work and Value Determination

Likewise, corrective actions need to be evaluated to determine the level of effectiveness. The 

remedial/corrective work must provide results that are more desirable than reducing item pay 

amounts. In certain instances, corrective actions may be used in combination with a contract bid 

price reduction.

When it is determined that the material or work does not meet the intended purpose or results in 

substantial quality or safety deficiencies, it shall be removed and replaced.
Division 100: Acceptance and Verification Procedures January 2020

Material Project Requirements 1-13

1.6 MATERIAL PROJECT REQUIREMENTS

To ensure a successfully completed construction project, specification compliant materials need 

to be incorporated into the work. The contractor quality control plan provides, among other items, 

the system to measure and validate the quality of the materials used. Major components of the 

plan are 1) personnel, 2) equipment and testing laboratories, and 3) sampling. The contract 

provides specific requirements for the contractor quality control system. The purpose of this 

portion of the manual is to provide general guidance regarding elements that may be included as 

part of the construction project quality control activities.

1.6.1 Personnel

Individuals performing sampling and testing of materials to be used in the construction of FLH 

projects must be knowledgeable in the sampling and testing procedures and requirements of the 

contract. In addition to sampling and testing requirements testing personnel must also be familiar 

with proper use and calibration of equipment required for the testing of materials.

In general, contractor personnel assigned to perform sampling, testing, or inspection functions 

should have 1 year or more of recent job experience in the type of sampling, testing or inspection 

required by the contract. Qualifications can also be demonstrated through other certifications or 

participation in proficiency testing. Examples of these types of qualifications include:

• NICET Level II certification in highway materials, or State Highway Agency (SHA) or 

industry certification-related sampling and testing equivalent to their contract 

responsibilities.

• Nationally accepted certification for intended sampling and testing responsibilities, i.e. 

WAQTC, ACI, NETTCP.

• Current or previous employment by an AASHTO accredited laboratory performing 

sampling and testing equivalent to their intended responsibilities.

• Demonstrated proficiency or successful testing of one or more proficiency samples (may 

be substituted for basic qualifications pending verification of test results).

1.6.1.1 Qualification Documentation

Before the start of the work, the Project Engineer should obtain documentation supporting 

personnel qualifications. Documentation requirements are listed in the contract.

1.6.1.2 Subcontracted Sampling and Testing

If sampling, testing or inspection is to be performed by a subcontractor, the Project Engineer 

should request from the prime contractor detailed information about how the sampling, testing 

and inspection by the subcontractor will interface with the prime contractor’s work and other 

subcontractors performing work required by the contract.

The contractor is required to have a quality control system that includes the appropriate process 

control of material. The Project Engineer is responsible to ensure that material being incorporated 
Division 100: Acceptance and Verification Procedures January 2020

1-14 Material Project Requirements

into the work conforms to the contract requirements as supported by the appropriate inspections, 

sampling, and testing.

1.6.2 Equipment and Testing Laboratories

Testing of materials used in highway construction projects requires specialized materials testing 

equipment. Laboratories are essential to assure quality materials are incorporated in the project. 

Laboratories must be adequately staffed and properly equipped to conduct materials tests 

required by the contract quality control provisions.

The Project Engineer is responsible for inspecting, verifying, and documenting that field 

laboratories are properly equipped and staffed prior to the start of the work that requires sampling 

and testing.

1.6.2.1 Contractor-furnished Laboratories

The contractor may use a commercial laboratory or an on-site contractor furnished laboratory. 

The commercial or on-site contractor furnished laboratory must be equipped with all the testing 

equipment and accessories to meet contract sampling and testing requirements.

Laboratory facilities should be kept clean and equipment maintained in proper working condition. 

Subject to the terms of the contract, the Project Engineer has unrestricted access to the laboratory 

for inspection and review.

1.6.2.2 Government-furnished Laboratories

A government-furnished field laboratory trailer may be available for rent. If this is the case, the 

government will offer to the contractor a furnished field laboratory with testing equipment. Field 

laboratory availability and a listing of the testing equipment included in each field laboratory may 

be obtained by contacting the CO. Due to the wide-range of construction complexity for FLH 

projects, the laboratory facility may not be equipped with all of the necessary testing equipment 

required for the project. It is the responsibility of the contractor to review the basic equipment list 

and provide any specialty or missing testing equipment needed for use on the project.

In general, the laboratory includes testing equipment to conduct process control and project 

acceptance testing for embankments, crushed aggregate base, asphalt paving materials, and 

plastic concrete. Other equipment, such as equipment for breaking and curing concrete cylinders, 

may be included on a specific contract basis. The Sampling and Testing tables located at the end 

of each Section in the contract will provide references to test methods and procedures that include 

the equipment requirements.

The laboratory facility should be kept clean and equipment maintained in proper working 

condition. Subject to the terms of the contract, the Project Engineer has unrestricted access to 

the laboratory for inspection and review.

1.6.2.2.1 Laboratory Cost

Field laboratory trailer and testing equipment are offered to the contractor at a cost specified in 

the contract. The contractor shall replace at their cost or be responsible for the replacement cost 

of all missing or damaged equipment (other than through reasonable wear and tear).
Division 100: Acceptance and Verification Procedures January 2020

Material Project Requirements 1-15

1.6.2.2.2 Laboratory Equipment

The contractor shall determine if the laboratory testing equipment is adequate to perform all 

testing required by the contract.

In addition, the following apply:

• The equipment has been checked and calibrated to applicable specifications. It is the 

contractor’s responsibility to ensure the equipment is maintained in proper operating 

condition.

• No nuclear devices will be furnished.

• The contractor is responsible for providing the laboratory trailer with a water supply and 

adequate 240-volt, 60-cycle, 200 amp single-phase current for all laboratory electrical 

needs. A minimum of 60 kilowatts of power at the entrance box is required for effective 

use of electrical equipment. Equip the power supply with a regulator that will limit the 

voltage of the power furnished to not more than 240 volts and not less than 220 volts.

• The contractor shall accept responsibility for the trailer and equipment upon receipt.

• All equipment provided by the Government and replaced by the contractor shall become 

the property of the Government.

• The rental rate specified in the contract is in effect for the duration of the contract, 

excluding periods of seasonal or other work shut downs.

• The laboratory shall be used only for testing materials for a specific contract.

Upon completion of the work, the contractor should clean the equipment and trailer. All equipment 

should be properly stored and secured for the transport of the trailer to the FLH office. Any 

damage that occurs prior to the trailer being received at the FLH office will be handled according 

to the contract.

1.6.2.3 Equipment Calibration

Use only equipment that has been calibrated or verified for the specific test and meets the 

applicable testing requirements of the contract. Equipment will be calibrated or standardized in 

accordance with national, FLH Standards, State Highway Agency (SHA), industry standard, or 

Standard Accreditation Programs.

Prior to the beginning of sampling and testing on a project, the Project Engineer should inspect 

and document the acceptability of the sampling and testing equipment that will be used on the 

project.

All necessary equipment should be marked with a tag indicating the date of last inspection, 

inspector, and calibration number. Checking and monitoring of the equipment during the life of 

the project should be performed and documented by the contractor to ensure equipment is 

performing properly. 
Division 100: Acceptance and Verification Procedures January 2020

1-16 Material Project Requirements

1.6.2.4 Equipment Calibration Documentation

The Project Engineer should obtain the following documentation supporting the calibration or 

verification of all necessary equipment prior to actual sampling and testing. The documentation 

should be on file.

1. Description of the equipment calibrated or verified, including model number, serial 

number, or other acceptable identification.

2. Identification of the individual performing the calibration or verification.

3. Identification of the calibration or verification procedure used.

4. Current calibration or verification date and the next due date.

5. Detailed report of calibration results of the work performed, i.e. dimension, mass, 

force, frequency, temperature, time etc.

The Project Engineer may check equipment to verify condition and calibration. If at any time, it is 

suspected that the test equipment is not functioning properly or is not calibrated within 

specification limits the Project Engineer should contact the FLH materials staff to determine what 

corrective action should be taken. 

Under no circumstances should test results obtained using faulty equipment be accepted.

1.6.3 Sampling

The control of material is an important part of any construction project. It can only be accomplished 

when the material being incorporated into the work is acceptably inspected, properly sampled, 

and accurately tested. The importance of obtaining a good representative sample cannot be 

overstated.

Samples obtained or used on construction projects have different purposes. Samples can be 

obtained to verify proper testing is being performed, to control production processes, or to verify 

product quality. Here are the general sample types and purposes that are typically used on FLH 

construction projects:

• Quality Control (also called process control) Samples. These samples are obtained by the 

contractor for the purpose of assessing and making adjustments to a production or 

construction process. Samples, taken during production, assist the contractor in making 

appropriate corrections for producing a quality product. Information obtained by testing 

these samples is used by the contractor to control the level of quality of the furnished end 

product. The contractor may take a quality control sample at any time. However, when the 

quality control sample test results are to be utilized in the material acceptance decision, 

the Government will randomly identify the material to be sampled and tested.

The Government will witness the sampling and splitting procedures and will immediately 

take possession of the Government’s split portion of the sample. The Government must 

maintain control and custody of the sample at all times to ensure the integrity of the testing 

and verification process.
Division 100: Acceptance and Verification Procedures January 2020

Material Project Requirements 1-17

• Acceptance Samples. These samples are tested by the government to determine 

conformance to contract requirements.

• Verification Samples. These samples are obtained by the contractor; witnessed and tested 

by the government or its designated laboratory for the purpose of verifying the results of 

contractor tested quality control samples. The results are used in a statistical evaluation 

for the purpose of acceptance and payment. In the event that the contractor’s test results 

are not verified, the Government’s test results will be used for acceptance and payment 

for the material.

• Independent Assurance Samples. Any qualified person from a qualified laboratory, as 

defined in the contract, which are not associated with the contractor or the FLH project 

inspection staff, can take an Independent Assurance (IA) sample. This sample can be 

taken at any location and at any time within the project. The purpose of this sample is to 

provide an unbiased and independent evaluation of the sampling and testing procedures 

used in the acceptance decision. IA samples evaluate the sampling and testing personnel 

and their associated equipment. The sample cannot be used in the acceptance decision 

for the material since it is a biased non-random sample used to evaluate testing personnel 

and equipment. The Division Materials Engineer evaluates the results to determine if any 

discrepancies exist in the sampling and testing.

• Proficiency Samples. These samples are manufactured by the FLH central laboratory and 

used as a tool to evaluate the quality of the testing being performed for a project. The 

results are used in the same manner as the independent assurance samples. The Division 

Materials Engineer evaluates the results to determine if any discrepancies exist in the 

testing.

In all cases, it is critical to obtain a representative portion of the manufactured product that will be 

tested to verify that the material used or the work done conforms to the requirements of the 

contract. The use of proper sampling procedures and techniques is a vital piece of the verification 

process for quality highway construction.

1.6.3.1 Sampling Responsibilities

Generally speaking, the contractor is responsible for obtaining all of the samples on a construction 

project. The sampling process takes place under the supervision or witness of the Project 

Engineer or government representative. In addition to acquiring the sample, the contractor is also 

responsible for splitting the sample, if appropriate, and providing a split portion of the sample to 

the government. When results of the contractor testing are to be considered in the acceptance 

decision, the contractor needs to ensure that a government representative is present during the 

sampling and splitting process. Once this has been accomplished, the government will take 

immediate control of the sample. This sample may then be tested and the results used as part of 

the verification process. It is vitally important for the integrity of the acceptance process that the 

sampling is witnessed and that the chain of custody for the government portion of the sample has 

not been compromised.

The contractor is responsible for following proper sampling and testing methods in accordance 

with the submitted quality control plan and the contract specifications. This includes monitoring, 

certifying, or verifying the quality of products manufactured off-site and delivered to the project 
Division 100: Acceptance and Verification Procedures January 2020

1-18 Material Project Requirements

meet contract specifications. At a minimum, the contractor is required to perform all sampling and 

testing listed in the sampling and testing tables provided in the contract.

The Project Engineer is responsible for verifying that the required sampling is accomplished 

according to standard procedures and that the material used and work performed on the project, 

whether produced on the project or manufactured off-site and delivered to the project from an 

outside source, comply with contract specifications. In addition, the Project Engineer will ensure 

that all samples used to evaluate work for acceptance are retained until final acceptance.

1.6.3.2 Sampling Procedures

Established sampling methods provide specific guidance regarding the amount of material 

required for the sample. This amount should not be confused with the amount of material needed 

to perform the proper testing. The sample obtained needs to be taken in accordance with the 

appropriate referenced method. Subsequent testing is usually performed on a smaller 

representative portion of that sample. These smaller testing amounts will be specifically stated in 

the appropriate test method for the given material.

Project personnel should be knowledgeable in the following sampling criteria that are required by 

the contract.

• Minimum required sample size. The sampling methods, typically cited as AASHTO or 

ASTM methods, identify the size sample required for the particular material.

• Sampling frequency. Sufficient samples must be taken to represent the material that is 

delivered to the project for assurance that it complies with specification requirements. A 

non-uniform product can require more samples than the minimum specified in the contract 

for acceptance of its quality. For acceptance purposes, the contract will specify the 

minimum sampling frequency.

• Sampling methods. Different materials require different sampling methods. The 

appropriate test methods should be used to ensure a proper sample has been obtained. 

These methods will be referenced in the contract documents and also in this manual.

• Sample location. Where practicable, samples to be tested for acceptance shall be 

obtained from the finished product. The contract specifications identify where samples are 

to be taken for acceptance and at what minimum frequency.

1.6.3.3 Sampling Methodologies

Samples may be obtained at any time and at any location. Specific contract language in 

subsection 106.01 states that the government may inspect, sample, or test all work at any time 

before final acceptance of the project. In general, there are two sampling methodologies.

• Selective sampling. This is a biased non-random procedure in which a sample of material 

is obtained from a specific location determined by observation. The information obtained 

from the testing of this sample can be used to determine compliance with the contract but 

cannot be included in any statistical evaluation. This methodology may be used at any 

time.
Division 100: Acceptance and Verification Procedures January 2020

Material Project Requirements 1-19

• Random sampling. This is an unbiased sampling procedure in which a sample of material 

is chosen in such a manner that any incremental amount of material placed has an equal 

probability of being selected. For the statistical concepts and comparisons to function 

properly, the sample used for statistical acceptance must be selected on a random basis. 

Random sampling locations are selected in advance of the production and placement of 

the material to be sampled. These locations should be selected using random numbers 

generated by use of random number tables, the random number function on a calculator, 

or the random number function in computer software. QL-PAY has a random number 

generator developed specifically for use with highway construction materials.

1.6.3.4 Sample Handling

Samples need to be stored and handled appropriately to ensure that the integrity of the material 

has not been compromised. The samples need to be properly labeled and identified so that all 

information regarding the sample location and test results can be correlated. If the samples are 

to be transported, use proper containers to maintain the integrity of the sample throughout the 

shipping process. Include a Request for Laboratory Tests form, FHWA 1600, for all samples 

shipped to the central laboratory.

1.6.3.4.1 Sample storage and retention

Once the government takes possession of the sample, it should be handled and stored in an 

appropriate manner. Care should be taken to avoid damage to the sample container, disturbance 

of the sample, or contamination. The Project Engineer will store, handle, label and date samples 

in a manner that will preserve the character of the material. Most samples should be stored in a 

dry environment and kept free from contamination until final acceptance of the project. It is 

important that all samples be cared for in this manner in the event that complete testing of 

verification or acceptance samples becomes necessary.

1.6.3.4.2 Sample labeling

When obtaining the sample, the contractor will need to label the sample container with the 

appropriate project information. As a minimum, the following information should be included on 

any sample. Additional information may be required depending on the specific location and/or 

purpose for the sample.

• Project name

• Project number

• Pay item number

• Pay item description

• Sample number

• Lot number

• Sublot number
Division 100: Acceptance and Verification Procedures January 2020

1-20 Material Project Requirements

• Date

• Location of sample

1.6.3.4.3 Sample transport and shipment.

Ship samples in a container of sufficient strength to prevent the loss, contamination or damage of 

the contents during shipment. Sufficiently identify all samples to facilitate reporting, logging, and 

tracking of sample information. Exhibit 1-1 provides a brief summary list of containers to be used 

for common highway materials. If additional guidance is needed for a particular material, contact 

the Division Materials Engineer.

Exhibit 1-1 Common Sample Containers

1.6.3.5 Request for laboratory testing.

All samples shipped to the FLH division laboratory must have a Request for Laboratory Tests 

form, form FHWA 1600, to provide instruction as to the testing to be performed. The form should 

be completed by the Project Engineer and attached to the outside of the sample container in a 

manner that will protect it during shipment. A duplicate copy should be placed inside the shipping 

container. The form can also be faxed or electronically sent in advance of shipment to alert the 

lab personnel that a sample will be arriving.

Material Appropriate Sample Container

Soil and Aggregate Clean tight woven canvas sacks

5-gallon plastic buckets with tight lids

Cement, Lime, Fly ash 1-gallon watertight containers

Asphalt binder and cutback asphalts 1-quart cans

Emulsified asphalt 1-gallon large mouth plastic jugs with 

screw top lids

Asphalt mixture – uncompacted 6” x 12” cylinders

5-gallon plastic or metal buckets

Cardboard box of sufficient size

Asphalt mixture – cores Cushioned container

4” x 8” or 6” x 12” plastic concrete cylinder 

molds with appropriate packing

Concrete cylinders Appropriate sized concrete cylinder molds 

shipped in a sturdy box with insulation and 

padding
Division 100: Acceptance and Verification Procedures January 2020

Form References 1-1

1.7 FORM REFERENCES

Form references for use in the transmittal of samples to the FLH central laboratory.

• Form FHWA 1600C – Request for Laboratory Tests (CFL)

• Form FHWA 1600E – Requests for Laboratory Tests (EFL)

• Form FHWA 1600W – Requests for Laboratory Tests (WFL)
Division 100: Acceptance and Verification Procedures January 2020

1-2 Form References

(This page intentionally left blank.)
Division 200: Earthwork Testing and Evaluation January 2020

Summary and Description 2-3

CHAPTER 2

DIVISION 200: EARTHWORK TESTING AND 

EVALUATION

2.1 SUMMARY AND DESCRIPTION

Typical highway construction involves the use of existing native materials to form the roadbed 

prior to the placement of the manufactured materials that compose the pavement structure. 

These native materials, if properly handled and compacted, can be used successfully to construct 

the roadbed. 

Soils are the most abundant material used in highway construction. They form the foundation or 

supporting surface for roadways, bridges, and other highway structures. Work involved in 

preparing the foundation and using soils in the construction of a normal highway project can be a 

major cost of the project. Due to this importance, knowledge of soil properties, condition, and 

proper construction practice is of utmost importance. 

Testing of soil is designed to provide information on the classification, engineering properties and 

address any unexpected conditions that may be encountered during construction. The project 

specifications will determine the required testing for the project, however in most cases earth 

embankment materials will need to be classified to determine proper handling and compaction.

Earthwork construction can also consist of excavating and embanking material, preparing the 

foundation, bedding, and backfilling for structures. In these instances, materials for construction

may be specified. To ensure compliance with the contract, testing will be required to verify the 

quality of material used.

Imported subgrade materials will typically need to be tested and evaluated prior to use. These 

materials include unclassified borrow, select borrow, and topping. In addition, subgrade 

stabilization techniques, where lime, fly ash, or hydraulic cement is incorporated into the upper 

layer of the subgrade, will require additional testing to establish the appropriate proportioning for 

the desired design properties. 

Tests listed in Exhibits 2-1, 2-3, 2-6 and 2-7 function to either evaluate or describe soils and 

control the manner in which they are to be used. Several different test procedures may be 

available to analyze the same material property. The tests accomplish the same evaluation but 

require different equipment or use a slightly different procedure. For instance, there are several 

tests for determining in-place density and for determining moisture content.

When contract specifications permit options, selection of one test over another is often a matter 

of personal preference. More often than not, a higher quality of test results is dependent on how 

carefully a test was performed rather than on the superiority of one piece of equipment or process

over another.
Division 200: Earthwork Testing and Evaluation January 2020

2-4 Material Properties and Test Methods

2.2 MATERIAL PROPERTIES AND TEST METHODS

There are a number of tests to determine properties of soils used in highway construction. Data 

from tests on the soil will provide useful information to ensure that the desired materials and 

properties of those materials are incorporated into the construction of the roadbed. Typical soil 

testing includes tests shown in Exhibit 2-1.

Exhibit 2-2 Soil Test Methods

Primary Categories AASHTO Test Method

Grain size analysis AASHTO T 11, T 27, & T 88

Moisture content determinations AASHTO T 265 & T 310

Density standards and density determinations AASHTO T 99, T 180, T 191, & T 310

Consistency and Plasticity (Atterberg Limits) AASHTO T 89 & T 90

2.2.1 Classification

Classification of the soil material is an important factor in determining handling and placement 

characteristics. Classification results indicate if the soil is granular (A-1, A-2, A-3) or fine grained 

silt-clay (A-4, A-5, A-6, A-7). It can also be used to determine the various components of a mixture 

such as larger sized stone (boulders, cobbles, gravel), sand, silt, or clay. The standard 

specification system used by FLH and stated in the FP is AASHTO M 145. Two items are needed 

to classify soil material; particle size distribution and consistency properties (Atterberg limits) of 

silt-clay materials.

Exhibit 2-3 Classification of Soil Material from AASHTO M 145
Division 200: Earthwork Testing and Evaluation January 2020

Material Properties and Test Methods 2-5

Exhibit 2-2 demonstrates how particle size distribution and consistency properties are used to 

determine the soil classification. Granular soils, those with higher percentages of rock and sand, 

are rated excellent to good for use in subgrade construction. As the amount of silt and clay 

increases, the rating of the material decreases to being either fair or poor. More detailed 

information and soil descriptions can be found in AASHTO M 145. 

2.2.1.1 Particle Size Distribution

AASHTO T 88, Particle Size Analysis of Soils, is used to determine the particle size distribution 

of soils that consist primarily of sand, silt and clay. The test consists of a sieve analysis, primarily 

on the granular portion of the soil, and a hydrometer analysis for the fine-grained material. The 

hydrometer portion of the test is not needed for classification and is typically not performed as 

part of the quality assurance testing. AASHTO T 11, Materials Finer than No. 200 Sieve in Mineral 

Aggregates by Washing and AASHTO T 27, Sieve Analysis of Fine and Coarse Aggregates are 

used to determine the particle size distribution of granular soils that contain a significant portion 

of gravel size particles. Particle size ranges as defined in AASHTO M 145 are shown in Exhibit 

2-3.

Exhibit 2-4 Particle Sizes

Soil Constituent Passing Sieve Retained on Sieve

Gravel 3 inch (75 mm) No. 10 (2.00 mm)

Coarse Sand No. 10 (2.00 mm) No. 40 (425 μm)

Fine Sand No. 40 (425 μm) No. 200 (75 μm)

Silt and Clay No. 200 (75 μm) —

Granular materials, as defined by AASHTO M 145, contain 35 percent or less material passing 

the No. 200 (75 μm) sieve and silt-clay materials contain more than 35 percent material passing 

the No. 200 (75 μm) sieve. See Exhibit 2-2.

Decisions regarding subsequent tests are made based on information gained from the particle 

size analysis. Most other soil tests are performed on a specific range of particle sizes that require 

the soil be separated accordingly.

2.2.1.2 Consistency and Plasticity (Atterberg Limits)

Consistency of silt-clay materials varies in proportion to the water content. At higher water 

contents, silt-clay materials possess properties of a liquid whereas at lower water contents 

possess properties of a plastic, semisolid or even a solid. The moisture content of a soil at the 

division between the liquid and plastic phase is defined as the liquid limit. The moisture content 

of a soil at the division between the plastic and semisolid phase is defined at the plastic limit. The 

algebraic difference between these two defined limits is known at the plasticity index. The liquid 

limit is determined from AASHTO T 89 and the plastic limit and plasticity index are determined 

from AASHTO T 90. The consistency properties (Atterberg limits) and the plasticity index are used 

to classify soils. They also provide an indication of some engineering properties of the soil. 

Generally, high liquid limits and high plasticity indices are indicative of potentially troublesome 

soils. Exhibit 2-4 graphically demonstrates the relationship of these properties.
Division 200: Earthwork Testing and Evaluation January 2020

2-6 Material Properties and Test Methods

AASHTO T 89 and T 90 provide for options in the preparation of the soil; the dry preparation 

method as stated in AASHTO R 58 or the wet preparation method as stated in AASHTO R 74. 

For the purposes of obtaining consistency and plasticity data for general highway construction, 

the material should be prepared using the dry preparation method, AASHTO R 58. The wet 

preparation method would be used only in unique circumstances and would be specifically 

designated in special contract requirements.

Exhibit 2-5 Relationship of Atterberg Limits

2.2.2 Moisture – Density Relations

The relative density of the soil largely influences the behavior of material. The soil type,

percentage of moisture, and the compactive effort will determine the density of the in-place 

material.

2.2.2.1 Moisture content 

Water can greatly influence engineering properties of soil. Too much or too little water can render 

some otherwise desirable and stable material virtually useless. Knowledge of the in-place 

moisture content is necessary for making decisions regarding design and control of material. 

AASHTO T 265, Laboratory Determination of Moisture Content of Soils, is the method 

recommended by FLH. In-place field moisture content may also be determined through the use 

of a nuclear density and moisture gage as provided in AASHTO T 310. The actual moisture 

content of the soil can be compared with the optimum moisture content to determine if the material 

is in a suitable condition for compaction. The optimum moisture content of a material will be 

determined through appropriate proctor testing (typically according to AASHTO T 99 or T 180 

depending on the soil classification). A proper proctor test includes five moisture density points to 

adequately define the relationship. Exhibit 2-5 is an example of a proper proctor test result.

Semisolid Liquid State

State

Solid State

Stages of Soil Consistency

Moisture Content Increasing

Plastic State

Plasticity Index

PI = LL - PL

SL

Shrinkage

Limit

PL

Plastic

Limit

LL

Liquid

Limit
Division 200: Earthwork Testing and Evaluation January 2020

Material Properties and Test Methods 2-7

Exhibit 2-6 Five Point Moisture Density Curve

Note that as the compactive effort increases (T 99 vs. T 180) the maximum dry density increases 

and the optimum moisture content decreases.

2.2.2.2 Density

Density determinations include both the determination of density in the field and the 

establishment, through standard tests, of reference or standard densities to which the field tests 

are compared. Results of a field density test cannot be properly evaluated until compared to an 

appropriate reference density. Tests used to establish density standards are those represented 

by AASHTO T 99 and T 180, Moisture-Density Relations of Soils. Four alternate methods are 

provided when using these test procedures. The specific method to be used will be indicated in 

the contract specifications.

Density determination, of the material placed on a project, using nuclear test methods AASHTO 

T 310 is the preferred method specified in the FP; however, the Sand-Cone Test AASHTO T 191 

is also an approved method.

Field density tests are performed on the project site. Each type of density equipment and test 

procedure is unique. An operator performing a density test should be aware of all special 

precautions for the equipment and test procedures being used. For example, the sand cone test 

is extremely sensitive to vibration and nuclear instruments require very careful and uniform 

surface preparation. Operators must be familiar with the equipment features and test methods.

In working with subgrade material it is common to encounter particles larger than can be tested. 

When this situation occurs, recognition must be made of the oversize material and a density 

correction needs to be made. A procedure for making this correction is described in AASHTO T 

99 and T 180. Oversized material is typically defined as particles larger than 0.75 inch (19 mm).
Division 200: Earthwork Testing and Evaluation January 2020

2-8 Material Properties and Test Methods

2.2.3 Soil Strength

Soil strength can be determined through various test methods. Most common are the Resistance 

R-value and the California Bearing Ratio, (CBR); however, other methods such as triaxial testing 

and resilient modulus have also been used. More specialized testing can also be performed to 

determine the shear strength, unconfined compressive strength, or cohesion of a soil. This testing 

would be performed during the development of a project, typically by the geotechnical engineer. 

Regardless of the method used, the purpose of the testing is to determine the support that can 

be provided by the soil. Results of the soil strength tests are used to determine the structural 

pavement design needed to accommodate traffic loading or the appropriate support needed for a 

structural member, such as a bridge or retaining wall. 

During construction, it may become necessary to verify the subgrade soil strength value. This is 

often done to compare the strength of the soil that is being compacted during the construction 

phase of the project to the design values used during the geotechnical investigation and 

recommendation phase of the project. These verification and testing requirements are typically 

located in the contract documents. When a question exists regarding this type of testing or the 

results, consult the Division Materials Engineer for guidance.

Soil strength testing may also be performed as part of a stabilization technique. Based on initial 

project development sampling and testing, a stabilization technique may be selected. Techniques 

may include treatment with cement, lime, fly ash, asphalt, or possibly some other chemical 

treatment. During construction, it may become necessary to validate the original stabilization 

through the testing of the on-site materials. Again, the contract requirements will address any 

strength testing that will be needed to verify the original design work. Specific sampling and testing 

requirements will be included based on the treatment method.
Division 200: Earthwork Testing and Evaluation January 2020

Imported Subgrade and Backfill Materials 2-9

2.3 IMPORTED SUBGRADE AND BACKFILL MATERIALS

For some projects, it may become necessary to import materials for the completion of 

embankments. These materials include:

• Unclassified borrow – granular material that has a maximum size of 24 inches (600 mm ) 

and used in deep embankment construction

• Select borrow – granular material with specific gradation requirements and typically used 

in areas as resistance to frost heave

• Topping – granular material that has a maximum size of 3 inches (75 mm )

Typically a bid item for the specific material will be listed in the contract documents for the project. 

Unlike in-situ soils, these materials will need to meet specific requirements as defined in the 

contract. These materials are described as granular in nature and will be tested for character and 

quality to ensure compliance with contract requirements. These tests include sieve analysis, 

Atterberg Limits, and soil classification. Requirements for unclassified borrow are often modified 

in the special contract requirements for projects in areas where granular materials are not readily 

available.

Backfill material for structures is also a product that is typically imported for use. These materials 

include:

• Foundation fill – typically used to replace unsuitable or unstable material for the 

construction of footings or other structural components

• Bedding material – typically used under culvert pipe

• Backfill material – typically used as backfill material for pipes

• Structural backfill – typically used to provide uniform material for backfill behind structures

These materials are often considered subsidiary to the installation of the structure. Like imported 

subgrade materials, backfill materials are granular and have specific requirements as indicated in 

the contract. Testing of these materials is important to ensure compliance with the contract. 

Sampling and testing requirements that are applicable to the contract may be found in the 

“Sampling and Testing Requirements” table located at the end of each section in the FP or in the 

special contract requirements.

Electrochemical requirements may also be included if the backfill will be used in connection with 

metallic construction elements. These elements include items such as reinforcement for 

mechanically stabilized earth walls, rock bolts, anchor bolts, gabion mattress material, or pipe 

elements. The primary use of this testing is to determine the corrosion potential of the soil on 

metal elements. Soil resistivity measurements supplemented by the soil pH value are used to 

identify conditions under which the corrosion of the metals in the soil may be sharply accentuated. 

Sulfate and chloride content are also used in determining the corrosive nature of soil. These tests 

measure the water-soluble ion content in the soil that would be detrimental to buried metal 

components.
Division 200: Earthwork Testing and Evaluation January 2020

2-10 Imported Subgrade and Backfill Materials

The quality of the backfill material used is critical to the service life of the constructed retaining 

structure. If the corrosion potential is a concern, the contract will include sampling and testing 

requirements to verify the quality of the backfill material. Any questions regarding the specific 

testing or sampling requirements may be directed to the Division Materials Engineer.

Exhibit 2-6 provides guidance on minimum sample sizes required for given testing.

Exhibit 2-7 Guidance for Sample Sizes for Transmitting to FLH Laboratory

Material

Minimum Split Size 

for Transmitted to 

FLH Laboratory

Purpose Test Method or 

Specification

Subgrade soil 50 lbs (23 kg) Classification 

Moisture - Density

AASHTO M 145 

AASHTO T 99 

OR T 180

Unclassified Borrow 50 lbs (23 kg) Classification 

Moisture - Density

AASHTO M 145

AASHTO T 99 

OR T 180

Select Borrow 50 lbs (23 kg) Gradation

Atterberg Limits

Moisture - Density

AASHTO T 11 & T 27

AASHTO T 89 & T 90

AASHTO T 99 

OR T 180

Topping 50 lbs (23 kg) Classification 

Moisture - Density

AASHTO M 145

AASHTO T 99 

OR T 180

Foundation fill 50 lbs (23 kg) Gradation

Atterberg Limits

Moisture - Density

AASHTO T 11 & T 27

AASHTO T 89 & T 90

AASHTO T 99 

OR T 180

Bedding material 50 lbs (23 kg) Gradation

Moisture - Density

AASHTO T 11 & T 27

AASHTO T 99 

OR T 180

Backfill material 50 lbs (23 kg) Classification 

Moisture - Density

AASHTO M 145 

AASHTO T 99 

OR T 180

Structural backfill 50 lbs (23 kg) Gradation

Atterberg Limits

Moisture - Density

AASHTO T 11 & T 27

AASHTO T 89 & T 90

AASHTO T 99 

OR T 180
Division 200: Earthwork Testing and Evaluation January 2020

Imported Subgrade and Backfill Materials 2-11

When field-testing soils, Exhibit 2-7 provides some of the test procedures to be used as 

appropriate and as specified in the contract.

Exhibit 2-8 AASHTO Soil Test Procedures

Test Number Test Title

AASHTO R 58 Dry Preparation of Disturbed Soil and Soil Aggregate Samples for Test

AASHTO T 89 Determining the Liquid Limit of Soils

AASHTO T 90 Determining the Plastic Limit and Plasticity Index of Soils

AASHTO T 99 Moisture-Density Relations of Soils Using a 2.5-kg (5.5-lb) Rammer and a 

305-mm (12-in.) Drop

AASHTO T 180 Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) Rammer and 

a 457-mm (18-in.) Drop

AASHTO T 190 Resistance R-Value and Expansion Pressure of Compacted Soils

AASHTO T 191 Density of Soil In-Place by the Sand-Cone Method

AASHTO T 193 The California Bearing Ratio

AASHTO T 255 Total Evaporable Moisture Content of Aggregate by Drying

AASHTO T 265 Laboratory Determination of Moisture Content of Soils

AASHTO T 272 One Point Method for Determining Maximum Dry Density and Optimum 

Moisture

AASHTO T 310 In-Place Density and Moisture Content of Soil and Soil-Aggregate by 

Nuclear Methods (Shallow Depth)
Division 200: Earthwork Testing and Evaluation January 2020

2-12 Roles and Responsibilities

2.4 ROLES AND RESPONSIBILITIES

2.4.1 Contractor’s Responsibilities

The contractor is responsible for excavation and constructing the subgrade and embankments 

according to the requirements provided in the contract. As part of these requirements, the 

contractor is to control the quality of the materials provided and also monitor the construction 

process to ensure compliance. The construction of embankments and the placing of backfill 

materials require that the material provided meet the specification and be in a suitable condition 

for compaction. The specific requirements will be established in the contractor quality control plan 

and contract specifications. In general, the sampling and testing responsibilities of the contractor 

include:

• Providing subgrade stabilization mix design submittals.

• Sampling material to be tested according to proper sampling methods.

• Providing split samples to the Government when required or requested.

• Testing material for conformance to material requirements. (i.e., classification, gradation, 

Atterberg Limits, etc.)

• Providing appropriate moisture density curves for a specific material type.

• Testing density of placed material to ensure proper compaction.

• Monitoring the production of any imported material to ensure compliance with the 

specifications.

• Providing appropriate certifications for material.

The contractor needs to provide information and test results according to the timeframe specified 

in the contract. Distribution of the test reports and certifications should be according to the contract 

documents and the quality control plan.

Exhibit 2-6 provides guidance on minimum sample sizes required for given testing.

2.4.2 Government’s Responsibilities

The Project Engineer or designated representative will review the test results and certifications 

for contract compliance. A decision regarding the acceptance of materials and work will be made 

in accordance with Subsection 106.01.

The Project Engineer or designated representative will also be present to witness all samples 

taken for the Government and split, when required. Upon completion of splitting, the samples will 

be secured and should immediately be in the control of the government. The Project Engineer 

needs to be aware of the contractor’s operations and be available to witness the sampling and 

splitting activities.
Division 200: Earthwork Testing and Evaluation January 2020

Roles and Responsibilities 2-13

The Project Engineer should review the testing protocols and equipment to ensure compliance 

with the contract requirements. In regard to subgrade materials, the testing should verify the 

appropriate material characteristic as listed in the contract requirements. The testing should also 

verify that the material is suitable for use in the work and may be constructed according to the 

contract documents.

Visual observations are an important part of the Project Engineer’s responsibilities with regard to 

earthwork operations. Because soils are not a manufactured product, there can be significant 

variations in the materials being used, especially in areas with many different soil deposits. The 

Project Engineer should review the Geotechnical and Pavement Design Reports to become 

familiar with the subsurface conditions and what to expect with on-site materials. It is important to 

view the contractor’s operations to ensure that proper materials are properly placed. The quality 

control tests should be used by the Project Engineer to confirm field observations. For instance, 

if tests indicate passing density results but the material is pumping under the weight of 

construction equipment, an investigation should be conducted to resolve the conflict in test results 

and field observations. By visually observing earthwork operations, problems can often be 

identified and addressed early in the construction process and future problems can be eliminated 

when placing final surfacing.
Division 200: Earthwork Testing and Evaluation January 2020

2-14 Material Certifications

2.5 MATERIAL CERTIFICATIONS

Many of the materials specified and used on a project are manufactured off-site and acceptance 

is based on materials certification. 

Certifications need to be in conformance with the contract requirements as provided in Subsection

106.03.

FP specifications reference two types of materials certifications, production and commercial. The 

Project Engineer needs to determine the appropriate certification for the type of material being 

provided and obtain the appropriate documentation in accordance with the certification being 

provided.

Exhibit 2-8 provides guidance for certifications that may be required.

Exhibit 2-9 Materials Certification

Section Description Material Frequency

Certification Sample

207 Earthwork 

geotextiles Geotextile 1 per shipment First shipment

213 Subgrade 

stabilization

Chemical 

admixtures

Fly ash

Hydraulic cement

1 per shipment

“

“

Upon request

“

“

251 Grout for riprap Material for grout 1 per mix –

253 Gabions and revet 

mattresses

Material for gabion 

structures 1 per source –

255 MSE walls Material for MSE 

walls 1 per shipment –

256 Ground anchors Material for ground 

anchors 1 per shipment –

258

Reinforced 

concrete retaining 

walls

As specified 1 per shipment –

259 Soil nail retaining 

walls As specified 1 per shipment –

260 Rock bolts and 

Rock dowels As specified 1 per shipment –
Division 200: Earthwork Testing and Evaluation January 2020

Form References 2-15

2.6 FORM REFERENCES

Form references for use in the testing of soils and subgrade materials.

