FHWA Report No. FHWA-RD-99-152

Materials and Procedures for

Rapid Repair of Partial-Depth Spalls in

Concrete Pavements

Manual of Practice

Federal Highway Administration

U.S. Department of Transportation

Strategic Highway Research Program

National Research Council
FOREWORD

This manual (FHWA-RD-99-152) presents guidelines and

recommendations to assist highway maintenance agencies and

other related organizations in planning, constructing, and

monitoring the performance of concrete pavement partial-depth

spall repair projects. Included in the manual are discussions

pertaining to when partial-depth spall repair operations are

appropriate, the types of repair materials and construction

methods that should be used, how each individual step in a spall

repair operation should be performed, and how the performance

and cost-effectiveness of spall repairs can be evaluated. This

report will be of interest and benefit to various levels of agency

maintenance personnel, from crew supervisors to the chief

maintenance engineer.

NOTICE

This document is disseminated under the sponsorship of the

Department of Transportation in the interest of information

exchange. The United States Government assumes no liability

for its contents or use thereof. This report does not constitute a

standard, specification, or regulation.

The United States Government does not endorse products or

manufacturers. Trade and manufacturers’ names appear in this

report only because they are considered essential to the object

of the document.
Technical Report Documentation Page

 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.

FHWA-RD-99-152

 4. Title and Subtitle 5. Report Date

 6. Performing Organization Code

 8. Performing Organization Report No.

 7. Author(s)

 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

 ERES Consultants

 A Division of Applied Research Associates, Inc. 11. Contract or Grant No.

 505 W. University Avenue DTFH61-93-C-00051

 Champaign, IL 61820-3915 13. Type of Report and Period Covered

 12. Sponsoring Agency Name and Address Updated Manual of Practice

 Federal Highway Administration October 1993 - June 1999

 Pavement Performance Division

 6300 Georgetown Pike 14. Sponsoring Agency Code

 McLean, Virginia 22101

 15. Supplementary Notes

 FHWA Contracting Officer's Technical Representative (COTR): Shahed Rowshan, HRDI

 Project Consultants: Charlie Smyth

 16. Abstract

 17. Key Words 18. Distribution Statement

 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No of Pages 22. Price

Unclassified Unclassified 135

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

No restrictions. This document is available to the 

public through the National Technical Information 

Service, Springfield, Virginia 22161.

T.P. Wilson, K.L. Smith, and A.R. Romine

The Strategic Highway Research Program (SHRP) H-106 maintenance experiment and the Federal Highway Administration

(FHWA) Long-Term Monitoring (LTM) of Pavement Maintenance Materials Test Sites project studied the repair of partialdepth spalls in concrete pavements. Many different repair materials and methods were investigated between 1991 and 1998

through test sites installed at four locations in the United States. The findings of these combined studies have been merged with 

standard highway agency procedures to provide the most useful and up-to-date information on the practice of concrete partialdepth spall repair.

This Manual of Practice is an updated version of the 1993 SHRP Spall Repair Manual. It contains the latest information

pertaining to the performance of repair materials and methods, the availability and relative costs of repair materials, and the

proper ways of planning, designing, constructing, and monitoring the performance of partial-depth spall repair projects. It also

provides an updated partial listing of material and equipment manufacturers.

This Manual is intended for field and office personnel within highway maintenance agencies and contracted maintenance firms.

It contains valuable information for supervisors and foremen in charge of individual spall repair operations, engineers in charge

of planning and overseeing many spall repair projects, and managers in charge of establishing repair policies and standards.

Concrete pavement, pavement maintenance, partialdepth spalls, spall repair, patching materials, 

bituminous patch, cementitious patch, performance, 

effectiveness, cost-effectiveness

Materials and Procedures for Rapid Repair of Partial-Depth Spalls in Concrete 

Pavements---Manual of Practice
 
iii

Preface

This manual is intended for use by highway maintenance

agencies and contracted maintenance firms in the field and in

the office. It is a compendium of good practices for portland

cement concrete (PCC) partial-depth spall repair operations,

stemming from the Strategic Highway Research Program

(SHRP) pavement maintenance studies and a follow-up study

sponsored by the Federal Highway Administration (FHWA).

In SHRP project H-105, Innovative Materials and Equipment

for Pavement Surface Repair, the researchers conducted a

massive literature review and a nationwide survey of highway

agencies to identify potentially cost-effective repair and

treatment options (Smith et al., 1991). The information and

findings from that study were then used in the subsequent field

experiments conducted under SHRP project H-106, Innovative

Materials Development and Testing.

In project H-106, the installation and evaluation of many

different test sections were conducted to determine the costeffectiveness of maintenance materials and procedures. Test

sections were installed at 22 sites throughout the United States

and Canada between March 1991 and February 1992, under the

supervision of SHRP representatives. The researchers collected

installation and productivity information at each site and

periodically evaluated the experimental repairs and treatments

through the end of 1992. The first version of this manual was

prepared in October 1993 and was based on this work effort.

Following the conclusion of the SHRP in 1993, the FHWA

sponsored a study to continue monitoring the performance of

the experimental repairs and treatments, beginning in October

1993. Under the Long-Term Monitoring (LTM) of Pavement

Maintenance Materials Test Sites project, the experimental

repairs and treatments were evaluated annually through the end
iv

of 1997. The pertinent long-term performance and costeffectiveness information generated by the continued

monitoring of the experimental spall repairs has been included

in this revised manual.

For the reader's convenience, potentially unfamiliar terms are

italicized at their first occurrence in the manual and are defined

in a glossary. Readers who want more information on topics

included in this manual should refer to the reference list

provided at the back. The final report for the H-106/LTM

partial-depth spall repair study may be of particular interest to

many readers (Wilson et al., 1999). It details the installation

procedures, laboratory testing of the materials, and field

performance of each spall repair type investigated.
v

Acknowledgments

The research described herein was supported by the Strategic

Highway Research Program (SHRP) and the Federal Highway

Administration (FHWA). SHRP was a unit of the National

Research Council that was authorized by Section 128 of the

Surface Transportation and Uniform Relocation Assistance Act

of 1987.

Special thanks are due the project management teams at SHRP

and the FHWA, and to the following highway agencies:

! Arizona Department of Transportation.

! Commonwealth of Pennsylvania Department of

Transportation.

! South Carolina Department of Highways and

Public Transportation.

! Utah Department of Transportation.

The contributions of the following individuals are also

acknowledged: Arti Patel and Cynthia A. Good Mojab (coauthors of the 1993 Manual of Practice), Michael Darter, Sam

Carpenter, and Leo Ferroni.
 