• Form FHWA 1600C – Request for Laboratory Tests (CFL)

• Form FHWA 1600E – Requests for Laboratory Tests (EFL)

• Form FHWA 1600W – Requests for Laboratory Tests (WFL)

• Form FHWA 1616 – Moisture content by microwave method

• Form FHWA 1618 – In-place nuclear moisture/density worksheet

• Form FHWA 1621 – Coarse and fine aggregate gradation worksheet

• Form FHWA 1624 – Liquid Limit and Plastic Limit worksheet

• Form FHWA 1625 – Moisture density worksheet (T 99/T 180)

• Form FHWA 1627 – Sieve analysis for fine and coarse aggregate worksheet

• Form FHWA 1636 – Correction for coarse particles in soil compaction worksheet
Division 200: Earthwork Testing and Evaluation January 2020

2-16 Form References

(This page intentionally left blank.)
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Summary and Description 3-1

CHAPTER 3

DIVISION 300: AGGREGATE BASE, SUBBASE, 

AGGREGATE-TOPSOIL AND BASE STABILIZATION

3.1 SUMMARY AND DESCRIPTION

Aggregate base and subbase typically provide the first layer of the structural pavement section. 

These are manufactured aggregate products that may be produced from mining or quarrying 

naturally occurring rock deposits or as a by-product of other manufacturing processes such as 

slag. Base aggregates may be combined with a binding agent to form a stronger stabilized base. 

Cement, lime, fly ash, emulsified asphalts, and other materials have been used to provide 

additional strength and stability to the aggregate base layer.

Testing of the aggregate for use as base is designed to provide information on the inherent quality 

properties of the rock to be used. Among these are hardness, soundness, stability, resistance to 

abrasion and other forms of mechanical breakdown, and resistance to weathering. Once the 

quality properties of the aggregate are established to meet the intended use, the aggregate will 

need to be crushed and processed to meet requirements of the finished product. During 

construction of the base layer, proper compaction is required to provide the proper support as 

required by the structural pavement design.

Other materials are also used as part of the construction of aggregate base construction. These 

include aggregate-topsoil courses and dust palliatives. These products serve a unique purpose 

and are used for specific applications. In general, these uses are limited compared with the more 

common use of aggregate base.

Tests in Exhibits 3-1, 3-2, 3-3 and 3-12 function to either evaluate the quality of aggregate, 

quality of the finished product, or verify proper construction. Base aggregate tests vary 

throughout the United States. When contract specifications permit options, the selection of one 

test over another is often a matter of local engineering judgment. Consideration needs to be 

given to local knowledge and past performance of aggregate bases to determine what testing is 

appropriate and applicable. The Project Engineer should consult the contract to determine what 

aggregate tests have been specifically included in the project.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-2 Aggregate Base Properties and Test Methods

3.2 AGGREGATE BASE PROPERTIES AND TEST METHODS

3.2.1 Aggregate Quality Properties

Quality of the aggregate material can be determined by testing samples obtained from the source. 

These samples should be obtained from various locations throughout the source. Sampling 

techniques used to obtain rock for testing including core samples, rock face grab samples, or 

crushed processed aggregate stockpiles to name a few. Regardless, the rock or aggregate that 

is sampled should be representative of the aggregate to be used in the production of the 

aggregate base. The tests listed in Exhibit 3-10 provide a listing of test methods typically used to 

determine aggregate quality. The Project Engineer should also review the contract to determine 

if other quality aggregate tests have been specified based on project location, local conditions, or 

other engineering judgment.

Resistance of an aggregate to abrasion, impact, and grinding is determined using the Los Angeles 

Abrasion test. The test measures the degree to which a graded aggregate is reduced in size when 

subjected to the rolling and pounding of steel spheres inside a rotating steel drum. This is also a 

measure of aggregate toughness or hardness.

Resistance of an aggregate to breakdown by freezing and thawing is determined using the 

Soundness test. With the Soundness test, weak porous aggregates often disintegrate from the 

pressure of the salt that crystallizes in the pores during the performance of the test. This pressure 

simulates the effect that ice crystals would have in the aggregate when subjected to severe 

multiple freeze thaw cycles.

The Aggregate Durability test measures resistance of an aggregate to mechanical methods of 

degradation. In this method, a sample of aggregate is agitated in the presence of water. The 

amount of fines generated during the test determines the durability index.

The Fractured Faces test is used when aggregate is obtained from a gravel or pit source. In order 

to provide for aggregate interlock, the round character of the rock needs to be altered by crushing. 

This test determines the percentage of aggregates that have mechanically fractured faces.

Exhibit 3-10 Aggregate Quality Test Methods

Aggregate Test Test Method Aggregate Performance 

Characteristic

L.A. Abrasion AASHTO T 96 Hardness

Sodium Sulfate Soundness AASHTO T 104 Freeze / Thaw Resistance

Aggregate Durability AASHTO T 210 Mechanical Abrasion

Fractured Faces ASTM D5821 Aggregate Interlock

A minimum 200-pound (90 kg) representative sample should be obtained in order to perform all 

of the quality tests listed in Exhibit 3-10. In the event that the contract includes additional quality 

tests, consult the FLH Division Materials Engineer for additional guidance.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Aggregate Base Properties and Test Methods 3-3

3.2.2 Processed Aggregate Properties

Once the quality of the aggregate has been determined to meet the contract requirements, 

processed aggregate properties will be determined. For any aggregate layer, the gradation of the 

material and moisture density relationship will be determined. In addition, other properties may 

be included depending on the use and particular specifications of the project. Certain aggregate 

base requirements may include a liquid limit or sand equivalent requirement to ensure that the 

fine portion of the aggregate mixture is granular in nature. A plasticity index requirement may be 

included when surface course aggregate is used to ensure that the fines exhibit a binding 

characteristic that would provide a higher quality driving surface. The contract may also include a 

minimum strength requirement, such as CBR or R-Value, for aggregates.

Gradation or particle size is the one characteristic subject to control by conventional field 

processing. Gradation is not an inherent geological property of the rock, although to some extent 

the type of rock does influence the amount and character of coarse and fine materials produced 

by crushing.

Gradation of the aggregate is determined by means of a sieve analysis, which is the separation 

of the aggregates into several designated sizes by passing the material through a series of sieves 

arranged from coarse to fine. The aggregate gradation is determined according to AASHTO T 11 

and T 27. Generally, aggregates for highways and structures are divided into two gradation 

classifications. See Exhibit 3-11.

Exhibit 3-11 Gradation Classification

Type of Aggregate Aggregate Size

Coarse aggregate Material retained on the #4 (4.75 mm) sieve

Fine aggregate Material passing the #4 (4.75 mm) sieve

When the #200 (75 μm) sieve is specified as part of the gradation requirements, washing the 

sample in accordance with AASHTO T 11 is required in conjunction with the sieving process.

The character and relative quality of the fine aggregate can be determined using the liquid limit, 

plastic index, and sand equivalent test methods. If certain binding characteristics of an aggregate 

are required, this can be determined using the liquid limit and plasticity index tests. Aggregate 

material should be prepared using the dry preparation method as stated in AASHTO R 58. For 

additional discussion on these tests, see Section 2.2.1.2 of this manual. The presence and 

amount of potentially detrimental clay-like fines in the aggregate can be determined using the 

sand equivalent test method. These tests may or may not be included in the contract depending 

on the purpose and function of the aggregate base layer being placed.

Exhibit 3-12 Supplemental Aggregate Base Tests

Fine Aggregate Tests Test Method Aggregate Characteristic

Liquid Limit AASHTO T 89 Liquid state of fine aggregate

Plastic Limit AASHTO T 90 Plastic state of fine aggregate

Sand Equivalent AASHTO T 176 Proportion of clay in 

aggregate
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-4 Aggregate Base Properties and Test Methods

3.2.2.1 Moisture Density Relationship

The moisture density relationship of an aggregate will be determined through laboratory testing. 

This testing will establish a reference density that will be used during the construction of the base 

layer to verify appropriate field compaction has been achieved. The test method most commonly 

used to establish the moisture density standard is AASHTO T 180 although there are other tests 

that may also be used. The contract documents will specify the method to be used to establish 

the target density and moisture content. Aggregates often contain oversized material, particles 

larger than 0.75 inch (19 mm). The maximum dry density and optimum moisture content of the 

aggregates containing more than 5 percent of oversized material should be corrected according 

to AASHTO T 99 or T 180.

During construction, field density tests are taken and compared to the established standard to 

verify that the material has been properly compacted. Results of any field density test cannot be 

properly evaluated until compared to the appropriate reference density and moisture content. 

There are several acceptable methods that may be used to determine the field density and 

moisture content of the aggregate. The method most common is AASHTO T 310. This method 

utilizes a nuclear gage to determine the moisture content and density of the aggregate. Other 

methods such as the sand-cone method (AASHTO T 191) and the oven-drying moisture method 

(AASHTO T 265) may still be used however they are becoming less common.

For additional information on moisture density relationship and field density testing, see Section 

2.2.2 of this manual.

3.2.3 Aggregate Sampling and Splitting

The importance of obtaining a proper sample of aggregate cannot be overemphasized. When 

obtaining a sample of aggregate, proper methods and technique need to be used to ensure a 

representative sample has been obtained. A proper sample is vital in order to provide correct 

information for evaluation purposes. If a proper sample is not obtained, any testing performed on 

that sample may be of little value. 

AASHTO provides a standard practice for sampling of aggregates in AASHTO R 90. This practice 

provides guidance on obtaining samples from various locations such as stockpiles, flowing 

aggregate stream, conveyor belts, transportation units, and roadways. Guidance is also provided 

for the sampling of aggregate for the exploration of potential aggregate sources. The following 

paragraphs will provide some additional guidance on proper sampling technique.

3.2.3.1 Sampling from Stockpiles

As a general rule, sampling from stockpiles should be avoided whenever possible. Because of 

the potential for segregation to occur during the construction of the stockpile, obtaining a 

representative sample must be undertaken with great care.

When taking a sample of coarse or mixed coarse and fine aggregate, exercise caution to ensure 

that only the material from the sampling area is incorporated into the sample. A barrier, such as 

a wooden board or metal sheet, should be used to restrict the flow of the material down the pile 

so that the sample may be obtained from the specified area. Power equipment, if available, could 

also be used to obtain material from various locations in the main pile. These increments would 
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Aggregate Base Properties and Test Methods 3-5

then be combined to compose one field sample. Samples should be made by obtaining material 

from at least three increments taken from the upper, middle, and lower third of the pile. See Exhibit 

3-13 and Exhibit 3-14.

Exhibit 3-13 Proper Sampling of Coarse Aggregate

NOTE: Sample the stockpile near its base, middle, and top as shown. Combine 

and mix the material obtained to form one sample and then reduce the size of 

the combined sample by splitting to the required testing size.

Exhibit 3-14 Proper Use of Shield for Sampling

A sampling tube may be used to sample stockpiles of fine aggregate. The sampling tube should 

be inserted into the pile at random locations to extract material. As is the case with coarse or 

mixed coarse and fine stockpiles, multiple locations throughout the pile should be selected to 

obtain one composite sample. See Exhibit 3-15.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-6 Aggregate Base Properties and Test Methods

Exhibit 3-15 Proper Sampling of Fine Aggregate Stockpile

NOTE: Insert the sampling tube horizontally near the base, middle, and top of 

the stockpile as shown. Combine and mix the material obtained to form one 

sample and then reduce the size of the combined sample by splitting to the 

required testing size.

3.2.3.2 Sampling from Flowing Aggregate Stream

It is recommended to obtain a sample from a flowing aggregate stream by cutting the entire cross 

section of material as it is being discharged. Another practice is to cut across the flowing material. 

In either case, special sampling devices are typically fabricated to obtain the sample. Exhibit 3-

16 is an example of a fabricated sampling device.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Aggregate Base Properties and Test Methods 3-7

Exhibit 3-16 Sampling Device Cutting Across Flowing Stream

3.2.3.3 Sampling from Conveyor Belt

In sampling from a conveyor belt, the belt must be stopped in order to obtain the sample. A 

template should be manufactured that conforms to the shape of the belt. Insert two templates in 

the aggregate stream and space them appropriately to obtain the recommended amount for the 

sample. The sample should be obtained for the full width of the belt. Exercise care to ensure 

that all of the fines are swept off the belt and into the sample container. Exhibits 3-17 and 3-18

show proper sampling technique and devices typically used when obtaining a sample from a 

conveyor belt. Exhibit 3-19 provides a schematic drawing of a device typically used to obtain 

conveyor belt samples.

Exhibit 3-17 Sampling from Conveyor Belt
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-8 Aggregate Base Properties and Test Methods

Exhibit 3-18 Proper Device for Belt Sampling

Exhibit 3-19 Schematic of Belt Sampling Device
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Aggregate Base Properties and Test Methods 3-9

3.2.3.4 Sampling from Roadbed or Windrow

Roadbed and windrow sampling is generally used in the acceptance process for aggregate base 

materials. The sample should be obtained from the windrow or the roadbed after the aggregate 

has been processed. The typical method of sampling a windrow is to strike off the top of the 

windrow and sample a minimum of three random locations and combine the material into one 

sample. Exhibit 3-20 shows a schematic of this type of sampling. 

When sampling from the roadbed, all of the material for the sample should be obtained full depth. 

Care should be exercised when obtaining this sample to ensure that none of the underlying 

materials are included in this sample. If this does occur, the sample would be considered 

contaminated and a new sample should be obtained.

Exhibit 3-20 Schematic of Sampling from a Windrow

NOTE: Flatten the windrow to approximately 12 inches (300 mm) in width. 

Sample material from at least 3 random locations as shown. Combine and 

mix the material obtained to form one sample and then reduce the size of 

the combined sample by splitting to the required testing size.

The Project Engineer should review the contract documents and identify sample locations or any 

special sampling or testing requirement that may be specified. The contract will also indicate the 

point of sampling and sampling frequency for various aggregate products that are included in the 

contract.

3.2.3.5 Splitting Samples

Once a field sample has been obtained, it will need to be reduced in size to the proper testing 

size. AASHTO R 90 provides guidance on the minimum sample sizes of aggregate that constitute 

an appropriate field sample. From this original field sample, a smaller representative testing 

sample can be obtained. AASHTO R 76, Reducing Samples of Aggregate to Testing Size, is the 

method for reducing large field samples to appropriate sizes for testing. Samples are reduced by 
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-10 Aggregate Base Properties and Test Methods

the use of a quartering blanket or a mechanical splitter. It is important to comply with both the 

minimum field sample size requirements and the minimum testing size requirements found in the 

specific test method to have valid test results. 

Minimum split sample sizes for general aggregate testing are provided in Exhibit 3-21. If multiple 

tests are to be performed on a single field sample, consult the FLH Division Materials Engineer 

for specific guidance on field sample sizes.

Exhibit 3-21 Guidance for Sample Sizes for Transmitting to FLH Laboratory

Material

Minimum Split Size 

for Transmitting to 

FLH Laboratory

Purpose Test Method or 

Specification

Subbase, Aggregate 

Base, and Aggregate 

Surfacing

50 lbs (23 kg)*

Gradation

Atterberg Limits

Moisture – Density

Sand Equivalent

AASHTO T 11 & T 27

AASHTO T 89 & T 90

AASHTO T 180

AASHTO T 176

Subbase, Aggregate 

Base, and Aggregate 

Surfacing

200 lbs (90 kg) Aggregate Quality 

Test

AASHTO T 96

AASHTO T 104

AASHTO T 210

ASTM D5821

* 100 lbs (50 kg) if CBR or R-value testing is required.

3.2.4 Typical Aggregate Base Treatments

Aggregate bases and subbases can be treated with various additives to improve the strength and 

performance characteristic as compared to water-bound (untreated) bases. Laboratory tests are 

used to determine the amount of additive required to provide the specified mixture requirements. 

Typically these tests are used to determine the amount of additive required to meet the mixture 

requirements. Aggregates can be treated as part of the construction of a new aggregate course 

or in-place aggregates can be stabilized to strengthen an existing base layer. 

The additives most commonly used to improve the structural capacity of a base layer are hydraulic 

cement, lime, or fly ash. It is critical during construction that the proportioning of the components 

be accurate in order to achieve the desired material properties. Using additional additive will 

produce a mixture with a higher strength but may also cause undesired side effects such as 

excessive shrinkage cracking. 

The process for determining the proportioning of a treated base is typically established in the 

contract documents. In general, the contract will specify the requirements for the treated base 

and the contractor will design a treated aggregate mixture that meets those requirements. As 

part of the mix design submittal, samples of aggregate and additive may also be obtained for the 

Government to perform verification testing. Consult your FLH materials staff or the contract for 

additional guidance.

In some instances, additives may be used to improve handling or alter material characteristics 

without providing a substantial increase in strength. Emulsified asphalt treated bases are an 

example of this type of treatment. The additive is used primarily to assist in the binding of the 

aggregate to provide a water-tight platform for paving and reduce dust generated by traffic.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Aggregate Base Properties and Test Methods 3-11

3.2.5 Other Associated Aggregate Products

3.2.5.1 Minor Crushed Aggregate

Minor crushed aggregate is a product that is typically specified on projects that have small 

quantities. The material requirements for this product are for crushed aggregate material normally 

used and available near the project location. The furnished aggregate should conform to the 

gradation and quality requirements used by local agencies in the construction of highway projects.

3.2.5.2 Recycled Aggregate Base and Road Reconditioning

Recycled aggregates and road reconditioning are methods that use existing roadway aggregate 

as the material for construction. The existing base material is processed on the roadway in the 

same manner as virgin material. Any organic or deleterious materials are removed during the 

processing and the material is shaped to provide a uniform surface. The material is compacted 

according to the methods specified in the contract. Typically for small quantities a method-type 

specification is used to monitor compaction; whereas for larger quantities compaction is monitored 

by obtaining a specified percentage of the maximum density determined by a proctor test such 

as AASHTO T 180. 

3.2.5.3 Aggregate-Topsoil

As the name suggests, aggregate-topsoil is a blended material of crushed aggregate and topsoil 

that is mixed together. The proportioning is roughly 50/50 by volume and is designed to provide 

some structural support within a medium that promotes vegetation. This material is typically 

placed and compacted as a shoulder finishing material. To complete the construction sequence, 

the completed surface is seeded.

3.2.5.4 Dust Palliatives and Stabilization Admixtures

There are several reasons to use dust palliatives or stabilizing agents to enhance the performance 

of aggregate surfacing. Using various additives can improve strength, waterproof, or control dust. 

The primary purpose of these additives is to provide a bound cohesive material and prevent the 

loss of fine particulates. If this is accomplished, the aggregate surfacing will provide improved 

service and prevent unwanted side effects. Aggregate surface roads will experience some loss 

of surfacing due to surface abrasion. Use of dust palliatives and stabilization admixtures will help 

to minimize the loss.

Dust palliatives are utilized to reduce airborne dust particulates and aid in maintaining an 

aggregate surface. The dust palliatives are applied on a properly constructed prepared surface 

or are mixed with the aggregate prior to final placement and compaction. The FP lists specific 

products for use as dust palliatives. Traditionally three categories of dust suppressants have 

been used in FLH. These categories are as follows:

• Salts. The primary salts used as dust suppressants are calcium chloride and magnesium 

chloride. These materials can be incorporated into the aggregate in two forms, dry flakes 

or as a brine solution. In either case, the material should be mixed into the top few inches 

of the aggregate to provide maximum benefit. The problems associated with using salts 

as dust palliatives include leaching during wet weather, vehicle corrosion potential, and 
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-12 Aggregate Base Properties and Test Methods

ineffectiveness in dry climates. Multiple applications within a single year may be 

necessary depending on the local weather and climate conditions. Application rates and 

construction requirements should be included in the contract if these materials are used.

• Lignosulfonates. Lignosulfonates are a waste product of the paper pulp industry and are 

refined and used as dust palliatives. They provide a cementing reaction with the coarse 

and fine aggregate to provide the dust suppressing action. This material is provided as a 

liquid and is sprayed on the road surface and allowed to penetrate. Similarly to the salts, 

lignosulfonates can leach out of the surfacing material during rainy weather and thus may 

have to be reapplied to provide adequate benefits. However, a distinct benefit of this 

material is its use in more variable climate conditions.

• Emulsified Asphalts. Asphalt and other petroleum-based products have been used as 

prime coats to provide a temporary driving surface. The use of emulsified asphalts as 

dust palliatives is very similar. When sprayed on the aggregate surface, the emulsified 

asphalt cements particles together and in doing so, reduces the airborne particulates. The 

aggregate surfacing must be low in fines content (typically less than 10% passing the #200 

(75 μm) sieve) for the application to be successful. The use of this material may also 

require covering with blotter material to prevent traffic from picking up the newly 

constructed dust palliative surface.

Other non-traditional stabilizing agents are currently available. These include enzymes, synthetic 

polymers, and organic non-petroleum derivatives. These products vary in material requirements 

and use and may be considered on a case-by-case basis. The FP does not currently provide 

specifications for these types of stabilizing agents.

3.2.6 Field Testing Requirements

When field-testing soil-aggregate and aggregate materials, Exhibit 3-22 provides test 

procedures to be used as appropriate and as specified in the contract.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Aggregate Base Properties and Test Methods 3-13

Exhibit 3-22 AASHTO, ASTM and FLH Aggregate Test Procedures

Test Number Test Title

AASHTO R 58 Dry Preparation of Disturbed Soil and Soil Aggregate Samples for 

Test

AASHTO R 76 Reducing Samples of Aggregate to Testing Size

AASHTO R 90 Sampling of Aggregates

AASHTO T 11 Materials Finer Than 75-μm (No. 200) Sieve in Mineral Aggregates 

by Washing

AASHTO T 27 Sieve Analysis of Fine and Coarse Aggregates

AASHTO T 89 Determining the Liquid Limit of Soils

AASHTO T 90 Determining the Plastic Limit and Plasticity Index of Soils

AASHTO T 96 Resistance to Degradation of Small-Size Coarse Aggregate by 

Abrasion and Impact in the Los Angeles Machine

AASHTO T 104 Soundness of Aggregate by Use of Sodium Sulfate or Magnesium 

Sulfate

AASHTO T 176 Plastic Fines in Graded Aggregates and Soils by Use of the Sand 

Equivalent Test

AASHTO T 180 Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) 

Rammer and a 457-mm (18-in.) Drop

AASHTO T 190 Resistance R-Value and Expansion Pressure of Compacted Soils

AASHTO T 191 Density of Soil In-Place by the Sand-Cone Method

AASHTO T 193 The California Bearing Ratio

AASHTO T 210 Aggregate Durability Index

AASHTO T 255 Total Evaporable Moisture Content of Aggregate by Drying

AASHTO T 265 Laboratory Determination of Moisture Content of Soils

AASHTO T 310 In-Place Density and Moisture Content of Soil and Soil-Aggregate 

by Nuclear Methods (Shallow Depth)

ASTM D5821 Determining the Percentage of Fractured Particles in Coarse 

Aggregate
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-14 Recycling Techniques

3.3 RECYCLING TECHNIQUES

3.3.1 Cold Recycling

A cold recycled asphalt base course can be accomplished through two different techniques; inplace recycled or central plant mixed. Both of these methods consist of processing recycled 

asphalt pavement, recycling agents, emulsified asphalt, and lime into a homogenous material that 

is placed as a layer. In some instances and usually at central mixing plant operations, reclaimed 

aggregate or virgin aggregates can be added. Generally speaking, in-place recycling 

incorporates only recycled asphalt pavement and does not include aggregates as part of the 

newly mixed material.

A mix design is usually performed to ensure proper proportioning of the ingredients of the cold 

recycled materials regardless of the technique used to mix and place the final product. Contract 

requirements will specify the amount of material to be submitted to the FLH division laboratory for 

testing to be completed. Unlike the verification process for hot asphalt concrete mix design, the 

FLH division laboratory will perform the mix design and provide the initial application rates for 

emulsified asphalt, recycling agent, lime or other additives for the mixture. Typically 21 days are 

allowed to complete the mix design process prior to beginning recycling operations; however 

consult the specific contract to verify time requirements for the submittals.

The quality of the emulsified asphalt used in the recycling operations is typically the only 

parameter that is verified through sampling and testing. Contract specifications will provide 

sampling and testing requirements for this material. Testing is performed by the FLH division 

laboratory.

3.3.2 Full Depth Reclamation (FDR) Techniques

Full depth reclamation (FDR) is a technique in which the asphalt pavement and underlying 

materials are pulverized and blended into a homogenous base layer. The underlying material 

may include base, subbase and subgrade depending on the design. Additional base aggregate 

can also be incorporated when necessary to improve the existing grade or cross-slope. This 

technique differs from cold recycling in that the reclamation depth is much greater and is intended 

to incorporate various layers of the existing pavement structure into the final product. 

A broad range of stabilizing additives can be used including cement, lime, emulsified asphalt, hot 

asphalt binder plus various proprietary products. FDR processes often have different names 

depending on the additive used. These include:

• Foamed asphalt stabilization

• Bituminous base stabilization

• Cement base stabilization

• Pulverized pavement

• Recycled aggregate base
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Recycling Techniques 3-15

Because the FDR method and additive can vary, it is important to review the contract documents 

to determine what specific material testing is required. In most instances, some type of mix design 

will be required prior to beginning production. The Project Engineer needs to review the contract 

for the submittal, sampling and testing requirements.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-16 Roles and Responsibilites

3.4 ROLES AND RESPONSIBILITES

3.4.1 Contractor’s Responsibilities

The contractor is responsible for constructing the aggregate base layers according to the 

requirements provided in the contract. As part of these requirements, the contractor is to control 

the quality of the materials provided and also monitor the construction process to ensure 

compliance.

Construction of the aggregate base layers and the placing of the aggregate materials require that 

the material provided meet the specification and that it be in a suitable condition for compaction. 

Specific requirements for the aggregate will be specified in the contract. The contractor will 

establish a process to verify that the material and construction requirements are met through a 

quality control plan. In general, the sampling and testing responsibilities of the contractor include:

• Sampling material to be tested according to proper sampling methods.

• Providing split samples to the Government when required or requested.

• Monitor the production of aggregate to ensure compliance with the specifications.

• Testing material for conformance to material requirements. (i.e., aggregate quality, 

gradation, Atterberg Limits, etc.)

• Providing appropriate moisture density curves for the aggregate base material.

• Testing density of placed aggregate to ensure proper compaction.

• Providing appropriate certifications for material.

• Submitting a mix design meeting the design parameters as specified in the contract for 

treated base material.

The contractor needs to provide information and test results according to the timeframe specified 

in the contract. Distribution of the test reports and certifications should be according to the 

contract documents and the quality control plan.

Exhibit 3-21 provides guidance on sample sizes required for given testing.

3.4.2 Government’s Responsibilities

The Project Engineer or designated representative will review the test results and certifications 

for contract compliance. A decision regarding the acceptance of the material will be made in 

accordance with Subsection 106.01.

The Project Engineer or designated representative will also be present to witness all required split 

samples taken for the Government. Upon completion of splitting, the samples will be secured 

and immediately placed in Government control. The Project Engineer needs to be aware of the 

contractor’s operations and be available to witness the sampling and splitting activities.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Roles and Responsibilites 3-17

The Project Engineer should review the testing protocols and equipment to ensure compliance 

with contract requirements. In regard to aggregate base materials, the testing should verify the 

appropriate material characteristic as listed in the contract requirements. Testing verifies that the 

material is suitable for use in the work and may be constructed according to the contract 

documents.
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-18 Material Certifications

3.5 MATERIAL CERTIFICATIONS

Exhibit 3-23 provides guidance for some of the certifications that may be required. Certifications 

need to be in conformance with the contract requirements as provided in Subsection 106.03.

Exhibit 3-23 Materials Certifications

Section Description Material Frequency

Certification Sample

302 Minor crushed 

aggregate Crushed aggregate 1 per source Upon request

304 Full depth 

reclamation Crushed aggregate 1 per source Upon request

305

Full depth 

reclamation with 

cement

Hydraulic cement

Crushed aggregate

1 per 

shipment

1 per source

Upon request

306

Full depth 

reclamation with 

asphalt

Asphalt binder

Emulsified asphalt

Fly ash

Portland cement

Crushed aggregate

1 per 

shipment

“

“

1 per source

Upon request

309

Emulsified 

asphalt treated 

base

Emulsified asphalt 1 per 

shipment Upon request

310

Cold in-place 

recycled asphalt 

base course

Emulsified asphalt

Lime

1 per 

shipment Upon request

311

Stabilized 

aggregate 

surface course

Calcium chloride 1 per 

shipment Upon request

312 Dust palliative Dust palliative 

material

1 per source 

per 

manufacturer

Upon request
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

Form References 3-19

3.6 FORM REFERENCES

Form references for use in the testing of aggregate base materials.

• Form FHWA 1600C – Request for Laboratory Tests (CFL)

• Form FHWA 1600E – Request for Laboratory Tests (EFL)

• Form FHWA 1600W – Request for Laboratory Tests (WFL)

• Form FHWA 1616 – Moisture content by microwave method

• Form FHWA 1618 – In-place nuclear moisture/density worksheet

• Form FHWA 1621 – Coarse and fine aggregate gradation worksheet

• Form FHWA 1624 – Liquid Limit and Plastic Limit worksheet

• Form FHWA 1625 – Moisture density worksheet (T 99/T 180)

• Form FHWA 1626 – Sand Equivalent worksheet

• Form FHWA 1627 – Sieve analysis for fine and coarse aggregate worksheet

• Form FHWA 1636 – Correction for coarse particles in soil compaction worksheet
Division 300: Aggregate Base, Subbase, Aggregate-Topsoil and Base Stabilization January 2020

3-20 Form References

(This page intentionally left blank.)
Division 400: Asphalt Pavements and Surface Treatments January 2020

Summary and Description 4-1

CHAPTER 4

DIVISION 400: ASPHALT PAVEMENTS AND 

SURFACE TREATMENTS

4.1 SUMMARY AND DESCRIPTION

Asphalt pavements and surface treatments provide the driving surface for the roadway facility. In 

the case of asphalt pavement, this is the strongest of the structural layers and is also the most 

expensive in a flexible pavement system. It is critical that various material elements are monitored 

for quality of product and construction.

Testing of the bituminous mixtures encompasses more facets than for base aggregate materials. 

The testing process not only verifies quality and gradation of the aggregates used, which is similar 

to the testing described in Chapter 3, but also verifies properties of the asphalt binder used and 

the properties of the aggregate/asphalt combination.
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-2 Superpave Hot Asphalt Concrete Aggregate and Mix Design

4.2 SUPERPAVE HOT ASPHALT CONCRETE AGGREGATE AND MIX 

DESIGN

4.2.1 Aggregate Quality and Gradation

Similar to aggregate base material, aggregates for Superpave hot asphalt concrete pavement, 

Section 401 of the FP, also have quality requirements. Samples need to be obtained from all 

sources and tested for quality parameters prior to the production of crushed aggregates for use 

in Superpave hot asphalt concrete pavement. When using a commercial asphalt mixture supplier, 

samples of the processed crushed coarse and fine aggregate should be sampled and tested for 

quality aggregate characteristics. Sampling of these aggregates follows the process outlined in 

Section 3.2.3.

Exhibit 4-24 Superpave Aggregate Quality Test Methods

Aggregate Test Test Method Aggregate Performance 

Characteristic

L.A. Abrasion AASHTO T 96 Hardness

Sodium Sulfate Soundness AASHTO T 104 Freeze / Thaw Resistance

Fine Aggregate Angularity AASHTO T 304 Angular Sand

Flat and Elongated Particles ASTM D4791 Flat and Elongated Coarse 

Aggregate

Fractured Faces ASTM D5821 Aggregate Interlock

Sand Equivalent AASHTO T 176 Plastic Fines in Aggregate

A minimum 200-pound (90 kg) representative sample should be obtained in order to perform all 

of the aggregate quality tests listed in Exhibit 4-1. In the event that the contract includes additional 

aggregate material requirements, consult the FLH Division Materials Engineer for guidance in 

obtaining an appropriate sample.

Following in similar manner to the production of aggregates for base materials, the source 

material, should it meet the quality requirements, will be crushed and processed to meet specific 

gradation requirements that will be established during the mix design process. Aggregates are 

processed and stockpiled in multiple piles to allow for recombining during the production of hot 

asphalt concrete. It is critical to test the gradation of the aggregates as material is produced and 

stockpiled. The gradation of the material being stockpiled should be tested according to AASHTO 

T 11 and T 27. The test results will be used to establish the gradation target values for the mix 

design.

4.2.2 Superpave Mix Design Process

The composition of the mix (or job-mix formula) establishes the blend percentages of the 

aggregate stockpiles, amount of asphalt binder, amount of recycled asphalt pavement (if used), 

and additives needed to meet the appropriate design parameters that are listed in the contract. 

The contractor will submit the mix design on form FHWA 1641 with all of the appropriate data 

included. In addition, samples of all of the materials used in the mix design are also submitted to 

the FLH division laboratory for verification purposes. It is important that the materials submitted 
Division 400: Asphalt Pavements and Surface Treatments January 2020

Superpave Hot Asphalt Concrete Aggregate and Mix Design 4-3

to the FLH division laboratory be split samples of the material that is used by the contractor in 

establishing the job-mix formula. The quantity of material to be supplied for the verification 

process is established in the contract.

Once the verification process, as established in contract documents, is complete and the mix 

design is accepted, a pre-paving meeting will be scheduled. After the pre-paving meeting and 

successful construction of the test strip (see Section 4.3.2, Production Start-up Procedures), the 

contractor may begin full mix production.

If a source of material for the production of hot asphalt concrete changes, a new mix design is 

needed to establish the job-mix formula. The contractor will follow the same submittal and 

verification process as was done for the original mix design. 

The FP contains specific requirements for the mix design submittal and verification process. If the 

submitted mix design does not meet the contract requirement or fails to be verified by the FLH 

division laboratory, it will be rejected. If any questions exist regarding materials used or the mix 

design process, consult the Division Materials Engineer.

Exhibit 4-2 provides a listing of the test methods used to establish and verify the job-mix formula.

Exhibit 4-25 Mix Design Test Methods

Test Number Test Title

AASHTO R 35 Superpave Volumetric Design for Hot-Mix Asphalt (HMA)

AASHTO R 47 Reducing Samples of Hot Mix Asphalt (HMA) to Testing Size

AASHTO T 11 Materials Finer Than 75-μm (No. 200) Sieve in Mineral 

Aggregates by Washing

AASHTO T 27 Sieve Analysis of Fine and Coarse Aggregates

AASHTO T 84 Specific Gravity and Absorption of Fine Aggregate

AASHTO T 85 Specific Gravity and Absorption of Coarse Aggregate

AASHTO T 166 Bulk Specific Gravity of Compacted Hot-Mix Asphalt Using 

Saturated Surface-Dry Specimens

AASHTO T 209 Theoretical Maximum Specific Gravity And Density of HotMix Asphalt Paving Mixtures

AASHTO T 283 Resistance of Compacted Asphalt Mixtures to MoistureInduced Damage

AASHTO T 312

Preparing and Determining the Density of Hot-Mix Asphalt 

(HMA) Specimens by Means of the Superpave Gyratory 

Compactor

The Asphalt Institute publication “Superpave Mix Design (SP-2)” provides excellent guidance to 

help understand the various processes involved in establishing proper proportions for a hot 

asphalt concrete. It provides information on material selection, test methods, calculations, and 

evaluation of Superpave mix designs.

4.2.2.1 Hveem and Marshall Mix Design Methods

Hveem and Marshall mix design methods have existed for decades and were the primary mix 

design methods used by DOTs in the United States until Superpave adoption in the late 1990’s. 
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-4 Superpave Hot Asphalt Concrete Aggregate and Mix Design

These methods have the same objective as the Superpave design method; to establish a job-mix 

formula for the hot asphalt concrete pavement. The contractor will submit the mix design on form 

FHWA 1607 (Hveem) or form FHWA 1622 (Marshall) with the appropriate data included. Split 

samples of materials used in the mix design are submitted to the FLH division laboratory for 

verification purposes per contract requirements.

Although these methods have unique features and testing apparatuses, both will provide asphalt 

concrete mixtures that are durable and long-lasting. The Asphalt Institute publication “Mix Design 

Methods for Asphalt Concrete (MS-2)” provides specific guidance and instruction for the Hveem 

and Marshall mix design methods. Additionally, the specific mix design test methods are 

AASHTO T 246 and T 247 for the Hveem method and T 245 for the Marshall method.

4.2.3 Asphalt Binder

The asphalt binder is the “glue” that holds the aggregate together. Asphalt binder is a visco-elastic 

material meaning that it has characteristics of both a fluid (visco) and solid (elastic) depending on 

the temperature. At high temperatures, asphalt binder behaves more like a fluid. As the 

temperature is decreased, the viscosity of the material increases and the material begins to take 

on characteristics of a solid. AASHTO M 320 is the standard specification used to define the 

performance characteristics of asphalt binder over a wide range of temperatures.

AASHTO M 320 provides the specification for Performance-Graded (PG) binders. The 

specification defines the temperatures where the binder will possess appropriate physical 

properties. For example, a PG 58-28 defines the temperature range for a specific asphalt binder. 

The first number, 58, is the high temperature designation for the binder. It designates that the 

binder will possess adequate physical properties up to pavement temperatures of 58 °C. Likewise, 

the second number, -28, is the low temperature designation for the binder. It designates that the 

binder will possess adequate physical properties down to minus 28 °C. 

The larger the difference between these numbers, the higher the temperature range needed for 

the binder to perform. In cases of large temperature ranges, the asphalt, as produced from the 

refining of crude petroleum, may need to be modified typically with the addition of an elastomeric 

additive. The term “polymer modified asphalt” is typically used to describe the asphalt that has 

been modified in this manner.

The binder for a particular project will be selected based on the climate conditions at the project 

location. Selection of the binder grade is a critical link in the overall performance of the completed 

pavement. The contract documents will specify the performance-graded asphalt binder to be 

used on the project. The asphalt binder supplied as part of the mix design process needs to meet 

the grade specified and be provided by the same asphalt supplier used during production of hot 

asphalt concrete pavement.

The Asphalt Institute publication “Superpave Performance Graded Asphalt Binder Specification 

and Testing (SP-1)” provides a more detailed discussion of the specification and test methods 

used to evaluate asphalt binder performance.
Division 400: Asphalt Pavements and Surface Treatments January 2020

Superpave Hot Asphalt Concrete Aggregate and Mix Design 4-5

4.2.4 Additives

Other additives may be added to obtain the appropriate asphalt mix properties. These include 

liquid additives, baghouse fines, lime, cement, mineral filler, recycling agents, warm mix additives, 

and recycled asphalt pavement. Any of these additives when used will change the mixture 

properties. Any proposed additive needs to be included in the mix design process to verify the 

effect on final mixture properties. 