vii

Contents

1.0 Introduction .............................. . 1

1.1 Scope of Manual .................... . 1

1.2 Purpose of Partial-Depth Spall Repair ..... . 1

1.3 Partial-Depth Patch Performance ........ . 2

1.4 Limitations ......................... . 3

2.0 Need for Partial-Depth Spall Repair ............ . 5

2.1 Pavement Condition .................. . 5

2.2 Climatic Conditions .................. . 7

3.0 Planning and Design ........................ . 9

3.1 Objectives in Selecting Materials and

Procedures ......................... . 9

3.2 Assessing Existing Conditions .......... . 10

3.3 Selecting a Repair Material ............. . 11

3.3.1 Cementitious Concretes ......... . 14

3.3.2 Polymer Concretes ............. . 17

3.3.3 Bituminous Materials ........... . 18

3.3.4 Material Testing ............... . 19

3.4 Selecting Accessory Materials .......... . 20

3.4.1 Bonding Agents ............... . 20

3.4.2 Joint Bond Breakers ............ . 20

3.4.3 Curing Materials ............... . 22

3.4.4 Joint Sealants ................. . 23

3.5 Selecting Dimensions of the Repair Area . . . 23

3.6 Selecting Patch Preparation Procedures ... . 29

3.6.1 Saw and Patch ................ . 29

3.6.2 Chip and Patch ................ . 31

3.6.3 Mill and Patch ................. . 32

3.6.4 Waterblast and Patch ........... . 33

3.6.5 Clean and Patch ............... . 36

3.7 Estimating Material, Equipment, and Labor . 36
viii

3.8 Overall Cost-Effectiveness ............. . 37

3.8.1 Cost-Effectiveness Worksheet ..... . 42

3.8.2 Determining Cost-Effectiveness

Inputs ....................... . 51

4.0 Construction ............................. . 53

4.1 Traffic Control ...................... . 53

4.2 Safety Precautions ................... . 54

4.3 Material Testing ..................... . 54

4.4 Initial Joint Preparation ................ . 55

4.4.1 Removing Old Sealant ........... . 55

4.4.2 Joint Sawing .................. . 55

4.4.3 Sawing Out Joint Inserts ......... . 56

4.5 Removing the Deteriorated Concrete ..... . 57

4.5.1 Saw and Patch ................ . 58

4.5.2 Chip and Patch ................ . 62

4.5.3 Mill and Patch ................. . 63

4.5.4 Waterblast and Patch ........... . 63

4.5.5 Clean and Patch ............... . 65

4.6 Cleaning the Repair Area .............. . 65

4.6.1 Sandblasting .................. . 65

4.6.2 Airblasting ................... . 66

4.6.3 Sweeping .................... . 67

4.7 Final Joint Preparation ................ . 67

4.7.1 Preparing Transverse Joints ....... . 69

4.7.2 Preparing Centerline Joints ....... . 70

4.7.3 Preparing Lane-Shoulder Joints .... . 70

4.7.4 Using Flexible Repair Materials .... . 70

4.8 Pre-Placement Inspection of the Repair

Area .............................. . 71

4.9 Mixing the Bonding Agent ............. . 71

4.10 Mixing the Repair Material ............. . 72

4.10.1 Cementitious Concretes ......... . 72

4.10.2 Polymer Concretes ............. . 73

4.10.3 Bituminous Materials ........... . 74
ix

4.11 Applying the Bonding Agent ............ . 75

4.12 Placing the Repair Material ............. . 76

4.12.1 Cementitious Concretes ......... . 76

4.12.2 Polymer Concretes ............. . 77

4.12.3 Bituminous Materials ........... . 78

4.13 Consolidating and Compacting .......... . 79

4.14 Screeding and Finishing ............... . 81

4.15 Curing ............................ . 81

4.15.1 PCC Patching Materials ......... . 83

4.15.2 Proprietary Patching Materials .... . 83

4.16 Joint Sealing ........................ . 83

4.17 Cleanup Requirements ................ . 84

4.18 Opening to Traffic ................... . 85

4.19 Inspection .......................... . 85

5.0 Evaluating Partial-Depth Patch Performance ..... . 87

5.1 Data Required ...................... . 87

5.2 Calculations ........................ . 89

Appendix A Material Testing Specifications .......... . 91

A.1 Rapid-Setting Cementitious Concretes .... . 91

A.2 Rapid-Setting Flexible Polymer Concretes . . 92

A.3 Bituminous Materials ................. . 92

Appendix B Sample Cost-Effectiveness Calculations ... . 93

B.1 Example 1 ......................... . 94

B.2 Example 2 ......................... . 98

Appendix C Material and Equipment Safety

Precautions ........................ . 103

C.1 Materials ......................... . 103

C.2 Equipment ........................ . 104

Appendix D Inspection Checklists for Construction ... . 105

D.1 Plans and Specifications .............. . 105

D.2 Equipment ........................ . 106
x

D.3 Material Quality .................... . 107

D.4 Field Installation .................... . 107

D.5 Preparing the Repair Area ............. . 108

D.6 Installing the Patch .................. . 113

D.6.1 Mixing ..................... . 113

D.6.2 Placement ................... . 114

D.6.3 Material Finishing and Curing .... . 116

D.6.4 Joint Resealing ............... . 117

D.7 Final Inspection .................... . 117

Appendix E Partial List of Material and Equipment

Sources .......................... . 119

E.1 Partial-Depth Patching Materials ....... . 119

E.1.1 Manufacturers of Cementitious

Concretes ................... . 119

E.1.2 Manufacturers of Polymer

Concretes ................... . 121

E.1.3 Manufacturers of Bituminous

Materials .................... . 122

E.1.4 Manufacturers of Bonding Agents . . 122

E.2 Partial-Depth Patching Equipment ...... . 122

E.2.1 Manufacturers of Sawing

Equipment .................. . 122

E.2.2 Manufacturers of Spray-Injection

Equipment .................. . 123

E.2.3 Manufacturers of Waterblasting

Equipment .................. . 124

E.2.4 Manufacturers of Milling

Equipment .................. . 124

E.2.5 Manufacturers of Jackhammers ... . 124

E.2.6 Manufacturers of Compacting

Equipment .................. . 124

Glossary ..................................... . 125

References .................................... . 133
xi

List of Figures

Figure 1. Partial-depth spall caused by incompressibles . . . 6

Figure 2. Scored joint bond breaker ................. . 21

Figure 3. Dimensions of patch at one joint ............ . 25

Figure 4. Dimensions of patch at one joint for spall

less than 300 mm apart ................... . 26

Figure 5. Dimensions of patch at two joints ........... . 27

Figure 6. Dimensions of patch at two joints for spalls

less than 300 mm apart ................... . 28

Figure 7. (a) Recommended orientation of milled patch.

(b) Milled patch with rounded edges ......... . 34

Figure 8. Cost-effectiveness worksheet .............. . 43

Figure 9. Dimensions of joint saw cut ............... . 57

Figure 10. Sawing patch boundaries with a small

handheld saw .......................... . 59

Figure 11. Sawing pattern for large repair areas ........ . 59

Figure 12. Spade bits ............................ . 60

Figure 13. Using a jackhammer ..................... . 61

Figure 14. Sounding repair area with a steel rod ........ . 61

Figure 15. Scalloped edge and 25-mm vertical edge ..... . 62
xii

Figure 16. Protective shield around waterblasting 

operation ............................. . 64

Figure 17. Sandblasting ........................... . 66

Figure 18. (a) Correct dimensions of joint bond breaker

placement at one joint. (b) Incorrectly installed joint

bond breaker at two joints ................ . 68

Figure 19. Joint bond breaker that has been stacked and

caulked .............................. . 69

Figure 20. Adding carefully measured components to a 

drum mixer ............................ . 73

Figure 21. Using a Jiffy mixer ...................... . 75

Figure 22. Applying bonding agent .................. . 76

Figure 23. Pumping polymer into a patch that was 

prefilled with aggregate .................. . 78

Figure 24. Using an internal vibrator ................. . 80

Figure 25. Screeding the patch ..................... . 82

Figure 26. Finishing the patch ...................... . 82

Figure 27. Removing the tear-off top strip of a joint

bond breaker .......................... . 84

Figure B-1.Example 1 cost-effectiveness worksheet ...... . 95

Figure B-2.Example 2 cost-effectiveness worksheet ...... . 99
xiii

List of Tables

Table 1. Properties of some rapid-setting partialdepth spall repair materials ................ . 12

Table 2. Initial material selection criteria for some

rapid-setting materials ................... . 15

Table 3. Minimum dimensions of repair area for

spalls at various locations ................. . 24

Table 4. Typical equipment used for the five patch

preparation procedures ................... . 38

Table 5. Typical mixing and placement equipment

and supplies ........................... . 39

Table 6. Typical personnel used for spall repair 

procedures ............................ . 40

Table 7. Typical personnel used for mixing and placing . . 41

Table 8. Sample patch performance data ............ . 88
 
*

 Italicized words are defined in the glossary.

1

1.0 Introduction

Spalling* is a common distress in jointed concrete pavements

that decreases pavement serviceability and can be hazardous to

highway users. When left unrepaired, it results in accelerated

pavement deterioration. This manual has been prepared for

maintenance engineers, maintenance field supervisors, crew

members, maintenance contractors, and inspectors to use as an

easy reference for the rapid repair of partial-depth spalls in

jointed portland cement concrete (PCC) pavements.

1.1 Scope of Manual

This manual describes procedures and materials recommended

for partial-depth spall repair in jointed PCC pavements. Only

rapid-setting materials are discussed. The manual presents

detailed guidelines on design, construction, and inspection. The

information in this manual is based on the most recent research,

obtained through reviews of literature and current practices,

and the results of a large-scale, long-term (6.5 years) spall

repair field study sponsored by the Strategic Highway Research

Program (SHRP) and the Federal Highway Administration

(FHWA) (Smith et al., 1991; Evans et al., 1993a; Wilson et al.,

1999).

1.2 Purpose of Partial-Depth Spall Repair

In brief, partial-depth spall repair is removing an area of

deteriorated concrete that is generally limited to the top third of

a concrete pavement slab, and replacing it with a repair material

and perhaps a new joint sealant system. Partial-depth spall
2

repairs may be placed along transverse and longitudinal joints,

and anywhere in the slab. 

Partial-depth patches improve the ride of jointed concrete

pavements by repairing surface spalls, scaling, and popouts. 

When placed along joints and combined with an appropriate

joint maintenance and resealing program, they reduce the

infiltration of moisture and the intrusion of incompressibles into

the joint. Properly placed partial-depth patches should last as

long as the rest of the pavement.

Partial-depth spall repair should also be considered before a

pavement is overlaid. If spalls are not repaired, the overlay is

likely to deteriorate and fail prematurely. Partial-depth spall

repairs should be completed after any undersealing or slab

jacking, but before diamond grinding and joint sealing.

1.3 Partial-Depth Patch Performance

Studies have shown that when partial-depth patches are

properly installed with good quality control, 80 to 100 percent

of the repairs perform well after 3 to 10 years of service

(Snyder et al., 1989; McGhee, 1977; Webster et al., 1978). In

the SHRP/FHWA-sponsored study, several types of partialdepth patches were observed to have failure rates less than 20

percent after more than 5 years of service (Wilson et al., 1999).

However, improper design and construction practices,

combined with poor quality control and inspection, result in

poor performance. The most frequent causes of partial-depth

patch failure are:

! Improper selection of repair materials.

! Lack of bond between the patch and the pavement.
3

! Compression failure.

! Variability of the repair material.

! Improper use of repair materials.

! Insufficient consolidation.

! Incompatible thermal expansion between the repair

material and the original slab.

! Feathering of the repair material.

This manual recommends practices that may help avoid these

causes of failure.

1.4 Limitations

The cause and depth of spalling can limit the benefits of partialdepth spall repair. If partial-depth spall repair is being

considered, cores should be taken at representative joints to

determine whether partial-depth spall repair should be used. 

Spalling deeper than the top third of the slab, or spalling caused

by misaligned dowel bars or d-cracking, should not be repaired

with a partial-depth patch. In these cases, partial-depth spall

repairs are likely to fail because of high shear stresses.
 
5

2.0 Need for Partial-Depth Spall Repair

Incompressibles can become lodged in unsealed joints or cracks

during cool weather when a jointed PCC pavement shrinks and

the joints open. During warm weather, the pavement expands

and joints close. Incompressibles in the joints will prevent the

joints from closing and will produce high compressive stresses

along the joint faces. This may cause spalling at both the top

and bottom of the slabs. Figure 1 shows a partial-depth spall

caused by incompressibles. Curling/warping of PCC slabs can

also contribute to spalling by forcing the top and bottom edges

of slabs together, again resulting in high compressive stresses.

Partial-depth spall repairs may be used instead of full-depth

repairs when deterioration is located primarily in the upper third

of the slab and when existing load transfer devices are still

working. Partial-depth repairs may be more cost-effective than

full-depth repairs, such as when repairing shallow, small spalls

along the entire length of a joint with a full lane-width partialdepth patch. Spalls caused by corroding metal joint inserts and

high reinforcing steel may also be repaired with partial-depth

patches. 

Spalls caused by misaligned dowel bars or d-cracking should

not be repaired with partial-depth patches. Partial-depth

patches replace concrete only. They cannot accommodate the

movement of joints and cracks, load-transfer devices, or

reinforcing steel without undergoing high stress and damage.

2.1 Pavement Condition

Partial-depth spall repairs may be needed when a pavement is

rehabilitated to restore structural integrity, improve ride, and
6

 Figure 1. Partial-depth spall caused by incompressibles.

extend the life of the pavement. Partial-depth spall repairs

should not be used if the pavement must be rehabilitated by

cracking and seating, breaking and seating, or rubblization

before overlaying.

Partial-depth spall repairs may also be needed as part of a joint

resealing project. Partial-depth repair of spalled joint areas

creates a well-defined, uniform joint reservoir before resealing. 

Partial-depth spalls must be repaired when using a preformed

compression seal to provide a uniform joint reservoir and to

prevent the seal from working out of the joint.
7

2.2 Climatic Conditions

The wetter and colder the climate, the greater the need for

timely partial-depth spall repair. However, spalling can occur in

any climate, and proper partial-depth spall repair will help

reduce further deterioration.

The damage caused by freezing and thawing cycles is a serious

problem in jointed PCC pavements. In wet and freezing

climates, the continued presence of water on and in the

pavement and the use of deicing salts often makes the damage

even worse.

Even in non-freezing climates, any moisture in the concrete can

cause corrosion of reinforcing steel in the pavement. Corroding

steel creates expansive forces that can lead to cracking, spalling,

and debonding of the concrete around it. Reinforcing steel

without enough concrete cover is even more likely to corrode. 

Timely partial-depth spall repair can protect high reinforcing

steel that has not yet corroded and can prevent more serious

spalling.

Spalling may also occur in dry and freezing climates. 

Incompressibles that are trapped in a joint when the adjacent

slabs contract during freezing create high compressive stresses

in the joint face when the slabs expand during thawing. Early

repair of nonfunctioning joint sealant systems, along with any

adjacent spalling, can protect the joint from further

deterioration.
 
9

3.0 Planning and Design

Spall repair performance is partially a function of design-related

parameters. Design-related causes of failure of partial-depth

patches include the following:

! Exclusion of some deteriorated concrete from the repair

boundaries.

! Incompatibilities between the climatic conditions during

repair placement and the materials or procedures used.

! Thermal incompatibility between the repair material and

the pavement.

! Climatic conditions during the life of the repairs that are

beyond the capabilities of the repair material.

! Inadequate cure time prior to opening repairs to traffic.

! Incompatibility between the joint bond breaker and the

joint sealant material.

3.1 Objectives in Selecting Materials and

 Procedures

The objectives for selecting the materials and procedures used

in partial-depth spall repair depend on climatic conditions,

urgency, and future rehabilitation schedules. In adverse

patching conditions, when the spall presents a hazard to

highway users, a temporary repair may be needed. In this case,

the design should provide for adequate temporary patch life

until a permanent repair can be made. Material properties and a

repair technique that will accommodate the existing or expected

adverse conditions should be selected.

Spalls that are repaired before a pavement overlay do not need

patch edges as vertical and straight as they should otherwise be,

and the repair material does not need to wear well. 
10

Furthermore, patches that are covered by an overlay will

undergo slower temperature changes than patches that are not

covered by an overlay. Therefore, thermal compatibility

between the patch and pavement may be less important for

these patches.