The most common are antistrip additives. These additives are used to improve the long term 

bonding of the asphalt binder to the aggregate. Antistrip additives come in two forms, as a liquid 

that is added to the binder and as a mineral additive (lime) that is added to the aggregate prior to 

the mixing phase. Liquid additives are commercially produced materials and should be used 

according to the manufacture recommendations.

The percentage of any additive will be established as part of the mix design procedures.

Contract specifications may prohibit the use of some additives. If there is a question regarding 

any specific additive, consult the Division Materials Engineer for guidance.
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-6 Construction Process

4.3 CONSTRUCTION PROCESS

4.3.1 Equipment for Production and Placement

Once the mix design has been approved, the contractor can begin production and placement of 

the hot asphalt concrete pavement. The production process has many different components that 

need to be checked and in good working order to produce a quality product. These components 

include the mixing plant, the hauling equipment, the paving equipment, and the compaction 

equipment. In some instances, there is a recognized standard for compliance. In other cases, 

the specifications will provide general characteristics of properly operating and maintained 

equipment. AASHTO M 156 is the cited standard that provides the best guidance for the mixing 

plants and the general operations required for the production of hot mix. This standard provides 

specific guidance and requirements for mixing operations that include:

• Requirements for mixing plants

• Requirements for the storage and preparation of mixture components

• Requirements for controlling gradation

• Weighing tolerances

• Adequate and appropriate mixing time

• Requirements for record keeping

In addition to the following proper procedures for the production of the hot asphalt concrete, the 

mixture must also be properly transported, placed, and compacted to provide a quality finished 

product. The FP provides specific contract requirements for hauling vehicles and pavers. 

Compaction of the material needs to be accomplished by proper equipment in order to meet the 

density requirement. Although specific compaction equipment is not listed in the specification, 

the compaction process will be monitored using nuclear density gauges and verified by testing 

core samples taken from the completed roadway to verify that appropriate compaction has been 

obtained.

The successful construction of an asphalt pavement does require knowledge in a number of 

different areas. The mixture delivery, placement, screed control, joint construction, and 

compaction are just a few of the many activities that need to be monitored and coordinated for 

successful asphalt pavement construction. The detailed discussion of these items is beyond the 

scope of this manual; however, the Hot-Mix Asphalt Paving Handbook is an excellent reference 

to address specific issues relating to asphalt paving. In addition, the publication also provides 

information for troubleshooting various mat problems.

4.3.2 Production Start-Up Procedures

As part of the sequence for full hot asphalt concrete production, a pre-paving conference is held. 

A general outline for this meeting can be found in Appendix D.1 of this manual. This is designed 

to ensure that all of the necessary information for full production has been obtained. This meeting 

alerts all on-site construction personnel of the processes and procedures for producing and 
Division 400: Asphalt Pavements and Surface Treatments January 2020

Construction Process 4-7

placing a quality asphalt concrete pavement. The FP provides general requirements and 

necessary submittals for the pre-paving conference.

The construction of a control strip is the final process in the start-up procedures for the production 

of hot asphalt concrete. This requires the contractor to produce and place the mixture following 

the production and delivery methods described during the pre-paving conference. The production 

is limited to a short production run to ensure that the quality of the produced, placed, and 

compacted mixture meets the contract requirements. Samples of the hot asphalt concrete are 

taken from the mat prior to compaction and tested to ensure compliance with the contract. In 

addition, core samples are taken from the completed pavement and tested to verify appropriate 

compaction has been obtained.

Complete evaluation of the control strip is essential to ensure that the produced hot asphalt 

concrete follows the established job-mix formula. Testing of the asphalt mixture samples verify 

that the hot plant is producing specification material. Density measurements are used in 

conjunction with various roller patterns, speeds, and passes to achieve a specified minimum 

compaction sufficient for a quality pavement. Corresponding mixing and placing temperatures 

are also measured.

It is also important to use the control strip density results to correlate the nuclear gauge. Prior to 

cutting the cores, nuclear gauge readings should be taken at the same location as the core 

samples. It is advantageous to obtain multiple gauge readings at the core location, preferably at 

right angles to each other, to verify the density value provided by the nuclear device. Once the 

core density values have been obtained, they can be compared to the nuclear gauge readings 

and a correlation established. This correlation factor will then be used during production to 

monitor the actual density being achieved. Nuclear gauges provide density data however without 

proper correlation this data can be misleading. For example, even though the nuclear gauge data 

indicates that the proper density has been achieved; in actuality the density values obtained by 

testing cores may indicate failing results. Since nuclear gauge readings do not always provide 

accurate density values, it is always necessary to verify their readings with actual density values 

obtained from pavement cores. Proper use of the nuclear gauge for monitoring density during lay 

down operations can only be accomplished through correlation to core density.

The contract provides criteria for the acceptance of a control strip. A control strip is required at 

the beginning of hot asphalt concrete production prior to full production activities, when material 

is being produced from a different plant or when resuming production after a terminated lot. Once 

a control strip has been accepted, full production can begin.

4.3.3 Full Production Operations

Placing, finishing and compacting the hot asphalt concrete needs to follow the same process that 

was established during control strip activities. The mixture should be mixed and placed at the 

temperature established during the start-up procedures. This needs to be continually monitored 

to maintain operational and finished product consistency.

Compaction of the mat needs to mimic operations established during start-up. Rollers should 

follow the same pattern, speed and number of passes used to obtain density of the control strip. 

The compaction operation needs to be monitored via contractor quality control personnel to 

maintain operational consistency. Correlated nuclear density readings established during start-
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-8 Construction Process

up will be an asset to help monitor density. Should density become difficult to achieve, 

comparisons between current operational practices and those used during production start-up will 

be helpful in troubleshooting the problem. 

During full production, samples of the mixture and binder will be taken by the contractor at 

randomly selected times or locations established by the Government in accordance with the 

frequency and sampling requirements of the contract. A Government representative witnesses 

sampling and sample splitting and takes possession of the Government’s samples. The results 

of these tests will be used to evaluate the quality of the material provided and determine the 

acceptance of work in accordance with Section 106. Binder samples are obtained according to 

AASHTO R 66 and will be sent to the FLH division laboratory for testing. See Exhibit 4-3 for 

example of asphalt binder sampling. Mixture samples obtained according to AASHTO R 97 will 

be split and tested by the contractor. The split sample will be provided to the Government for 

possible verification testing. See Exhibits 4-4, 4-5, 4-6 and 4-7 for a sequencing example of 

proper mixture sampling and splitting.

Exhibit 4-26 Sampling Asphalt Binder
Division 400: Asphalt Pavements and Surface Treatments January 2020

Construction Process 4-9

Exhibit 4-27 Placing Separator for Obtaining Mixture Sample

Exhibit 4-28 Obtaining Mixture Sample Prior to Compaction
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-10 Construction Process

Exhibit 4-29 Splitting the Uncompacted Mixture Sample
Division 400: Asphalt Pavements and Surface Treatments January 2020

Construction Process 4-11

Exhibit 4-30 Quartering the Mixture Sample to Obtain the Proper Split

The mixture sample is obtained from behind the paver prior to compaction. This sample location 

is critical in evaluating the quality of the mixture after final placement. Any mishandling or 

segregation will be discovered based on samples taken at this location. When obtaining a sample, 

it is critical to obtain the material throughout the full depth of the lift being paved. Care should be 

taken to avoid contamination from the underlying material and the loss of any fines that may cling 

to sampling equipment.

As with the testing of aggregate samples, asphalt mixture samples need to be reduced to the 

proper testing size. AASHTO R 97 provides guidance on the minimum field sample sizes that 

constitute an appropriate field mixture sample. From this original field sample, a smaller 

representative testing sample can be obtained. Asphalt mixture samples should be split and 

reduced in a manner similar to AASHTO R 47. The size of the testing sample varies according 

to the test method; each specific test method will list the size of the testing sample required. See 

Exhibit 4-8 for example of technique in reducing field sample to testing size.
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-12 Construction Process

Exhibit 4-31 Reducing Mixture Sample to Testing Size

The density of the placed mat will be determined based on 6-inch (150-mm) diameter core 

samples obtained from the compacted cooled pavement. The core samples will be tested by the 

contractor and then provided to the Project Engineer. Some of these cores will be sent to the 

FLH division laboratory for verification testing. When cutting, removing, handling or shipping 

asphalt cores, extreme care needs to be taken not to damage the core sample. If any damage 

has occurred, the core should be discarded and a new sample obtained because the damaged 

core will not be representative of the completed mat. If the core contains more than one pavement 

layer, it is recommended that the layers be separated by sawing to minimize possible damage 

prior to testing. See Exhibits 4-9, 4-10 and 4-11 for examples of cutting, removing and sawing 

asphalt cores.

Exhibit 4-32 Cutting Core
Division 400: Asphalt Pavements and Surface Treatments January 2020

Construction Process 4-13

Exhibit 4-33 Proper Core Removal Device

Exhibit 4-34 Sawing to Separate Pavement Layers

4.3.4 Pavement Smoothness

Once project paving has been completed, the final surface will be measured for smoothness. The 

smoothness measurement may follow two different methods including international roughness 

index (IRI) or straight edge measurement. The contract documents will define the method to be 

used on the project. Typically there will be incentive or disincentive payments associated with 

the final pavement smoothness measure. If the project is 3-R type project, these pay adjustments 

may be based on the percent improvement in the smoothness measurements from the original 

surface condition compared to the final paved surface.

Contract documents will specify any corrective action that may be performed by the contractor to 

improve defective areas. It is important to note in the contract the definition of a defective area 

and the allowed methods for correction. Contact the Division Materials Engineer should you have 

questions regarding smoothness measurement for the specific contract.
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-14 Construction Process

4.3.5 Other Types of Asphalt Mixtures

The most common mixture type used throughout FLH divisions is dense-graded hot asphalt 

concrete; however other mixture types are sometimes used. Some of these mixtures include:

• Open-graded friction course

• Open-graded hot mix

• Open-graded emulsified asphalt mixture

• Dense-graded emulsified asphalt mixture

These mixture types do not have the same aggregate or mix design requirements as densegraded hot asphalt concrete mixtures. Additionally, the mix design methods and requirements 

have not been formalized into nationally recognized standards. Design methods and 

requirements for these mixtures can be found in FHWA Technical Advisories, Asphalt Institute 

publications and State DOT test methods. 

The composition and submittal requirements for these materials are very similar to those for 

dense-graded hot mix. Job-mix formulas need to be submitted prior to production. Along with the 

job-mix formula, materials used in the mixture should be submitted to the FLH division laboratory 

for evaluation and verification. In most instances, there is a 21-day evaluation process to review 

the quality of the materials and verify the job-mix formula submitted. The Project Engineer should 

review the contract and have an understanding of the processes involved for the use of these 

materials. If questions arise, contact the Division Materials Engineer for clarification and 

guidance.
Division 400: Asphalt Pavements and Surface Treatments January 2020

Surface Treatments 4-15

4.4 SURFACE TREATMENTS

Surface treatment is a broad term used to describe several types of asphalt and asphaltaggregate applications placed directly on a finished roadway surface. These applications are 

relatively thin, typically less than 1 inch (25 mm), and can be applied to paved surfaces or finished 

granular bases.

4.4.1 Single or Multiple-Course Chip Seals

Chip seals involve spraying an asphalt product directly on the roadway surface immediately 

followed by a uniform application of aggregate, often referred to as “chips”. When the asphalt 

cures (breaks), it will develop adhesive strength to hold the aggregate in place. For multiplecourse chip seals, this process is repeated a second time with smaller sized aggregates used on 

successive applications. The completed product will provide an all-weather driving surface, 

improved skid resistance, moisture barrier and a uniform appearance. Exhibits 4-12, 4-13 and 4-

14 show the construction process and completed sealed surface.

Exhibit 4-35 Chip Seal Aggregate Placement

Exhibit 4-36 Close-up of Placement
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-16 Surface Treatments

Exhibit 4-37 Completed Chip Seal Surface

Since the aggregate will be directly exposed to traffic and weather, it is imperative that it meet the 

quality and gradation requirements. Aggregate quality and gradation test results should be 

provided by the contractor prior to incorporating the aggregate into the work. The Government 

may request that split samples be obtained and tested by the FLH division laboratory to verify the 

aggregate quality. The gradation of the aggregate is critical to performance. The aggregate 

needs to be uniform (i.e., the majority of the aggregate is all the same size), clean (a minimal 

amount of material passing the No. 200 (75 μm) sieve), angular (minimal amount of round 

aggregate) and cubical (a minimal amount of flat and elongated pieces). The aggregate 

application rate established should provide uniform coverage of the surface at a depth equal to 

the maximum particle size. If too much aggregate is placed, it will not be embedded in the asphalt 

and will be wasted. Over application of aggregates may cause embedded aggregate to break 

loose.

Asphalt for the chip seal may either use a paving-grade asphalt binder or an asphalt emulsion to 

adhere the rock to the surface. Regardless of what asphalt product is specified, the product 

should meet the contract specifications. The application temperature and rate should be 

established prior to placement operations.

Aggregate and asphalt samples should be submitted to the FLH division laboratory according to 

the contract. Laboratory testing will verify the quality and gradation of the materials as well as 

provide information for the initial application rates of aggregate and asphalt.

4.4.2 Fog Seal

A fog seal is a light application of emulsified asphalt that has been diluted with water and applied 

directly to an asphalt surface. The application rate depends largely on the texture of the existing 

pavement; the more open the surface the heavier the application. The FP provides a range of 

application rates and short test sections should be performed to verify and adjust as necessary 

the specified application rate. Once allowed to penetrate the surface, cure and break, traffic may 

be allowed on the surface. In the instance that excess asphalt is not absorbed into the surface, 

blotter material may be used to cover and prevent tracking due to vehicles. 

Contract specifications will provide sampling and testing requirements for the emulsified asphalt. 

Typically, the material will be accepted by certification under Subsection 106.03; however, in 
Division 400: Asphalt Pavements and Surface Treatments January 2020

Surface Treatments 4-17

instances where a large quantity is being supplied, the quality of the material will be verified by 

Government testing. Exhibit 4-15 shows proper application of a fog seal.

Exhibit 4-38 Fog Seal Application

4.4.3 Slurry Seal and Micro-Surfacing

Slurry seal or micro-surfacing is a mixture of aggregate/sand, emulsified asphalt, fillers, and other 

additives that is applied as a thin surfacing on an existing pavement. These treatments do not 

increase the structural strength of the existing pavement section but are used to generally protect 

and improve the existing driving surface. 

Slurry seals and micro-surfacing mixtures follow a mix design process to provide a job-mix formula 

that meets the contract requirements. Although these design methods are not as complex as for 

dense-graded hot mix, it is necessary that the mixture conform to these requirements. The 

contract documents define the methods to follow for the composition of the mix. The contractor 

must submit the job-mix formula and material components for approval prior to production. The 

Project Engineer should review the documentation to ensure compliance to the specification. In 

addition, the material samples should be submitted to the FLH division laboratory to verify 

compliance to the material specifications. If there are questions regarding material quality or the 

job-mix formula documentation, the Project Engineer should consult the Division Materials 

Engineer for guidance. 

4.4.4 Prime Coat

Prime coats are constructed similarly to fog seals with the exception that they are placed on an 

aggregate surface. Emulsified asphalts are used in construction; however, cut-back asphalts 

were traditionally used in the construction of prime coats. Oftentimes, prime coats are covered 

with blotter material to minimize damage caused by traffic due to picking of the surface. 

Contract specifications will provide sampling and testing requirements for the emulsified asphalt. 

Typically, the emulsified asphalt and blotter will be accepted by certification under Subsection 

106.03.
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-18 Roles and Responsibilities

4.5 ROLES AND RESPONSIBILITIES

4.5.1 Contractor’s Responsibilities

The contractor is responsible for constructing the asphalt pavement layers, surface treatments 

and recycled layers to meet the requirements provided in the contract. As part of these

requirements, the contractor is to control the quality of the materials provided and the construction 

process to ensure compliance. The contractor’s submitted quality control plan should address 

sampling, testing, and inspection work that will be accomplished to check and validate the quality 

of material components that will be supplied.

Asphalt pavements and surface treatments require that the material components meet the 

specifications and that the finished product conforms to contract specifications. For example, the 

contractor needs to verify that the individual material components produced or supplied meet the 

material requirements for hot asphalt concrete pavement and that when combined and placed 

these materials will meet the mixture and finished product requirements. The responsibilities for 

quality cover three general areas; individual supplied material (i.e., asphalt binder, aggregate, 

etc.), combined material requirements (i.e., job-mix formula, etc.), and finished product (i.e., 

density, smoothness, etc.). In general, the sampling and testing responsibilities of the contractor 

include:

• Sampling material to be tested according to the proper sampling methods.

• Providing split samples to the Government when required or requested.

• Quality control of aggregate production to ensure compliance with specifications.

• Proper submittals for job-mix formulas and mix designs including contractor supplied 

stockpile gradations, aggregate blends and target values for percent passing each 

specified sieve size.

• Providing split samples for mix design verifications.

• Monitoring the production of material to ensure compliance with specifications.

• Monitor construction processes as appropriate and have documented test results to verify 

quality of construction.

• Final in-place testing of finished product according to contract requirements.

• Providing appropriate certifications for materials.

The contractor needs to provide information and test results according to the timeframes stated 

in the contract. Distribution of the test reports or certifications should be according to the contract 

documents and the established quality control plan.
Division 400: Asphalt Pavements and Surface Treatments January 2020

Roles and Responsibilities 4-19

4.5.2 Government’s Responsibilities

The Project Engineer or designated representative will review the test results and certifications 

for contract compliance. A decision regarding the acceptance of the material will be made in 

accordance with Subsection 106.01

The Project Engineer or designated representative will be present to witness all required split 

samples taken for the Government. This is critical for not only acceptance samples but also for 

samples submitted for the purpose of mix design verification. Upon completion of splitting, the 

samples will be secured and immediately placed in Government control. The Project Engineer 

needs to be aware of the contractor’s operations and be available to witness the sampling and 

splitting activities.

Many of the material requirements for asphalt pavements and surface treatments require various 

points of acceptance throughout the construction process. In addition, there are also production 

start-up procedures that need to be completed prior to beginning full production activities. Some 

of the general responsibilities of the Project Engineer for these various stages of construction 

include:

• Reviewing aggregate quality test results and/or obtain Government samples for source 

approval testing.

• Obtaining proper mix design submittals and provide split samples to the FLH division 

laboratory for mix design verification.

• Reviewing quality control data to ensure compliance with contract requirements during 

production.

• Ensuring pre-work conferences occur and are attended by the appropriate people.

• Being aware of the time requirements in the contract for mix design submittals and 

verifications processes.

• Reviewing contractor’s quality control plan to ensure compliance with contract 

requirements. Verify that the testing technicians are qualified to perform the testing 

specified in the contract. Request proficiency samples from the Division Materials 

Engineer as needed to confirm contractor personnel competency and proper functioning 

equipment.

• Reviewing test methods, equipment and protocols with contractor testing personnel. Verify 

that contractor supplied testing equipment has been properly checked, standardized, 

calibrated and/or verified in accordance with the applicable testing standard.

• Obtaining proper product certifications prior to incorporating material into the work.

The Project Engineer should review and be familiar with the contract requirements for the material 

used in pavements and surface treatments and the testing required. Testing verifies that the 

material is suitable for use in the work and may be constructed according to the contract 
Division 400: Asphalt Pavements and Surface Treatments January 2020

4-20 Roles and Responsibilities

documents. If in doubt regarding material testing or requirements, consult the Division Materials 

Engineer.
Division 400: Asphalt Pavements and Surface Treatments January 2020

Material Certifications 4-21

4.6 MATERIAL CERTIFICATIONS

Exhibit 4-16 provides guidance for certifications that may be required. Certifications need to be 

in conformance with the contract requirements as provided in Subsection 106.03.

It should be noted that materials accepted by certification may be either a production or 

commercial certification according to Subsection 106.03 of the FP. The Project Engineer should 

review the contract requirements to ensure that the proper certifications have been submitted.

Exhibit 4-39 Materials Certifications

Section Description Material Frequency

Certification Sample

401, 402, and 

403

Hot asphalt 

concrete 

additives

Mineral filler

Antistrip additive

Recycling agent

Warm mix additive

1 per source or 

shipment Upon request

405

Open-graded 

asphalt friction 

course additive

Mineral filler

Antistrip additive

1 per source or 

shipment Upon request

406 Fog seal Emulsified asphalt 1 per shipment Upon request

409 Micro surfacing Mineral filler 1 per source Upon request

410 Slurry seal Mineral filler 1 per source Upon request

411 Asphalt prime 

coat

Blotter

Emulsified asphalt

1 per source or 

shipment Upon request

412 Asphalt tack 

coat Emulsified asphalt 1 per shipment Upon request

414

Asphalt crack 

sealing and 

filling

Joint sealant

Crack filler 1 per shipment Upon request

415 Paving 

geotextiles

Geotextile material 1 per shipment Upon request

418

Asphalt 

concrete 

pavement 

patching

Geotextile material

Geogrid material 1 per shipment Upon request

Division 400: Asphalt Pavements and Surface Treatments January 2020

Form References 4-1

4.7 FORM REFERENCES

Form references for use in the testing of soils and subgrade materials.

• Form FHWA 1600C – Request for Laboratory Tests (CFL)

• Form FHWA 1600E – Request for Laboratory Tests (EFL)

• Form FHWA 1600W – Request for Laboratory Tests (WFL)

• Form FHWA 1607 – Hveem mix design worksheets

• Form FHWA 1611 – Bulk specific gravity of compacted mixtures worksheet

• Form FHWA 1622 – Marshall mix design worksheets

• Form FHWA 1628 – Maximum specific gravity of asphalt mixtures worksheet (flask)

• Form FHWA 1629 – Maximum specific gravity of asphalt mixtures worksheet (bowl)

• Form FHWA 1639 – Control of asphalt mixtures worksheet

• Form FHWA 1640 – Ignition furnace binder correction factor worksheet

• Form FHWA 1641 – Superpave mix design worksheet

• Form FHWA 1642 – Volumetric properties of Superpave asphalt concrete worksheet
Division 500 – Concrete January 2020

5-2 Summary and Description

CHAPTER 5

DIVISION 500 – CONCRETE

5.1 SUMMARY AND DESCRIPTION

Concrete is one of the most widely used building materials in the world and a primary component 

of many highway structures. It is used in many highway applications such as roadway surfacing, 

bridges, retaining walls, head walls, culverts, guardrails, anchors, and posts. Concrete is a 

composite material that consists of a binding medium within which are embedded particles or 

fragments of aggregate, usually a combination of fine and coarse aggregate. In portland cement 

concrete, the binder is a mixture of portland cement and water, with or without admixtures.

The material presented herein will focus primarily on structural concrete and minor concrete as 

denoted in the Standard Specifications for Construction of Roads and Bridges on Federal 

Highway Projects (FP). Shotcrete and other topics relating to the construction of structures will 

also be addressed. Generally, structural concrete is specified in a contract when load analysis 

(i.e. bridges, culverts, wall and foundations) is required and the total concrete mixture quantity is 

greater than or equal to 50 yd3 (38 m3). Minor concrete is typically specified when load analysis 

is not required (i.e. headwalls, curb and gutter, sidewalks, waterways) and the total concrete 

mixture quantity is less than 50 yd3 (38 m3). The FP provides requirements for quality construction 

and materials that include: 

• Material Component Requirements

• Concrete Composition, Mixture Proportioning and Mix Design Approval

• Construction and Materials Acceptance
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-3

5.2 CONCRETE MATERIALS SPECIFICATIONS

Concrete is typically composed of the following basic materials:

• Hydraulic cement

• Mineral admixtures (i.e. fly ash, silica fume, ground granulated blast furnace slag)

• Water

• Aggregates (coarse and fine)

• Chemical admixtures (i.e. air entraining, water reducing, set retarding, etc.) 

• Fibers

The standard specifications typically used for each of these basic materials are shown in Exhibit 

5-40. Both AASHTO and ASTM standards have been developed for most concrete materials. 

Exhibit 5-40 shows both the AASHTO and ASTM materials standards. Although both standards 

have been listed for ready reference and comparative purposes, their individual requirements may 

differ in some circumstances. It should be noted that contract specifications will state the 

standards that are applicable for a given construction project and also may provide additional 

requirements which supplement the AASHTO/ASTM specifications.

Exhibit 5-40 Concrete Material Specifications

Material Component Test Method

Hydraulic Cement:

Portland Cement

Blended Hydraulic Cement

AASHTO M 85

AASHTO M 240

Pozzolans and Mineral Admixtures:

Fly Ash

Ground granulated blast furnace slag

Silica Fume (microsilica)

AASHTO M 295, Class C or F

AASHTO M 302, Grade 100 or 120

AASHTO M 307

Water AASHTO M 157

Aggregates:

Coarse Aggregates

Fine Aggregates

AASHTO M 80, Class A with 

amendments

AASHTO M 6, Class B with 

amendments

Chemical Admixtures:

Air-entraining

Water-reducing and set-controlling

Concrete Coloring

AASHTO M 154

AASHTO M 194

ASTM C979

Fibers

Fibrillated polyolefin

Steel

ASTM D7508

ASTM A820
Division 500 – Concrete January 2020

5-4 Concrete Materials Specifications

The basic material types used to proportion a concrete mixture are hereafter discussed on an 

individual basis in association with their materials standards. The benefits of using each of these 

material types as well as the potential constructability issues are also addressed.

5.2.1 Hydraulic Cement

Hydraulic cement is defined as cement that sets and hardens by chemical interaction with water 

and is capable of doing so underwater. Both portland cement and blended cement are considered 

hydraulic cements, however, the physical and chemical properties of each are governed by 

different materials specifications indicated in Exhibit 5-40.

5.2.1.1 Portland Cement

Portland cement is hydraulic cement produced by pulverizing portland-cement clinker, usually in 

combination with calcium sulfate. It exhibits a specific gravity of about 3.15. The typical material 

standard used for portland cement is AASHTO M 85. There are eight types of portland cement 

that are currently specified, namely types I, IA, II, IIA, III, IIIA, IV and V. Typically only types I, II 

or V are used; however, special contracts requirements may specify others (i.e. type III cement 

for prestressed concrete applications).

Type I cement is the most common and is known as general use cement. Type II is also general 

use cement that provides moderate sulfate resistance and moderate heat of hydration. Type V 

cement provides high sulfate resistance. The “A” suffix after the type designation denotes airentraining cement so type I cement is non air entraining whereas type IA cement is air entraining. 

In lieu of utilizing air-entraining cement, a concrete mixture can be air entrained by use of a 

chemical admixture (i.e. air entraining agent).

AASHTO M 85 details standard chemical composition and physical properties requirements for 

each cement type as well as the applicable test methods used for evaluation. In addition, 

allowable optional provisions and their associated chemical and physical requirements are also 

included. The contract specifications will state any optional provisions that have been included as 

part of the material requirement. Consult the Division Materials Engineer for additional 

information. 

5.2.1.2 Blended Cement

Blended cement is a hydraulic cement consisting essentially of a uniform blend of: 

• Granulated blast-furnace slag and hydrated lime

• Portland cement and granulated blast-furnace slag

• Portland cement and pozzolan

• Portland blast-furnace slag cement and pozzolan.

It is produced by: 

• Intergrading portland cement clinker with blast furnace slag, fly ash or silica fume
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-5

• Blending portland cement with finely ground blast furnace slag, fly ash or silica fume

• By a combination of intergrinding and blending.

AASHTO M 240 is the standard specification for blended hydraulic cement. It is used in a fashion 

similar to portland cement. There are four general types of blended hydraulic cements:

• Type IS – Portland blast-furnace slag cement,

• Type IP – Portland-pozzolan cement,

• Type IL – Portland-limestone cement,

• Type IT – Ternary blended cement.

The physical and chemical requirements for various compositions of blended hydraulic cement 

are covered in AASHTO M 240. Special properties can be specified by adding various suffixes 

to the blended cement selected. Special properties are denoted as:

• (A) – Air-entraining

• (LH) – Low heat of hydration

• (MH) – Moderate head of hydration

• (MS) – Moderate sulfate resistance

• (HS) – High sulfate resistance

• (R) – Resistance to alkali-silica reaction

AASHTO M 240 details standard chemical composition and physical properties requirements for 

each blended cement type as well as the applicable test methods used for evaluation. In addition, 

allowable optional provisions and their associated chemical and physical requirements are also 

included. As was the case with portland cement, contract specifications will include references to 

optional provisions should they apply. Consult the Division Materials Engineer for additional 

information. 

Blended cements can be used as the only cementing material in concrete or they can be used in 

combination with other supplementary mineral admixtures, which are added at the batch plant. If 

the blend consists of a proportion of fly ash or slag, blended cements can develop lower early 

compressive strength, up to 28 days, when compared to an equivalent weight of portland cement 

alone. If the blend consists of a proportion of silica fume, blended cements can develop higher 

compressive strengths, up to 28 days, when compared to an equivalent weight of portland 

cement. A comparison of portland cement types and their associated options is shown in Exhibit 

5-41.
Division 500 – Concrete January 2020

5-6 Concrete Materials Specifications

Exhibit 5-41 Portland and Blended Hydraulic Cement Comparison

Cement 

Specification

General 

Use

Moderate 

Sulfate 

Resistance

Moderate 

Heat of 

Hydration

High Early 

Strength

Low Heat 

of 

Hydration

High 

Sulfate 

Resistance

ASR 

Resistance

AASHTO M 85 

Portland 

Cement

I II II(MH) III IV V Low Alkali 

Option

5.2.1.3 Hydraulic Cement Constructability Issues

When hydraulic cement and water are mixed, a series of chemical reactions begin that result in 

slump loss, setting, hardening, evolution of the heat of hydration and strength development. This 

overall process is referred to as cement hydration. The quantity of mixing water required to 

completely hydrate portland cement is a water-cementitious materials ratio of about 0.40 by 

weight. When chemical admixtures are used the water-cementitious materials ratio can be halved 

to as low as about 0.20. Cement fineness and chemical composition are the major characteristics 

of cement that influence rate of reaction and strength development.

Hydration of cement, however, is a temperature dependent process. When cured at room 

temperature about 70 °F (21°C), the final set of concrete is typically achieved in about 2 1⁄2 to 4 1⁄2 

hours and the specified compressive strength is normally reached in 28 days. Environmental 

conditions, which affect the temperature of the concrete mixture, therefore influence the behavior 

of cement. Since the time of set, the strength development and the temperature rise of concrete 

are all related to the hydration rate, these fresh and hardened concrete properties are influenced 

by the ambient temperature conditions present at the project site. Hydration rate proceeds very 

slowly below 40° F (4 °C) but increases rapidly with increasing temperature. As a rule of thumb, 

the rate of hydration doubles for each 18 °F (10 °C) increase in temperature and, conversely, is 

halved for each 18 °F (10 °C) decrease. It is of paramount importance that concrete is cured 

properly at the project site in conjunction with cold or hot weather conditions in order to achieve 

specified concrete strengths in a timely fashion. In this manner, construction processes which are 

dependent upon concrete strength (i.e. form removal, etc.) may also proceed.

Premature stiffening in fresh concrete and/or mortar is another issue of concern. Premature 

stiffening can occur as a result of false set or flash set. False set occurs as a significant loss of 

plasticity or slump without the generation of heat shortly after mixing. False set is caused by rapid 

crystallization of excess gypsum from the cement mill. Concrete that has undergone false set can 

be handled and placed without difficulty. Additional mixing breaks up the crystals and restores 

workability. It is not necessary or acceptable to add water to the mixture in this process. Flash set 

occurs as a rapid loss of workability with considerable generation of heat shortly after mixing. The 

plasticity cannot be regained by further mixing; only with the addition of water. Flash set is caused 

by a chemical imbalance in the cement. Concrete experiencing flash set should be rejected and 

the cement should be tested for conformance to specification requirements. A cement sample 

should be obtained and the Division Materials Engineer should be contacted for consultation and 

appropriate testing.

5.2.2 Mineral Admixtures / Pozzolans

Mineral admixtures, otherwise known as pozzolans, are siliceous or siliceous and aluminous 

materials that in themselves possess little or no cementitious value that will, in finely divided form 
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-7

and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures

to form compounds possessing cementitious properties. Pozzolans are both artificial and natural. 

Materials such as fly ash, ground granulated blast furnace slag and silica fume are artificial 

pozzolans. Raw or calcinated materials that possess pozzolanic properties such as volcanic tuffs 

or pumicites, opaline cherts, shales and clays are natural pozzolans. These mineral admixtures 

are finely divided inorganic materials that may be added to concrete to modify its performance 

and/or cost.

5.2.2.1 Fly Ash

Fly ash is a product from coal burning. It is defined as the finely divided residue that results from 

the combustion of ground or powdered coal and that is transported by flue gases from the 

combustion zone to the particle removal zone. It consists of solid and hollow, silt-sized glass 

spheres that are typically finer than portland cement or lime. Fly ash exhibits a tan to dark gray 

color and its specific gravity ranges from 1.9 to 2.8. 

AASHTO M 295 is the standard specification for fly ash and details standard chemical 

composition and physical properties requirements for each fly ash type as well as the applicable 

test methods used for evaluation. Fly ash is categorized into three classes based on its chemical 

composition as follows: 

• Class N is a raw or calcinated pozzolan that is not allowed by FP specifications.

• Class C or high calcium fly ash is derived from sub-bituminous coals. It possesses a free 

lime (CaO) content in excess of 20 percent and as such has some cementitious (i.e. 

strength gaining) properties in and of itself.

• Class F or low calcium ash is derived from bituminous and anthracite coals. It possesses 

less than 10 percent free lime (CaO) and as such has very little cementitious properties in 

and of itself. Class F fly ash must be mixed with portland cement to serve as a cementing 

material.

Concrete made with class F fly ash and portland cement will typically gain compressive strength 

at a slower rate than concrete made with an equivalent weight of portland cement up to 28 days 

age. However, at later ages, the strength of concrete made with the class F fly ash will be greater. 

Concrete made with class C fly ash wherein the portland cement is replaced at a proportion of 

one part fly ash to one part cement typically exhibits a 28 day strength equal to or greater than 

concrete containing an equivalent weight of portland cement without fly ash. However, concrete 

made with class C fly ash will likely not show the later age strength gain typical of concrete made 

with class F fly ash, although strength gain will continue to occur over that of portland cement 

alone. 

The FP limits the amount of fly ash that can be used in concrete mixtures. Not more than 25

percent of the total cementitious materials can be fly ash or other pozzolans. 

5.2.2.1.1 Fly Ash Benefits

The benefits of incorporating fly ash into a concrete mixture include:
Division 500 – Concrete January 2020

5-8 Concrete Materials Specifications

• Increased workability – Spherical shaped particles act as ball bearings and produce a 

lubricating effect providing improved pumping, reduced bleeding and enhanced flat work 

finishing.

• Decreased water demand – Replacement of portland cement with fly ash reduces the 

water demand. When 20 percent of the cement weight is replaced with fly ash, the water 

demand is reduced about 10 percent. Reductions of 5 to 10 percent are normal.

• Reduced heat of hydration – Replacing portland cement with fly ash typically reduces the 

overall temperature rise of concrete and the associated potential for temperature cracking.

• Increased long term strength.

• Reduced permeability and increased corrosion resistance.

• Improved resistance to sulfate attack – Class F fly ash is very effective. Class C ash is 

less effective.

• Improved resistance to Alkali-Silica Reactivity (ASR) – At least 15 percent of the 

cementitious material should be fly ash. Lower amounts may increase ASR.

5.2.2.1.2 Fly Ash Constructability Issues

Constructability issues which may arise as a result of using fly ash in a concrete mixture include:

• Lower early compressive strength – Strength gain of concrete containing fly ash is minimal 

in the colder months. Below 40°F (4° C) strength gain occurs at a very slow rate. Chemical 

admixtures may be used to partially offset this effect.

• Air entrainment – The use of fly ash in concrete usually requires a higher dose of air 

entraining agent to meet air requirements if the loss on ignition of the fly ash is greater 

than 3 percent. Use of Class F fly ash with high loss on ignition can cause difficulty in 

consistent air entrainment. Additionally, entrained air is lost more rapidly in conjunction 

with prolonged mixing or agitation. There can also be problems with fly ash compatibility 

with certain types of chemical admixtures.

• Time of set – Replacement of portland cement with fly ash will usually extend the concrete 

set time. Longer set times increase the potential for plastic shrinkage cracking and 

premature finishing (i.e. sealing bleed water under the top surface of the concrete thereby 

causing a plane of weakness).

5.2.2.2 Ground Granulated Blast-furnace Slag (GGBFS)

Blast-furnace slag is a product from iron and steelmaking. It is defined as the nonmetallic product 

consisting essentially of silicates and aluminosilicates of calcium and other bases that is 

developed in molten condition simultaneously with iron in a blast furnace. Ground granulated 

blast-furnace slag (GGBFS) is granulated blast-furnace slag that has been finely ground and is 

hydraulic cement. It is lighter in color than conventional concrete and exhibits a specific gravity 

ranging from 2.85 to 2.95. AASHTO M 302 is the standard specification for ground granulated 
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-9

blast-furnace slag. GGBFS is classified by performance in the slag activity test in three grades 

including grade 80, grade 100 and grade 120. The slag activity test compares the ratio of the 

compressive strength of slag and portland-cement mortar samples made with 50-50 weight 

combinations to equivalent weight samples made with portland cement only. This AASHTO 

standard details the chemical composition and physical properties requirements for each GGBFS 

grade as well as the applicable test methods used for evaluation. There are no supplementary 

optional provisions.

When using a blend of 50 percent GGBFS and 50 percent portland cement by weight, grade 100 

GGBFS typically exhibits a 28-day compressive strength equivalent to concrete made with an 

equivalent weight of portland cement only. Grade 120 GGBFS, however, normally shows reduced 

strength at early ages but increased strength at later ages (i.e. 7 days and beyond).

The FP allows the use of grades 100 and 120 GGBFS only. It further restricts the amount of 

GGBFS to no more than 50 percent of the total weight of the cementitious materials. Blends less 

than 50 percent of the total weight of cementitious materials may be desirable when higher early 

concrete strengths are required to facilitate quick form removal or when thin sections are placed 

at low temperatures. However, some of the GGBFS benefits noted below may be sacrificed. 

5.2.2.2.1 GGBFS Benefits

The benefits of incorporating GGBFS into a concrete mixture include:

• Increased workability.

• Decreased water demand – Reductions of 1 to 10 percent are common.

• Reduced permeability and increased corrosion resistance.

• Improved resistance to sulfate attack.

• Improved resistance to Alkali-Silica Reactivity (ASR).

5.2.2.2.2 GGBFS Constructability Issues

Constructability issues which may arise as a result of the using GGBFS in a concrete mixture 

include:

• Concrete color change - During the second to fourth days after casting, a blue-green 

surface color may appear which diminishes with age as oxidation occurs.

5.2.2.3 Silica Fume

Silica fume is a product from silicon metal refining. It is defined as very fine noncrystalline silica 

produced in electric arc furnaces as a byproduct of the production of elemental silicon or alloys 

containing silicon. Silica fume ranges from light to dark gray in color and generally exhibits a 

specific gravity ranging from 2.2 to 2.25; although its specific gravity can be as high as 2.5. In raw 

powdered form, silica fume is a very fine material, on the order of 100 times finer than portland 

cement. As such, it presents unique handling and safety concerns. Silica fume is therefore 
Division 500 – Concrete January 2020

5-10 Concrete Materials Specifications

available in four different forms, some of which are designed to minimize clogging of batch plant 

equipment and dust generation. The four forms are as follows:

• As produced silica fume – Available in bulk or bags as collected in raw powder form.

• Slurried silica fume – Available in slurry form, typically in a 50-50 blend of water and silica 

fume by weight. The water portion of the slurry counts as mixing water and should be 

compensated for in the water-cementitious materials ratio calculation. The slurry is 

available with and without chemical admixtures.

• Densified (compacted) silica fume – Available in compacted form where raw powder has 

been densified by mechanical means or by compressed air. The densified silica fume is 

available with and without chemical admixtures.

• Pelletized silica fume – Available in pellet form where raw powder has been mixed with a 

small portion of water. Pellets should not be used as a mineral admixture in concrete 

because they do not break down sufficiently or disperse properly.

AASHTO M 307 is the standard specification for silica fume. It details standard chemical 

composition and physical properties requirements as well as the applicable test methods used for 

evaluation. In the cases of slurried or densified silica fume, tests are performed on the raw material 

from which these products have been made.

Concrete in which a percentage of the weight of portland cement has been replaced with silica 

fume will exhibit 28-day compressive strengths higher, sometimes substantially higher, than 

concrete made with an equivalent weight of portland cement. However, the contribution of silica 

fume to strength development after 28 days is minimal.

The FP limits the amount of cementitious materials that may be replaced with silica fume. Not 

more than 10 percent of the total cementitious materials may be replaced with silica fume.

5.2.2.3.1 Silica Fume Benefits

The benefits of incorporating silica fume into a concrete mixture include:

• Substantially increased compressive strength up to 28 days age.

• Improved scaling resistance - At least 5 percent of the cementitious material should be 

silica fume.

• Excellent abrasion resistance

• Reduced permeability and increased corrosion resistance.

• Slightly improved resistance to sulfate attack.

• Improved resistance to Alkali-Silica Reactivity (ASR).

• Reduced heat of hydration 
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-11

5.2.2.3.2 Silica Fume Constructability Issues

Constructability issues which may arise as a result of the using silica fume in a concrete mixture 

include:

• Increased water demand – Water demand increases in proportion to the amount of silica 

fume used. In order to achieve the desired workability, permeability and strength, silica 

fume concrete must always be made with chemical admixtures consisting of a waterreducing admixture, a high range water-reducing admixture or both.

• Increased air entrainment admixture dosage requirements – In order to obtain the desired 

air content, admixture dosages must be increased in proportion to the amount of silica 

fume used.

• High slump – Due to the use of chemical admixtures, silica fume concrete typically exhibits 

a much higher slump than conventional concrete. Slumps on the order of 8 inches (200 

mm) are common and acceptable.

• Workability loss – Due to the use of chemical admixtures, the slump loss of silica fume 

concrete will occur much more rapidly than conventional concrete.

• High susceptibility to plastic shrinkage cracking – Bleeding does not occur for silica fume 

concrete. Therefore, when the surface water evaporates, it is not replenished by bleed 

water and the silica fume concrete is highly susceptible to plastic shrinkage cracking. The 

surfaces of freshly placed silica fume concrete must be protected from rapid water 

evaporation by proper curing as soon as is practicable after placement.

• Color - The color of silica fume concrete will be darker than conventional concrete.

5.2.2.4 Collective Mineral Admixture Limitation

As previously noted, the FP stipulates individual material limits regarding the maximum amount 

of portland cement that may be replaced with mineral admixtures of fly ash, ground granulated 

blast furnace slag and silica fume. In addition, when more than one mineral admixture is used in 

combination with portland cement, inclusive of blended cements, the collective combination of 

materials is also limited. These collective material limitations are applicable in very severe 

circumstances for concrete exposed to freezing and thawing and in continuous contact with 

moisture and exposed to deicing chemicals.

The FP has limitations on the individual and collective amount of supplemental cementitious 

materials for structural concrete and minor concrete and are summarized in Exhibit 5-42. 
Division 500 – Concrete January 2020

5-12 Concrete Materials Specifications

Exhibit 5-42 Maximum Cementitious Material Requirements

Supplemental Cementitious Materials

Maximum Percent 

of Total 

Cementitious 

Material by Weight

Fly ash or other pozzolans, AASHTO M 295 25

Slag (GGBFS), AASHTO M 302 50

Silica Fume, AASHTO M 307 10

Total of fly ash or other pozzolans, slag, and silica fume 50(1)

Total fly ash or other pozzolans and silica fume 35(1)

(1) Limit fly ash or other pozzolans to no more than 25 percent of the total mass of cementitious 

material and limit silica fume to no more than 10 percent of the total mass of cementitious 

material.

5.2.3 Water

Mixing water is defined as the water in freshly mixed sand-cement grout, mortar, or concrete, 

exclusive of any previously absorbed by the aggregate (for example, water considered in the 

computation of the net water-cement ratio). Almost any water that is drinkable can be used for 

mixing concrete. The standard specification for Ready-Mix Concrete is AASHTO M 157. This 

AASHTO standard listed as part of the requirements in the FP covers mixing and curing water 

requirements for concrete, irrespective of whether or not it is ready-mix concrete.

Although AASHTO M 157 stipulates that the quality of water to be used in concrete must be 

tested, the FP allows potable water of known quality to be used without testing. The definition 

applied to “potable water that is safe for human consumption” is noted in the FP as being provided 

by the public health authority having local jurisdiction. 

Water of questionable quality can be used for making concrete if it meets established 

requirements for sulfate content, alkali content, and total solids. In addition, fabricated mortar 

specimens made with this water must pass tests for compressive strength, time of set, and 

chloride content. The water and mortar tests that are used to evaluate these parameters as well 

as the parameter limitations are provided in AASHTO M 157. The component tested, the test 

methodology and the limits are summarized in Exhibit 5-43.
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-13

Exhibit 5-43 Water and Mortar Requirements for Questionable Water Source

Component Test Method Limits

Compressive strength AASHTO T 106* 90% min of control at 7 days

Time of set AASHTO T 131* From 1:00 earlier to 1:30 later deviation from 

control

Chloride as Cl(-1) ASTM D512 Prestressed concrete – 0.06%

Conventionally reinforced concrete in a moist, 

chloride exposed environment – 0.10%

Conventionally reinforced concrete in a moist 

environment, but not exposed to chloride –

0.15%

Above ground building construction where the 

concrete will stay dry – no limit

Sulfate as SO4** AASHTO T 290 3000 ppm

Alkalis as 

(Na2O+0.658 K2O)

AASHTO T 105 600 ppm

Total solids ASTM C1603 50,000 ppm

* Comparison shall be based on fixed proportions and the same volume of test water 

compared to control mix using water or distilled water.

** Wash water reused as mixing water in concrete may exceed listed concentrations of 

sulfate if it can be shown that the concentration calculated in the total mixing water, including 

mixing water on the aggregate and other sources, does not exceed the stated limits.

5.2.4 Concrete Aggregates

Aggregates are granular materials, such as sand, gravel, crushed stone, crushed hydrauliccement concrete or iron blast-furnace slag, used with a hydraulic cementing medium to produce 

either concrete or mortar. Fine and coarse aggregates occupy about 60 to 70 percent of concrete 

by volume and about 70 to 80 percent by weight.

5.2.4.1 Concrete Aggregate Gradation

Gradation is a measure of aggregate source quality, uniformity and consistency. The combined 

gradation from the fine and coarse aggregate is determined by a sieve analysis detailed in 

AASHTO T 27 and AASHTO T 11. The aggregate particle size is determined by using wire-mesh 

sieves with square openings. A laboratory sieve shaker is used to perform the analysis. Grading 

limits are specified to control aggregate proportions as well as cement and water requirements 

and overall concrete workability, durability and economy. Variations in grading can adversely 

affect the uniformity and quality of concrete from batch to batch. Very fine sands are often 

uneconomical in that they require high water contents to sustain mixture workability. Very coarse 

sands can produce harsh, non-workable mixtures. Aggregates that do not have a large deficiency 

or excess of any size produce the most satisfactory concrete.

5.2.4.2 Concrete Fine Aggregate

Concrete fine aggregate generally consists of natural sand or crushed stone (manufactured sand) 

or a combination of the two with particles smaller than the No. 4 (4.75 mm) sieve. Technically, 
Division 500 – Concrete January 2020

5-14 Concrete Materials Specifications

fine aggregate is defined as almost entirely passing the No. 4 (4.75 mm) sieve while being 

predominantly retained on the No. 200 (75 μm) sieve.

The FP requires fine aggregate source quality verification testing and states that fine aggregate 

must conform to AASHTO M 6, class B, including the reactive aggregate supplementary 

requirement as well as additional supplemental FP requirements. AASHTO M 6 is a very 

comprehensive material standard. It provides requirements for gradation, aggregate quality and 

uniformity of grading (fineness modulus). To provide guidance in the submittal of fine aggregate 

quality test data, the requirements for the aggregate are shown on form FHWA 1608. Aggregates 

not meeting all of the gradation requirements may still be used based on a satisfactory service 

record. If the gradation criteria are not met, consult the Division Materials Engineer for additional 

review to determine if acceptable performance can be documented. 

The test used to assess the uniformity of the fine aggregate grading is the fineness modulus. The 

fineness modulus is determined by summing the cumulative percent retained for each sieve size, 

excluding the No. 200 (75μm) sieve, and dividing the summation by 100. The list of sieves used 

for this calculation can be found in AASHTO T 27. An example illustrating the calculation of the 

fineness modulus is shown in Section 5.12.2 in this manual. 

The required fine aggregate source quality tests, test methods and aggregate characteristics have 

been summarized in Exhibit 5-44.
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-15

Exhibit 5-44 Fine Aggregate Source Quality Characteristics

Aggregate Test Test Method Aggregate Characteristic

Clay lumps and friable particles 

(Deleterious substance) AASHTO T 112 Injurious to workability and durability, may cause pop-outs. Increases water demand

Coal and Lignite

(Deleterious substance) AASHTO T 113 Affects durability, may cause stains and pop-outs

Materials finer than No. 200 

(75 μm) sieve 

(Deleterious substance)

AASHTO T 11

Injurious to bond, causes large increases 

in water demand

Organic Impurities

(Deleterious substance) AASHTO T 21 Injurious to setting and hardening, may cause deterioration

Sodium Sulfate Soundness, 

5-cycles AASHTO T 104 Measure of weathering resistance

Alkali-Silica Reactivity (ASR) ASTM C1260

ASTM C1567

ASTM C1293

ASTM C295

ASTM C856

Measure of ASR potential as well as 

effectiveness of mineral admixtures in 

ASR mitigation

5.2.4.3 Concrete Coarse Aggregate

Concrete coarse aggregate generally consists of gravel, crushed stone, crushed blast-furnace 

slag, crushed concrete or a combination of any of these materials with particles larger than the 

No. 4 (4.75 mm) sieve and mostly between 3/8 and 1 1⁄2 inches (9.5 and 37.5 mm). Technically, 

coarse aggregate is defined as being predominantly retained on the No. 4 (4.75 mm). The 

standard specification for coarse aggregate quality is AASHTO M 80 and the gradation 

requirements can be found in AASHTO M 43. The FP allows all AASHTO M 43 standard sizes 

except numbers 8, 89, 9 or 10.

The FP requires coarse aggregate source quality verification testing and states that coarse 

aggregate must conform to AASHTO M 80, class A, including the reactive aggregate 

supplementary requirement as well as additional supplemental FP requirements. To provide 

guidance in the submittal of coarse aggregate quality test data, the requirements for the aggregate 

are shown on form FHWA 1608. 

The required coarse aggregate source quality tests, test methods, and aggregate characteristics 

have been summarized in Exhibit 5-45.
Division 500 – Concrete January 2020

5-16 Concrete Materials Specifications

Exhibit 5-45 Coarse Aggregate Source Quality Characteristics

Aggregate Test Test Method Aggregate Characteristic

Clay lumps and friable particles

(Deleterious substance) AASHTO T 112 Injurious to workability and durability, may cause pop-outs. Increases water demand

Chert (lightweight pieces less 

than 2.4 specific gravity SSD)

(Deleterious substance) 

AASHTO T 113

Injurious to durability, may cause pop-outs

Materials finer than No. 200 

(75 μm) sieve

(Deleterious substance) 

AASHTO T 11

Injurious to bond, large increases water 

demand

Coal and Lignite

(Deleterious substance) AASHTO T 113 Affects durability, may cause stains and pop-outs

Los Angeles Abrasion AASHTO T 96 Measure of wear resistance and index of 

aggregate quality

Sodium Sulfate Soundness, 

5-cycles AASHTO T 104 Measure of weathering resistance

Mass of Insoluble Residue

for Bridge Decks and Surface 

Courses Only

ASTM D3042

Measure of wearing resistance of 

carbonate aggregates

Alkali-Silica Reactivity

(ASR)

ASTM C1260

ASTM C1567

ASTM C1293

ASTM C295

ASTM C856

Measure of ASR potential as well as 

effectiveness of mineral admixtures in ASR 

mitigation

5.2.4.4 Aggregate Tests Used During Concrete Mixture Proportioning

In order to meet the water requirement of the approved concrete mixture (i.e. to maintain the 

water-cementitious materials ratio), the FP requires the amount of water to be adjusted at the 

mixing plant on an ongoing basis to account for the existing moisture conditions of the aggregates. 

The fine and coarse aggregate tests needed to perform mixture proportioning adjustments as well 

as the definitions of the parameters measured are shown in Exhibit 5-7. Since these tests are 

performed to gather information for mixture adjustments only, testing limitation requirements are 

typically not specified.
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-17

Exhibit 5-46 Aggregate Tests Used During Concrete Mixture Proportioning

Parameter 

Measured Test method Definition

Bulk specific 

gravity AASHTO T 19

The ratio of the weight of dry aggregate to the weight of 

water having a volume equal to the volume of the aggregate 

including both its permeable and impermeable pores. 

Dry-rodded unit 

weight AASHTO T 19

Mass per unit volume of dry aggregate compacted by 

rodding under standardized conditions. Used to measure 

density of aggregate including aggregate and voids 

between aggregate particles.

Absorption AASHTO T 85 

(Coarse)

AASHTO T 84 (Fine)

The increase in the weight of aggregate due to water in the 

pores of the material, but not including water adhering to the 

outside of the particles, expressed as a percentage of the 

dry weight.

Bulk SSD 

specific gravity

AASHTO T 85 

(Coarse)

AASHTO T 84 (Fine)

The ratio of the weight of aggregate, including the weight of 

water it contains when its permeable voids are saturated, to 

the weight of an equal volume of water. 

Moisture 

content AASHTO T 255 The ratio of the weight of water lost in drying to the oven dry weight expressed as a percentage.

5.2.5 Chemical Admixtures

An admixture is a material other than water, aggregates, hydraulic cement, and fiber 

reinforcement, used as an ingredient of a cementitious mixture to modify freshly mixed, setting, 

or hardened properties and that is added before or during mixing. They are provided in liquid, 

suspension, or water-soluble solid forms. Chemical admixtures are used to reduce the cost of the 

concrete mixture, to increase the efficiency of cementitious materials, to achieve desirable fresh 

and hardened concrete properties, to maintain concrete quality during mixing, transporting, 

placing and curing and to overcome construction emergencies (i.e. slump loss). 

When admixtures are employed in a concrete mix design, it is imperative that trial mixtures be 

conducted to evaluate their compatibility with one another as well as their compatibility with 

mixture materials. Admixture effects on fresh and hardened concrete properties should be 

determined. The trial mixtures should be conducted at temperatures and humidity levels as close 

as possible to conditions anticipated at the project site. Admixture dosage rates should be within 

the ranges recommended by the admixture manufacturer and at the optimums determined by trial 

mixture evaluations.

5.2.5.1 Air-entraining Admixtures

Air-entraining admixtures are used to develop a system of uniformly dispersed microscopic air 

bubbles in the cement paste. These bubbles serve to improve freeze-thaw and deicer scaling 

resistance as well as to enhance concrete workability, reduce water demand and minimize 

segregation and bleeding. AASHTO M 154 is the standard specification for air entraining 

admixture. It details physical properties requirements as well as applicable test methods used for 

evaluation. In addition, allowable optional provisions for uniformity are also included. Airentrainment in a concrete mixture is produced by liquid admixture during mixing, by use of airentraining cements or by a combination of both methods. Too little air will result in minimal benefits 

whereas too much air can have detrimental effects on other concrete properties.
Division 500 – Concrete January 2020

5-18 Concrete Materials Specifications

5.2.5.2 Water-reducing and Set-controlling Admixtures

AASHTO M 194 is the standard specification for water-reducing, set-controlling, and hydration 

stabilizing admixtures. It details physical properties requirements as well as applicable test 

methods used for evaluation. It further defines seven different types of admixtures consisting of 

the following:

• Type A – water-reducing

• Type B – set retarding

• Type C – set accelerating

• Type D – water-reducing and set retarding

• Type E – water-reducing and set accelerating

• Type F – water-reducing, high range

• Type G – water-reducing, high range, and set retarding

As the names and types imply, water-reducing and set controlling admixtures reduce the water 

requirements of a concrete mixture for a given slump and/or modify the time of setting or both. 

Set retarding admixtures, inclusive of types B, D and G, are used to delay the effects of high 

ambient temperatures in accelerating concrete set time such that the mixture is kept workable 

during placement.

Extended set-control admixtures or hydration stabilizers meet the technical requirements for types 

B and D admixtures although they differ from conventional set-retarding admixtures in that they 

stop the cement hydration process altogether. Thus, they are specified separately in the FP but 

will typically meet the requirements of AASHTO M 194. Hydration stabilizers are used to maintain 

concrete in a stabilized, non-hardened state during long hauls. The stabilizer is added during or 

immediately after initial batching and is adjusted so that the setting time of the concrete is 

extended for the duration of the haul. If the concrete remains in a stabilized state after arrival at 

the job site, an activator can be added to facilitate normal hydration and setting. When hydration 

stabilizers are used, the FP limits the maximum allowable discharge time to 3 1⁄2 hours. The design 

discharge limit and associated admixture dosage should be included in the concrete mix design 

submittal. 

Set accelerating admixtures, inclusive of types C and E, are used to accelerate the rate of set and 

strength development of concrete at an early age. Calcium chloride can be used in this admixture 

which can cause corrosion of reinforcement steel. For this reason, chloride accelerators are 

prohibited by the FP. Set accelerating admixtures are also prohibited for use with class P 

(prestressed) concrete. 

Water-reducing admixtures are used to reduce the water to cementitious materials ratio and 

consequently produce higher strengths at lower cement contents. They are also used to provide 

workability by increasing slump without increasing water content. Normal water reducing 

admixtures, inclusive of types A, D and E, typically reduce the water content about 5 to 10 percent. 
Division 500 – Concrete January 2020

Concrete Materials Specifications 5-19

Concrete made with these admixtures commonly exhibits a slump around 4 inches (100 mm) with 

a slump loss of about 3 inches (75 mm) in 2 hours. High range water reducing admixtures or 

superplasticizers, inclusive of types F and G, reduce the water content from 10 to 30 percent. 

Concrete exhibiting slumps of 6 to 7 inches (150 to 175 mm) can be produced with water content 

reductions ranging from 10 to 15 percent. Flowing concrete, which exhibits a slump greater than 

7 1⁄2 inches (190 mm) while remaining self leveling and cohesive, is also typically made with the 

aid of high range water reducing admixtures. Slump loss of concrete made with these admixtures 

can be very rapid and occur at a rate of about 3 to 4 inches (75 to 100 mm) per hour. Some 

admixtures are marketed as midrange water reducing admixtures, although there is no such 

classification. These admixtures typically meet type A requirements and provide up to 12 percent 

water reduction without delaying the setting time of concrete.

5.2.5.3 Concrete Coloring Admixtures

Concrete coloring admixtures are used to color concrete for aesthetic and safety purposes. ASTM 

C 979 is the standard specification. Coloring pigments should normally not exceed 10 percent by 

weight of cementitious material. Before a coloring admixture is used on a project, its historical 

performance should be checked for color fastness in sunlight, chemical stability in cement and 

non-detrimental effects on concrete properties.

5.2.5.4 Miscellaneous Admixtures

Many miscellaneous admixtures are available for use in concrete. They include corrosion 

inhibitors, shrinkage reducers, alkali-silica reactivity inhibitors and pumping aids to name a few. 

As is the case for all admixtures, they must be compatible with other ingredients of the concrete 

mixture and pre-approved prior to use.

5.2.6 Fibers

Fibers are long and slender filaments with lengths typically ranging from 1⁄4 inch to 6 inches (6 to 

150 mm) and thicknesses ranging from 0.001 to 0.2 inches (0.025 to 5 mm). Fibers are added to 

the concrete during mixing to provide resistance to tensile and flexural stresses in the concrete. 

They do not affect drying shrinkage but increase the resistance to cracking as well as decrease 

crack width. Fibers are typically added in low volume dosages ranging from less than one to 2 

percent. The standard specification covering fiber reinforced concrete is ASTM C1116. It allows 

three types of fibers including steel, glass and synthetic.

• Steel fibers may be stainless, alloy, or carbon steel in composition. Steel fibers only slightly 

affect concrete compressive strength but can dramatically increase tensile and flexural 

strengths. Steel fibers are used in airport and highway pavements, bridge decks and 

floors.

• Glass fibers are designed to be alkali-resistant in that they have the potential to react with 

alkalis in the cement paste when exposed to humid or moist environments. Such a reaction 

can cause reductions in concrete properties including strength, toughness and impact with 

age. They have been primarily used in the exterior panels of buildings.

• Synthetic fibers are man-made products such as polyolefins (polypropylene and 

polyethylene) as well as acrylic, aramid, carbon, nylon and polyester. They are used to 
Division 500 – Concrete January 2020

5-20 Concrete Materials Specifications

reduce plastic shrinkage and subsidence cracking. Polypropylene fibers have been used 

in bridge decks, pavements, low water crossing and other applications where plastic 

shrinkage cracking may be a concern.

The use of fibers and the requirements for the mixture will typically be stated in the special contract 

requirements for a project.
Division 500 – Concrete January 2020

Concrete Materials Acceptance Requirements 5-21

5.3 CONCRETE MATERIALS ACCEPTANCE REQUIREMENTS

5.3.1 Materials Certification Acceptance

Proper materials certifications pertaining to each applicable material type and source must be 

obtained by the Project Engineer and retained in project files. As part of the process for approving 

a Contractor’s mix design, representative certifications should be submitted to the Division 

Materials Engineer for review and recommendation for approval along with the concrete mix 

design, form FHWA 1608. The FP requires hydraulic cement production certifications for 

structural concrete, prestressed concrete, shotcrete and minor concrete. For a discussion and 

explanation of commercial and production certification requirements, see Division 100, Section 

1.1.2. Also, individual materials standards that have been specified in the contract should be 

referenced. They set forth additional detail pertaining to Contractor submittal of valid manufacturer 

certifications including required statements, test data and frequency. Certifications must be signed 

and dated as well as certify that the specified requirements of applicable standards and project 

specific special contracts requirements have been met. Exhibit 5-47 summarizes individual 

concrete materials requiring manufacturer certifications as required in the FP in conjunction with 

the applicable materials standard to which they must be certified.

Exhibit 5-47 Required Concrete Material Certifications

Material Test Method Frequency

Hydraulic Cement:

Portland Cement

Blended Cement

AASHTO M 85

AASHTO M 240

1 per shipment

1 per shipment

Mineral Admixtures:

Fly Ash

Ground granulated blast furnace slag

Silica Fume (microsilica)

AASHTO M 295

AASHTO M 302

AASHTO M 307

1 per shipment

1 per shipment

1 per shipment

Water AASHTO M 157 1 for each source

Coloring Agents ASTM C979 1 per type

Chemical Admixtures:

Air-entraining

Water-reducing, Set-controlling, 

Hydration stabilizing

AASHTO M 154

AASHTO M 194

1 per shipment

1 per shipment per 

admixture used

The FP further notes that material accepted by certification may be sampled and tested at any 

time to verify the properties stated as part of the certification. Sampling of concrete materials 

should be in accordance with the procedures and sample sizes noted in Exhibit 5-48.

In general, it is good practice to obtain one sample with each shipment of material. These samples 

should be retained on the project until final project acceptance or provided to the Division 

Materials Engineer when required for the purpose of Government testing to verify conformance 

to the contract specifications.
Division 500 – Concrete January 2020

5-22 Concrete Materials Acceptance Requirements

Exhibit 5-48 Material Sampling Specifications and Sample Sizes

Material Component Test Method Sample Size

Hydraulic Cement:

Portland Cement

Blended Hydraulic 

Cement

AASHTO R 71

AASHTO R 71

Representative of not more than 100 tons 

(90 Mg): Two grab samples at ≥ 10 lb (5 kg) 

each

Representative of not more than 100 tons (90 

Mg): Two grab samples at ≥ 10 lb (5 kg) each

Mineral Admixtures:

Fly Ash

Ground granulated 

blast-furnace slag

Silica Fume

(microsilica)

ASTM C311

AASHTO M 302

AASHTO M 307

Representative of not more than 

400 tons (360 Mg): One grab sample at ≥ 4 lb (2 

kg) each

Representative of not more than 

125 tons (115 Mg): Two grab samples at ≥ 5 lb 

(2 kg) each. Remove a 12-in. (300 mm) layer of 

slag in a hole before sampling. 

Representative of not more than 

110 tons (100 Mg): 2 grab samples at ≥ 2 lb (1 

kg) each.

Water:

Compressive strength

Time of set

Chloride as Cl

Sulfate as SO4

Alkalis

Total Solids

AASHTO M 157

AASHTO T 106

AASHTO T 131

ASTM D512

AASHTO T 290

AASHTO T 105

ASTM C1603

As required for pertinent tests: liquid grab 

samples at ≥ 1 pt (0.5 L) each.

Aggregates 

(Coarse and Fine)

Aggregate Sample 

Splitting 

AASHTO R 90

AASHTO R 76

Coarse Aggregate: 150 lb (75 kg)

Fine Aggregate: 100 lb (50 kg)

Samples are properly split and reduced in size 

by use of sample splitters or quartering

Chemical Admixtures:

Air-entraining

Water-reducing,

Set-controlling

AASHTO M 154

AASHTO M 194

Representative of not more than 2500 gal (9500 

L): 3 liquid grab samples at ≥ qt (1 L) each

Representative of not more than 2 tons 

(2 metric tons): 4 non-liquid tube samples at ≥ lb 

(1 kg) each

Representative of a unit shipment or a single 

production lot: 3 liquid grab samples at ≥ 1 pt 

(0.5 L) each Representative of not more than 2 

tons (2 Mg): 4 non-liquid tube samples at ≥ 2 lb 

(1 kg) each

As always, special contract requirements should be reviewed to ascertain if additional materials 

certifications and samples are required on a project-specific basis.
Division 500 – Concrete January 2020

Concrete Materials Acceptance Requirements 5-23

5.3.2 Water Acceptance

The FP allows potable water of known quality to be used without testing and certification. Water 

of questionable quality, however, must be tested in accordance with AASHTO M 157 as 

summarized in Exhibit 5-43 and certified thereto. The Contractor must submit the certification, 

including test results, to the Project Engineer. In turn, the Project Engineer must submit the 

certification to the Division Materials Engineer for approval with the concrete mix design.

5.3.3 Aggregate Acceptance

Concrete aggregate acceptance involves a three phase testing process that progresses 

throughout the life of a project. These phases include testing to:

• assess source suitability

• evaluate mixture proportioning characteristics

• verify uniformity of supply and moisture content 

Initial source approval does not constitute acceptance. If an approved aggregate source does not 

continue to supply acceptable material, further use of the source may be denied and a new 

concrete mix design may be required.

The first phase entails performing laboratory tests to determine source suitability and acceptability 

for use as a concrete material. The FP requires that the source quality of fine and coarse 

aggregates be verified by testing prior to production of concrete. The aggregate samples must be 

split with the Government taking control of its portion of the split sample. If more than one source 

is used, split samples must be obtained from each source. Samples should be submitted to the 

FLH Division Materials Laboratory along with transmittal form FHWA 1600. It is emphasized that 

aggregate source samples should be submitted far in advance of the submittal of the mix design 

since some aggregate source quality tests take weeks to perform. The Contractor should ensure 

that aggregate samples are submitted as soon as a source is identified. In addition, the Contractor 

is required to submit test results from each aggregate source and to certify that they meet the 

specified quality, including the supplemental requirements, established in the contract. Aggregate 

testing results are generally submitted as part of the proposed mix design on form FHWA 1608. 

The Government typically tests to verify the Contractor’s results and the quality of the aggregate 

provided. See Exhibits 5-5 and 5-6 for characteristics. Upon source approval, these tests are 

typically not checked again unless there is reason to question source quality or when there is an 

unforeseen change in aggregate source(s).

The second phase involves conducting laboratory tests to determine physical properties 

characteristics necessary for concrete mixture proportioning. These tests are stated in the FP in 

the Composition (Concrete Mix Design) and Acceptance subsections. Since these tests are 

performed to gather information for mixture adjustments only, testing limitation requirements are 

usually not specified. With the exception of aggregate moisture tests, mixture proportioning tests 

are generally checked one time by the Government on both the fine and coarse aggregate and 

include measures of parameters shown in Exhibit 5-7. The tests are typically performed by the 

FLH Division Materials Laboratory on the same samples that are submitted for aggregate source 

quality verification testing. 
Division 500 – Concrete January 2020

5-24 Concrete Materials Acceptance Requirements

The third phase entails performing daily laboratory tests on produced aggregate at the project site 

during construction to verify the continuous uniformity of the aggregate supply as well as to 

determine aggregate moisture contents necessary for adjustment of the concrete mixtures water 

content. The testing and frequency is specified in the FP in the Acceptance subsection. Uniformity 

of aggregate supply is monitored by gradation and fineness modulus tests. Concrete water 

content is adjusted in accordance with existing moisture conditions of the fine and coarse 

aggregate, which fluctuate with environmental and ambient conditions at the mixing plant site. 

The existing moisture condition of each stockpile is tested and used to adjust batch water contents 

to maintain the water-cementitious materials ratio of the approved mix design. 

During aggregate production, the aggregates should be sampled and tested by the Contractor for 

gradation, fineness modulus and moisture content at a minimum frequency of one sample per 

day per stockpile. Split samples should be obtained during the production of the aggregates and 

tested by the Government to verify the Contractor’s gradation and fineness modulus results. The 

Project Engineer should obtain the Contractor’s daily aggregate gradation and moisture test 

results. As required by the FP under the Composition (Concrete Mix Design) and Acceptance 

subsections, the Project Engineer must ensure that there is not a change in approved aggregate 

sources, that the gradations stay within acceptable limits and that the fineness modulus of the 

fine aggregate does not change by more than 0.20. The Project Engineer must also ensure that 

the Contractor uses aggregate moisture tests to properly adjust the amount of mix water in 

concrete batches such that the water-cementitious materials ratio of the approved mix design is 

maintained. The use of form FHWA 1638 can assist in performing these calculations. The water 

content of the approved mix design should never be exceeded and concrete must not be retempered. These items are discussed in detail in Section 5.5 – Concrete Construction 

Requirements.
Division 500 – Concrete January 2020

Concrete Mixture Proportioning and Approval Requirements 5-25

5.4 CONCRETE MIXTURE PROPORTIONING AND APPROVAL 

REQUIREMENTS

5.4.1 Concrete Mixture Composition and Proportioning Requirements

For structural concrete, the FP denotes mixture composition requirements for various classes of 

concrete and specifies nominal maximum aggregate sizes and minimum air contents. Concrete 

and/or exposure classes, which dictate mixture proportioning, specified compressive strength and 

other durability requirements, are usually specified in the plans on contract drawings or in projectspecific special contract requirements. Similar requirements are stipulated in the minor concrete 

section of the FP; however, only one mixture composition is specified in conjunction with a 

specified concrete compressive strength. Classes are typically not utilized.

The FP requires concrete mixtures to be proportioned in accordance with specific ACI practices 

and guides as applicable. The ACI practices and guides and the definitions associated thereto 

are discussed below. Applications and use on FLH projects are also addressed in association 

with each definition and practice.

5.4.1.1 ACI 211.1 Standard Practice for Selecting Proportions for Normal, 

Heavyweight and Mass Concrete

• Normal concrete - Concrete having a density of approximately 150 lb/ft3 (2400 kg/m3) 

made with normal-density aggregates. Normal concrete is used in the majority of 

construction applications including typical FLH project applications (i.e. pavements, 

bridges, culverts, walls, foundations).

• Heavyweight concrete – Concrete of substantially higher density than that made using 

normal-density aggregates (i.e. up to 350 lb/ft3 (5600 kg/m3)), usually obtained by use of 

high-density aggregates. Heavyweight concrete is used in radiation shielding, counterbalancing, ballasting and sound attenuation applications. As such, it has not been 

employed on FLH projects.

• Mass Concrete - Any volume of concrete with dimensions large enough to require that 

measures be taken to cope with generation of heat from hydration of the cement and 

attendant volume change, to minimize cracking. Mass concrete is used in thick-section 

applications for structures such as dams, mat foundations, pile caps, bridge piers, walls 

and tunnel linings. It has been used on FLH projects in rare occasions when the size of 

structural member (i.e. bridge piers) has necessitated measures to prevent temperaturedependent cracking.

5.4.1.2 ACI 211.2 Standard Practice for Selecting Proportions for Structural 

Lightweight Concrete

Lightweight concrete - Concrete of substantially lower density than that made using aggregates 

of normal density. The concrete is made with lightweight aggregates with a concrete compressive 

strength exceeding 2500 psi (17 MPa) at 28 days of age and an air dry density not exceeding 115 

lb/ft3 (1840 kg/m3). Lightweight concrete is used in applications where normal density aggregates 

(exhibiting specific gravities from 1.6 to 3.2) are not locally available and light density aggregates 
Division 500 – Concrete January 2020

5-26 Concrete Mixture Proportioning and Approval Requirements

are used in whole or in part in the concrete mixture. When compared to normal concrete, 

proportioning and control procedures for lightweight concrete are modified to account for greater 

absorptions and rates of absorptions. Lightweight concrete has been used on rare occasions on 

FLH projects for standard applications such as headwalls or foundations.

5.4.1.3 ACI 211.3 Guide for Selecting Proportions for No-Slump Concrete

No Slump Concrete - Freshly mixed concrete exhibiting a slump of less than 1⁄4 inch (6 mm). No 

slump concrete is used in applications where normal workability impairs constructability. These 

applications have historically included four types of concrete including roller compacted concrete 

(RCC), roof tiles, concrete masonry units and pervious concrete. Roller compacted concrete has 

been employed for dams, pavements and horizontal construction. When compared to normal 

concrete, proportioning and control procedures for no slump concrete are modified in accordance 

with specific procedures for each concrete type to account for lower water contents and other 

factors. No slump concrete has been used on rare occasions on FLH projects in applications such 

as RCC grade control structures within washes for the purposes of dissipating erosion and bridge 

scour.

5.4.1.4 ACI 211.4 Guide for Selecting Proportions for High-Strength Concrete 

using Portland Cement and other Cementitious Materials

• High Strength Concrete - Concrete that has a specified compressive strength for design 

of 6000 psi (41 Mpa) or greater. High strength concrete is used in applications where 

superior strength is needed in the design and performance of structural members. 

Optimization of mixture proportioning and attainment of a low water-cementitious materials 

ratio is critical to achieving high strength. Select mineral and chemical admixture 

combinations and aggregate sizes are typically specified in this process. Typical 

applications for high strength concrete include bridges and pavement overlays although 

these structures can be designed with normal concrete. Both of these applications have 

been used on FLH projects on a limited basis. 

• High Performance Concrete - Concrete meeting special combinations of performance and 

uniformity requirements that cannot always be achieved routinely using conventional 

constituents and normal mixing, placing and curing practices. High performance concrete 

(HPC) differs from high strength concrete in that superior performance in a particular 

application is required. The application may or may not require higher compressive 

strength. In addition to compressive strength, specialized testing and performance 

requirements are typically specified to address one or more desirable durability 

characteristics including freeze-thaw, scaling, abrasion, chloride penetration, ASR and 

sulfate resistance. Testing and performance requirements related to structural integrity 

may also be specified for rigidity, shrinkage and creep as well as placeability (i.e. flow). 

As such, examples of HPC when compared to normal concrete include high-ultimate 

strength, high early strength, high rigidity, high durability, increased workability, 

pumpability and finishability and increased placeability in hot and cold weather. HPC has 

been applied on FLH projects in a fashion similar to high strength concrete. Its use is 

expected to increase in the future.

A properly proportioned concrete mixture must be designed for strength, durability, workability 

(i.e., placeability, pumpability, finishability), economy and appearance. The water-cement ratio 
Division 500 – Concrete January 2020

Concrete Mixture Proportioning and Approval Requirements 5-27

determines the strength and durability properties. When mineral admixtures are used, the watercement ratio becomes the water-cementitious materials ratio. In other words, the cementitious 

materials portion is calculated by summing the weight of the cement plus the weights of the 

mineral additives (i.e. cement + fly ash + silica fume + ground granulated blast furnace slag). The 

weight of the water is then divided by the weight of the cementitious materials. The water-cement 

and water-cementitious ratio are denoted as w/c in the FP.

For structural concrete, the FP requires the concrete mixture to be proportioned to meet durability 

requirements for maximum water-cementitious materials ratio, minimum specified compressive 

strength (f’c) and may include additional criteria for durability as stated in ACI 301. Durability is 

discussed in Section 5.4.2 below. 

For structural concrete, the FP also requires the concrete mixture to be proportioned to meet the 

required average compressive strength requirements (f’cr) stipulated in ACI 301. These strength 

requirements are discussed in Section 5.4.3 below.

5.4.2 Concrete Mixture Durability Requirements

Durability is the ability of concrete to resist weathering action, chemical attack, abrasion and other 

conditions while retaining its engineering properties. To provide adequate durability, structural 

concrete must be proportioned by the Contractor to meet FP requirements. 