A partial-depth patch that will not be covered or destroyed in a

future rehabilitation will be exposed to traffic and climate for a

long time. In this case, it may be more cost-effective to choose

a material and repair procedure that cost more initially, but that

provide long-term performance.

Sometimes a spall must be repaired because it is hazardous to

highway users, but the pavement (and the patch) will be

destroyed during an upcoming rehabilitation. In this case,

design considerations should reflect the expected short life of

the patch. It may be more cost-effective to choose a low-cost

combination of material and repair methods.

The highway agency must determine the most cost-effective

material and repair method in light of the urgency of the partialdepth spall repair and the rehabilitation schedule for the

pavement. Section 3.8 provides guidelines for doing so.

3.2 Assessing Existing Conditions

Before the design stage of partial-depth spall repair, the

highway agency should assess the local climate and condition of

the pavement. Factors to consider include the climatic

conditions expected during construction and throughout the life

of the patch; the degree, depth, and cause of spalling; the time

available before the patch must be opened to traffic; and the

need for other repairs, such as drainage, stabilization, etc. The

National Highway Institute (NHI) 4R Manual (Techniques for
11

Pavement Rehabilitation) is an excellent guide for assessing

and performing many highway repairs (ERES, 1993).

The highway agency can select an appropriate material and

procedure combination based on the results of this assessment,

equipment availability, maintenance crew or contractor

experience, cost constraints, and performance demands.

3.3 Selecting a Repair Material

The highway agency must determine which materials are suitable

for its particular environment and working conditions. Some

materials have tight working tolerances, such as air temperatures

and surface-wetting conditions during placement, mixing

quantities and times, and maximum depths of placement. 

Material specifications must be carefully consulted during

material selection.

Material cost, shelf life, physical properties, workability, and

performance vary greatly among the different types of materials,

and from brand to brand within each type. When comparing

costs, the initial material cost plus the cost of installation in terms

of time, equipment, and labor must be considered. Section 3.8

presents a worksheet to help calculate these costs. Table 1 lists

properties and approximate cost factors for some materials

(Evans et al., 1991; Krauss, 1985; Tempe et al., 1984). The cost

factor is the ratio of the cost of the given material to the cost of a

typical rapid-setting Type III PCC material.

Material cost varies with the amount of material purchased and

the distance the material must be shipped. The cost factors

listed in table 1 are for illustration only. They do not include

the cost of shipping or discounts that may be realized through

large-volume purchases. Cementitious materials may be
12

Table 1. Properties of some rapid-setting partial-depth spall repair materials.

Product Material Category

Working Time,

minutes

Installation

Temp. Rangea

Time-to-Traffic

(21EC), hours

Moisture Conditionsb Material Cost

Factorc

Repair Surface Aggregate

Type III

PCC

Cementitious

(PCC)

20 0 to 43EC 4 to 6 SSD to dry 1-3% to dry 1

Duracal Cementitious

(gypsum-based)

20 0 to 43EC 1.5 SSD to dry 1-3% to dry 0.7d

Set-45 Cementitious

(magnesium phosphate)

10 0 to 32EC 1.5 dry 1-3% to dry 3.5d

Five Star

HP

Cementitious

(high alumina)

20 0 to 32EC 1.5 SSD to dry 1-3% to dry 3

Pyrament

505

Hydraulic cement 30 0 to 43EC 2 to 3 SSD to dry 1-3% to dry 2

a The installation temperature range shown is the temperature range at which the material manufacturer claims it can be installed. However, patching is

generally not recommended when the temperature is below 4oC or above 32oC. At cold or hot temperatures, special precautions may be needed, such as

the use of warmed or iced water during mixing, or insulating blankets during curing. 

b SSD = saturated, surface-dry; dry aggregate = oven-dried; 1-3% = 1-3% moisture allowed in the aggregate.

c The cost factor is the ratio of the cost of a given material to the cost of a typical rapid-setting Type III PCC material. It includes the cost of bagged

aggregate, bonding agent if required, and admixtures if required.

d Does not include the cost of the bonding agent. Bonding agent recommended if used in shallow patches.

e The manufacturer states that an SSD pavement surface is acceptable; however, lab tests indicate that bonding needs a dry surface (Evans et al., 1993a).

f The cost of spray-injection bituminous patching material represents averages provided by the manufacturers. These costs include the cost of purchasing

the equipment (amortized over the life expectancy of the equipment), maintenance, binder, aggregate, and other variable costs.
13

Table 1. Properties of some rapid-setting partial-depth spall repair materials (continued).

Product Material Category

Working Time,

minutes

Installation

Temp. Rangea

Time-to-Traffic

(21EC), hours

Moisture Conditionsb Material Cost

Factorc

Repair Surface Aggregate

SikaPronto 11 Polymer (modified

methacrylate)

30 2 to 32EC 1.5 SSD to dryedry 16

Penatron R/M

3003

Polymer (epoxyurethane)7 to 10 -23 to 66EC 0.5 dry dry 17

MC-64 Polymer (epoxy) 10 4 to 32EC 2 dry dry 23

Percol FL Polymer (urethane) 1 > -18EC 0.15 to 0.30 dry dry 9

UPM High

Perf. Cold Mix

Bituminous Not applicable 0 to 38EC immediately SSD to dry 1-3% to dry 0.5 to 0.6

Spray-injection

mix

Bituminous Not applicable -23 to 38EC immediately SSD to dry 1-3% to dry 0.2 to 0.4f

a The installation temperature range shown is the temperature range at which the material manufacturer claims it can be installed. However, patching is

generally not recommended when the temperature is below 4oC or above 32oC. At cold or hot temperatures, special precautions may be needed, such as

the use of warmed or iced water during mixing, or insulating blankets during curing. 

b SSD = saturated, surface-dry; dry aggregate = oven-dried; 1-3% = 1-3% moisture allowed in the aggregate.

c The cost factor is the ratio of the cost of a given material to the cost of a typical rapid-setting Type III PCC material. It includes the cost of bagged

aggregate, bonding agent if required, and admixtures if required.

d Does not include the cost of the bonding agent. Bonding agent recommended if used in shallow patches.

e The manufacturer states that an SSD pavement surface is acceptable; however, lab tests indicate that bonding needs a dry surface (Evans et al., 1993a).

f The cost of spray-injection bituminous patching material represents averages provided by the manufacturers. These costs include the cost of purchasing

the equipment (amortized over the life expectancy of the equipment), maintenance, binder, aggregate, and other variable costs.
14

purchased from local distributors. Other materials may require

shipping and may therefore cost more. Manufacturers will

provide exact material and shipping costs upon request. 

Highway agencies should select the most cost-effective material

that meets the requirements of the project. Cost-effectiveness is

a function of patch performance and life, as well as the

characteristics of a given project, such as traffic and user costs

(see section 3.8). Results from the recently concluded SHRP

H-106 spall repair study indicate good long-term (>5 years)

performance capabilities among most of the cementitious and

polymeric repair materials (Wilson et al., 1999). However, the

much lower material costs associated with these materials often

resulted in the lowest total life-cycle costs. In addition,

although bituminous cold-mix materials (including sprayinjection mixes) were shown to perform for much shorter

durations (2 to 4 years), their low installation costs occasionally

made them as cost-effective as the cementitious materials.

Table 2 shows some of the information in table 1 in a different

format. When the expected installation temperature, time-totraffic, and moisture conditions are known, table 2 can be used

to identify materials that may be acceptable for a project. 

However, tables 1 and 2 show information on just a few rapidsetting materials. Additional factors that can restrict material

selection are discussed in the following sections. Material

manufacturers should be consulted for complete details on the

correct use of their product.