Durability requirements pertaining to the maximum water-cementitious materials ratio and 

minimum compressive strength (f’c) are dependent upon designated exposure categories and 

classes. ACI 301 defines four different exposure categories and their individual applications as 

follows:

• Exposure Category F (Freezing and thawing) - applied to exterior concrete that is exposed 

to moisture and cycles of freezing and thawing with or without deicing chemicals.

• Exposure Category S (Sulfates) - applied to concrete in contact with soil or water 

containing deleterious amounts of water-soluble sulfate ions.

• Exposure Category W (Permeability) – applied to concrete in contact with water requiring 

low permeability.

• Exposure Category C (Corrosion) - applied to reinforced and prestressed concrete 

exposed to conditions that require additional protection against corrosion of reinforcement

The severity of exposure within each category is further subdivided into exposure classes. 

Increasing numerical values are used to represent increasingly severe exposure class conditions. 

A classification of “0” indicates that the exposure severity has negligible effect or does not apply 

to the structural member.

Specific and applicable exposure classes are assigned to structural members by the Division 

Materials Engineer on a project-by-project basis in conjunction with the severity of exposure 

conditions anticipated at the project site. When a structural concrete member is assigned more 

than one exposure class (i.e. F3, SO, W1 and C2), the concrete mixture must be proportioned by 
Division 500 – Concrete January 2020

5-28 Concrete Mixture Proportioning and Approval Requirements

the Contractor to meet the most restrictive requirements for maximum water-cementitious 

materials ratio and minimum specified compressive strength (f’c). 

The mixture proportioning durability requirements for maximum water-cementitious materials ratio 

and minimum specified compressive strength (f’c) are specified in the FP and special contract 

requirements. Other durability requirements are also specified in association with each assigned 

exposure category and class (with the exception of Exposure Category W (Permeability), which 

has no additional durability requirements). Exposure class categories F, S and C will be hereafter 

discussed with respect to the attack method, the corresponding deterioration appearance and 

specifications pertaining to concrete mix design mitigation measures. Thereafter, other FP 

durability requirements will be addressed.

5.4.2.1 Exposure Category F (Freezing and thawing)

Freeze-thaw attack occurs in climates of repeated freezing and thawing. When temperatures drop 

below freezing, ice starts to form in concrete pores. Water increases in volume on freezing. Water 

confined in pores between freezing bodies is under compression and pores dilate causing the 

cement paste to rupture or crack. When concrete contains porous aggregate, the aggregate itself 

is prone to freeze-thaw damage even when the concrete contains air entrainment.

Exhibit 5-49 Concrete freeze-thaw damage (1) on the surface in the form of 

deicer scaling; (2) throughout the thickness in the form of cracks in paste 

around aggregate; and (3) at pavement joints in the form of D-cracking.

Freeze-thaw deterioration is manifested on the exposed concrete surface by deicer scaling, 

crumbling and delamination. It is manifested throughout the thickness of the concrete by parallel 

surface cracks in paste and cracks in paste around aggregate. In pavements, freeze-thaw 

deterioration sometimes takes the form of D-cracking. D-cracking consists of closely spaced 

cracks that form parallel to pavement joints and progressively move outward. D-cracks are 

caused by porous aggregates. As water accumulates under pavements, the porous aggregates 

become saturated. When freezing and thawing cycles occur, cracking of the concrete typically 

starts in the saturated aggregate at the bottom of the slab and progresses upward to the 

wearing surface.

Freeze-thaw damage may be avoided by proper air entrainment of fresh concrete and use of 

nonporous aggregate. A good air void system provides free space to which water can diffuse 

and freeze without damaging the concrete. From a microscopic standpoint, air bubbles should 

be spaced no more than 230 μm apart and 10 to 1000 μm in size. Concrete air content 

requirements are based on the maximum aggregate size used.
Division 500 – Concrete January 2020

Concrete Mixture Proportioning and Approval Requirements 5-29

In addition to specifying mixture proportioning requirements for maximum water-cementitious 

materials ratio and minimum specified compressive strength (f’c) for each freezing and thawing 

exposure class (F0, F1, F2 or F3), the FP and special contract requirements further mandate 

allowable air content ranges. To provide protection against freeze-thaw attack, the concrete 

mixture must be designed by the Contractor to meet air content requirements of the assigned 

freeze-thaw exposure class. It is noted that too much entrained air will result in detrimental 

strength loss. As a rule of thumb, the compressive strength loss is about 5 percent for each 1 

percent of air content.

It is further noted that the FP limits the maximum total cementitious materials content pertaining 

to collective combinations of mineral admixtures (i.e. for concrete exposed to freezing and thawing 

and in continuous contact with moisture and exposed to deicing chemicals or the F3 exposure 

class). The requirements have been previously discussed and are shown in Exhibit 5-42.

5.4.2.2 Exposure Category S (Sulfates)

Naturally occurring sodium, potassium, calcium or magnesium sulfates found in soil, dissolved in 

groundwater or from deicing chemicals can enter concrete and attack the cementing materials. 

Wetting and drying can replenish and concentrate salts on the concrete surface leading to 

continual attack. Sulfate attack disrupts the cement paste through one of two mechanisms: (1) 

formation of additional ettringite or (2) formation of additional gypsum. The formation of ettringite 

results in an increase in solid volume leading to expansion and cracking of paste. The formation 

of gypsum leads to paste softening and loss of strength. The presence of ettringite and gypsum 

in concrete, in and of itself, is not an indication of sulfate attack as these components are present 

in all concrete. In addition to chemical analysis, petrographic examination (ASTM C856) of 

hardened concrete samples is necessary to verify sulfate attack.

Exhibit 5-50 At the microstructure level, salt deposits (i.e. the formation 

of ettringite) are shown on a hardened concrete sample as well as cracking 

in the paste due to the formation and expansion of ettringite.

When in-service concrete will be exposed to soil or solutions (groundwater or deicing solutions) 

containing sulfates, a sulfate condition must be determined and the concrete mixture designed 

with the appropriate sulfate resisting cementitious materials types. Soil and/or water testing to 

determine the sulfate condition is accomplished as part of the project development with test 

results typically being included in Geotechnical reports. Measured test results are used by the 

Division Materials Engineer to assign an applicable sulfate exposure class which in turn is 

specified in special contract requirements on a project-by-project basis.
Division 500 – Concrete January 2020

5-30 Concrete Mixture Proportioning and Approval Requirements

In addition to specifying mixture proportioning requirements for maximum water-cementitious 

materials ratio and minimum specified compressive strength (f’c) for each sulfate exposure class 

(S0, S1, S2 and S3), the FP and special contract requirements further mandate the use of sulfate 

resisting cementitious materials types. To provide protection against sulfate attack, the concrete 

mixture must be designed by the Contractor to meet the required cementitious materials type of 

the assigned sulfate exposure class. Alternatively, combinations of cementitious materials 

proposed for use in the mix design may be tested by mortar bar expansion in a sulfate solution. 

Mortar bar samples must be fabricated and tested in accordance with the procedure designated 

in the contract and meet the expansion limitation requirement of the assigned sulfate exposure 

class. The Contractor is further required to submit valid hydraulic cement materials certifications 

with the concrete mix design as part of form FHWA 1608. These certifications must include 

pertinent chemical and physical properties test data, including mortar bar expansion data when 

applicable, allowing verification of the use of appropriate sulfate resisting cement on the project 

(See Section 5.3.1).

5.4.2.3 Exposure Category C (Corrosion)

Concrete protects reinforcing steel because it provides a high pH environment around it. The pH 

of concrete, including that of the pore solution, is about 12.5. At a pH of 11.5 and higher, a 

passivating oxide film will form on the steel surface in contact with the concrete which protects 

the steel from corrosion. As long as the passivating oxide film forms and the high pH environment 

is maintained, the reinforcing steel will be protected from corrosion.

Reinforcement in concrete corrodes as a result of the failure to establish an initial passivating 

environment or by loss of an established passivating environment over time. The passivating 

environment may not initially form if the concrete exhibits excessive voids throughout its depth 

and at or near steel reinforcement if the concrete is porous. The passivating environment may be 

lost over time by concrete carbonation which lowers the pH pore solution near reinforcement steel 

to about 8.5. All concrete carbonates as a result of exposure to carbon dioxide in the atmosphere. 

The passivating environment may also be lost over time by ingress of the chloride ion into 

concrete which destroys the passive oxide film surrounding the steel.

As reinforcement corrodes, it increases substantially in volume resulting in delamination of 

overlying concrete and further structural deterioration. The effective load carrying area of the 

reinforcement is also reduced.

In addition to specifying mixture proportioning requirements for maximum water-cementitious 

materials ratio and minimum specified compressive strength (f’c) for each corrosion exposure 

class (C0, C1 and C2), the FP and special contract requirements further mandate limitations on 

the water soluble chloride ion (Cl-) of the concrete mix ingredients when concrete is placed over 

reinforcing steel. To provide protection against reinforcement corrosion, the concrete mixture 

must be designed by the Contractor to meet the maximum water soluble chloride ion (Cl-) content 

by weight of cement for the assigned corrosion exposure class and structural member type. The 

Contractor is further required to submit water soluble chloride ion (Cl-) data on hardened concrete 

with the concrete mix design on form FHWA 1608. The data must verify that the maximum water 

soluble chloride ion (Cl-) content of the mix ingredients has not been exceeded at the designated 

test age and that the concrete has been tested in accordance with the procedure designated in 

the contract.
Division 500 – Concrete January 2020

Concrete Mixture Proportioning and Approval Requirements 5-31

Finally, for proper corrosion protection of the reinforcing steel, it is imperative that minimum 

concrete cover requirements stipulated by contract drawings be provided. Concrete cover over 

reinforcing steel should be checked in the field by the Project Engineer. Reinforcement steel cover 

can best be assessed in the forms prior to concrete placement.

5.4.2.4 Delayed Ettringite Formation (DEF)

Delayed Ettringite Formation (DEF), also known as internal sulfate attack, results in the formation 

of ettringite and associated expansion after heat curing at too high of a temperature. Many 

experiments have shown that pastes, mortars and concretes exposed to excessive temperatures 

during the hardening process exhibit expansion and cracking when subsequently exposed to 

moist conditions. The critical temperature for DEF is related to cement alkali content. Cements 

containing higher alkali contents (i.e. type III cements) exhibit lower critical temperatures. The FP 

limits elevated curing temperature to a maximum of 160 °F (71 °C). 

The temperature of reinforced and prestressed concrete subjected to elevated temperature curing 

must be monitored by the Contractor and the maximum curing temperature recorded. It must be 

submitted with the concrete mix design (see FHWA form 1608).

5.4.2.5 Alkali-Silica Reactivity (ASR)

Alkali aggregate reactivity is the chemical reaction in either mortar or concrete between alkalis 

(sodium and potassium) from portland cement or other sources and certain constituents of some 

aggregates; under certain conditions, deleterious expansion of concrete or mortar may result. 

ASR is a type of alkali aggregate reactivity which involves reactions of the alkalis in portland 

cement and certain siliceous rocks or minerals (i.e. opaline, chert, strained quartz, volcanic glass).

In order for ASR to be operative, three components are required including reactive silica, sufficient 

alkalis and sufficient moisture. Eliminating any one of these components will stop ASR reactivity 

and subsequent concrete damage.

Reactive silica refers to aggregates that tend to breakdown under exposure to highly alkaline pore 

solution in concrete and thereafter react with the alkalis to form an expansive ASR gel. Not all 

siliceous aggregates are reactive. Reactivity depends on aggregate mineralogy, crystalline 

structure and solubility of silica in the pore solution of concrete.

Sufficient alkalis refer to the alkalis predominately contributed by the sodium and potassium in 

portland cement but also from other constituent materials and/or external sources. Such alkali 

sources include supplementary cementitious materials (fly ash, slag and silica fume), aggregates, 

chemical admixtures, deicing salts, seawater and wash water. The alkalis serve to raise the pH 

of the pore solution which in turn increases the solubility of the reactive silica.

Sufficient moisture refers to the moisture that is necessary to promote ASR expansion. If the 

internal relative humidity of the concrete exceeds 80 percent, sufficient moisture is present to 

allow ASR expansion. Such moisture is typically inherently present within concrete structures that 

are exposed to the environment or in contact with the ground (i.e. pavements, bridges, canals).

ASR occurs as the alkali and silica react to form a gel reaction product. The gel reaction product 

absorbs water and subsequently swells. When the volume of the reaction product is greater than 
Division 500 – Concrete January 2020

5-32 Concrete Mixture Proportioning and Approval Requirements

the volume of the individual reacted materials, expansive tensile stress are exerted on the 

concrete and cracking occurs. The only indisputable evidence that ASR has developed in 

concrete is the detection of ASR reaction products. In the early stages of reactivity or under 

conditions where only small quantities are produced, ASR gel is virtually undetectable by the 

unaided eye. Final confirmation of the ASR mechanism must be performed at the microstructure 

level by a skilled petrographer.

A characteristic and advanced ASR cracking pattern is known as map or pattern cracking. The 

crack pattern resembles that which develops on dried mud flats. On concrete pavement surfaces, 

ASR cracks are typically more prominent in the wheel paths in the longitudinal direction. Below 

the pavement surface, ASR can be manifested by a predominance of vertical cracks in the upper 

1 to 2 inches of pavement as well as cracks with sub-horizontal orientation. ASR cracks can 

extend completely through the pavement thickness.

Exhibit 5-51 At the microstructure level, the characteristic ASR gel is shown 

within cracks that have formed through and around aggregate and into the 

surrounding paste. At the macrostructure level, an advanced and characteristic 

ASR cracking pattern known as map or pattern cracking is shown.

To prevent ASR in new concrete, the concrete mixture is designed to (1) control and limit the 

availability of alkalis in cement and/or (2) the type and amount of reactive aggregate.

Lowering of alkalis in the concrete mixture is accomplished by specifying the optional low alkalicement requirement found in portland cement specifications in AASHTO M 85. The low alkali 

content serves to lower the pH of the concrete pore fluid which in turn decreases the solubility of 

the reactive silica. The optional low alkali-cement provision may be specified in the special 

contract requirements as a secondary, but not stand alone, means of ASR mitigation. If the lowalkali option is allowed, the Contractor must submit valid hydraulic cement materials certifications 

with the concrete mix design which includes pertinent chemical and physical properties test data 

verifying the use of low-alkali cement on the project (See Section 5.3.1). 

Limiting the type and amount of reactive aggregate in the concrete mixture is accomplished by 

one or more of the following:

• Testing aggregate sources to determine whether or not they contain reactive aggregates.
Division 500 – Concrete January 2020

Concrete Mixture Proportioning and Approval Requirements 5-33

• Testing reactive sources to determine if the reactivity can be effectively mitigated by use 

of supplementary cementitious materials (i.e. fly ash, silica fume ground granulated blast 

furnace slag).

The FP and special contract requirements will specify reactive aggregate supplemental 

requirements for fine and coarse aggregates. Limiting the type and amount of reactive aggregate 

is the preferred and primary means of ASR mitigation. 

The reactive aggregate supplemental requirements call for the use of non-reactive aggregates in 

the concrete mixture. Aggregate producers should be able to provide test results demonstrating 

the reactivity level of their product. The reactive aggregate supplemental requirements do allow 

for the use of reactive aggregates if supplementary mineral admixtures are added that 

demonstrably show prevention of harmful expansion by subsequent testing.

The Contractor is required to submit data from aggregate producers for both fine and coarse 

aggregate which documents aggregate reactivity levels as well as the test methodology used for 

measurement. If reactive aggregate is proposed for use, then test data must be included which 

shows that harmful expansion has been effectively mitigated by use of supplementary 

cementitious materials. However, the proportions of supplementary materials proposed for use in 

the concrete mix design must be similar to those showing effective mitigation by testing. The mix 

design proportions must also meet the maximum cementitious material requirements shown in 

Exhibit 5-42. ASR testing as well as expansion criteria which is accepted by Federal Lands 

Highway is shown in Exhibit 5-52.
Division 500 – Concrete January 2020

5-34 Concrete Mixture Proportioning and Approval Requirements

Exhibit 5-52 FLH Accepted ASR Testing

Test 

Name

ASR Test Type and 

Application*

Sample Type and 

Size

Test Duration Expansion 

Criteria

ASTM 

C1260

Immersion of mortar 

bars in NaOH solution 

at 80° C. (Evaluates 

aggregates only)

At least 3 mortar 

bars 1 x 1 x 10-

inches long 25 x 25 

x 250 mm long)

16 days total – 14 

days from zero 

measurement. 

Cannot be used to 

evaluate SCMs or 

Lithium

0.10% max 

at 16 days

after casting

ASTM 

C1293

Concrete prisms 

stored at 38°C and 

100% humidity. 

(Evaluates aggregate, 

SCMs and Lithium)

Three prisms per 

cement-aggregate 

combination not less 

than 3 x 3 x 10-

inches long (75 x 75 

x 250 mm long)

Measure after 1, 2, 

4, 8, 13, 18, 26, 39 

and 52 weeks. 

Every 6 months 

thereafter as 

necessary

0.04% max 

at one year

ASTM 

C1567

Immersion of mortar 

bars in alkaline 

solution at 80°C. 

(Evaluates SCMs)

At least 3 mortar 

bars 1 x 1 x 10-

inches long (25 x 25 

x 250 mm long)

16 days total – 14 

days from zero 

measurement 

Cannot be used to 

evaluate Lithium

0.10% max 

at 16 days 

after casting

ASTM 

C295

Petrographic 

examination of 

aggregates

Varies; quarry 

samples of fine and 

coarse aggregate

Short term: visual 

and microscopic to 

assess reactive 

aggregate types

Used with 

ASTM 

C1260

ASTM 

C856

Petrographic 

examination of 

hardened concrete

One core specimen 

6 inch diameter x 12 

inches long (150 

mm diameter x 300 

mm long) or mortar 

bar sample

Short term: visual 

and microscopic to 

assess reactivity, 

cracks etc.

Used with 

ASTM 

C1260

* SCM stands for supplementary cementitious materials such as fly ash, silica fume or ground 

granulated blast furnace slag or a combination thereof. 

It is emphasized that ASR testing is included as part of the aggregate source quality testing shown 

in Exhibits 5-5 and 5-6 and discussed in Section 5.3.3. The Contractor should ensure that 

aggregate samples are submitted to the Government far in advance of the submittal of the 

concrete mix design in that some aggregate ASR tests take weeks to perform. As a minimum, 

ASTM C1260, which is used to ascertain whether or not aggregate is reactive, takes 16 days to 

perform after receipt and casting of test samples. Additional time will be necessary if 

supplementary petrographic analysis is required. Also, if reactive aggregate is employed in the 

concrete mix design, ASTM C1567, which is used to ascertain whether or not the use of 

supplementary cementitious materials has been effective in mitigating ASR expansion, takes 

another 16 days after receipt and casting of test samples. It is important to recognize and plan 

sufficient time for the Government verification testing for contract compliance with ASR 

requirements.
Division 500 – Concrete January 2020

Concrete Mixture Proportioning and Approval Requirements 5-35

5.4.3 Concrete Mixture Strength Requirements

In addition to the durability requirements discussed in Section 5.4.2, the FP also requires 

structural concrete to be proportioned to meet the required average compressive strength 

requirements (f’cr) stipulated in ACI 301.

Compressive strength is the measured maximum resistance of a concrete specimen to axial 

compressive loading or the specified resistance used in design calculations. Compressive 

strength requirement notation is as follows:

• f’c = specified compressive strength of concrete, psi (MPa)

• f’cr = required average compressive strength of concrete used as the basis for selection 

of concrete proportions, psi (MPa)

• ss = sample standard deviation, psi (MPa)

• k = factor used for the increase in standard deviation if the total number of tests is less 

than 30.

To account for variability that will occur in the field during construction and placement, a suitable 

concrete mixture must be designed for an average strength (f’cr) appreciably higher than the 

specified compressive strength (f’c). In order for a concrete mix design to be approved, proper 

strength documentation and calculations must be provided by the Contractor. The data should be 

supplied as part of the mix design submittal on form FHWA 1608. The process for establishing 

and documenting a suitable concrete mixture consists of three basic steps:

• Step 1: Determine a sample standard deviation from suitable test records (strength tests).

• Step 2: Determine a required average compressive strength (f’cr) from formulas which 

consider the sample standard deviation or suitable supplemental information documenting 

average strength potential.

• Step 3: Select mixture proportions that produce an average compressive strength at least 

as great as the required average compressive strength and also meet durability 

requirements for the applicable exposure categories noted in Section 5.4.2.

5.4.3.1 Determine a Sample Standard Deviation from Suitable Test Records 

(Strength Tests)

Concrete strength is assessed by strength tests. One strength test (Xi) is defined as the average 

of the strengths of at least two 6 by 12-inch (150 by 300 mm) cylinders or three 4 by 8-inch (100 

by 200 mm) cylinders made from the same sample of concrete and tested at 28 days, or at the 

test age designated in the contract, for f’c. The average of all the strength tests is calculated and 

used to determine a sample standard deviation. The sample standard deviation is in turn used to 

determine the required average compressive strength (f’cr).

Suitable test records not more than 12 months old must be used or developed to establish a 

sample standard deviation. When a concrete production facility is presenting strength test records 
Division 500 – Concrete January 2020

5-36 Concrete Mixture Proportioning and Approval Requirements

from which a sample standard deviation is calculated, it is required to represent materials, quality 

control procedures and conditions similar to those expected on the project. For instance, the same 

mineral and chemical admixtures should be employed in the concrete mix design as will be used 

on the project. Changes in materials and proportions within test records are not to be more 

restricted than those proposed for the work. Additionally, the production facility is required to 

present test records which represent concrete that meets a specified compressive strength or 

strengths (f’c) within 1000 psi (7 MPa) of that specified for the proposed work. Where different 

materials are used for different portions of proposed work (i.e. different classes of concrete), each 

mix design combination must be evaluated separately by use of strength tests and approved. The 

Division Materials Engineer can assist in evaluation of the mixtures and recommendation for their 

use.

The formulas used for the computation of the sample standard deviation are dependent upon the 

number of suitable test records. There are three different cases of test records.

• Case 1

When a concrete production facility has one test record of at least 30 consecutive tests

of similar materials and conditions expected, the sample standard deviation (ss) is 

calculated from those results in accordance with the following formula:

 (n -1)

(X - X ) s

2 ∑ i

s =

Where:

ss = sample standard deviation, psi (MPa)

Xi = individual strength tests

X = average of n strength test results

n = number of consecutive strength tests.

If two groups of consecutive tests or two test records are used to obtain at least 30 

tests, the sample standard deviation (s s ) is the statistical average of the values calculated 

from each test record in accordance with the following formula:

 (n n 2)

(n -1)(s ) (n -1)(s )

s

1 2

2

2 s 2

2

1 s1

s + −

+ =

Where:

s s = statistical average standard deviation where two test records are used to 

estimate the sample standard deviation

ss1, ss2 = sample standard deviations calculated from two test records, 1 and 2, 

respectively

n1, n2 = number of tests in each test record, respectively.
Division 500 – Concrete January 2020

Concrete Mixture Proportioning and Approval Requirements 5-37

• Case 2

When a concrete production facility has one test record of 15 to 29 consecutive 

strength tests, the sample standard deviation is established as the product of the 

calculated sample standard deviation (ss) above and the k-modification factor shown in 

Exhibit 5-54 below. The test record must represent only a single record of consecutive 

tests that span a period of not less than 45 calendar days.

• Case 3

When less than 15 consecutive strength tests are available, there is insufficient data to 

establish a sample standard deviation and additional supplemental information must be 

submitted as discussed in section 5.4.3.2 below in order to document average strength 

potential and to establish mixture proportions.

5.4.3.2 Determine a Required Average Strength (f’cr)

The determination of the required average strength is hereafter addressed for the same three 

cases of test records previously discussed in section 5.4.3.1.

• Case 1

When suitable test records from 30 or more consecutive tests are available to establish a 

standard deviation, the required average compressive strength is determined from the 

equations shown in Exhibit 5-53. The required average compressive strength (f’cr) is 

based on the specified compressive strength (f’c) which is either (1) less than or equal to 

5000 psi (35 MPa) or (2) greater than 5000 psi (35 MPa).

Exhibit 5-53 Required Average Compressive Strength with Test Records of 30 or 

More Consecutive Tests

Specified Compressive 

Strength,

f’c, psi (MPa)

Required Average Compressive 

Strength*

f’cr, psi (MPa)

f’c ≤ 5000 psi (35 MPa)

Use the larger value computed from the 

following equations:

f’cr = f’c + 1.34kss (1)

f’cr = f’c + 2.33kss - 500 psi (2)

 (f’c + 2.33kss - 3.45 MPa)

Over 5000 psi (35 MPa)

Use the larger value computed from the 

following equations:

f’cr = f’c +1.34kss (1)

f’cr = 0.90f’c + 2.33kss (3)

* k is equal to 1 if the total number of tests are greater than or equal to 30
Division 500 – Concrete January 2020

5-38 Concrete Mixture Proportioning and Approval Requirements

In the first instance (f’c ≤ 5000 psi (35 MPa)), two computations are made using equations 

1 and 2. In the second instance (f’c > 5000 psi (35 MPa), two computations are again 

made using equations 1 and 3.

Since the total number of tests are greater than or equal to 30, the sample standard 

deviation does not have to be modified and k = 1 in equations 1, 2 and 3. As was discussed 

in Step 1 above, either the calculated sample standard deviation, ss, for one test record or 

the calculated statistical average standard deviation, s s , for two test records is actually 

used in the required average compressive strength formula calculations (f’cr). The largest 

f’cr value computed from equations 1 and 2 for f’c ≤ 5000 psi (35 MPa) or equations 1 and 

3 for f’c >5000 psi (35 MPa) in Exhibit 5-53 is ultimately used as the required average 

compressive strength (f’cr).

• Case 2

When test records from 15 to 29 consecutive strength tests are available, the sample 

standard deviation is established as the product of the calculated sample standard 

deviation (ss) for one test record and the k-modification factor shown in Exhibits 5-14 and

5-15. The procedure results in a more conservative or increased required average 

compressive strength (f’cr) and is statistically equivalent to that of a 30-test record.

Exhibit 5-54 Required Average Compressive Strength with 

Test Records of 15 to 29 Consecutive Tests

Number of Tests* k-modification Factor for Sample 

Standard Deviation+

Less than 15 Use Exhibit 5-55

15 1.16

20 1.08

25 1.03

30 or more 1.00

*Interpolate for intermediate numbers of tests

+k-modified standard deviation used to determine required average 

strength f’cr in Exhibit 5-53

After applying the appropriate k-modification factor, the largest f’cr value computed from 

equations 1 and 2 for f’c ≤ 5000 psi (35 MPa) or equations 1 and 3 for f’c > 5000 psi (35 

MPa) in Exhibit 5-53 is ultimately used as the required average compressive strength (f’cr).

• Case 3

When less than 15 consecutive strength tests are available, there is insufficient data to 

establish a sample standard deviation. The required average compressive strength is 

therefore established by a predetermined increase in the specified compressive strength 

in accordance with Exhibit 5-55 provided suitable supplemental information is submitted 

documenting average strength potential. Suitable supplemental information includes 

strength test records and associated trial mixture proportions.
Division 500 – Concrete January 2020

Concrete Mixture Proportioning and Approval Requirements 5-39

Exhibit 5-55 Required Average Compressive Strength with Test

Records less than 15 Consecutive Tests

Specified Compressive Strength,

f’c, psi (MPa)

Required Average 

Compressive Strength

f’cr, psi (MPa)

f’c < 3000 psi ( 21 MPa) f’cr = f’c + 1000 psi (7 

MPa)

3000 psi (21 MPa) ≤ f’c ≤ 5000 psi (35 

MPa)

f’cr = f’c + 1200 psi (8.5 

MPa)

f’c > 5000 psi (35 MPa) f’cr = 1.10f’c + 700 psi (5

MPa)

When strength test records and associated trial mixture proportions are submitted to 

document average strength potential, test records consisting of less than 30 but not less 

than 10 consecutive tests are acceptable provided test records encompass a period of 

time not less than 45 days. Required concrete proportions may be established by 

interpolation between the strengths and proportions of two or more test records.

When test records are not available, concrete proportions established from trial mixtures 

may be used to develop test records for cases 1, 2 or 3. As noted in ACI 301 the trial 

mixtures must meet the following requirements:

• Materials shall be those for proposed work.

• Trial mixtures with a range of proportions that will produce a range of compressive 

strengths encompassing f’cr and meet the durability requirements for applicable 

exposure categories noted in Section 5.4.2.

• Trial mixtures shall have slumps within the range specified for the proposed work; 

for air-entrained concrete, air content shall be within the tolerance specified for the 

proposed work.

• For each trial mixture, at least two 6 by 12 inch (150 by 300 mm) or three 4 by 8 

inch (100 by 200 mm) cylinders shall be made and cured in accordance with ASTM 

C192. Cylinders shall be tested at 28 days or at the test age designated for f’c.

• The compressive strength results, at designated test age, from the trial mixtures 

shall be used to establish the composition of the concrete mixture proposed for the 

work. The proposed concrete mixture shall achieve an average compressive 

strength as required in Exhibits 5-14 or 5-16 and meet the durability requirements 

for applicable exposure categories noted in Section 5.4.2.

When no suitable test records or trial mixture data is available, other experience and 

information may be submitted and used if approved by the Division Materials Engineer.
Division 500 – Concrete January 2020

5-40 Concrete Mixture Proportioning and Approval Requirements

5.4.3.3 Select Mixture Proportions

Select mixture proportions that produce an average compressive strength at least as great as the 

required average compressive strength and also meet durability requirements for the applicable 

exposure categories in Section 5.4.2. In order for a concrete mix design to be approved, proper 

strength documentation and calculations must be submitted by the Contractor which demonstrate 

that the proposed concrete mixture produces an average compressive strength equal to or greater 

than the required average compressive strength for the applicable case. As noted above, such 

documentation consists of a field test record, strength test records, trial mixtures or other 

information approved by the Division Materials Engineer. The data should be supplied as part of 

the mix design submittal on form FHWA 1608. The Division Materials Engineer may be contacted 

for assistance and direction in the compressive strength evaluation.

5.4.4 Concrete Mix Design Submittal

The concrete mix design for structural concrete must be recorded and submitted on form FHWA 

1608. The form should be submitted to the Project Engineer at least 36 days before concrete 

production. All forms require documentation of individual mix constituents, specific gravities, 

weights, and absolute volumes expressed in the proper units indicated on the form. Mix designs 

should be reported such that the total volume of mix constituents equals one cubic yard (27 cubic 

feet) or one cubic meter inclusive of design air contents. However, it is acceptable practice to 

design a concrete mixture with a total volume that is slightly higher (i.e. a few tenths) to allow for 

some variation in the as-produced air content. Admixture dosages in fluid ounces per cubic yard 

or liters per cubic meter must also be recorded. In addition, design fresh and hardened concrete 

properties and other information must be provided as indicated on the forms. 

5.4.5 Concrete Mix Design Approval

The FP requires concrete mix designs be submitted for approval. The Contractor should submit 

the required forms to the Project Engineer who in turn will submit them to the Division Materials 

Engineer for review and recommendation for approval. Prior to submitting the forms, the 

Contractor should review to verify all data and information has been provided according to the 

contract.

The Division Materials Engineer will review the submitted forms and documentation to ensure 

compliance with contract requirements.
Division 500 – Concrete January 2020

Concrete Construction Requirements 5-41

5.5 CONCRETE CONSTRUCTION REQUIREMENTS

Section 5.5 discusses the testing and inspection of concrete during the construction phase once 

the concrete mix design and materials submittals have been approved.

In addition, the contractor should supply a complete concrete batch ticket with every batch 

delivered to the project. The Project Engineer should verify that the proportions shown on the 

ticket match the concrete mix design that was approved for the project. An example of a concrete 

batch ticket is shown in Exhibit 5-56.

Exhibit 5-56 Example of Concrete Batch Ticket

As part of the construction phase of the work, a pre-concreting meeting should be held to discuss 

various aspects of concrete placement. A sample pre-concreting meeting agenda is included in 

Appendix D.2 of this manual.
Division 500 – Concrete January 2020

5-42 Concrete Construction Requirements

5.5.1 Aggregate Testing for Uniformity and Water Content Adjustment of Concrete 

Mixtures

Aggregate source and concrete mix design approval do not constitute final acceptance. If the 

approved source(s) do not continue to supply acceptable aggregates during the construction 

process, further use of the source(s) will be denied and a new mix design will be required using 

another source. For structural concrete, the FP requires that the concrete as well as the as 

produced aggregate used in the concrete be sampled, tested and evaluated. Aggregate tests are 

required to be performed on a daily basis to verify the uniformity of the supply as well as to 

determine properties necessary for adjustment of the water content of the concrete mixture.

Uniformity of aggregate supply is verified by gradation and fineness modulus tests. A new 

concrete mix design is required if there is a change in source of material or when the fineness 

modulus of the fine aggregate changes by more than 0.20. 

The water content needs to be monitored and adjusted in accordance with moisture condition of 

the aggregate, which fluctuates in accordance with environmental conditions at the mixing plant 

site. The moisture condition is tested on a daily basis and used in conjunction with the aggregate 

absorption to adjust the batch water amount to meet the water cementitous materials ratio 

requirement of the approved mix design. If the water-cementitious materials ratio is not kept 

constant, the compressive strength, workability and other properties will vary from batch to batch. 

For example, an increase in the fine aggregate moisture content of one percent will increase the 

slump of the concrete as much as 1 1⁄2 inches (40 mm) and decrease the compressive strength 

by as much as 300 psi (2.1 MPa).

In order to adjust batch water contents, it is necessary to understand the moisture conditions of 

an aggregate particle. Each aggregate particle is made up of internal voids which may or may not 

contain water. Four potential moisture conditions are depicted in Exhibit 5-57.

Exhibit 5-57 The four moisture conditions of an aggregate particle
Division 500 – Concrete January 2020

Concrete Construction Requirements 5-43

These moisture conditions are defined as follows:

• Oven Dry – Particle is completely dry and fully absorbent.

• Air Dry – Particle is dry at the surface but contains some interior moisture and is still 

partially absorbent.

• Saturated Surface Dry (SSD) – Particle is fully absorbent and neither absorbs water from 

nor contributes water to the concrete mixture.

• Damp or wet – Particle contains excess moisture on the surface known as free water.

Concrete mix designs are based on a saturated surface dry aggregate condition. Therefore, the 

existing moisture condition of the aggregate must be determined to properly apply aggregate 

moisture corrections. Existing moisture conditions are found by determining absorption and 

moisture contents. Provided the quality of the aggregate remains the same, the aggregate 

absorption should remain constant. However, since the moisture content reflects the 

environmental condition of the stored aggregate and since these conditions continually change 

as a normal course of the daily temperature and humidity cycles, new moisture contents need to 

be periodically determined. It is a good idea to conduct moisture contents tests at least two times 

daily, in the morning and afternoon.

The moisture condition of any aggregate and its effect on the concrete mix water can be found by 

subtracting the existing moisture content of the aggregate, determined according to AASHTO T 

255 from the aggregate absorption determined according to AASHTO T 84 and T 85. If the 

existing moisture content is less than the absorption, as in the case of air dry aggregate, the result 

will be negative and the aggregate will absorb some of the mixing water. If the existing moisture 

content is greater than the absorption, as in the case of the wet aggregate, the result will be 

positive and the aggregate will provide excess mixing water. In both cases, the amount of water 

added at the batch plant needs to be adjusted to account for the moisture condition of the 

aggregates such that the water requirement of the approved mix design can be maintained. Form 

FHWA 1638, Worksheet for Determining Concrete Batch Moisture/Absorption Corrections, can 

be used as a means of checking that adjustments have been properly calculated and performed. 

In this manner, the Project Engineer can verify that water content of the approved mix design has 

not been exceeded.

5.5.2 Fresh Concrete Properties

For structural concrete and minor concrete, fresh concrete properties inclusive of slump, air 

content, unit mass and temperature must be measured and evaluated for acceptance. The 

specific sampling, testing and properties requirements are included in the contract specifications. 

They define the frequency, methods for evaluation and allowable tolerances. The importance of 

proper sampling and testing cannot be over emphasized. Only by following proper procedures for 

fresh concrete sampling and testing can the quality of the delivered product be evaluated. The 

Project Engineer should witness fresh concrete properties testing for acceptance and take 

possession of the Governments portion of the concrete cylinders for future hardened concrete 

properties testing. Typical fresh concrete testing includes methods shown in Exhibit 5-58.
Division 500 – Concrete January 2020

5-44 Concrete Construction Requirements

Exhibit 5-58 Fresh Concrete Test Methods

Concrete Test Test Method Concrete Characteristics

Sampling Fresh Concrete AASHTO R 60 Proper method for obtaining 

fresh concrete sample

Slump AASHTO T 119 Concrete consistency and 

uniformity

Air content AASHTO T 152

AASHTO T 196

Freeze / thaw resistance

Temperature AASHTO T 309 Temperature of mixture for 

proper placement

Unit Weight AASHTO T 121 Yield

Making Test Specimen AASHTO T 23 Proper method for making, 

curing and transporting 

cylinders

The frequency of sampling is established in the contract and is typically one sample per 30 cubic 

yards (25 cubic meters) but not less than one per day. The truck loads or batches of concrete to 

be tested must be selected on a random basis by the Project Engineer before commencement of 

the concrete placement. 

5.5.2.1 Sampling

Fresh concrete is sampled in accordance with AASHTO R 60. Samples are acquired from the 

discharge stream at the point of placement. They should be taken between the 10 and 90 percent 

points of the discharge. Concrete should be collected in two or more portions at regularly spaced 

intervals throughout the discharge stream. The elapsed time should not exceed 15 minutes 

between taking the first and final portions of the sample. The samples should be transported to a 

place where fresh concrete property tests are to be conducted and remixed with a shovel. Slump, 

temperature and air content tests should be started within five minutes after sampling whereas 

molding specimens for compressive strength testing should initiate within 15 minutes after 

sampling.

5.5.2.2 Concrete Slump

The slump test is conducted in accordance with AASHTO T 119. It is a measure of concrete 

consistency or uniformity. The standard slump cone is filled in three layers of approximate equal 

volume and each layer is rodded 25 times with a standard rod. The top layer of concrete is 

horizontally struck off to a flat surface and the slump cone is vertically raised to allow the concrete 

to slump. The slump cone is placed next to the slumped concrete and the slump rod is placed 

horizontally on top of the slump cone. Concrete slump is measured as the vertical distance from 

the displaced original center of the top surface of the fresh concrete to the bottom of the rod. 

Slump is measured to the nearest 1⁄4 inch (5 mm) and recorded.

5.5.2.3 Air Content

Air content can be measured by use of a pressure air meter (AASHTO T 152) or a volumetric air 

meter (AASHTO T 196). Pressure air meters are calibrated to read air content directly as pressure 
Division 500 – Concrete January 2020

Concrete Construction Requirements 5-45

is applied. Since the measured air content includes air that is trapped in aggregates, a small 

aggregate correction factor must be subtracted from the pressure meter gauge reading to obtain 

the correct air content. Pressure type meters cannot be used with porous or lightweight aggregate. 

Type A pressure meters must be calibrated at the elevation at which they are used since changes 

in barometric pressure will affect the function of the meter. Volumetric air meters can be used 

with concrete containing any type of aggregate. They can be used at different elevations and do 

not require an aggregate correction factor. Volumetric air meters utilize isopropyl alcohol to 

accelerate air removal and dispel foam. Concrete is placed in the air meter container in three 

equal layers and rodded in a fashion similar to that of the slump test. After each layer is rodded, 

the sides of the air meter container are tapped with a rubber or rawhide mallet to close any voids 

left by the rod and to release any trapped air. Air content is measured to the nearest 0.1 percent 

and recorded.

5.5.2.4 Concrete Temperature

Concrete temperature is measured in accordance with AASHTO T 309 to assess whether the 

concrete is too hot or too cold at the time of placement. When performing a temperature 

measurement, the sensor should be placed within the fresh concrete at a location that allows it to 

be completely immersed and surrounded by at least three inches (75 mm). The temperature 

measuring device is left in place and monitored for at least two minutes or until the concrete 

temperature stabilizes before a reading is acquired. Temperature is measured to the nearest 1°F 

(0.5°C) and recorded.

5.5.2.5 Concrete Unit Weight

AASHTO T 121 is used to verify batch weights, to determine yield and to measure gravimetric air 

content. The test requires knowledge of mixture proportions in order to calculate yield and air 

content. The size of the unit weight container used for measurement varies with the maximum 

aggregate size of the mixture being tested. The air meter container is typically used to measure 

unit weight.

5.5.3 Hardened Concrete Properties

Compressive strength is the main hardened concrete property that is tested and evaluated. It is 

important to fabricate, cure, and handle the specimens appropriately. AASHTO T 22 provides the 

method for testing concrete specimens for compressive strength. Compressive strength concrete 

cylinders are made and cured on a construction project in accordance with AASHTO T 23. 

Cylinder molds must be made of watertight, non-absorbing material that is capable of holding its 

dimensions and shape under use. Cylinder length must be twice the diameter. Cylinder diameter 

must be at least three times the nominal maximum size of the coarse aggregate. Standard 6 by 

12-inch (150 by 300 mm) cylinders are typically used when the nominal maximum size of the 

coarse aggregate does not exceed 2-inches (50 mm). However, AASHTO T 23 does allow the 

use of 4 by 8-inch (100 by 200 mm) cylinders when the nominal maximum size of the coarse 

aggregate does not exceed 1-inch (25 mm).

For concrete slumps greater than 1-inch (25 mm), cylinders may be consolidated by rodding or 

internal vibration. The number of required layers as well as the roddings or vibrator insertions per 

layer varies in conjunction with the cylinder size. After consolidation, the top surfaces are finished 

with a wood float or trowel to produce a flat even surface that is level with the mold edge. 
Division 500 – Concrete January 2020

5-46 Concrete Construction Requirements

Cylinder specimens may be either field cured or standard cured. Field cured cylinders are marked 

for identification, stored near the point of deposit of the concrete and subjected to the same 

temperature and environment as the structural work. They are tested in the moisture condition 

resulting from the specified curing treatment.

Standard cured cylinders are subjected to a twofold process consisting of initial and final curing. 

During initial curing, cylinders are marked for identification and placed within a level, protected 

and controlled on-site storage area immediately after molding and finishing. They are initially 

cured for up to 48 hours in a controlled environment that provides temperatures between 60 to 

80°F (16 to 27°C) and prevents moisture loss. For concrete mixtures with a specified strength of 

6000 psi (40 MPa) or greater, the initial curing temperatures must be controlled between 68 and 

78°F (20 and 26°C).

Cylinders must not be transported for final curing until at least 8 hours after final set. During 

transportation, cylinders must be protected from moisture loss, freezing and jarring. After arrival 

at the testing laboratory, the molds are removed. Cylinders are then final cured with free water 

maintained on their surfaces at all times at a temperature of 73 ± 3°F (23 ± 2°C) using water 

tanks or moist storing rooms.

Compressive strength testing is conducted in accordance with AASHTO T 22. In order to be 

tested, specimens must be within the specified tolerances for diameter and the ends must be 

plane. Specimens may need one or both ends trimmed or ground prior to testing if they do not 

meet planeness requirements. Immediately prior to testing, cylinders must be capped using 

bonded or unbonded material. Bonded caps consist of sulfur mortar, high strength gypsum 

plaster, neat cement paste or other materials. They must meet the requirements of AASHTO T 

231. Unbonded caps consist of neoprene pads or other materials that are used in conjunction 

with capping plates. They must meet the requirements of ASTM C1231. 

AASHTO T 22 provides permissible time tolerances for various test ages (ranging from 12 hours 

to 90 days) in which test specimens must be broken. The permissible time tolerances for 7 and 

28-day test ages are 6 and 20 hours, respectively. 

Specimens are tested by compression loading at a constant rate to failure. The type of fracture, 

maximum load, cross-sectional area and calculated compressive strength are recorded. Length 

and diameter measurements are also made prior to testing. If the specimen length-to-diameter 

ratio is 1.75 or less, the length and diameter measurements must also be recorded and the 

compressive strength corrected by the appropriate correction factor.

The compressive strength of concrete cylinders is dependent upon the moisture condition, curing 

temperature and specimen size and shape. For these reasons compressive strength data 

obtained from field cured and standard cured specimens are used for different purposes. 

Compressive strength data obtained from field cured specimens (cured with the structure) may 

be used for the purposes of:

• Determination of whether a structure is capable of being placed into service

• Comparison with test results of standard cured specimens or with test results from various 

in-place test methods (destructive and nondestructive)
Division 500 – Concrete January 2020

Concrete Construction Requirements 5-47

• Adequacy of curing and protection of concrete in the structure

• For falsework or shoring removal time requirements

Compressive strength data obtained from standard cured specimens (initially cured in the field 

and final cured in a water storage tank or fog room) may be used for the purposes of:

• Acceptance testing for specified strength

• Checking the adequacy of mixture proportions for strength

• Quality control

For acceptance testing, the FP requires the compressive strength cylinders to be standard cured 

and tested at 28-days. At least four 6 by 12 inch (150 by 300 mm) or six 4 by 8 inch (100 by 200 

mm) cylinders should be molded and cured for each sample taken from the same load. Two 6 by 

12 inch (150 by 300 mm) or three 4 by 8 inch (100 by 200 mm) cylinders are typically tested for 

acceptance at 28-days age with the compressive strength result being the average of the tests. 

The other cylinders are retained or used for informational purposes such as obtaining 7-day 

strengths. They may also be used for acceptance testing if specimen(s) that have been previously 

tested show evidence of improper sampling, molding or testing and have to be discarded. 

The Project Engineer should closely monitor the compressive strength of the concrete during the 

construction process. If low strength test results occur, designers must perform calculations to 

assure that the load-carrying capacity of the structure is not impaired. If the likelihood of lowstrength concrete is confirmed and there is a need for additional investigation, tests of cores drilled 

from the area in question may be performed. If it is necessary to obtain cores, the specimens will 

be obtained in accordance with AASHTO T 24. Contact the Division Materials Engineer for 

specific guidance regarding the sampling and testing of concrete that does not meet the contract 

compressive strength requirement.
Division 500 – Concrete January 2020

5-48 Shotcrete

5.6 SHOTCRETE

The term shotcrete is used to describe a process where mortar or concrete is pneumatically (by 

the pressure or exhaustion of air) projected at high velocity onto a surface. The process may be 

wet mix or dry mix. In the wet-mix process, all of the mix ingredients, including water, are mixed 

together, sent to the delivery hose and projected through a nozzle into which compressed air is 

injected. In the dry-mix process, all mix ingredients, except water, are mixed together, carried 

through the delivery hose by compressed air and projected through a nozzle into which water is 

injected. Both types of processes are permitted and will typically produce shotcrete suitable for 

normal construction requirements.

The wet-mix process facilitates more accurate measurement of mix water, assures thorough 

mixing of water with other ingredients, promotes less dust, results in lower rebound and overspray 

and provides a higher volume of mix for a given hose size. The dry-mix process provides 

instantaneous adjustment of the mixing water in accordance with variable field conditions, 

facilitates transport of materials over longer distances, allows for easier movement of delivery 

hoses, assures better consistency of mixtures containing lightweight aggregates and provides a 

lower volume of mix for a given hose size. 

On FLH projects conventional shotcrete has been used for walls, shafts, foundation shoring, 

artificial rock, slope protection, erosion control, structural steel encasement and repair for 

deteriorated concrete.

5.6.1 Shotcrete Material Specifications

Shotcrete is composed of the same basic materials as structural concrete, namely hydraulic 

cement, mineral admixtures, water, aggregates, chemical admixtures and fibers. As such, the 

standard specifications for each of these materials, except aggregates, and the pertinent 

subsections of the FP which reference these material standards are applicable to shotcrete. For 

additional information, see Section 5.2.

The FP specifies that shotcrete fine and coarse aggregate must conform to AASHTO M 6, class 

B and AASHTO M 80, class A, respectively, including FP supplemental requirements. The fine 

and coarse aggregate source quality characteristics are similar to those shown in Exhibits 5-5 

and 5-6, although the testing limitation requirements are different for shotcrete coarse aggregate. 

Shotcrete aggregate must meet a combined grading requirement. The coarse aggregate amount 

is limited to less than 30 percent of the total mass. Shotcrete with more than 30 percent coarse 

aggregate has greater rebound, is more difficult to finish, cannot be used for thin layers and 

creates voids in the plastic shotcrete when shot at high velocity. The specific combined grading 

requirement is specified in the FP or by special contract requirements. 

Acceptance of shotcrete materials is in the same fashion as acceptance of concrete materials. 

See Section 5.3 for an applicable discussion pertaining to materials certification acceptance as 

well as water and aggregate acceptance.
Division 500 – Concrete January 2020

Shotcrete 5-49

5.6.2 Shotcrete Mixture Proportioning and Preconstruction Requirements

The FP requires shotcrete mixtures to conform to specific ACI practices, specifications and guides 

including:

• ACI 506R Guide to Shotcrete

• ACI 506.2 Specification for Shotcrete

Shotcreting is a process which is highly dependent upon the specific equipment used, the unique 

placement skills of the nozzle operator and crew and conditions at the job site. Because of these 

factors, it is not standard practice to conduct laboratory trial mixtures. Instead, proposed shotcrete 

mix designs are submitted and preconstruction testing is performed in an environment that 

simulates actual job conditions to assess the quality of shotcrete produced by the crew and 

equipment that are proposed for use on the job. Shotcrete test panels are shot as a means to 

approve mix designs and pre-qualify crew and equipment.

5.6.2.1 Fresh Shotcrete Properties Sampling and Testing

Fresh shotcrete properties sampling and testing should be in accordance with ASTM C1385, 

which requires composite samples. A composite sample consists of several individual samples 

which are taken at various times during discharge and then combined into a single sample for 

testing. The final composite sample size must be large enough to perform the required tests. 

Sampling is performed as shotcrete material is delivered to the shotcrete machine.

For dry-mix shotcrete, the material is acquired by collecting two or more portions taken at regularly 

spaced intervals during discharge of the middle of the batch or at two or more random portions 

from the discharge of continuous mixers. The portions are combined into one sample for testing 

purposes. Portions should not be acquired from the first or last 15 percent of the discharge.

For wet-mix shotcrete, the sampling procedure is the same as the dry-mix process except the 

elapsed time between obtaining the first and last portions of the composite sample are as short 

as possible but no longer than 15 minutes.

Tests for air content by either AASHTO T 152 or AASHTO T 196 and unit mass per AASHTO T 

121 must initiate within five minutes after obtaining the last portion of the composite sample. See 

Section 5.5.2 – Fresh Concrete Properties for discussion of these tests.

5.6.2.2 Making and Curing Shotcrete Test Panels

Test panels are prepared and tested in accordance with ASTM C1140. Separate test panels are 

fabricated for:

• Each proposed test mixture representing each admixture type and dosage

• Each nozzle operator being qualified in association with each shooting position 

encountered at the jobsite (i.e. horizontal, vertical, overhead).

The test mixture must be of the same materials, admixtures and proportions proposed for use on 

the project as well as meet the required fresh and hardened concrete properties. The shotcrete 
Division 500 – Concrete January 2020

5-50 Shotcrete

must be applied using the same equipment, operating pressures and personnel as those 

proposed for the project. 

Test panels must be constructed of wood or steel that is sufficiently rigid to prevent dislodging of 

shotcrete through vibration or deformation. To evaluate shotcrete mixture properties, mixture 

proportion test panels, containing no reinforcement are fabricated to a minimum width and length 

of 24 inches (600 mm) and a minimum depth of 6 inches (150 mm) with either square or sloped 

sides. When shotcrete is applied over reinforcement, additional test panels are constructed to 

evaluate reinforcement encasement and to determine the water-soluble chloride-ion 

concentration of the shotcrete mix ingredients. These panels must contain reinforcement of the 

same size and spacing as that required for the work. They must also be large enough to simulate 

jobsite conditions and are typically fabricated to a minimum width and length of 30 inches (760 

mm) and a minimum depth of 3 inches (75 mm) with either square or sloped sides.

Panels containing no reinforcement are generally used to evaluate mix designs whereas panels 

containing reinforcement are used to prequalify personnel, equipment and application techniques. 

In instances where project shotcrete will not be applied over reinforcement, mixture proportioning 

panels containing no reinforcement are also used for prequalification purposes. Once nozzle 

operators and equipment have been approved, panels containing reinforcement are no longer 

constructed or evaluated on a project (i.e. they are needed for preconstruction testing purposes 

only). 

Panels must be cured by tightly wrapping with a sheeting material meeting the requirements of 

ASTM C171 or stored in a moist room meeting the requirements of AASHTO M 201 as soon as 

is practicable after fabrication.

5.6.2.3 Hardened Shotcrete Properties Testing

Three-inch (75 mm) diameter cores are drilled from test panels to evaluate the compressive 

strength of the shotcrete mixture, the quality of the shotcrete coating produced by the nozzle 

operator and the water soluble chloride ion concentration of the mix ingredients. Cores are drilled, 

moisture conditioned and delivered to the designated laboratory for testing in accordance with 

contract specifications. 

To evaluate compressive strength, at least three strength cores are drilled from mixture 

proportioning test panels, which contain no reinforcement, in accordance with AASHTO T 24. The 

3-inch (75 mm) diameter cores must be acquired from the central 15 by 15 inch (380 by 380 mm) 

sample area and drilled perpendicular to the surface. Core ends should be sawed to ensure 

parallel, flat and smooth surfaces. Core specimens with length to diameter ratios equal to or less 

than 1.75 require corrections to the measured compressive strength. A 28-day compressive 

strength test result is calculated as the average strength of three individual core specimens taken 

from the same test panel. Additional cores can be obtained and used for information purposes 

such as obtaining 7-day strengths or other tests. They may also be used for mix design approval 

testing if specimens that have been previously tested show evidence of improper sampling, coring 

or testing and have to be discarded.

To evaluate the quality of the shotcrete coating that does not contain reinforcement, at least three 

samples are obtained in accordance with AASHTO T 24 from each mixture proportioning test 

panel that has been cured at least seven days. Samples may consist of cores or pieces of cores 
Division 500 – Concrete January 2020

Shotcrete 5-51

or test panels that are free from observable cracks, fissures or shattered edges. The samples are 

tested in accordance with ASTM C642 for density, boiling absorption and permeable void volume. 

No individual test may be greater than the maximum permissible boiling absorption and 

permeable void volume shown in the contract. 

To evaluate the quality of the shotcrete coating for reinforcement encasement, at least three cores 

are obtained in accordance with AASHTO T 24 from nozzle operator and shooting position test 

panels that have been cured at least seven days. Cut surfaces are visually examined to check 

the uniformity of the shot material and to provide a basis for qualifying each nozzle operator in 

accordance with ACI 506.2. Cores are visually examined for voids, sand pockets, laminations, 

complete reinforcement encasement and other inadequacies. When initial prequalification test 

panel is rejected by the Project Engineer, a second test panel may be shot. 

Additionally, the cores obtained for visual examination or others acquired from each test panel 

containing reinforcement are typically analyzed in accordance with ASTM C1218 at ages from 28 

to 48 days to assess the water-soluble chloride ion concentration of the mix ingredients. No 

individual test may be greater than the maximum permissible water soluble chloride ion content 

shown in the contract. Water soluble chloride ion content analysis is performed during 

preconstruction testing only. 

The discussion provided above is generalized to a typical shotcrete process. The FP as 

supplemented by special contract requirements provides the specific requirements for the 

preconstruction testing and the nozzle operator approval process for each project. The testing, 

evaluation and approval must be completed before proceeding to shotcrete construction.

5.6.3 Shotcrete Mixture Approval Requirements

The FP requires shotcrete mix designs be submitted for approval. The submittal must be received 

at least 30 days before placing shotcrete. 

The contractor must submit the required information to the Project Engineer who in turn will submit 

it to the Division Materials Engineer for approval. The Division Materials Engineer will review the 

submittal to ensure compliance with the contract requirements. Once the mix design and 

preconstruction testing has been approved, shotcrete construction may initiate.

5.6.4 Shotcrete Construction Requirements

The ACI practices, specifications and guides noted in the FP should be consulted regarding 

industry standards for producing shotcrete of acceptable quality throughout the construction 

process. The importance of proper sampling and testing cannot be over emphasized.

The FP requires that the as produced aggregate used in the shotcrete be sampled, tested and 

evaluated during construction. Combined aggregate gradation tests must be conducted to verify 

the uniformity of the supply. In addition, the Contractor should ensure that the water content of 

shotcrete mixture is adjusted in accordance with existing moisture conditions of the aggregate, 

which fluctuate in accordance with environmental conditions at the mixing plant site. Batch water 

content adjustments have been previously discussed in Section 5.1
Division 500 – Concrete January 2020

5-52 Shotcrete

The Project Engineer must ensure that the Contractor follows proper procedures for fresh 

shotcrete sampling and testing as well as witness the associated results for acceptance. The 

procedures used during construction are the same as for preconstruction. Shotcrete is typically 

tested and evaluated for air content, unit mass and compressive strength. The sampling and 

testing table included in the specifications provides guidance and direction on the sampling 

frequency and acceptance procedures. It is noted that wet mix shotcrete air content values are 

typically specified and applicable to composite samples that have been acquired from material 

delivered to the shotcrete machine prior to pumping. It is therefore expected that shotcrete will 

lose some entrained air during the pumping process and that the in-place air content will be less 

than the pre-pumped air content. The amount of air loss after pumping should be checked 

periodically. The final in-place air content should be at least 4 percent.

The compressive strength of the shotcrete is evaluated statistically during construction. A single 

compressive strength test result is the average result from three cores taken from the same test 

panel and tested at 28 days. The sampling and testing table included in the specifications will 

define the frequency for constructing panels to obtain cores for the compressive strength 

evaluation. The Project Engineer must ensure that the contractor follows proper procedures for 

making and curing test panels and obtaining compressive strength cores for hardened shotcrete 

properties acceptance testing. 

The compressive strength and quality of the shotcrete coating must be closely monitored by the 

Project Engineer during the construction process. The shotcrete coating should also meet boiling 

absorption and permeable void volume requirements. If the compressive strength or quality of the 

shotcrete coating is unacceptable, corrective action must be taken before continuing shotcrete 

construction. If low strength test results occur, designers must perform calculations to assure that 

the load-carrying capacity of the structure is not impaired. If the likelihood of low-strength 

shotcrete is confirmed and there is a need for additional investigation, tests of cores drilled from 

the area in question may be performed. If it is necessary to obtain cores, the specimens will be 

obtained in accordance with AASHTO T 24. Contact the Division Materials Engineer for specific 

guidance regarding the sampling and testing of shotcrete that does not meet the contract 

compressive strength or coating quality requirements.
Division 500 – Concrete January 2020

Driven Piles 5-53

5.7 DRIVEN PILES

Materials requirements for driven piles depend on the pile type. Typical piles include:

• Steel H-piles

• Concrete-filled steel shell piles

• Concrete-filled pipe piles

• Precast concrete piles

• Prestressed concrete piles

• Sheet piles and 

• Timber piles.

Driven piles are normally required to comply with AASHTO or ASTM materials requirements. 

Detail materials specifications are provided in Section 715 of the FP.

5.7.1 Steel H-piles

The FP requires that steel H-piles be fabricated from structural steel conforming to ASTM A572, 

ASTM A588, or ASTM A690, Grade 50 (345). The piles should be of the specified steel grade, 

length and section/weight. Steel H-piles sometimes require toe attachments (shoes) for hard 

driving conditions. Shoes fabricated from cast steel conforming to ASTM A27, Grade 65-35 (450-

240) or ASTM A148, Grade 90-60 (620-415) are recommended because of their strength and 

durability. H-piles are easily spliced either by full penetration groove welding along the web and 

both flanges or with manufactured splicers. Steel for manufactured splicers should also conform 

to ASTM A572, ASTM A588, or ASTM A690, Grade 50 (345).

5.7.2 Concrete-filled Steel Shell Piles

The FP requires that steel shell piles be either cylindrical or tapered pile shells of spiral welded, 

straight-seam welded, or seamless tube steel material. Steel shells can be driven with or without 

a mandrel, a heavy tubular steel section inserted into the pile to improve drivability. Mandrel driven 

steel shells are often fabricated from corrugated steel conforming to ASTM A36. Separate shell 

sections are usually screw-connected and waterproofed with an o-ring gasket. Steel shells that 

are driven without a mandrel are typically tapered or step-tapered and are required to be 

fabricated from no less than 3/16-inch plate stock conforming to ASTM A36. Separate shells 

driven without a mandrel may be either spirally welded or longitudinally welded. Concrete and 

reinforcement steel should comply with Sections 552 and 554.

5.7.3 Concrete-filled Pipe Piles

Pipe piles consist of seamless, welded or spiral welded steel pipes. The FP requires ASTM A252, 

grade 2 or 3 steel pipe piles. Pipe piles may be driven either open or closed end. Closed end pipe 

piles should be closed by welding a flat steel plate meeting ASTM A572, ASTM A588, or ASTM 

A690, Grade 50 (345). The pipe piles should be of the specified steel grade, length and minimum 

wall thickness. Typically pipe piles are spliced using full penetration groove welds. Manufacture

splices, conforming to ASTM A572, ASTM A588, or ASTM A690, Grade 50 (345), should only be 

used if the splice can provide full strength in bending. Open ended piles may be reinforced with a 

steel cutting shoes meeting AASHTO M 103. Concrete should comply with Section 552.
Division 500 – Concrete January 2020

5-54 Driven Piles

5.7.4 Precast / Prestressed Concrete Piles

Precast and prestressed concrete piles are required to be manufactured to the applicable class 

of concrete specified in the contract. Additionally, they must have reinforcement consisting of a 

steel cage made up of several longitudinal bars or prestressing steel and lateral or tie steel in the 

form of individual hoops or a spiral. The piles should be of the specified length and section. 

Concrete piles should not be moved or transported until they have cured the minimum specified 

number of days or until concrete cylinders indicate that the concrete has reached the specified 

compressive strength requirements. Concrete piles delivered to the site should be free of cracks 

and spalling. They should be stored above ground with adequate blocking to prevent undue 

bending. Concrete piles can be difficult to splice and extend. The FP requires dowels or other 

acceptable mechanical means to splice precast and prestressed concrete piles. The contractor 

must submit drawings of proposed splices for acceptance. A short piece of structural H-section 

or “stinger” may be cast into or attached to the pile toe to assist in penetration. Concrete and 

reinforcement steel should comply with Sections 552, 553 and 554.

5.7.5 Sheet Piles

Sheet piles may be timber, reinforced concrete, vinyl, fiberglass, or plastic, but are most 

commonly steel. Steel sheet piles need to conform to AASHTO M 202 or ASTM A572. Timber 

and reinforced concrete sheet piles should conform to the same material requirements as timber 

and precast concrete piles. Vinyl, fiberglass and plastic sheet piles should conform to the 

manufacturers and special contract requirements. Joints between sheet pile sections should be 

made practically watertight when the piles are in place.

5.7.6 Timber Piles

Timber piles may be treated or untreated depending on the in-place conditions. Timber piles need 

to conform to AASHTO M 168 and treated, if required, according to AASHTO M 133, pressure 

method procedure AWPA Standard C1. Treated timber piles should be imprinted with the name 

of the treating company and type and year of the treatment according to AWPA Standards M1 

and M6. The FP requires that timber piles be fabricated from Douglas fir, Larch, Red pine, Red 

oak or Southern pine. Steel straps are required to be placed on timber piles at not more than 10-

foot centers. The timber piles should be of the specified species, minimum length, and have the 

correct pile toe and butt sizes. The twist of spiral grain and the number and distribution of knots 

should be acceptable and the pile should be acceptably straight. Timber pile splices are difficult 

and generally undesirable. Cast steel shoes conforming to ASTM A27, Grade 65-35 (450-240) or 

ASTM A148, Grade 90-60 (620-415) should be used in hard driving situations.

5.7.7 Driven Piles Materials Acceptance

Driven pile materials acceptance, as stipulated in the FP, is based on visual inspection and 

certification. The contractor is required to furnish production certifications with each shipment of 

concrete piles, sheet piles, steel H-piles, steel shells, steel pipes and treated timber piles.

5.7.8 Driven Pile Materials Sampling and Testing

Concrete for steel shells and pipe piles are required to be sampled and tested according to 

Section 552. 
Division 500 – Concrete January 2020

Painting 5-55

5.8 PAINTING

Protective coating systems are widely used on bridge and highway structures primarily for 

corrosion control of metals and to protect timber and concrete from deterioration. The coating 

system protects by isolating the environment from the substrate, by barrier, sacrificial means or a 

combination. There are many ingredients that constitute a coating material, but they can generally 

be categorized as non-volatiles and volatiles. The non-volatile component is that which remains 

on the surface after the volatile component evaporates. Non-volatiles include resins, pigments 

and additives. The resin or binder is the film-forming component of the coating. It promotes 

adhesion to the substrate or previous coating layers. Resin systems include acrylic, alkyd, oil, 

vinyl, epoxy, and urethane. The pigment gives the coating system its color and determines gloss 

level, but can also be used for corrosion resistance, act as a barrier and to increase the solids 

content. Additives are used to adjust certain properties of the coating. The volatile component is 

a solvent or solvent blend. The solvents are used to dissolve the resin in the coating and reduce 

the viscosity so that it can be applied. The non-volatiles are stated as a percentage of the total 

volume, known as the “Solids by Volume”. The percentage of solids by volume is used to calculate 

wet film thickness and coverage rates of the coating.

5.8.1 Coating System Components

A coating system includes the surface preparation and the application of a specified number of 

coats. The coats include a primer, intermediate and top. Each coat requires the application of 

multiple passes to achieve the specified thickness. Contrasting colors are often used to assist the 

contractor in assuring coverage. Each coating layer has a specific purpose. The primer provides 

adhesion to the substrate and can act as a barrier, rust inhibitor or sacrificial layer. The 

intermediate coat provides additional barrier protection, thickness and forms a tie between the 

primer and top coat. The top coat is used for aesthetics and corrosion protection. For a successful 

coating system it is critical to ensure that the specified surface preparation has been achieved 

and that each coat is applied to the specified thickness.

5.8.2 Coating Types

The following generic coating types are specified in the FP:

• Alkyd

• Epoxy

• Urethane

• Moisture cured urethane

• Zinc-rich and

• Acrylic latex.

5.8.2.1 Alkyd

Alkyd coatings are relatively inexpensive, flexible, easy to apply and can be modified with other 

resin systems for enhanced characteristics. An alkyd modified with silicone will provide good 

ultraviolet resistance and gloss retention. Alkyds cure by oxidation and can be very slow drying. 

They can also tend to chalk and fade (without silicone modification), have fair to poor acid and 

alkali resistance and poor solvent resistance. 
Division 500 – Concrete January 2020

5-56 Painting

5.8.2.2 Epoxy

Epoxy coatings exhibit excellent adhesion, acid, alkali and solvent resistance and good flexibility. 

They offer abrasion, corrosion and chemical resistance. Epoxy coatings cure by cross-link 

polymerization. If too much time passes before top coating, they may harden to the point where 

subsequent coats will not adhere. Epoxy coatings are two-component and must be mixed properly 

to achieve full cure. They have a limited pot life and have poor resistance to sunlight.

5.8.2.3 Urethane

Urethanes are commonly specified as top coats because they have superior gloss and color 

retention. They also have good adhesion, as well as good acid, alkali, impact and abrasion 

resistance. Urethane coatings are typically higher priced than other coatings. They are sensitive 

to moisture during curing and may develop a haze or blush that must be removed prior to top 

coating and they can cause pinholing in the top coat. Urethanes cure by cross-link polymerization 

and require careful mixing to achieve full cure. They also have a limited pot life.

5.8.2.4 Moisture-cured Urethane

Moisture-cured urethane coatings cure by a reaction with moisture in the air. They are single 

component, surface tolerant, easy to apply and some can cure at low temperatures. They also 

have excellent chemical and solvent resistance and gloss retention. During packaging, a “nitrogen 

blanket” is floated along the top of the coating prior to sealing the lid. Once opened, the nitrogen 

dissipates, exposing the content to moist air. The coating may subsequently harden in the 

container, even if the lid is re-secured. The minimum relative humidity should be 40 percent during 

application and curing of moisture-cured urethane coatings.

5.8.2.5 Zinc-rich

Zinc-rich coatings are primarily used as primers to provide galvanic protection. There are two 

categories of zinc-rich coatings: inorganic and organic. The difference is with the binder. Inorganic 

zinc-rich coatings contain an inorganic binder such as ethyl silicate, while organic zinc-rich 

coatings contain an organic binder such as, alkyd, vinyl, epoxy and urethane. The inorganic zincrich coatings may provide better corrosion protect but are not as easy to apply as the organic 

zinc-rich coatings. The inorganic zinc-rich coatings are less tolerant of deficient surface 

preparation and can mudcrack at excessive thickness and are more difficult to topcoat. They are 

also very porous and can cause pinholes in the top coat.

5.8.2.6 Acrylic Latex

Acrylic latex coatings are relatively easy to apply and clean up. They cure by solvent evaporation 

and coalescence. Because the solvent system is primarily water, these coatings comply with VOC 

regulations. Acrylic latex coatings have poor resistance to alkali and solvent, and have moderate 

abrasion resistance. They must be applied in temperatures above 50 °F.
Division 500 – Concrete January 2020

Painting 5-57

5.8.2.7 Vinyl

Vinyl top coats were regularly used by highway agencies in the past. However, vinyl coatings are 

typically 65-70% solvent. Therefore, vinyl coatings are typically not VOC compliant and are no 

longer used on highway structures.

5.8.3 Curing

There are four basic coating curing mechanisms:

• Solvent evaporation

• Polymerization

• Oxidation

• Moisture cure

Coatings that cure by solvent evaporation contain a resin and pigment in a solvent blend. The 

solvent evaporates leaving the resin and pigment behind. Because there is no chemical reaction 

the resin can be redissolved. Therefore, coating that cure by solvent evaporation cannot be over 

coated with a coating containing strong solvents, as it will dissolve the underlying layer. Acrylic 

latex coatings cure by solvent evaporation. Coatings that cure by polymerization are multicomponent. The components, once mixed together, react chemically to form a solid, rigid, 

resistant coating film. Coatings that cure by polymerization include two part epoxies, urethanes 

and two part organic zincs. Similar to polymerization, oxidation is the reaction of two components 

to form a single coating layer. However, the coatings are one component and oxygen in the 

atmosphere is the catalyst. Alkyds cure by oxidation. Moisture cure coatings react to moisture to 

cure. Moisture cure coatings include inorganic zinc-rich primer and moisture-cure urethane.

5.8.4 Surface Preparation

Surface preparation is the key element in determining the ultimate success or failure of a 

protective coating system. Prior to surface preparation, structural steel and concrete surfaces may 

require some amount of repair. For steel surfaces, welding, cutting, grinding or filling of crevices 

may be required. For concrete surfaces, patching and filling cracks and pores with surfacing 

compounds may be required. The purpose of surface preparation is to impart a specified level of 

cleanliness and roughness into the surface. This can in some cases be achieved in one step, 

however, cleanliness and roughness are two different specification criteria and must be examined 

independent of one another. There are eleven cleanliness standards provided in the Society for 

Protective Coatings (SSPC) specifications. The standards typically used for cleaning steel 

structures include solvent cleaning, hand tool cleaning, power tool cleaning, commercial blast 

cleaning, and near-white blast cleaning. Contact the Division Materials Engineer for SSPC 

specifications and visual reference guides for surface preparation.

5.8.5 Application

It is important to review and be familiar with the Manufacturer’s product data sheets. They have 

important information that is critical to a successful application. They should also be reviewed to 

make sure that they comply with the specifications. There are three primary methods of 

transferring the coating material from the can to the surface. These include brush, roller and spray. 

The contractor will choose the method of application based on the coating type and location of 
Division 500 – Concrete January 2020

5-58 Painting

application. Regardless of the application method selected the coating must be applied to provide 

uniform coverage to the specified thickness.

5.8.6 Inspection

The painting contractor is required to be certified according to SSPC-QP1, “Painting of Complex 

Industrial Structures” and SSPC-QP2, “Removal of Toxic Coatings form Complex Industrial 

Structures”. The approved contractor’s quality control plan should identify the personnel 

responsible for painting inspections and should include a detail list of quality control test to be 

performed. Inspections should include verifying the removal of weld spatter, grinding of sharp 

edges and removal of grease, oil, dirt and debris, prior to surface preparation. Measurements 

should be made and recorded for the weather conditions, including air and wet bulb temperature, 

relative humidity, dew point temperature, surface temperature and wind velocity. Readings should 

be taken about every four hours, more often if conditions appear to be changing. Weather 

conditions should be within the limits of specifications and the coating manufacturer’s data sheets. 

Cleanliness and surface profile should also be verified prior to applying the coating. If compressed 

air is used, the cleanliness of the compressed air should be verified. Inspections of the coating 

materials should be performed to verify that the components are mixed properly, proper thinning 

procedures are being followed and that materials are discarded once the pot life has expired. At 

the start of the application, the inspector should verify that good coating application techniques 

are being used. After the coating is applied the wet and dry film thicknesses need to be measured. 

Finally, adhesion and gloss retention may also be checked.

It is a good idea to have a pre-painting meeting to identify the role and responsibilities of those 

involved, and to discuss safety measures, contractual details and inspection and measuring 

requirements.

5.8.7 Safety

The contractor is required to submit a plan for approval that details the measures to be used for 

protecting the environment, public, adjacent property and workers. The primary source of 

information for coatings, thinners and abrasive blasting material is the Material Safety Data 

Sheets (MSDS). The contractor is responsible for ensuring that MSDSs are available for each 

chemical used on the jobsite and are readily accessible to employees when they are in the work 

area. Employees should follow the precautions for safe handling and use personal protective and 

mechanical equipment if required. In addition all containers must be labeled, marked and tagged. 

The contractor safety plan should also include information about fall protection/fall prevention. 

Approved fall protection/fall prevention systems should be used during painting operations.

Toxic metals, including lead and chromium, may be found in paints or coatings already in place 

on bridges. The contractor must follow all OSHA health standards to protect employees working 

with toxic metals. The contractor must also follow all applicable federal, state and local 

environmental regulations for the protection of air, soils and water. Waste must be properly stored 

and disposed. The generator is always the owner, but the contractor can be named as a cogenerator. The generator will provide an EPA identification number, which is obtained from the 

state or local EPA office. Waste cannot be transported or disposed of without an EPA identification 

number. Samples of the waste stream must be randomly selected and analyzed to determine the 

toxicity. When working with hazardous waste, the contractor must monitor the ambient air levels 
Division 500 – Concrete January 2020

Painting 5-59

and conduct pre- and post-job sampling and testing of soil and water/sediment, to ensure 

compliance with regulations.

5.8.8 Painting Materials Acceptance

Painting materials acceptance, as stipulated in the FP, is based on visual inspection and 

certification. See Section 1.1.2 for definition and certification requirements.

Should there be a need to sample the paint for verification of the certification provided, contact 

the Division Materials Engineer for guidance in the proper sample size and method to obtain 

material for testing.
Division 500 – Concrete January 2020

5-60 Drilled Shafts

5.9 DRILLED SHAFTS

Materials requirements for drilled shafts depend on the method of installation. There are three 

primary methods of installation. These include:

• Dry method

• Casing method

• Wet method

The dry method is applicable to soil and rock that are above the water table and that will not cave 

or slump when the hole is drilled to its full depth. The casing and wet methods are applicable to 

sites where soil conditions are such that caving or excessive soil or rock deformation can occur 

when a borehole is excavated. With the casing method, a steel pipe is placed at locations of 

instability. Slurry is sometimes used to temporarily stabilize the hole until the casing is inserted. 

The pipe is removed during placement of the concrete or remains permanently in-place. With the 

wet method, water or mineral slurry is used to keep the borehole stable for the entire depth of the 

excavation. The water or mineral slurry is displaced from the borehole when the concrete is 

placed. Detail materials specifications are provided in Section 717 and 725 of the FP.

As part of the construction phase of the drilled shaft work, a meeting should be held to discuss 

various aspects of drilling, constructing and logging of the drilled shaft. A sample drilled shaft 

meeting agenda is included in Appendix D.3 of this manual.

5.9.1 Casings

The FP requires that steel casing that are smooth, clean and watertight be used. The casings 

should be of sufficient strength to withstand handling and installation stresses and the concrete 

and surrounding earth pressures. The outside diameter should be no less than the specified size 

of the shaft. Steel casings need to conform to AASHTO M 270. 

5.9.2 Mineral Slurry

Mineral slurry is a mixture of a clay mineral and potable water. Bentonite is most commonly used; 

however, attapulgite has been used in place of bentonite, usually in saline ground water 

conditions. Slurries made from synthetic polymers have been used as an alternative to mineral 

slurries, however, polymer slurries should be approved prior to use. 

The bentonite and water need to be mixed outside the borehole and allowed to hydrate for several 

hours before using. The contractor should properly design and test the mineral slurry to ensure 

borehole stability. Because the properties of the mineral slurry change during excavation the FP 

requires that the contractor test and maintain density, viscosity and pH during excavation and 

until concrete placement. Chemical additives are sometimes used to control these properties. 