3.3.1 Cementitious Concretes

Cementitious materials include PCC-based, gypsum-based,

magnesium phosphate, and high alumina concretes. Regular

PCC is the most common material used for spall repair;

however, if the road must be opened to traffic relatively quickly,

rapid-setting or high early-strength materials must be used.
15

IIIDurSet455HPPyrSP11PenMC64PFLUPMSpray

Table 2. Initial material selection criteria for some rapid-setting

materials.

Criteria

Materialsa

Installation temperatureb

-23oC < T < 0oC T T T T

0

oC # T < 4oCb T T T T T T T T T

4

oC < T # 32oC T T T T T T T T T T T

T> 32oC

b T T T T T T

Time-to-traffic at 21oC

5 min T T

30 min T T T T

2 hr T T T T T T T T T T

4 hr T T T T T T T T T T T

Aggregate moisture

1-3% moisture allowed T T T T T T

Oven-driedc T T T T T T T T T T T

Pavement surface

moisture

Saturated, surface-dry T T T T Td T T

Drye T T T T T T T T T T T

a

III = Type III PCC, Dur = Duracal, St45 = Set-45, 5HP = Five Star HP, Pyr =

Pyrament 505, SP11 = SikaPronto 11, Pen = Penatron R/M-3003, MC64 =

MC-64, PFL = Percol FL, UPM = UPM High-Performance Cold Mix, Spray =

Spray-Injection Mix.

b Patching is generally not recommended when the temperature is below 4oC or

above 32oC. At cold or hot temperatures, special precautions may be needed,

such as the use of warmed or iced water during mixing, or insulating blankets

during curing. 

c Water content should be adjusted as needed.

d The manufacturer states that a saturated, surface-dry pavement surface is

acceptable; however, lab tests indicate that bonding needs a dry surface.

e Wet surface before material placement if required by manufacturer.
16

Portland Cement Concrete

Typical PCC mixes combine Type I, II, or III portland cement

with coarse and fine aggregate. Type III portland cement, or

Type I portland cement, with the addition of a set-accelerator,

may be used when the concrete repair must be opened quickly

to traffic. The main difference between Type I and Type III

portland cement is that Type III is more finely ground than

Type I. When cement is ground more finely, more cement

surface area comes into contact with the water in the mix. This

speeds up the hydration rate, which speeds up strength

development and heat release during the first 7 days of curing. 

Type II portland cement, even though it is ground to the same

fineness as Type I, gains strength too slowly to be used for

rapid repair.

Type III portland cement, with or without admixtures, has been

used for fast, permanent repairs longer and more widely than

most other materials because of its relatively low cost,

availability, compatibility with existing pavements, and ease of

use. Rich mixtures (420 kg/m3 to 540 kg/m3) gain strength

quickly in warm weather (4 to 12 hours). However, the rate of

strength gain may be too slow to permit quick opening to traffic

in cool weather. Insulating layers can be used to retain the heat

of hydration and reduce curing time.

Gypsum-Based Concrete

Gypsum-based (calcium sulfate) patching materials (e.g.,

Duracal, Rockite) gain strength rapidly and can be used in

temperatures above freezing (up to 43oC, for example, in the

case of Duracal). However, gypsum concrete does not appear

to perform well when exposed to moisture or freezing weather

(Stingley, 1977). In addition, the presence of free sulfates in

the typical gypsum mixture may promote steel corrosion in

reinforced pavements (Smith et al., 1991).
17

Magnesium Phosphate Concrete

Magnesium phosphate concretes (e.g., Set-45, Eucospeed MP,

Propatch MP) set very quickly, and make high early-strength,

impermeable patches that bond to clean and dry surfaces. 

However, these materials are extremely sensitive to water on

the pavement, and even very small amounts of extra water in the

mix severely decreases strength. They also cannot be used with

limestone aggregates (Smith et al., 1991). These limitations

have led to variable field performance (Stingley, 1977; Tyson,

1977).

High Alumina Concrete

Calcium aluminate concretes (e.g., Five Star HP) gain strength

fast, bond well (adhere best to a dry surface), and shrink very

little during curing. However, they may lose strength over time

because of a chemical conversion that takes place, particularly

at high curing temperatures (Snyder et al., 1989; Stingley, 1977;

Smith et al., 1991).

3.3.2 Polymer Concretes

Polymer concretes are a combination of polymer resin,

aggregate, and a set initiator. The aggregate makes the

polymer concrete more economical, provides thermal

compatibility with the pavement, and provides a wearing

surface. The polymer concretes described in this manual are

epoxy, methyl methacrylate, and polyurethane concretes.

Epoxy Concrete

Epoxy concretes (e.g., MC-64, Burke 88/LPL, Mark 103

Carbo-Poxy) are impermeable and are excellent adhesives. 

They have a wide range of setting times, application

temperatures, strengths, and bonding conditions. The epoxy
18

concrete mix design must be thermally compatible with the

pavement, otherwise the patch may fail. Deep epoxy repairs

often must be placed in lifts to control heat development. 

Epoxy concrete should not be used to patch spalls caused by

reinforcing steel corrosion, as the rate of deterioration of

adjacent sound pavement may be accelerated (Furr, 1984).

Methyl Methacrylate Concrete

Methyl methacrylate concretes and high molecular weight

methacrylate concretes (e.g., SikaPronto 11, Degadur 510) are

polymer-modified concretes that could also be classified as

cementitious materials. They have relatively long working

times, high compressive strengths, and good adhesion. Many

methyl methacrylates are volatile and may pose a health hazard

from prolonged exposure to the fumes (Krauss, 1985). As with

all materials, material safety data sheets (MSDS’s) must be

obtained from the manufacturer and followed to ensure the safe

use of these materials.

Polyurethane Concrete

Polyurethane concretes (e.g., Percol FL, Penatron R/M-3003)

generally consist of a two-part polyurethane resin mixed with

aggregate. Polyurethanes generally set very quickly (90 sec). 

Some manufacturers claim their materials are moisture-tolerant;

that is, they can be placed on a wet surface with no adverse

effects. This type of material has been used for several years

with variable results (Krauss, 1985; Mueller, 1988).

3.3.3 Bituminous Materials

Bituminous patches are used almost everywhere in all climates. 

They are often considered temporary, but are sometimes left in

place for many years. They are fairly inexpensive, widely

available, and easy to place with small crews. They usually need
19

little, if any, cure time. The most effective bituminous materials

are the hot-mix asphalt concretes (HMAC). A few States have

successfully used bituminous spray-injection mixes (e.g., AMZ,

Rosco). Many proprietary bituminous cold mixes also perform

well (e.g., UPM High-Performance Cold Mix), although they

may become sticky and hard to work with at the upper end of

their placement temperature range.

3.3.4 Material Testing

Materials must be rigorously tested in a laboratory to determine

whether the product or mix design is suitable for a given region

or condition. The suggested approval or acceptance tests for

cementitious materials include:

! Compressive strength.

! Modulus of elasticity.

! Flexural strength.

! Bond strength.

! Freeze-thaw resistance.

! Scaling resistance.

! Surface abrasion resistance.

! Thermal compatibility.

! Coefficient of thermal expansion.

The suggested tests for bituminous cold mixes include:

! Workability.

! Stripping.

! Drainage.

! Cohesion.

These laboratory tests are index tests and do not necessarily

predict performance. Therefore, initial field testing should be

conducted. MSDS’s should be examined, as well as storage

requirements and shelf life.
20

3.4 Selecting Accessory Materials

Many materials besides the patching materials are used in the

partial-depth spall repair process. Bonding agents, joint bond

breakers, joint sealants, and curing compounds may also be

required. This section provides guidance in selecting these

accessory materials.

3.4.1 Bonding Agents

Different bonding agents require varying cure periods. 