Because of economic and environmental concerns, slurries are typically circulated, conditioned 

and reused. To maintain the required properties the slurry usually needs to be decanted to remove 

sand. The FP limits the slurry sand content to less than 4 percent by volume.
Division 500 – Concrete January 2020

Drilled Shafts 5-61

5.9.3 Integrity Testing

Integrity testing is performed on drilled shafts using crosshole sonic logging according to ASTM 

D6760. The integrity testing is performed to identify any defective zones along the shaft, such as 

voids or borehole caving. The integrity testing is performed by lowering crosshole sonic logging 

probes down 2-inch diameter access tubes to measure and record pulse velocity according to 

ASTM C597. The access tubes, black steel pipe per ASTM A53, are installed with the 

reinforcement cage prior to placing the concrete. Integrity testing may not be required for relatively 

small diameter or short drilled shafts.

5.9.4 Concrete and Reinforcing Steel for Drilled Shafts

Concrete and reinforcement steel should comply with Sections 552 and 554.

5.9.5 Drilled Shaft Materials Acceptance

Drilled shaft materials acceptance, as stipulated in the FP, is based on visual inspection, 

certification and measured or tested conformance. The contractor is required to furnish a 

commercial certification and test results for the mineral slurry. Concrete and reinforcement steel 

are evaluated under Sections 552 and 554. The contractor is required to submit a detailed cross 

hole sonic logging report and test data in ASCII format for all production drilled shafts.

5.9.6 Drilled Shaft Materials Sampling and Testing

The contractor must sample and test the mineral slurry during excavation to ensure that the slurry 

properties stay within the acceptable ranges. Concrete for drilled shafts are required to be 

sampled and tested according to Section 552. Integrity testing is to be performed on all production 

drilled shafts according to ASTM D6760.
Division 500 – Concrete January 2020

5-62 Roles and Responsibilities

5.10 ROLES AND RESPONSIBILITIES

5.10.1 Contractor’s Responsibilities

The contractor is responsible for constructing concrete pavements, structures, and various 

associated components to the requirements provided in the contract. As part of these 

requirements, the contractor is to control the quality of the materials provided and the construction 

process to ensure compliance. The contractor’s submitted quality control plan should address

sampling, testing, and inspection work that will be accomplished to check and validate the quality 

of workmanship and material components supplied.

There are various established procedures referenced in the specifications for concrete pavements 

and structures regarding furnishing products and materials. The contractor needs to follow these 

procedures to ensure that the material components produced or supplied meet the required 

specifications; and when combined, the resulting mixture meets the contract specifications. 

Therefore, the responsibilities for quality cover three general areas; individual supplied material 

(i.e. cement, aggregate, admixtures, steel, etc.), combined material requirements (i.e. concrete 

mix design, etc.), and finished product (i.e. placement, curing, strength, etc.). As a general list, 

the requirements of the contractor include:

• Provide an inspection system for processes and materials quality control.

• Submit and follow the written quality control plan detailing the inspection system.

• Monitor processes to ensure materials provided and work accomplished comply with 

contract requirements.

• Sample materials to be tested according to the proper sampling method.

• Testing and providing aggregate meeting quality requirements.

• Quality control of aggregate during production to ensure continued compliance with the 

specifications.

• Proper submittal for mix designs.

• Providing material components and split samples to the Government for verification 

testing, when requested.

• Monitor construction processes and verify on-site quality and consistency with proper 

testing.

• Provide appropriate documented test results.

• Provide appropriate certifications (either production or commercial) as established in the 

contract for supplied material.

• Provide consistent delivery methods for construction (i.e. shotcrete placement, pile driving, 

drilled shaft construction, etc.)
Division 500 – Concrete January 2020

Roles and Responsibilities 5-63

The contractor needs to provide information and test results according to the timeframes and 

formats stated in the contract. Distribution of the test reports or certifications should be according 

to the contract and quality control plan and contain the appropriate information to verify the quality 

of the material provided.

5.10.2 Government’s Responsibilities

The Project Engineer or designated representative will review the test results and certifications 

for contract compliance. If clarification or additional expertise is required, the Division Materials 

Engineer should be contacted.

The Project Engineer or designated representative will also be present to witness all required split 

samples taken for the Government. In addition, samples that are taken and tested solely by the 

Government for acceptance, such as concrete strength specimens should be identified in some 

manner to verify the authenticity. Witnessing and proper sample identification are critical in 

maintain proper custody of the material samples. Any split samples or samples taken for testing 

and acceptance by the Government should be secured and immediately be placed in Government 

control. The Project Engineer needs to be aware of the contractor’s operations and be available 

to witness the sampling, splitting, and testing activities.

As a general list, the responsibilities of the Government include:

• Review the quality control plan for completeness.

• Review aggregate quality test result and/or obtain Government samples for testing.

• Review all material data to ensure compliance with the contract requirements.

• Review and approve submitted mix designs.

• Review test methods, equipment, and protocols with contractor testing personnel.

• Ensure pre-work conferences occur and are attended by appropriate personnel.

• Obtain proper product certifications prior to incorporating material into the work.

• Ensure proper sampling and testing methods are used to evaluate materials and quality 

during construction.

• Verify proper sampling and testing techniques have been employed at the required 

frequencies.

• Witness on-site testing of concrete to ensure delivered material is in conformance with the 

contract.

• Monitor construction processes to ensure material and workmanship conform to contract 

requirements.

• Review batch tickets to ensure proper mix proportioning.
Division 500 – Concrete January 2020

5-64 Roles and Responsibilities

• Coordinate investigative process for any significant non-compliance issue, in particular 

low compressive strength concrete.

There are numerous resources available to project personnel to assist in the performance of these 

tasks. Trade organizations such as ACI, ACPA, and PCA provide excellent technical guidelines 

and documentation that can help project personnel in the execution of their duties. Additionally, 

the Division Materials Engineer will provide guidance and assistance to the project should the 

need arise.
Division 500 – Concrete January 2020

Form References 5-65

5.11 FORM REFERENCES

Form references for use in the testing of concrete and associated materials.

• Form FHWA 1600C – Request for Laboratory Tests (CFL)

• Form FHWA 1600E – Requests for Laboratory Tests (EFL)

• Form FHWA 1600W – Requests for Laboratory Tests (WFL)

• Form FHWA 1606 – Minor portland cement concrete mix design trial batch summary

• Form FHWA 1608 – Concrete mix design submittal

• Form FHWA 1621 – Worksheet for sieve analysis of fine and coarse aggregate

• Form FHWA 1627 – Worksheet for sieve analysis of fine and coarse aggregate

• Form FHWA 1638 – Worksheet for determining concrete batch moisture/absorption 

corrections
Division 500 – Concrete January 2020

5-66 Form References

Example Calculations

5.11.1 Fineness Modulus of Fine Aggregate Calculation

As shown in Exhibit 5-59 below, the arrows within the percent passing and individual percent 

retained columns, pointing left and down, indicate subtraction of the two connecting values. 

Arrows pointing to the right within the rows of these same columns indicate the associated 

subtraction result for each sieve size. After these subtraction calculations have been performed, 

the fineness modulus is ultimately determined by summing the cumulative percent retained for 

each sieve size (except the No. 200 (75 μm)) and dividing the summation by 100. In the exhibit 

below, the fineness modulus is 2.99. The fineness modulus should range between 2.3 to 3.1 and 

its uniformity should not vary by more than 0.20 from the base fineness modulus of the aggregate 

source.

Exhibit 5-59 Fineness Modulus Calculation

Sieve Size

Individual 

Percent 

Retained

by Mass

Percent 

Passing

by Mass

Cumulative 

Percent 

Retained by 

Mass

3/8” (9.5 mm) 0 100 0

No. 4 (4.75 mm) 2 98 2

No. 8 (2.36 mm) 8 90 10

No. 16 (1.18 mm) 20 70 30

No. 30 (600 μm) 43 27 73

No. 50 (300 μm) 14 13 87

No. 100 (150 μm) 10 3 97

No. 200 (75 μm) 3 0 -

Total 100 - 299

Fineness Modulus = 299 ÷ 100 = 2.99 

(Range within 2.3 – 3.1) (Uniformity 0-0.2)
Appendix January 2020

Appendix A: Forms A-1

APPENDIX

APPENDIX A: FORMS
Appendix January 2020

A-2 Appendix A: Forms

FHWA Forms

The most current version of FHWA forms are found at the following website: 

https://flh.fhwa.dot.gov/resources/materials/

1600C Request for Laboratory Test (CFL)

1600E Request for Laboratory Test (EFL)

1600W Request for Laboratory Test (WFL)

1606 Minor Portland Cement Concrete Mix Design - Trial Batch Summary

1607 Worksheet for a Hveem Mix Design AASHTO T 246

1608 552 Structural Concrete Mix Design Submittal

1611 Worksheet for Determining Bulk Specific Gravity of Compacted Bituminous 

Mixtures AASHTO T 166 and AASHTO T 269

1612 Worksheet for Reporting Miscellaneous Tests

1616 Worksheet for Determining Moisture Content of Soil and Aggregates using a 

Microwave Oven AASHTO T 255

1618 Worksheet for In-Place Nuclear / Moisture Density Testing AASHTO T 310

1621 Worksheet for Sieve Analysis of Fine and Coarse Aggregate AASHTO T 11 and 

AASHTO T 27

1622 Worksheet for a Marshall Mix Design AASHTO T 245

1624 Worksheet for Determining Liquid Limit and Plastic Limit of Soils AASHTO T 89 

and AASHTO T 90

1625 Worksheet for Determining Moisture / Density Relationships AASHTO T 99 and 

AASHTO T 180

1626 Worksheet for Determining Sand Equivalent AASHTO T 176

1627 Worksheet for Sieve Analysis of Fine and Coarse Aggregate AASHTO T 11 and 

AASHTO T 27

1628 Worksheet for Determining Maximum Specific Gravity of Bituminous Paving 

Mixtures AASHTO T 209 (Flask Determination)

1629 Worksheet for Determining Maximum Specific Gravity of Bituminous Paving 

Mixtures AASHTO T 209 (Bowl Determination)
Appendix January 2020

Appendix A: Forms A-3

1636 Worksheet for Determining Correction for Coarse Particles in the Soil Compaction 

Test AASHTO T 99 and AASHTO T 180

1637 Construction Project Material Certification

1638 Worksheet for Determining Concrete Batch Moisture / Absorption Corrections

1639 Worksheet for Control of Asphalt Mixes AASHTO T 30, AASHTO T 176, AASHTO 

T 308, and ASTM D 5821

1640 Worksheet for Ignition Furnace Binder Correction Factor and Aggregate Gradation 

Correction Factor AASHTO T 308

1641 Worksheet for Superpave Asphalt Concrete Mix Design AASHTO R 35

1642 Worksheet for Determining Volumetric Properties of Superpave Asphalt Concrete 

at Ndes AASHTO T 209, AASHTO T 166, AASHTO T 269, and AASHTO R 35

1643 Materials Register – Item Summary

1644 Materials Register – Sampling & Testing Summary

1645 Materials Register – Visual Inspection

1646 Asphalt Control Strip Worksheet

Appendix January 2020

Appendix B: FLH Test Methods and Addendums B-1

APPENDIX B: FLH TEST METHODS AND ADDENDUMS
Appendix January 2020

B-2 Appendix B: FLH Test Methods and Addendums

FLH TEST METHODS AND ADDENDUMS

FLH Test Methods

T 521 Determining Riprap Gradation by Wolman Count

T 522 Determination of Optimum Emulsified or Foamed Asphalt Content of Full Depth 

Reclamation Mixtures

T 523 Discontinued

T 524 Determination of Optimum Emulsified Asphalt Content of Cold In-Place Recycled 

Mixtures

FLH Addendums

T 308 Addendum to AASHTO T 308 – Correction Factors for Hot Mix Asphalt (HMA) 

Containing Recycled Asphalt Pavement (RAP) by the Ignition Method
Appendix January 2020

T521 13

Appendix B: FLH Test Methods and Addendums B-3

Standard Method of Test for

Determining Riprap Gradation by Wolman 

Count

FLH Designation: T 521-13

1. SCOPE

1.1 This method describes the procedure that will be used to determine riprap gradation by 

Woman count. The method is designed to determine a size distribution of riprap rock based 

on a random sampling of individual particles within a matrix. 

1.2. After individual particles have been measured, a gradation curve can be developed based 

on the frequency of the various sizes.

2. REFERENCED DOCUMENTS

2.1. National Cooperative Highway Research Program:

 Report 568, Riprap Design Criteria, Recommended Specifications, and Quality 

Control.

3. TERMINOLOGY

3.1. Intermediate dimension – The longest, straight-line distance across the rock that is 

perpendicular to the longest axis on the face of the rock with the largest projection plane. 

This dimension can be visualized as the smallest sieve opening that will pass a given rock 

particle. For the idealized rock particle shown in Figure 1, this would be dimension ‘B’.

Figure 1 – Rock particle dimensions (dimensions exaggerated for illustrative purposes)

3.2. Transect – A single transverse crossing of a riprap pile or installation for the purpose of 

measuring individual rock particles.

Note 1– In order to obtain the minimum number of particles to be measured as stated in the method, 

multiple transects may need to be performed depending on size and shape of the riprap mass.

4. PROCEDURE

4.1. Stretch a suitable flexible tape measure across the top and completely over riprap mass. 

Index the ‘zero’ value on the tape as the count starting point.

B (width)

A (length)

C (thickness)
Appendix January 2020

T521 13

B-4 Appendix B: FLH Test Methods and Addendums

4.2. At intervals equal to the maximum particle size specified for the riprap class or one foot, 

whichever is greater, select the rock particle directly below the interval mark on the tape 

measure. Measure and record the intermediate dimension of the particle. (The dimension 

should be estimated as accurately as possible if direct access is obstructed by large rock 

or other heavy debris.) If the size of the selected rock is larger than the selection interval, 

record the measured intermediate dimension of the rock twice as if two rock particles are 

present.

4.3. Continue across the riprap mass measuring the rock particles at the specified interval until 

the traverse is completed. This constitutes one transect of the riprap mass.

4.4. Repeat the procedures in 4.1 to 4.3 for additional transects if necessary until a minimum 

of 100 particles have been measured. Multiple transects must be evenly spaced over the 

rock mass.

4.5. Once a minimum of 100 particles have been measured, record the particle count for the 

various size ranges listed in Table 1. The particle count is the number of individual rocks 

that meet the particle size range listed in the table.

4.6. Determine the cumulative percent smaller by dividing the cumulative particle count by the 

total number of particles measured.

Table 1— Particle Count and Cumulative Percent Smaller Determination

Particle Size 

(inches) Particle Size Range Particle Count

Cumulative 

Particle 

Count

Cumulative Percent 

Smaller (Cum. Particle 

count / total particles)

3.00 ≤ 3.00

4.25 3.00 < x ≤ 4.25

6.00 4.25 < x ≤ 6.00

8.50 6.00 < x ≤ 8.50

12.00 8.50 < x ≤ 12.00

17.00 12.00 < x ≤ 17.00

24.00 17.00 < x ≤ 24.00

34.00 24.00 < x ≤ 34.00

48.00 34.00 < x ≤ 48.00

68.00 48.00 < x ≤ 68.00

96.00 68.00 < x ≤ 96.00

5. REPORT

5.1. The report shall include the following:

5.1.1. Report the intermediate dimension for all rock particles measured.

5.1.2. Plot the cumulative percent smaller versus the particle size on a semi-log graph to produce 

the representative Wolman count gradation curve as shown in Figure 2.
Appendix January 2020

T521 13

Appendix B: FLH Test Methods and Addendums B-5

Figure 2 – Example Gradation Plot

5.1.3 Report the particle sizes that are cumulatively 15, 50, 85 and 100 percent smaller by size 

(i.e. D15, D50, D85, and D100).
Appendix January 2020

T521 13

B-6 Appendix B: FLH Test Methods and Addendums

APPENDIX (EXAMPLE)

(Example)

X. WOLMAN COUNT AND ANALYSIS

X1.1. Conduct a Wolman count and analysis on the rock produced and stockpiled for use on the 

project.

X1.2. Given the configuration of this particular pile, three transects of the pile will be needed in 

order to obtain a minimum of 100 particle measurements. The three transects were taken 

at equal intervals along the pile. The data collected is shown in Table 2, Table 3, and Table 

4. 

Table 2— Particle Count Transect No. 1

Rock Count

Intermediate 

Dimension 

(inches)

Rock Count

Intermediate 

Dimension 

(inches)

Rock Count

Intermediate 

Dimension 

(inches)

1 0.6 36 71

2 4.8 37 72

3 12 38 73

4 7.2 39 74

5 3.6 40 75

6 9.6 41 76

7 9.6 42 77

8 4.8 43 78

9 6 44 79

10 8.4 45 80

11 4.8 46 81

12 10.8 47 82

13 8.4 48 83

14 7.2 49 84

15 6 50 85

16 4.8 51 86

17 15.6 52 87

18 6 53 88

19 4.8 54 89

20 10.8 55 90

21 8.4 56 91

22 10.8 57 92

23 8.4 58 93

24 18 59 94

25 12 60 95

26 9.6 61 96

27 7.2 62 97

28 7.2 63 98

29 6 64 99

30 8.4 65 100

31 18 66 101

32 12 67 102

33 10.8 68 103

34 4.8 69 104

35 15.6 70 105
Appendix January 2020

T521 13

Appendix B: FLH Test Methods and Addendums B-7

Table 3— Particle Count Transect No. 2

Rock Count

Intermediate 

Dimension 

(inches)

Rock Count

Intermediate 

Dimension 

(inches)

Rock Count

Intermediate 

Dimension 

(inches)

1 12 36 8.4 71

2 13.2 37 12 72

3 7.2 38 12 73

4 9.6 39 13.2 74

5 3.6 40 8.4 75

6 7.2 41 76

7 8.4 42 77

8 7.2 43 78

9 2.4 44 79

10 4.8 45 80

11 6 46 81

12 7.2 47 82

13 4.8 48 83

14 6 49 84

15 8.4 50 85

16 12 51 86

17 13.2 52 87

18 8.4 53 88

19 16.8 54 89

20 6 55 90

21 10.8 56 91

22 18 57 92

23 7.2 58 93

24 7.2 59 94

25 7.2 60 95

26 14.4 61 96

27 16.8 62 97

28 6 63 98

29 18 64 99

30 15.6 65 100

31 10.8 66 101

32 6 67 102

33 15.6 68 103

34 12 69 104

35 18 70 105
Appendix January 2020

T521 13

B-8 Appendix B: FLH Test Methods and Addendums

Table 4— Particle Count Transect No. 3

Rock Count

Intermediate 

Dimension 

(inches)

Rock Count

Intermediate 

Dimension 

(inches)

Rock Count

Intermediate 

Dimension 

(inches)

1 18 36 71

2 12 37 72

3 10.8 38 73

4 4.8 39 74

5 15.6 40 75

6 6 41 76

7 8.4 42 77

8 6 43 78

9 13.2 44 79

10 4.8 45 80

11 6 46 81

12 7.2 47 82

13 10.8 48 83

14 4.8 49 84

15 8.4 50 85

16 7.2 51 86

17 6 52 87

18 15.6 53 88

19 12 54 89

20 6 55 90

21 10.8 56 91

22 10.8 57 92

23 3.6 58 93

24 12 59 94

25 2.4 60 95

26 9.6 61 96

27 2.4 62 97

28 8.4 63 98

29 10.8 64 99

30 3.6 65 100

31 12 66 101

32 13.2 67 102

33 7.2 68 103

34 9.6 69 104

35 3.6 70 105
Appendix January 2020

T521 13

Appendix B: FLH Test Methods and Addendums B-9

X1.3. From the 110 particles measured, determine the number of particles that fit in the 

appropriate established particle size ranges. From the particle count, the “Cumulative 

Particle Count” and the “Cumulative Percent Smaller” can be computed (Table 5).

Table 5— Particle Count and Cumulative Percent Smaller Determination

Particle Size

(inches)

Particle Size 

Range

Particle 

Count

Cumulative 

Particle Count

Cumulative 

Percent Smaller

(cum. Particle 

count / total 

particles)

3.00 ≤ 3.00 4 4 3.6

4.25 3.00 < x ≤ 4.25 5 9 8.2

6.00 4.25 < x ≤ 6.00 25 34 30.9

8.50 6.00 < x ≤ 8.50 27 61 55.5

12.00 8.50 < x ≤ 12.00 29 90 81.8

17.00 12.00 < x ≤ 17.00 14 104 94.5

24.00 17.00 < x ≤ 24.00 6 110 100.0

34.00 24.00 < x ≤ 34.00 0

48.00 34.00 < x ≤ 48.00 0

68.00 48.00 < x ≤ 68.00 0

96.00 68.00 < x ≤ 96.00 0

X1.4. To complete the report, plot the cumulative percent smaller versus the particle size on a 

semi-log graph, as shown in Figure 3, and report D15 = 4.8”, D50 = 7.8”, D85 = 13.0”, and 

D100 = 24”.

Figure 3 – Example Gradation Plot
Appendix January 2020

T 522

B-10 Appendix B: FLH Test Methods and Addendums

Standard Practice for

Determination of Optimum Emulsified or 

Foamed Asphalt Content of Full Depth 

Reclamation Mixtures

FLH Designation: T 522

1. SCOPE

1.1 This procedure is used to determine the percent of emulsified or foamed asphalt and other 

needed additives for recycling asphalt concrete and aggregate base materials using Full 

Depth Reclamation (FDR). 

2. REFERENCED DOCUMENTS

2.1 AASHTO Standards:

 T 11, Materials Finer Than No. 200 (75 μm) Sieve in mineral Aggregates by Washing

 T 27, Sieve Analysis of Fine and Coarse Aggregates

 T 30, Mechanical Analysis of Extracted Aggregate

 T 209, Theoretical Maximum Specific Gravity (Gmm) and Density of Hot Mix Asphalt 

(HMA)

 T 269, Percent Air Voids in Compacted Dense and Open Asphalt Mixtures

 T 283, Resistance of Compacted Asphalt Mixtures to Moisture-Induced Damage

 T 312, Preparing and Determining the Density of Asphalt Mixture Specimens by 

Means of the Superpave Gyratory Compactor

 T 331, Bulk Specific Gravity (Gmb) and Density of Compacted Hot Mix Asphalt (HMA) 

Using Automatic Vacuum Sealing Method

ASTM Standards:

 D6857, Maximum Specific Gravity and Density of Bituminous Paving Mixtures Using 

Automatic Vacuum Sealing Method

3. SAMPLING MATERIALS

3.1 Sampling Existing Pavement Materials

3.1.1 Obtain pavement cores, auger borings, or test pit samples from the areas to be recycled. 

Depending upon project length and existing pavement thickness, develop a sampling plan 

that will provide at least 350 lbs. of RAP and aggregate base for each mix design.

In all cases, the material provided must be representative of the material to be recycled. 

Where visual differences in the pavement surface are noted, additional cores may be 

required to evaluate the differences. If these additional samples show significant material 

differences, a separate mix design should be performed for each identified pavement 

segment.

3.1.2 Cores are to be cut for the full depth of the asphalt pavement. Sample aggregate base to 

the depth specified for the full depth reclamation project. 
Appendix January 2020

T 522

Appendix B: FLH Test Methods and Addendums B-11

3.1.3 Crush cores and sieve to obtain materials that meet the gradation shown in Table 1.

Table 1—RAP Gradation Requirements

Sieve Size Percent Passing

1.5 in. (38 mm) 100

1 in. (25 mm) 85-95

3⁄4 in. (19 mm) 75-85

No. 4 (4.75 mm) 30-40

No. 30 (0.600 mm) 1-5

3.1.4 Milled RAP from the areas and depth to be recycled or other approved means of obtaining 

RAP samples can be used as an alternative to cores. 

3.1.5 Sieve the milled pavement or crushed cores according to AASHTO T 27 with the exception 

that drying the RAP to constant mass shall be performed at 104 ± 4°F (40 ± 2°C). The 

washed sieve analysis of AASHTO T 11 is not required.

RAP material will be recombined to meet the gradation requirements shown in Table 1 for 

additional testing as described in this method.

3.1.6 For the aggregate base material obtained, perform a washed sieve analysis in accordance 

with AASHTO T 11 and AASHTO T 27 and report the obtained gradation.

3.2 Sampling of Emulsified Asphalt Binder or Asphalt Binder

3.2.1 Obtain 3 gallons of the emulsified asphalt or 2 gallons of asphalt binder that will be used to 

produce the recycled mix. Include the name and location of the supplier in the mix design 

report. Include the grade and properties of the asphalt product used in the mix design 

report.

3.3 Sampling of Other Additives

3.3.1 Obtain 10 lbs. of cement, lime, or other mineral filler if these additives will be used as a 

part of the mix design. 

3.3.2 Obtain a sufficient amount of other additives that will be used to complete the mix design. 

List the name and source of all additives in the mix design report.

4. DETERMINING FOAMED ASPHALT CHARACTERISTICS

4.1 For FDR mixtures using foamed asphalt, determine the asphalt expansion ratio and halflife of the asphalt binder to be used.

4.2 Using a laboratory asphalt foaming device designed for the purpose of evaluating asphalt 

foaming characteristics, determine the asphalt expansion ratio and the half-life of the 

foamed expansion for asphalt binder temperatures of 320, 338, and 356°F (160, 170, and 

180°C) and a range of water contents from 1.5% to 3.5% in increments of 0.5%.

The asphalt expansion ratio is defined as the ratio between the maximum volume achieved 

in the foamed state and the volume of binder once the foam has completely subsided.

The half-life of the foamed expansion is the time for the foamed asphalt to reduce to half 

of the maximum volume attained during the foaming process.
Appendix January 2020

T 522

B-12 Appendix B: FLH Test Methods and Addendums

4.3 Discharge foamed asphalt into a sufficiently sized container with the capability of 

measuring the volume of the foam asphalt at various time intervals.

4.4 Measure the maximum volume of the foamed asphalt after being initially discharged into 

the container.

4.5 Measure the time, in seconds, for the foam to dissipate to half of the maximum volume. 

Record this time as the half-life of the foamed asphalt.

4.6 Allow the foamed asphalt to completely dissipate. Calculate the expansion ratio by dividing 

the maximum foamed asphalt volume by the volume of binder after the foam has been 

dissipated.

4.7 Plot the percent water added versus asphalt expansion ratio and half-life of foamed 

expansion for each asphalt binder temperature.

5. COMBINING RAP AND AGGREGATE BASE MATERIALS

5.1 Combined Materials

5.1.1 Combine RAP prepared to the gradation in Table 1 with aggregate base of the gradation 

determined in 3.1.6 to the planned percentages as determined from the depth of the 

respective layers. Calculate the combined gradation of RAP and aggregate base. 

5.1.2 Batch material to the combined gradation determined in Subsection 5.1.1.

5.1.3 Perform a Modified Proctor test on the combined material in accordance with AASHTO T 

180, Method D, to determine optimum moisture content (OMC) at peak dry density of the 

combined RAP and base material. Materials shall be mixed with the selected amount of 

water, sealed, and allowed to hydrate for a minimum of 3 hours prior to compaction. The 

OMC shall be defined by a best-fit curve. 

6. DETERMINATION OF INDIRECT TENSILE STRENGTH AND TENSILE 

STRENGTH RATIO

6.1 Specimen Size

6.1.1 Determine the amount of RAP and aggregate base, before the addition of water, required 

to produce a 95 ± 5 mm tall specimen when compacting 150 mm diameter specimens with 

the gyratory compactor at 35 gyrations for testing. 

6.1.2 Batch the RAP and aggregate base material according to the proportions established in 

Subsection 5.1.1 and 5.1.2.

6.1 Select a minimum of three emulsified or foamed asphalt contents in either 0.5% or 1.0% 

increments covering a range typically between 2.0% and 4.0% by dry weight of batched 

material. Six specimens will be compacted and tested for each emulsified or foamed 

asphalt content selected. As an option, additional specimens may be batched, compacted, 

and tested that have varying percentages of other additives such as cement, lime or 

mineral filler.
Appendix January 2020

T 522

Appendix B: FLH Test Methods and Addendums B-13

In addition, batch two samples for use in determining the theoretical maximum specific 

gravity value according to AASHTO T 209. Determine the theoretical maximum specific 

gravity according to Section 7.

6.2 Mechanical Mixing

6.2.1 Place the batched RAP and aggregate in a mixing bowl. Add sufficient water so that the 

total moisture content of water plus added emulsified asphalt or foamed asphalt will be 

equal to the OMC as determined in Subsection 5.1.3. 

6.2.2 Mix samples for testing using a mechanical bucket mixer or laboratory sized pugmill or a 

combination of the two. Mix specimens with the required amount of water before addition 

of emulsified or foamed asphalt. If any additives (such as lime) are in the mixture, introduce 

the additives in a similar manner that they will be added during field production.

6.2.3 Mix specimens thoroughly with water first, or water and additives as appropriate, then add 

the emulsified asphalt or foamed asphalt. Thoroughly mix the material to provide uniform 

coating. One specimen will be mixed at a time. Mixing time should not exceed 60 seconds.

6.2.4 Transfer mixture to a sealed container and cure at 77 ± 4°F (25 ± 2°C) for 30 ± 3 minutes.

6.3 Compacting

6.3.1 Compact the mixture immediately after the curing specified in 6.2.3.

6.3.2 Compact the specimens using 35 gyrations according to AASHTO T 312 compaction 

procedures with the exception that the materials and the molds are not heated.

6.3.3 Compact six specimens at each asphalt content selected for tensile strength testing; three 

for unconditioned (dry) tensile strength on cured samples and three for conditioned tensile 

strength on cured samples for moisture conditioning.

6.3.4 If paper disks are used, place paper disks on the top and bottom of the specimen before 

compaction and remove paper disks from specimens immediately after compaction.

6.4 Curing

6.4.1 Extrude the specimens from the molds after compaction. Handle specimens carefully as to 

not disturb or damage. Carefully remove the paper disks from the top and bottom of the 

specimens.

6.4.2 Place specimens in 140 ± 2°F (60 ± 1°C) forced draft oven with ventilation on sides and 

top. Place each specimen in a small container to account for material loss from the 

specimens. Cure compacted specimens at 140 ± 2°F (60 ± 1°C) to constant mass but do 

not heat for more than 48 hours and not less than 16 hours. Constant mass is defined as 

0.05% change in mass in 2 hours. After curing, cool specimens at ambient temperature a 

minimum of 12 hours and a maximum of 24 hours.

6.5 Sample Conditioning and Testing

6.5.1 After curing of specimens, determine the bulk specific gravity of each compacted, cured 

and cooled specimen according to AASHTO T 331.
Appendix January 2020

T 522

B-14 Appendix B: FLH Test Methods and Addendums

6.5.2 Determine specimen heights according to AASHTO T 245. Alternatively, the height can be 

obtained from the SGC readout.

6.5.3 Determine air void contents of the compacted and oven-cured samples at each asphalt 

content according to AASHTO T 269 using the theoretical maximum specific gravity as 

determined in Section 7.

6.5.4 For each asphalt content tested, separate the specimens into two subsets of three 

specimens each so the average air void contents of the two subsets are approximately 

equal.

6.5.5 Perform moisture conditioning on three compacted samples at each asphalt content by 

applying a vacuum of 13 to 67 kPa absolute pressures (10 to 26 in. of Hg partial pressure) 

for a time duration required to vacuum saturate samples to 55 to 75 percent. Saturation 

calculation shall be in accordance with AASHTO T 283. Soak moisture conditioned 

samples in a 77 ± 2°F (25 ± 1°C) water bath for 24 ± 1 hours.

6.5.6 Determine tensile strength ratio by AASHTO T 283. Dry or unconditioned samples are 

tested after a minimum of 45 minutes temperature conditioning by immersing in a 77 ± 2°F 

(25 ± 1°C) water bath. Place dry specimens in a leak proof bag to prevent samples from 

coming in contact with water. This testing is performed at the same time that moistureconditioned specimens are tested.

6.5.7 Report the dry indirect tensile strength and the tensile strength ratio according to AASHTO 

T 283.

7. DETERMING THE THEORECTRICAL MAXIMUM SPECIFIC GRAVITY

7.1 Batch samples according to Subsection 6.1

7.2 Mix samples according to Subsection 6.2.

7.3 Two specimens are required for determination of theoretical maximum specific gravity. 

Follow AASHTO T 209 with the exception that loose mixtures are cured in a forced draft 

oven at 140 ± 2°F (60 ± 1°C) to constant mass. Cure for no more than 48 hours and no 

less than 16 hours. Constant mass is defined as 0.05% change in mass in 2 hours. Do not 

break any agglomerates that will not easily reduce with a flexible spatula. Test both 

specimens at the highest asphalt content in the design and back calculate for the lower 

asphalt contents. Use the dry-back procedure of AASHTO T 209 to account for uncoated 

particles. ASTM D6857 may be used as an alternative to AASHTO T 209.

8. EMULSIFIED ASPHALT OR FOAMED ASPHALT CONTENT SELECTION

8.1 Choose the design emulsified or foamed asphalt content that meets the requirements listed 

in the specification. For the foamed asphalt mixture, include the water content and asphalt 

binder temperature required for proper foaming.

9. REPORT

9.1 Report the following information:

9.1.1 Gradation of RAP;
Appendix January 2020

T 522

Appendix B: FLH Test Methods and Addendums B-15

9.1.2 Gradation of aggregate base;

9.1.3 Planned percentages of RAP and aggregate base;

9.1.4 Combined gradation of the blended RAP and aggregate base material;

9.1.5 Foamed asphalt expansion and half-life plots;

9.1.6 Density and OMC from Proctor compaction of the blended material;

9.1.7 Moisture content used in mix design;

9.1.8 Range of emulsified asphalt or foamed asphalt contents used for the mix design;

9.1.9 Density, Gmm, and air voids at each emulsified asphalt or foamed asphalt content 

(individual and average values) of AASHTO T 283 samples;

9.1.10 Indirect tensile strength at each emulsified asphalt or foamed asphalt content (individual 

and average values);

9.1.11 Level of saturation and conditioned indirect tensile strength at each emulsified asphalt or 

foamed asphalt content (individual and average values);

9.1.12 Tensile strength ratio;

9.1.13 Design emulsified or foamed asphalt content;

9.1.14 Design water content;

9.1.15 Emulsified asphalt or asphalt binder grade, supplier company name and location;

9.1.16 Additive type, company name and location;

9.1.17 Certificates of compliance for emulsified asphalt, asphalt binder, and any additives, as 

necessary.
Appendix January 2020

T 524

B-16 Appendix B: FLH Test Methods and Addendums

Standard Practice for

Determination of Optimum Emulsified Asphalt 

Content of Cold In-Place Recycled Mixtures

FLH Designation: T 524

1. SCOPE

1.1. This standard practice is used to determine the percent of emulsified asphalt and other 

additives to use for recycling asphalt concrete when using Cold In-Place Recycling (CIR) 

of bituminous pavements.

2. REFERENCED DOCUMENTS

2.1. AASHTO Standards:

 T 27, Sieve Analysis of Fine and Coarse Aggregates

 T 30, Mechanical Analysis of Extracted Aggregate

 T 166, Bulk Specific Gravity (Gmb) of Compacted Hot Mix Asphalt (HMA) Using 

Saturated Surface-Dry Specimens

 T 209, Theoretical Maximum Specific Gravity (Gmm) and Density of Hot Mix Asphalt 

(HMA)

 T 245, Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus

 T 269, Percent Air Voids in Compacted Dense and Open Asphalt Mixtures

 T 283, Resistance of Compacted Asphalt Mixtures to Moisture-Induced Damage

 T 312, Preparing and Determining the Density of Asphalt Mixture Specimens by 

Means of the Superpave Gyratory Compactor

 T 331, Bulk Specific Gravity (Gmb) and Density of Compacted Hot Mix Asphalt (HMA) 

Using Automatic Vacuum Sealing Method

2.2. ASTM Standards:

 D6857, Maximum Specific Gravity and Density of Bituminous Paving Mixtures Using 

Automatic Vacuum Sealing Method

 D7196, Raveling Test of Cold Mixed Emulsified Asphalt Samples

3. OBTAINING AND PREPARATION OF MATERIALS 

3.1. Sampling and Processing of Recycled Asphalt Pavement (RAP) Materials

3.1.1. Obtain cores from the areas to be recycled. Depending upon project length and existing 

pavement thickness, develop a coring plan that will provide at least 350 pounds of RAP for 

each mix design. Additional cores will need to be obtained for more specific asphalt content 

and gradation analysis if desired. 

In all cases, the material provided must be representative of the material to be recycled. If 

the pavement is not being recycled full depth, cores should be cut to the specified milling 

depth with the bottom portion being discarded. 
Appendix January 2020

T 524

Appendix B: FLH Test Methods and Addendums B-17

Where visual differences in the pavement surface are noted, additional cores may be 

required to evaluate the difference. If these additional cores show significant material 

differences, a separate mix design should be performed for each identified pavement 

segment.

3.1.2. Cut cores to the depth specified for the cold recycled layer. 

3.1.3. Crush cores to obtain materials that meet the gradation shown in Table 1.

As an alternative to obtaining and crushing cores, RAP may be obtained by milling. Mill the 

pavement from areas to be recycled to the specified depth. 

3.1.4. Sieve the milled pavement or crushed cores according to AASHTO T 27 with the exception 

that drying the RAP to constant mass shall be performed at 104 ± 4°F (40 ± 2°C). The 

washed sieve analysis of AASHTO T 11 is not required.

RAP material will be recombined to meet the gradation requirements shown in Table 1 for 

additional testing as described in this method.

Table 1— RAP Gradation Requirements

Sieve Size Percent Passing

1.5 inch (37.5mm) 100

1 inch (25.0mm) 90-100

3/4 inch (19.0mm) 85-95

1/2 inch (12.5mm) 75-85

No. 4 (4.75mm) 35-50

No. 16 (1.18mm) 5-16

No. 200 (75μm) 0-7

4. MIX DESIGN BINDER AND ADDITIVES FOR MIX DESIGN

4.1. Sample of Emulsified Asphalt Binder Agent

4.1.1. Obtain 3 gallons of the emulsified asphalt that will be used to produce the cold recycled 

mix. Include the name and location of the supplier in the mix design report. Include the 

grade and properties of the emulsified asphalt in the mix design report.

4.2. Sample of Other Additives

4.2.1. Obtain 5 pounds of quicklime, if quicklime will be used as a part of the mix design.

4.2.2. Obtain a sufficient amount of other additives that will be used to complete the mix design. 

List the name and source of all additives in the mix design report.