Therefore, the bonding agent should be selected after the repair

material has been chosen and the time-to-traffic has been

determined. Not all patching materials need a bonding agent. 

The manufacturer's recommendation should always be followed. 

Epoxy bonding agents should be used with Type III PCC

materials, as they provide a curing time of 6 hours or less.

3.4.2 Joint Bond Breakers

Joint bond breakers (polyurethane, polystyrene, or polyethylene

strips, and fiberboards) prevent patches installed at a joint from

bonding to the adjacent slab. Joint bond breakers must be nonabsorbent, closed cell, chemically inert, compressible with good

compression recovery, and compatible with the joint sealant. 

Bond breakers used with hot-poured sealants must be heatresistant for the installation temperature of the sealant. Section

4.5 describes how to install joint bond breakers.

Joint bond breakers that have been scored at an appropriate

depth before placement, as shown in figure 2, are

recommended, as they save time and labor. Once the scored

bond breaker has been placed in the clean joint, and the patch

has been installed and has cured or set, the top strip is removed. 

This provides a clean surface and a pre-formed joint reservoir

that is ready for the installation of the joint sealant. Fiberboard
21

Figure 2. Scored joint bond breaker.

is more rigid than other types of bond breakers. It should be

used at the lane-shoulder joint where more support is needed.

For information on selecting dimensions for the joint reservoir

(the width of the joint bond breaker, and the depth of scoring),

consult Materials and Procedures for Repair of Joint Seals in

Concrete Pavements–Manual of Practice (Evans and Romine,

1993b).
22

3.4.3 Curing Materials

Water loss during curing causes the patch volume to decrease. 

This can lead to shrinkage cracks and poor bond. Therefore,

curing methods that reduce water loss should be used. The

recommended moist curing methods are:

! Water curing.

ý continuous water spraying.

ý saturated coverings (burlap, sand, or straw).

! Sealed curing.

ý plastic sheeting.

ý curing compounds.

Water curing supplies additional water and prevents moisture

loss. Continuous water spraying works well only when water

and labor are plentiful and runoff is not a problem. 

Furthermore, vigorous spraying can erode the patch. Saturated

coverings need periodic wetting, but may provide insulation in

winter if topped with a dry layer. Potable water that is clean

and free of oil, salt, and other contaminants must be used when

water curing.

Sealed curing does not add water to the patch, but does prevent

moisture loss when uniformly and adequately applied. 

Pigmented, liquid, membrane-forming curing compounds are

popular because their opaque color shows whether they have

been adequately applied; they can reflect or absorb sunlight; and

they do not blow away. They also do not require rewetting or

large amounts of water on the construction site.

Curing compounds can interfere with bonding between the

overlay and the patch. However, unless the patch is large, such

as a full lane-width patch, the effect on bonding should not be

that great. A large patch can be cleaned before overlaying if the

curing compound has not already worn off. Curing compounds
23

should not be used in the fall if the patch will soon be exposed

to deicing salts. Curing compounds should be white in color in

hot weather, and gray or black in cold weather.

3.4.4 Joint Sealants

An appropriate joint sealant must be installed to ensure the

performance of the partial-depth patch. The sealant must

prevent water and incompressibles from entering the joint. If

the pavement will not be overlaid and the remaining life of the

pavement is expected to be long, silicones and high-quality hotpoured rubberized or polymerized asphalt sealants are generally

recommended. If the pavement will be overlaid, the joints

should still be filled, but lower quality materials may be

acceptable. For information on selecting a joint sealant, consult

the Materials and Procedures for Repair of Joint Seals in

Concrete Pavements–Manual of Practice (Evans and Romine,

1993b).

3.5 Selecting Dimensions of the Repair Area

Partial-depth patches should be limited in depth to the top third

of the slab and should never come in contact with dowel bars. 

If dowel bars are reached, a full-depth spall repair must be

used. Partial-depth patches must be at least 50 mm deep for

weight and volume stability. They should extend 50 mm to 150

mm in each possible direction beyond the spalled area, and be at

least 100 mm wide and 250 mm long. Table 3 shows the

minimum dimensions for patches in various locations. Figures 3

and 4 show the minimum dimensions of partial depth patches

located at one joint; figures 5 and 6, at two joints.
24

Table 3. Minimum dimensions of repair area for spalls at

various locations.

Location

of

Spalling

Minimum Dimensions of Repair Area 

Depth

(mm)

Length

(mm)

Width

(mm)

At One

Joint 50 

250 or length of

spalled area + 100

whichever is greater

100 or width of 

spalled area + 50

whichever is greater

At Two

Joints 50

200 or length of

spalled area + 50

whichever is greater

100 or width of

spalled area + 50

whichever is greater

Away

From

Joints

50

250 or length of

spalled area + 100

whichever is greater

140 or width of

spalled area + 100

whichever is greater

Areas less than 150 mm long or 40 mm wide are normally not

patched, but are filled with a sealant. Patches less than 300 mm

from each other should be repaired with one patch, as shown in

figures 4 and 6. When several small spalls exist at one joint, it

usually costs less to patch the entire joint length than to repair

individual spalls.

In the early stages of spalling, there are often weak areas in the

slab that cannot be seen. The extent of deterioration should be

determined by sounding–striking the concrete with a solid steel

rod, chain, or ball-peen hammer and listening to the sound

produced. A clear ringing sound indicates sound concrete,

while a dull sound indicates weak concrete. All weak concrete

must be located and included within the patch boundaries.
25

Figure 3. Dimensions of patch at one joint.
26

Figure 4. Dimensions of patch at one joint for spall

less than 300 mm apart.
27

Figure 5. Dimensions of patch at two joints.
28

Figure 6. Dimensions of patch at two joints for spalls less

than 300 mm apart.
29

3.6 Selecting Patch Preparation Procedures

The patch preparation procedures discussed in this manual

include the saw-and-patch procedure, the chip-and-patch

procedure, the mill-and-patch procedure, the waterblast-andpatch procedure, and the clean-and-patch procedure. The only

difference between these patch preparation procedures is the

method used to remove the deteriorated concrete. Sandblasting

and airblasting are highly recommended for all preparation

procedures, though they may be impractical under adverse

conditions.

When selecting a procedure, the highway agency should

consider equipment availability and cost, the availability of a

crew trained in the procedure, the available construction time,

and the performance and cost-effectiveness (section 3.8) of the

procedure. Results from the recently concluded SHRP H-106

spall repair study indicate no significant differences in the

performance capabilities of the saw-and-patch, chip-and-patch,

mill-and-patch, and waterblast-and-patch methods (Wilson et

al., 1999). However, the lower installation costs associated

with the chip-and-patch procedure make it the more attractive

approach from an overall cost-effectiveness standpoint.

3.6.1 Saw and Patch

The first step in the saw-and-patch procedure is sawing the

patch boundaries with a diamond blade saw. The deteriorated

concrete in the center of the patch is then removed using a light

jackhammer with a maximum weight of 6.8 kg; a jackhammer

with a maximum weight of 13.6 kg may be allowed if damage to

sound pavement is avoided. Finally, the deteriorated concrete

near the patch borders is removed using a light jackhammer

with a maximum weight of 6.8 kg and handtools. The work

should progress from the inside of the patch toward the edges,
30

and the chisel point should be directed toward the inside of the

patch.

The advantages of the saw-and-patch procedure include the

following:

! The saw leaves vertical edge faces.

! The forces experienced by the pavement during chipping

are isolated within the sawed boundaries.

! Very little spalling of the remaining pavement occurs.

! Removing the deteriorated concrete within the sawed

boundaries is usually easier and faster when the

boundaries are sawed than when they are not sawed.

! Most crews are familiar with the method.

The disadvantages of the saw-and-patch procedure include the

following:

! More workers are required than in the other procedures.

! Since water is used when sawing, the repair area is

saturated for some time, possibly delaying the repair.

! Saw overcuts weaken the repair area and must be

cleaned and sealed.

! The saw may encroach into the open lane of traffic.

! The polished, vertical patch boundary faces may lead to

poor bonding.

If the patching material is moisture-sensitive and will not bond

to a wet surface, placement must be delayed. This can be

avoided by sawing joints and boundaries 1 to 2 days before

removing and replacing the material. (Sawed edges do not spall

when traffic is allowed onto repair areas that have been cut 1 to

2 days in advance.) However, if more unsound concrete is later

found beyond the sawed boundaries, the saw must be brought

back to saw new boundaries, possibly causing further delay. 
31

Also, the saw may encroach into the open lane of traffic if the

spall is near the open lane, creating a hazardous situation.

Saw overcuts occur because the boundaries must be overcut 50

mm to 75 mm in each direction to obtain the needed depth of

cut. These overcuts create weak areas that may deteriorate

unless cleaned and sealed.

3.6.2 Chip and Patch

The chip-and-patch procedure is the same as the saw-and-patch

procedure, except the patch boundaries are not sawed. The

deteriorated concrete in the center of the patch is removed using

a light jackhammer with a maximum weight of 6.8 kg; however,

a jackhammer with a maximum weight of 13.6 kg may be

allowed if damage to sound pavement is avoided. The

deteriorated concrete near the patch borders is then removed

using a light jackhammer with a maximum weight of 6.8 kg and

handtools. The work should progress from the inside of the

patch toward the edges, and the chisel point should be directed

toward the inside of the patch.

The advantages of the chip-and-patch procedure include the

following:

! The rough vertical edge produced promotes bonding.

! There are no saw overcuts.

! It has fewer steps than the saw-and-patch method.

! Spalling is controlled by using light hammers at the

edges.

! It may be quicker than the saw-and-patch method.

The chip-and-patch procedure may be faster because it has

fewer steps: the patch boundaries are not sawed, and there are

no saw overcuts to be cleaned and sealed. Once joint sawing is
32

completed (see section 4.2.2), the saw is not needed again, even

if more unsound concrete is later found beyond the boundaries.

The disadvantages of the chip-and-patch procedure include the

following:

! Sound concrete may be damaged by heavy hammers.

! Jackhammers can cause feathered patch edges.

! Vertical sides are difficult to achieve.

The transmission of destructive forces may be reduced by using

a heavy hammer only at the center of the repair area and a light

hammer around the edges. If the selected repair material should

not be feathered (e.g., some cementitious materials), a minimum

25-mm vertical face on all sides must be specified; that is, the

top portion of the patch boundaries must be vertical for at least

25 mm.

3.6.3 Mill and Patch

Some States have successfully used carbide-tipped milling

machines for spall repair (Zoller et al., 1989). Standard milling

machines with 305-mm- to 457-mm-wide cutting heads have

proven efficient and economical, particularly when used for

large areas (e.g., for full lane-width repairs). The milling

operation leaves a rounded cavity that may be made vertical by

hammering or sawing. The milling machine should have a drum

diameter of 0.9 m or less and make a 305-mm-wide cut or

narrower.

The advantages of the mill-and-patch procedure include the

following:

! It is efficient and economical when repairing large areas.

! It leaves a rough, irregular surface that promotes

bonding.
33

The disadvantages of the mill-and-patch procedure include the

following:

! If the spall is less than 0.09 m2, the patch may be larger

than needed, because the smallest milling head currently

available provides a 0.09 m2 cut.

! The milling operation may cause spalling on the adjacent

pavement edges.

! The milling machine makes a hole with two rounded

edges (perpendicular to the direction of milling) that

should be made vertical by chiseling if they are

perpendicular to the direction of traffic.

Some milling machines seem better suited for milling asphalt

and than for milling concrete. More powerful equipment may

increase concrete milling efficiency and reduce spalling of the

adjacent pavement.

The orientation of the rounded edges should be parallel to the

direction of traffic whenever possible, as shown in figure 7. 

However, due to traffic in the adjacent lane, the equipment may

not always be able to maneuver into such an orientation. The

larger the repair areas and the farther they are from the adjacent

lane of traffic, the higher the efficiency of the milling operation. 

The efficiency of milling is also affected by the number of

milling teeth that must be replaced per day.

Milling machines are readily available in many regions of the

United States. However, a suitable machine at a reasonable

cost may not be available at a specific project site.

3.6.4 Waterblast and Patch

The waterblast-and-patch procedure uses a high-pressure water

jet to remove the deteriorated concrete. Several States are

testing this method for repairing pavements. The waterblasting
34

Figure 7a. Recommended orientation of milled patch.

Figure 7b. Milled patch with rounded edges.
35

machine should be capable of producing a stream of water at

100,000 kPa to 200,000 kPa and should be controlled by a

mobile robot. The waterblasting equipment must be capable of

removing deteriorated concrete at an acceptable production

rate, be under continuous automatic control, and have filtering

and pumping units operating with a remote-controlled robotic

device. The noise level must be less than 90 decibels at a

distance of 15 m from either the power pack unit or the remote

robot.

The advantages of waterblasting include the following:

! It requires fewer workers than the other procedures.

! Once an experienced operator adjusts the operating

parameters, only weak concrete is removed.

! The patch surfaces produced are vertical, rough, and 

irregular, and enhance bonding.

! No hauling is required.

The disadvantages of waterblasting include the following:

! The finished surfaces are saturated. Placement must be

delayed until the area dries unless the repair material is

not moisture-sensitive.

! The fine slurry laitance remaining after the procedure

requires careful attention during cleaning.

! A shield must be built around the repair area to protect

traffic if the patch is next to a lane carrying traffic.

! It can be difficult to control the depth of removal and,

hence, patch size/volume.

! Equipment rental is expensive.

! It can be difficult to obtain a good production rate;

performance of waterblasting equipment has been

variable, and waterblasting had to be abandoned in

several recent projects.
36

Some manufacturers expect a concrete removal rate of 5.6

m

2

/hour from their waterblasting equipment. But problems with

equipment or very tough aggregate (such as granite) can quickly

drop the production rate to as low as 0.7 to 1.4 m2/hour. The

waterblasting equipment must function properly, and the

operator must be very skilled to achieve high production rates.

3.6.5 Clean and Patch

Adverse patching conditions consist of an air temperature below

4

oC and a repair area that is saturated with surface moisture. 

Under these conditions, highway agencies often use the cleanand-patch procedure to perform emergency repairs. 

Deteriorated and loose concrete is removed with handtools and

swept away using stiff brooms. Occasionally, a light

jackhammer may be used if the spalled area is large or if the

cracked concrete is held tightly in place. The clean-and-patch

procedure should be used only if a spall is hazardous to highway

users and the climate is so adverse that no other procedure can

be used.

3.7 Estimating Material, Equipment, and Labor

Estimates of the amount of materials needed will depend on the

size and number of spalls, as well as the type of repair material

selected. Many repair materials have a range within which they

may be extended with aggregate (e.g., Type III PCC, Duracal,

Set-45, Five Star HP, Pyrament 505). Other materials require

that the aggregate be placed in the repair hole before the

material itself is applied (e.g., Percol FL, Penatron R/M-3003). 

Volume yields of these two types of materials will depend on

the size and amount of the aggregate used to extend the

material. Extending a material with aggregate (up to the

manufacturer's approved limit) will make the mix more

thermally compatible with the existing pavement and will reduce
37

its overall cost. The total volume needed to fill all the patches

should be estimated, and material manufacturers should be

consulted to determine the necessary amount of materials.