5. DETERMINATION OF INDIRECT TENSILE STRENGTH AND TENSILE 

STRENGTH RATIO

5.1. Batching RAP Material
Appendix January 2020

T 524

B-18 Appendix B: FLH Test Methods and Addendums

5.1.1. Select a minimum of three emulsified asphalt contents in either 0.5% or 1.0% increments 

covering a range typically between 1.0% and 4.0% by dry weight of RAP. Batch RAP 

material for each specimen conforming to the gradation selected for the mix design and 

meeting the gradation requirements shown in Table 1. Six specimens will be compacted 

and tested for each emulsified asphalt content selected. As an option, additional specimens 

may be batched, compacted, and tested that have varying percentages of other additives 

such as quicklime.

Determine the amount of RAP material required to produce a 150 mm diameter and 95 ± 

5 mm tall specimen when compacted in the gyratory compactor at 35 gyrations.

In addition, batch two RAP material samples for use in determining the theoretical 

maximum specific gravity value according to AASHTO T 209. Determine the theoretical 

maximum specific gravity according to Section 6.

5.2. Mechanical Mixing

5.2.1. Mix samples for testing using a mechanical bucket mixer, laboratory sized pugmill or a 

combination of the two. Add moisture that is expected to be added at the milling head, 

typically 1.5 to 2.5 percent, and mix thoroughly. If any additives (such as lime) are in the 

mixture, introduce the additives in a similar manner that they will be added during field 

production.

5.2.2. Mix RAP thoroughly with water first or water and additives as appropriate, then mix with 

emulsified asphalt at room temperature, 77 ± 4°F (25 ± 2°C). One specimen will be mixed 

at a time. Mixing time should not exceed 60 seconds.

5.3. Compacting

5.3.1. Immediately after mixing, compact the specimens. Compact the specimens at 77 ± 4oF (25 

± 2oC).

5.3.2. Compact the specimens using 35 gyrations according to AASHTO T 312 compaction 

procedures with the exception that the materials and the molds are not heated.

5.3.3. Compact six specimens at each emulsified asphalt content for tensile strength testing; 

three for unconditioned (dry) tensile strength on cured samples and three for conditioned 

tensile strength on cured samples for moisture conditioning.

5.4. Curing

5.4.1. Extrude the specimens from the molds after compaction. Handle specimens carefully as to 

not disturb or damage. Carefully remove the paper disks from the top and bottom of the 

specimens.

5.4.2. Place specimens in 140 ± 2°F (60 ± 1°C) forced draft oven with ventilation on sides and 

top. Place each specimen in a small container to account for material loss from the 

specimens. Cure compacted specimens at 140 ± 2°F (60 ± 1°C) to constant mass but do 

not heat for more than 48 hours and not less than 16 hours. Constant mass is defined as 

0.05% change in mass in 2 hours. After curing, cool specimens at ambient temperature a 

minimum of 12 hours and a maximum of 24 hours.

5.5. Sample Conditioning and Testing
Appendix January 2020

T 524

Appendix B: FLH Test Methods and Addendums B-19

5.5.1. After curing of specimens, determine the bulk specific gravity of each compacted, cured 

and cooled specimen according to AASHTO T 166 Method A or AASHTO T 331, if required.

5.5.2. Determine specimen heights according to AASHTO T 245. Alternatively, the height can be 

obtained from the SGC readout.

5.5.3. Determine air void contents of the compacted and oven-cured samples at each emulsified 

asphalt content according to AASHTO T 269 using the theoretical maximum specific gravity 

as determined in Section 6.

5.5.4. For each emulsified asphalt content tested, separate the specimens into two subsets of 

three specimens each so the average air void contents of the two subsets are 

approximately equal.

Perform moisture conditioning on three compacted samples at each emulsified asphalt 

content by applying a vacuum of 10 to 26 in. of Hg partial pressure (13 to 67 kPa absolute 

pressure) for a time duration required to vacuum saturate samples to 55 to 75 percent. 

Saturation calculation shall be in accordance with AASHTO T 283. Soak moisture 

conditioned samples in a 77 ± 2°F (25 ± 1°C) water bath for 24 ± 1 hours.

5.5.5. Determine tensile strength ratio by AASHTO T 283. Dry or unconditioned samples are 

tested after a minimum of 45 minutes temperature conditioning by immersing in a 77 ± 2°F 

(25 ± 1°C) water bath. Place dry specimens in a leak proof bag to prevent samples from 

coming in contact with water. This testing is performed at the same time that moistureconditioned specimens are tested.

5.5.6. Report the dry indirect tensile strength and the tensile strength ratio according to AASHTO 

T 283.

6. DETERMINING THE THEORETICAL MAXIMUM SPECIFIC GRAVITY

6.1. Batch samples according to 5.1.

6.2. Mix samples according to 5.2.

6.3. Two specimens are required for determination of theoretical maximum specific gravity. 

Follow AASHTO T 209 with the exception that loose RAP mixtures are cured in a forced 

draft oven at 140 ± 2°F (60 ± 1°C) to constant mass. Cure for no more than 48 hours and 

no less than 16 hours. Constant mass is defined as 0.05% change in mass in 2 hours. Do 

not break any agglomerates that will not easily reduce with a flexible spatula. Test both 

specimens at the highest emulsified asphalt content in the design and back calculate for 

the lower emulsified asphalt contents. Use the dry-back procedure of AASHTO T 209 to 

account for uncoated particles. ASTM D6857 may be used as an alternative to AASHTO 

T 209.

7. RAVELING TEST

7.1. Mix specimens at the target optimum emulsified asphalt content established. Mix according 

to ASTM D7196 for lab blended mixtures.

7.2. Cure the specimens for 4 hours at 50°F and 50% relative humidity.
Appendix January 2020

T 524

B-20 Appendix B: FLH Test Methods and Addendums

7.3. Abrade the specimens for 15 minutes according to ASTM D7196.

7.4. Record the percent mass loss according to ASTM D7196.

8. EMULSIFIED ASPHALT CONTENT SELECTION

8.1. Choose the design emulsified asphalt content that meets the cold mix requirements listed 

in the specification.

9. REPORT

9.1. Report the following information: 

9.1.1. Gradation of RAP;

9.1.2. Recommended water content range as a percentage of dry RAP;

9.1.3. Amount of additive as a percentage of dry RAP;

9.1.4. Range of emulsified asphalt contents used for the mix design;

9.1.5. Theoretical maximum specific gravity of the mixture at selected emulsified asphalt content, 

Gmm

9.1.6. Air voids and bulk specific gravity at each emulsified asphalt content (individual and 

average values) of AASHTO T 283 samples;

9.1.7. Indirect tensile strength at each emulsified asphalt content (individual and average values);

9.1.8. Level of saturation and conditioned indirect tensile strength at each emulsified asphalt 

content (individual and average values);

9.1.9. Tensile strength ratio;

9.1.10. Theoretical maximum specific gravity, air void content, tensile strength, tensile strength 

ratio, and raveling at recommended moisture and emulsified asphalt contents;

9.1.11. Optimum emulsified asphalt content as a percentage of dry RAP;

9.1.12. Emulsified asphalt and additive designation, supplier company name and location;

9.1.13. Emulsified asphalt residue content;

9.1.14. Additive designation, company name and location;

9.1.15. Certificates of compliance for emulsified asphalt and additive.
Appendix January 2020

T 308

Appendix B: FLH Test Methods and Addendums B-21

FLH Addendum to AASHTO T 308 Standard Method of Test for

Correction Factors for Hot Mix Asphalt (HMA) 

Containing Recycled Asphalt Pavement (RAP) 

by the Ignition Method

FLH Designation: Addendum T 308

A1. ASPHALT BINDER AND AGGREGATE

A1.1. Asphalt binder content results may be affected by the type of virgin aggregate and RAP 

material in the mixture and the ignition furnace. Therefore, asphalt binder and aggregate 

correction factors must be established by testing a set of correction factor specimens for 

the job mix formula (JMF) containing RAP. Correction factor(s) must be determined before 

any acceptance testing is completed and repeated each time a change in the mix design 

occurs. Any changes greater than 5 percent in stockpiled aggregate proportions shall 

require new correction factors.

A1.1.1. Asphalt binder correction factor—Certain virgin aggregate types or RAP materials may 

result in unusually high correction factors (greater than 1.0 percent). Such mixes should be 

corrected and tested at a lower temperature as described in Subsection A2.11.1. Each 

ignition furnace will have its own unique asphalt binder correction factor determined in the 

location where testing will be performed.

A1.1.2. Aggregate gradation correction factor—Due to potential virgin and RAP aggregate 

breakdown during the ignition process, an aggregate gradation correction factor will be 

determined for each ignition furnace in the location where testing will be performed.

A2. CORRECTION FACTOR PROCEDURE

A2.1. Obtain samples of virgin aggregate and RAP in accordance with T 2.

A2.2. Obtain samples of asphalt binder in accordance with T 40.

Note A1—Include other additives that may be required by the JMF.

Note A2 – If lime is included as a component of the mixture and it has not been previously 

added to the virgin aggregates, add the appropriate amount of lime per the mix design 

proportion. Add the lime to the virgin aggregates by making a lime slurry (lime and water 

mixture) and thoroughly mixing with the virgin aggregates prior to the oven-dry process.

A2.3. Oven-dry the virgin aggregate at a temperature of 230°F (110°C) and RAP at a temperature 

of 140°F (60°C) to a constant mass.

A2.4. Prepare an initial, or “butter mix” at the design asphalt binder content. Mix and discard the 

butter mix prior to preparing any of the correction specimens to ensure accurate asphalt 

binder content.
Appendix January 2020

T 308

Appendix B: FLH Test Methods and Addendums B-22

A2.5. Prepare two correction specimens at the JMF design asphalt binder content and virgin 

aggregate and RAP gradations. Virgin aggregate and RAP used for correction specimens 

shall be sampled from the stockpiles designated for use in production. 

A2.6. Prepare a “blank” (virgin aggregate only) specimen at the JMF gradation. Determine the 

virgin aggregate gradation in accordance with T 30 on the “blank” specimen. Provide an 

additional gradation analysis on a representative sample of burned RAP aggregate.

A2.7. Mathematically compute the “calculated blank” gradation for the virgin aggregate and the 

burned RAP aggregate by combining the individual gradation analyses at the specified 

batch percentages for each material as determined in the JMF. Adjust the percentages of 

virgin aggregate and RAP aggregate accordingly to account for binder present in the RAP 

specimen.

A2.8. Place the freshly mixed specimens directly into the specimen basket assembly. If 

specimens are allowed to cool prior to placement in the specimen basket assembly, the 

specimens must be dried to constant mass at a temperature of 110 ± 5°C (230 ± 9°F). Do 

not preheat the specimen basket assembly.

A2.9. Test the specimens in accordance with Method A or Method B of the procedure.

A2.10. Once both of the correction specimens have been burned, determine the asphalt binder 

content for each specimen by calculation or from the printed oven tickets, if available.

A2.11. If the difference between the asphalt binder contents of the two specimens exceeds 0.15 

percent, repeat Subsection A2.3 through A2.7 with two more specimens and, from the four 

results, discard the high and low result. Determine the correction factor from the two 

original or remaining results, as appropriate. Calculate the difference between the actual 

and measured asphalt binder contents for each specimen. The asphalt binder correction 

factor, Cf, is the average of the differences expressed as percentage by mass of the HMA.

A2.11.1. If the asphalt binder correction factor exceeds 1.0 percent, the test temperature should be 

lowered to 483 ± 5°C (900 ± 8°F) for convection type furnace. If there is no improvement 

in the correction factor, it is permissible to use the higher temperature. 

Note A3—The temperature for determining the asphalt binder content of HMA specimens 

by this procedure shall be the same temperature determined for the correction specimens.

A2.11.2. For the direct IR irradiation-type furnaces, the DEFAULT burn profile should be used for 

most materials. The operator may select burn-profile OPTION 1 or OPTION 2 to optimize 

the burn cycle. Option 1 is designed for aggregate that require a large aggregate correction 

factor (greater than 1 percent)—typically very soft aggregate (such as dolomite). Option 2 

is designed for samples that may not burn completely using the DEFAULT burn profile. 

The burn profile for testing HMA samples shall be the same burn profile selected for 

correction samples.

A2.12. Perform a gradation analysis on the residual aggregate in accordance with T 30, if required. 

The results will be utilized in developing an aggregate gradation correction factor and 

should be calculated and reported to the nearest 0.1 percent.

A2.12.1. From the gradation results, subtract the percent passing for each sieve from the percent 

passing each sieve on the “calculated” blank gradation results from Subsection A2.7.

A2.12.2. Determine the average difference for the two values. If the difference for any single sieve 

exceeds the allowable difference for that sieve as listed in Table A1, then aggregate 

gradation correction factors (equal to the resultant average differences) for all sieves shall 

be applied to all acceptance gradation test results determined by T 30, prior to final 
Appendix January 2020

T 308

Appendix B: FLH Test Methods and Addendums B-23

rounding and reporting. If the 0.075-mm (No. 200) sieve is the only sieve outside the limits 

in Table A1, apply the aggregate correction factor to only the 0.075-mm (No. 200) sieve.
Appendix January 2020

T 308

Appendix B: FLH Test Methods and Addendums B-24

Table A1—Permitted Sieving Difference

Sieve Allowable Difference

Sizes larger than or equal to 2.36 mm (No. 8) ±5.0 percent

Sizes larger than 0.075 mm (No. 200) and smaller than

2.36 mm (No. 8) ±3.0 percent

Sizes 0.075 mm (No. 200) and smaller ±0.5 percent

APPENDIX (EXAMPLE CALCULATIONS)

CALCULATION OF CORRECTION FACTORS FOR HMA CONTAINING 

RAP

(Example calculations follow data entries using form FHWA 1648)

1. ASPHALT BINDER CORRECTION FACTOR

Determine quantity of virgin asphalt binder required to achieve target asphalt content by 

mass of mix.

Table A2—Mix Design Parameters

Target binder content by mass of mix, % 6.20

Binder content of RAP by mass of mix, % 5.15

Mix composition, by mass of mix, %

Virgin aggregate blend 80.0

RAP blend 20.0

Total sample mass (virgin aggregate + 

RAP), g

2001.2

Dry virgin aggregate mass, g 1601.0

Mass of RAP, g 400.2

1.1. Determine the amount of aggregate and binder present in the RAP portion:

1.1.1. BBBBBBBBBBBBRRRRRR = MMMMMMMMRRRRRR × AAAA%RRRRRR

Binder mass from RAP = 400.2 g x 5.15%

Binder mass from RAP = 20.6 g Form FHWA 1648 (F)

1.1.2. AAAAAA AA AA RRRRRR = MMMMMMMMRRRRRR − BBBBBBBBBBBBRRRRRR

Aggregate mass from RAP = 400.2 g – 20.6 g

Aggregate mass from RAP = 379.6 Form FHWA 1648 (E)

1.2. Determine the total amount of aggregate present between the virgin aggregate and the 

RAP combined:
Appendix January 2020

T 308

Appendix B: FLH Test Methods and Addendums B-25

1.2.1. AAAAAA AA AA TTTTTT TT = MMMMMMMMTTTTTT TT − BBBBBBBBBBBBRRRRRR

Total aggregate in sample = 2001.2 g – 20.6 g

Total aggregate in sample = 1980.6 g

1.3. Determine the total weight of binder required to achieve the target binder content by mass 

of mix:

1.3.1. BBBBBBBBBBBBTTTTTT TT = �� 100

100− AA%TTTTTTTTTTTT

� × AAAAAA AA AA TTTTTT TT� − AAAAAA AA AA TTTTTT TT

Total binder = �� 100

100− 6.20� × 1980.6� − 1980.6

Total binder = 2111.5 g – 1980.6 g = 130.9 g Form FHWA 1648 (I)

1.4. Determine the amount of virgin binder required for the mix:

1.4.1. BBBBBBBBBBBBVVVV VVVVVV = BBBBBBBBBBBBTTTTTT TT − BBBBBBBBBBBBRRRRRR

Virgin binder = 130.9 g – 20.6 g

Virgin binder = 110.3 g Form FHWA 1648 (H)

Note A4—Follow procedures indicated on Form FHWA 1648 for Hot Mix Asphalt 

Containing RAP to determine the asphalt binder correction factor for the proposed mix.

2. AGGREGATE GRADATION CORRECTION FACTOR

Determine the calculated "blank" gradation for the virgin aggregate and RAP blend using 

the individual gradations.

Table A3—Mix Design Parameters

Binder content of RAP by mass of mix, % 5.15

Mix composition, by mass of mix, %

Virgin aggregate blend 80.0

RAP blend 20.0

Table A4—Individual Gradations

Sieve Size Virgin Aggregate 

Gradation

Burned RAP 

Aggregate 

Gradation

1" (25.0mm) 100.0 100.0

3/4" (19.0mm) 100.0 100.0

1/2" (12.5mm) 87.3 100.0

3/8" (9.5mm) 68.5 78.7

#4 (4.75mm) 51.1 65.6

#8 (2.36mm) 37.5 55.9

#30 (600μm) 32.3 43.2

#40 (425μm) 16.7 25.1

#50 (300μm) 13.4 19.4

#200 (75μm) 6.5 9.8
Appendix January 2020

T 308

Appendix B: FLH Test Methods and Addendums B-26

2.1. Determine the mix composition by mass of aggregate, %.

NOTE A5—The percentages of virgin aggregate and RAP aggregate must be adjusted to account for the 

binder in the RAP specimen.

2.1.1. AAAAAA AA AA RRRRRR,

% = MMMMMMMMRRRRRR,% − �MMMMMMMMRRRRRR, % × BBBBBBBBBBBBRRRRRR,%�

AggregateRAP, % = 20.0 - (20.0 x 0.0515)

AggregateRAP, % = 19.0%

2.1.2. AAAAAA AA AA VVVV VVVVVV,

% = 100 − AAAAAA AA AA RRRRRR,%

AggregateVIRGIN, % = 100.0 - 19.0

AggregateVIRGIN, % = 81.0%

2.2. Determine the calculated "blank" gradation using the adjusted percentages of Virgin 

Aggregate and RAP aggregate and the individual gradations for each specimen.

2.2.1. CCCCCCCC “bb bb”SS SS SS =

�AAAAAA AA AA VVVV VVVVVV,

% × %PP VVVV VVVVVV SS SS SS� + (AAAAAA AA AA RRRRRR × %PP RRRRRR SS SS SS)

Calculated "blank" for the 3/8” (9.5 mm) sieve = (81.0% x 68.5) + (19.0% x 78.7)

Calculated "blank" for the 3/8” (9.5 mm) sieve = 70.4%

2.2.2. Repeat the calculation for each sieve to determine the calculated "blank" gradation.
Appendix January 2020

T 308

Appendix B: FLH Test Methods and Addendums B-27

3. EXAMPLE USING FORM FHWA 1648.
Appendix January 2020

T 308

Appendix B: FLH Test Methods and Addendums B-28
Appendix January 2020

Appendix C: Sample Quantities Guide C-1

APPENDIX C: SAMPLE QUANTITIES GUIDE

Division 200

Material / Product Characteristic Sampling 

Method

Minimum Field 

Sample lbs (kg)

Minimum Split Size 

to FLH Lab lbs (kg)

Section 204

Topping Classification AASHTO R 90

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)

Moisture - Density AASHTO R 90 330 (150) 50 (23)

Unclassified Borrow Classification AASHTO R 90

 2" AASHTO R 90 220 (100) 44 (20)

 1" AASHTO R 90 110 (50) 22 (10)

Moisture-density AASHTO R 90 330 (150) 50 (23)

Select Borrow Classification AASHTO R 90

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)

Gradation AASHTO R 90

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)

Liquid Limit/Plasticity Index AASHTO R 90 12 (5) 12 (5)

Moisture-density AASHTO R 90 330 (150) 50 (23)

Earth Embankment Classification AASHTO R 90

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)

 3/4" 55 (25) 11 (5)

 1/2" 35 (15) 4 (2)

Moisture-density AASHTO R 90 330 (150) 50 (23)

Section 208

Foundation Fill Classification AASHTO R 90

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)

Gradation AASHTO R 90

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)

Liquid Limit/Plasticity Index AASHTO R 90 12 (5) 12 (5)

Moisture-density AASHTO R 90 220 (100) 50 (23)

Structural Backfill Gradation AASHTO R 90 330 (150) 130 (60)

Liquid Limit/Plasticity Index AASHTO R 90 12 (5) 12 (5)

Moisture-density AASHTO R 90 330 (150) 50 (23)

Section 209

Backfill Material Gradation AASHTO R 90

 3" 330 (150) 130 (60)

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)

Liquid limit AASHTO R 90 12 (5) 12 (5)

Moisture-density AASHTO R 90 330 (150) 50 (23)

Bedding Material Moisture-density AASHTO R 90 35 (15) 50 (23)

Foundation Fill Moisture-density AASHTO R 90 220 (100) 50(23)

Unclassified Borrow Classification AASHTO R 90

 3" 330 (150) 130 (60)

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)
Appendix January 2020

C-2 Appendix C: Sample Quantities Guide

Division 200 (continued)

Material / Product Characteristic Sampling 

Method

Minimum Field 

Sample lbs (kg)

Minimum Split Size 

to FLH Lab lbs (kg)

Section 213

Subgrade Stabilization Mix Design

Soil AASHTO R 90 ― 200 (90)

Fly Ash ASTM C311 ― 50 (25)

Lime AASHTO T 218 ― 25 (10)

Hydraulic Cement AASHTO R 71 ― 25 (10)

Section 

251

Riprap

Quality Requirements

Apparent specific gravity & absorption, 

Sodium Sulfate Soundness, LA Abrasion AASHTO R 90 ― 200 (90)

Section 

252

Rock for Buttresses Quality 

Requirements

Apparent specific gravity & absorption, 

Durability AASHTO R 90 ― 200 (90)

Rock for Rockeries

Quality Requirements

Apparent specific gravity & absorption, 

Durability, LA Abrasion, Sodium Sulfate 

Soundness

AASHTO R 90 ― 200 (90)

Section 255

Select Granular Backfill

Quality Requirements

Gradation, Angle of internal friction, 

Soundness, Plasticity index, LA 

Abrasion, Electrochemical

AASHTO R 90

 3" 330 (150) 130 (60)

 2" 220 (100) 44 (20)

 1" 110 (50) 22 (10)

Moisture - Density AASHTO R 90 330 (150) 50 (23)
Appendix January 2020

Appendix C: Sample Quantities Guide C-3

Division 300

Material / Product Characteristic Sampling 

Method

Minimum Field 

Sample lbs (kg)

Minimum Split Size 

to FLH Lab lbs (kg)

Section 301

Aggregate source quality LA abrasion, Sodium sulfate soundness, 

Durability index, Fractured faces AASHTO R 90 300 (150) 200 (90)

Subbase course

(grading A & B)

Gradation, Liquid Limit AASHTO R 90 165 (75) 33 (15)

Moisture - Density AASHTO R 90 110 (50) 50 (23)

Base course

(grading C, D, & E)

Gradation, Liquid Limit AASHTO R 90 110 (50) 22 (10)

Moisture - Density AASHTO R 90 110 (50) 50 (23)

Surface course aggregate 

Gradation, Liquid Limit, Plasticity Index, 

Fractured faces AASHTO R 90 110 (50) 22 (10)

Moisture density (max. density) AASHTO R 90 110 (50) 50 (23)

Section

302

Crushed aggregate Moisture - Density AASHTO R 90 110 (50) 50 (23)

Section

304

Pulverized material Moisture - Density AASHTO R 90 110 (50) 50 (23)

Section 

309

Aggregate source quality LA abrasion, Sodium sulfate soundness, 

Durability Index, Fractured faces AASHTO R 90 ― 200 (90)

Emulsified asphalt treated base Gradation, Sand Equivalent AASHTO R 90 110 (50) 22 (10)

Emulsified asphalt treated base 

(submittal) Quality (mixture properties) AASHTO R 90 ― 300 (150)

Section 

310

Recycled base course, Type A 

(mix design) Pavement samples ― 10 6-inch (150 mm) cores

Emulsified asphalt AASHTO R 66 ― 2 1-quart samples

(2 1-liter samples)

Lime AASHTO T 218 ― 2 (1)

Emulsified asphalt Quality AASHTO R 66 ― 2 1-quart samples

(2 1-liter samples)

Section 

311

Aggregate source quality LA abrasion, Sodium sulfate soundness, 

Durability Index, Fractured faces AASHTO R 90 300 (150) 200 (90)

Surface course aggregate Gradation, Liquid Limit/Plasticity Index AASHTO R 90 110 (50) 22 (10)

Moisture density (max. density) AASHTO R 90 110 (50) 50 (23)
Appendix January 2020

C-4 Appendix C: Sample Quantities Guide

Division 400

Material / Product Characteristic Sampling 

Method

Minimum Field 

Sample lbs (kg)

Minimum Split Size 

to FLH Lab lbs (kg)

Section 401

Aggregate source quality

LA abrasion, Sodium sulfate soundness, 

Fine aggregate angularity, Flat and 

elongated particles, Sand equivalent, 

Fractured faces

AASHTO R 90 ― 200 (90)

Asphalt binder source Quality AASHTO R 66 ― 5 1-quart samples 

(5 1-liter samples)

Superpave Asphalt Concrete 

(mix design) Mix design aggregate AASHTO R 90 ― 600 (270)

Bag house fines ― 20 (10)

Mineral filler ― 20 (10)

Lime AASHTO T 218 ― 10 (5)

Recycled asphalt pavement (RAP) ― 200 (100)

Hot asphalt concrete pavement 

(production)

Gradation, Asphalt content, VMA, VFA, 

Maximum specific gravity AASHTO R 97 100 (45) 45 (20)

Asphalt binder AASHTO R 66 ― 2 1-quart samples

(2 1-liter samples)

Core density ASTM D 5361 6 inch (150 mm) 

core

6 inch (150 mm) 

core

Section 402

Aggregate source quality

LA abrasion, Sodium sulfate soundness, 

Durability Index, Fractured faces, Sand 

equivalent

AASHTO R 90 ― 200 (90)

Hveem or Marshall Asphalt 

Concrete

(mix design)

Mix design aggregate AASHTO R 90 ― 600 (270)

Bag house fines ― 20 (10)

Mineral filler ― 20 (10)

Asphalt binder AASHTO R 66 ― 5 1-quart samples 

(5 1-liter samples)

Lime AASHTO T 218 ― 10 (5)

Recycled asphalt pavement (RAP) ― 200 (100)

Hot asphalt concrete pavement 

(production) Gradation, Asphalt content AASHTO R 97

 3/4" 32 (14) 16 (7)

 1/2" 24 (10) 12 (5)

 3/8" 16 (8) 8 (4)

Asphalt binder AASHTO R 66 ― 2 1-quart samples

(2 1-liter samples)

Core density ASTM D5361 6 inch (150 mm) 

core

6 inch (150 mm) 

core

Section 

403

Hot asphalt concrete pavement 

(production) Core density ASTM D5361 6 inch (150 mm) 

core

6 inch (150 mm) 

core

Section

405

Open-graded asphalt friction 

course Gradation AASHTO R 97 8 (4) 8 (4)

Asphalt binder Quality AASHTO R 66 ― 2 1-quart samples

(2 1-liter samples)

Section 407

Aggregate source quality

LA abrasion, Sodium sulfate soundness, 

Durability Index, Fractured faces, Flat 

and elongated particles

AASHTO R 90 ― 200 (90)

Chip seal (produced aggregate) Gradation / Fractured faces AASHTO R 90

 1" 110 (50) 22 (10)

 3/4" 55 (25) 11 (5)

 1/2" 35 (15) 4 (2)

 3/8" 25 (10) 2 (1)

Asphalt binder Quality AASHTO R 66 ― 2 1-quart samples

(2 1-liter samples)

Emulsified asphalt Quality AASHTO R 66 ― 2 1-quart samples

(2 1-liter samples)
Appendix January 2020

Appendix C: Sample Quantities Guide C-5

Division 400 (continued)

Material / Product Characteristic Sampling 

Method

Minimum 

Field Sample 

lbs (kg)

Minimum Split 

Size to FLH Lab 

lbs (kg)

Section 409

Aggregate source quality LA Abrasion, Sand equivalent, 

Sodium sulfate soundness AASHTO R 90 ―

12 (5) Material 

retained on #4 

(4.75 mm) sieve

Microsurfacing 

(Produced aggregate) Gradation AASHTO R 90 25 (10) 4 (2)

Polymer modified emulsified 

asphalt Quality AASHTO R 66 ― 2 1-quart samples(2 1-liter samples)

Section 410

Aggregate source quality LA Abrasion, Sand equivalent, 

Sodium sulfate soundness AASHTO R 90 ―

12 (5) Material 

retained on #4 

(4.75 mm) sieve

Slurry Seal 

(Produced aggregate) Gradation AASHTO R 90 25 (10) 4 (2)

Emulsified asphalt Quality AASHTO R 66 ― 2 1-quart samples

(2 1-liter samples)
Appendix January 2020

C-6 Appendix C: Sample Quantities Guide

Division 500

Material / Product Characteristic Sampling 

Method

Minimum Field 

Sample lbs (kg)

Minimum Split Size 

to FLH Lab lbs (kg)

Section 501

Aggregate source quality

Coarse aggregate: Alkali-silica Reaction 

(ASR) and AASHTO M 80

Gradation, AASHTO M 43

AASHTO R 90 ― 200 (90)

Fine aggregate: Alkali-silica Reaction 

(ASR) and AASHTO M 6

Gradation, AASHTO M 6

AASHTO R 90 ― 25 (10)

Structural concrete Compressive Strength

AASHTO R 60 

and 

AASHTO T 23

― 1 set of cylinders

Section 502

Aggregate source quality

Coarse aggregate: Alkali-silica Reaction 

(ASR) and AASHTO M 80

Gradation, AASHTO M 43

AASHTO R 90 ― 200 (90)

Fine aggregate: Alkali-silica Reaction 

(ASR) and AASHTO M 6

Gradation, AASHTO M 6

AASHTO R 90 ― 25 (10)

Structural concrete Compressive Strength

AASHTO R 60 

and 

AASHTO T 23

― 1 set of cylinders

Section 552

Aggregate source quality

Coarse aggregate: Alkali-silica Reaction 

(ASR) and AASHTO M 80

Gradation, AASHTO M 43

AASHTO R 90 ― 200 (90)

Fine aggregate: Alkali-silica Reaction 

(ASR) and AASHTO M 6

Gradation, AASHTO M 6

AASHTO R 90 ― 25 (10)

Structural concrete Compressive Strength

AASHTO R 60 

and 

AASHTO T 23

― 1 set of cylinders

Section 

553

Prestressed concrete Compressive Strength

AASHTO R 60 

and 

AASHTO T 23

― 1 set of cylinders

Section 566

Aggregate source quality

Coarse aggregate: Alkali-silica Reaction 

(ASR) and AASHTO M 80

Gradation, AASHTO M 43

AASHTO R 90 ― 200 (90)

Fine aggregate: Alkali-silica Reaction 

(ASR) and AASHTO M 6

Gradation, AASHTO M 6

AASHTO R 90 ― 25 (10)

Shotcrete (Production) Permeable void volume, Boiling 

absorption, Compressive Strength AASHTO T 24 ― Cores from production panels
Appendix January 2020

Appendix D: Pre-Construction Meeting Agendas D-1

APPENDIX D: PRE-CONSTRUCTION MEETING AGENDAS

APPENDIX D.1: PRE-PAVING MEETING AGENDA

Pre-Paving Meeting

Asphalt Concrete Pavement – Section 401

ATTENDANCE SIGN IN SHEET

Name Organization Phone No.
Appendix January 2020

D-2 APPENDIX D.1: PRE-PAVING MEETING AGENDA

Pre-Paving Meeting Agenda

Asphalt Concrete Pavement – Section 401

PROJECT: _________________________________________

DATE: _______________________

1. Introductions and Titles (please sign sheet)

a. Contractor’s Personnel

b. Federal Highway Administration Personnel

c. Suppliers / subcontractors

d. Others

2. Contractor’s Production Schedule

a. Begin Paving:

i. When

ii. Where (include station and direction)

b. Daily production tonnage and number of trucks

c. Projected work hours / days

3. Mix Design Information / Plant Operations

a. Mixing Temperature: ____  ̊C ( ____ ̊F)

b. Target Values and Allowable deviations

Asphalt Concrete Pavement

Nominal Maximum Aggregate Size 

SIEVE SIZE TARGET VALUES ALLOWABLE DEV. (+/-)

19 mm (3/4”)

12.5 mm (1/2”)

4.75 mm (3/8”)

2.36 mm (#8)

600 μm (#30)

300 μm (#50)

75 μm (#200) 2

AC (%) 0.4

Bin Combinations:

BIN PERCENT
Appendix January 2020

APPENDIX D.1: PRE-PAVING MEETING AGENDA D-3

4. Lime introduction procedure

a. Use of baghouse fines

b. Procedure for introducing RAP into the mixture

c. Bins and aggregate preparation

5. Control (test) strip (See Subsection 401.12)

a. Where (include station and direction)

b. Length, width and thickness requirements

c. Process control

d. Sample size

e. Cores

f. Acceptance criteria

g. Timely reporting

h. Split samples

6. Construction

a. Surface preparation (See Subsection 401.06)

b. Weather limitations (See Subsection 401.07)

c. Asphalt preparation (See Subsection 401.08)

d. Aggregate Preparation (See Subsection 401.09)

e. Hauling units

i. Bed condition

ii. Tarps / covering

iii. Approved release agents

f. Laydown Operations

i. Grade control

ii. Paver operations

iii. Skis – reference and length

iv. Paver condition 

v. Paving thickness, widths and fore slopes

vi. Method(s) for placing material when mechanical spreading and finishing 

is impractical

vii. Joints, trimming and clean-up

g. Compaction

i. Rollers – size and type 

ii. Density requirement

h. Weighing procedures and delivery

i. Scale tickets (See Subsection 109.03)

ii. Scale certification (See Subsection 109.03)

iii. Spread person (See Subsection 109.04)

7. Contractor Sampling (Acceptance, see Section 154 and Section 401 Sampling and 

Testing Table)

a. Location - Behind paver prior to compaction

b. Designated sampler

c. Sampling procedures and device

d. Sampling frequencies

e. Testing procedures

i. Ignition method

ii. Correction factor

iii. Gradation and asphalt content

iv. Volumetrics

v. Maximum specific gravity
Appendix January 2020

D-4 APPENDIX D.1: PRE-PAVING MEETING AGENDA

vi. Core density

vii. Laboratory equipment

viii. Testing forms

f. Project engineer splits samples

g. Binder sampling(between storage and drum, contract frequency)

8. Contractor Quality Control (See Section 153)

a. Moisture content

b. Gradation, cold feed

c. Compaction, on grade-nuclear gauge

d. Placement temperature

9. Pavement Smoothness/Roughness (see Subsection 401.16)

a. Pavement smoothness/roughness type 

b. Defective areas

c. Measurement and corrective action

d. Pay incentives and deducts

10. Statistical Acceptance Procedures 

a. Parameters (i.e., density, binder content, volumetrics, etc.) (See Section 401 

Sampling and Testing Table)

b. Lot definition (See Subsection 106.05)

c. Lot termination and reject (See Subsection 106.05)

d. Incentive/disincentive (See Subsection 106.05)

11. Traffic Control

a. Pilot Car, flaggers, temporary stripping and signing

b. Traffic delays

c. Work Zone control
Appendix January 2020

APPENDIX D.2: PRE-CONCRETING MEETING AGENDA D-5

APPENDIX D.2: PRE-CONCRETING MEETING AGENDA

PRE-CONCRETING MEETING AGENDA

PROJECT: _________________________________________

DATE: _______________________

1. Introduction and Titles (please sign sheet)

a. Contractor’s Personnel

b. Federal Highway Administration Personnel

c. Suppliers/subcontractors

d. Other Agencies

e. Other

2. Purpose of the meeting

a. To discuss standard specification and special contract requirements as they 

pertain to structural concrete Item 552 and drilled shafts Item 565.

3. Schedule of work

a. Proposed schedule for concrete work

b. Work hours/days

4. Review approved concrete mix design/proportioning

a. Review/discuss all mix design classes of concrete for structural concrete 

b. Methods of proportioning, cement, water, aggregates, additives (Subsection

552.06)

c. Allowable tolerances for proportioning (Subsection 552.05)

d. Calibrated batching equipment (Subsection 552.06) 

e. Batch tickets (Subsection 552.09)

5. Quality Control 

a. Designated QCS for concrete sampling and testing

b. Batch corrected weights, tickets

c. Gradations, moisture and FM-CA & FA, --minimum testing requirements

d. Truck mixing—revolutions 70 min and 100 max.

e. Delivery

i. Time restriction

ii. Use of set retarders

iii. Retempering

f. Slump, air content, unit weight and temperatures—sampling frequency and 

methods

g. Compressive strength:

i. acceptance—1 set per ___ cubic yards (meters)

ii. shipping cylinders

h. Discuss proper concrete cylinder curing

i. Discuss statistical evaluation (Subsection 106.05)
Appendix January 2020

D-6 APPENDIX D.2: PRE-CONCRETING MEETING AGENDA

j. Reporting strengths

k. Discuss acceptance for incidental items accepted by certification---rebar, cement, 

additives, steel, etc., 

6. Placing

a. False work approval (Section 562)

b. Cold/hot weather plan---monitor temperatures for aggregates, water, placement, 

protecting, curing and temperature monitoring (Subsection 552.10)

c. Discuss pumping(loss of air and slump) if applicable (Subsection 552.11)

d. Vibrator/vibrating requirements (Subsection 552.11)

e. Delivery rate

f. Maximum drop

g. Rebar placement

7. Finishing (Subsections 552.14 and 552.16)

a. Striking-off and floating

b. Straight edging

c. Texturing (Subsection 552.14)

d. Deck finishing machine (Subsection 552.14)

8. Curing (Subsection 552.15)

a. Curing times

b. Water method

c. Form method

d. Membrane method

e. Deck curing

9. Loading

a. Form Removal (Subsection 562.08)

b. Loads on deck and other members (552.18)
Appendix January 2020

APPENDIX D.3: PRE-DRILLED SHAFT MEETING AGENDA D-7

APPENDIX D.3: PRE-DRILLED SHAFT MEETING AGENDA

Pre-Drilled Shaft Meeting Agenda

PROJECT: _________________________________________

DATE: _______________________

1. Construction requirements, review/discuss drilled shaft installation plan

a. Construction Schedule

b. Personnel

c. Equipment

2. Construction Procedures

a. Excavation, dry/wet methods

i. Use of casing

ii. Use of slurry

b. Vertical alignment of shaft - tolerances

c. Record keeping during shaft excavation

d. Cage installation requirements

3. Concrete for Drilled Shafts

a. Class of concrete—structural or seal

b. Placement procedure—pumped or free fall

c. Placement in wet conditions

4. Cross Hole Sonic Logging

a. Access tube placement

b. Access tube materials requirements

c. CSL integrity testing requirements

d. CSL results and reporting requirements

e. Interpretation of data

f. Correction of defects