Once a repair material has been chosen, the manufacturer's

material specifications should be consulted for equipment

requirements. Table 4 shows the equipment typically used for

the five spall preparation procedures that are discussed in this

manual. Table 5 shows the mixing and placement equipment

and supplies typically used with some rapid-setting spall repair

materials. Table 6 shows the personnel typically used with the

five spall preparation procedures. Table 7 shows the personnel

typically used for the mixing and placement of some rapidsetting partial-depth spall repair materials.

In certain cases (e.g., the pre-placement of the aggregate with

Percol FL or Penatron R/M-3003, and the insertion of the joint

bond breaker), one person can be used for two activities that do

not occur at the same time. A supervisor may be needed to

oversee the crews and their operations. Additional personnel

may be needed for inspection and traffic control.

3.8 Overall Cost-Effectiveness

Calculating overall cost-effectiveness of a partial-depth patching

operation requires an estimate of the cost of materials, labor,

equipment, the expected life of the partial-depth patch when

constructed with a particular material and method, and user

inconvenience. The initial cost of materials, labor, and

equipment can be estimated fairly easily. However, the

adjustment of all costs to reflect the expected life of the given

repair requires that the expected life be known. Calculating

user costs is even more difficult.
38

Table 4. Typical equipment used for the five patch

preparation procedures.

Equipment

Preparation Procedurea

S C M W A

Sounding equipment: rod, chain, or

ball-peen hammer

T T T T Tb

Double-bladed concrete saw for joint

sawing

T T T T

Single-bladed concrete saw for sawing

patch boundaries

T

6.8-kg jackhammer with air

compressor

T T Tc Td

13.6-kg jackhammer with air

compressor

Te Te

Stiff brooms for debris removal T T T T T

Handtools (pick axe, etc.) T T T

Truck for hauling removed material T T T T

Waterblasting machine T

Milling machine T

Sandblasting equipment with

directional nozzle, sand, air compressor

T T T T Tb

Airblasting equipment with oil and

water filtering capability, air

compressor

T T T T Tb

a S = saw and patch, C = chip and patch, M = mill and patch, W = 

waterblast and patch, and A = adverse-condition clean and patch.

b Sounding, sandblasting, and airblasting may not be practical

under adverse conditions.

c To remove rounded edges.

d

Jackhammering may be used for large areas, or when the

deteriorated concrete cannot be removed using handtools.

e

6.8-kg jackhammers are preferred. 13.7-kg hammers should never

be used at patch boundaries.
39

III

Dur

St45

5HP

MC64

SP11

Pen

Pyr

PFL

UPM

Spray

Table 5. Typical mixing and placement equipment and supplies.

Typical Equipment and

Suppliesa

Potable water/hose/pump T T T T T T

Drum mixerb (1.9-2.5 m3) T T T

Mortar mixer (0.9-1.2 m3) T T T

483-mm elec. drills &

533-mm stainless steel

Jiffy mixers

Tc Tc Tc T

Bonding agent brush/roller T T

Vibrators and/or screeds T T T T T

Trowels T T T T T T T

Shovels T T T T T T T

Curing compound,

applicator, burlap, or

plastic sheetingd

T T T T

Insulating blanketse T T

Vibratory roller or plate T

Electric generatorf T T T T T T T T T

Grayco Percat 500g T

Spray-injection machineh T

Non-water cleaning solvent T T T T T

Compression cylinders/rod T T T T T

Slump cone T T T T T

Air meter, rod, water bulb T

a

III = Type III PCC, Dur = Duracal, St45 = Set-45, 5HP = Five Star HP, M64 =

MC-64, SP11 = SikaPronto 11, Pen = Penatron R/M-3003, Pyr = Pyrament

505, PFL = Percol FL, UPM = UPM High-Performance Cold Mix, Spray =

Spray-Injection Mix.

b Mixer should have twice the volume of the amount of material to be mixed.

c Capable of 400 to 600 rpm.

d May be used in hot (> 29oC), windy (> 40 km/h) weather.

e

In weather below 7oC.

f As needed; sufficient for demand.

g Air-driven, automatic, ration-metering pump.

h Capable of delivering chip-size aggregate and asphalt emulsion (e.g., AMZ,

Rosco, Durapatcher).
40

Table 6. Typical personnel used for spall repair procedures.

Procedure Typical Personnel Total

Joint sawing 1 person operating saw

1 person directing saw

2

Saw and patch 1 person operating saw

1 person directing saw

2 persons operating jackhammers

2 persons cleaning repair hole

1 person removing debris

7

Chip and

patch

2 persons operating jackhammers

2 persons cleaning repair hole

1 person removing debris

5

Mill and patch 1 person operating milling machine

1 person directing milling machine

2 persons operating jackhammers

2 persons cleaning repair hole

1 person removing debris

7

Waterblast

and patch

1 person operating waterblaster

1 person operating water truck

1 person cleaning repair hole

3

Clean and

patch

1 person using handtools (or

jackhammer if necessary)

1 person cleaning repair hole

2

Inserting joint

bond breaker

1 person installing bond breaker

(otherwise available for other

activities)

1
41

Table 7. Typical personnel used for mixing and placing.

Material Typical Personnel Total

Type III

PCC

2 persons mixing and applying epoxy

1 person proportioning and mixing Type III mix

2 persons placing, compacting, and finishing

5

Duracal 1 person proportioning and mixing Duracal

2 persons placing, compacting, and finishing

3

Five Star HP 1 person proportioning and mixing Five Star HP

2 persons placing, compacting, and finishing

1 person spraying curing water

4

Set-45 1 person proportioning and mixing Set-45

2 persons placing, compacting, and finishing

3

Pyrament

505

1 person proportioning and mixing Pyrament 505

2 persons placing, compacting, and finishing

3

Sika

Pronto 11

2 persons mixing and applying SikaPronto 19

1 person proportioning and mixing SikaPronto 11

2 persons placing, compacting, and finishing

5

MC-64 4 persons mixing MC-64

2 persons placing and finishing

6

Percol FL 1 person placing rock into prepared hole

1 person driving truck with pumps and tanks

1 person applying Percol FL

1 person applying broadcast aggregate

4

Penatron

R/M-3003

1 person placing rock into prepared hole

2 persons mixing Penatron R/M-3003

3 persons placing and finishing

6

UPM HighPerformance

Cold Mix

2 persons shoveling and placing mix

1 person operating vibratory roller or plate 3

SprayInjection

Mix

1 person driving truck

1 person operating binder/aggregate sprayer 2
42

3.8.1 Cost-Effectiveness Worksheet

This section presents a worksheet that helps calculate the cost

of a partial-depth spall repair operation. The worksheet asks

the user to enter values and perform calculations in a step-bystep fashion. When worksheets have been completed for

different combinations of materials and procedures, they can be

compared to determine which combination is the most costeffective. 

The cost-effectiveness worksheet is shown in figure 8. 

Explanations for the variables included in the worksheet follow.

Project Size or Seasonal Partial-Depth Patching Needs

(A) Expected Number of Patches–The number of

partial-depth patches (not the number of spalls, as

several small spalls may be repaired with one patch)

expected in the project or in a given season. This

number could be based either on the number of

spalls repaired in the previous season or on a field

survey.

(B1) Average Finished Patch Length–The expected

average length of the finished patches, in millimeters. 

This value could be based either on data from the

previous season or on a field survey where several

patches throughout the project are sounded to

determine the dimensions of the deteriorated area. 

This value is helpful in estimating the amount of

repair materials needed in the project (e.g., bonding

agent, curing compound, joint bond breaker, etc.)
43

ESTIMATE OF PROJECT SIZE OR SEASONAL PARTIALDEPTH PATCHING NEEDS

amount units

Expected Number of Patches _______ (A) 

Average Finished Patch Length _______ mm (B1)

Average Finished Patch Width _______ mm (B2)

Average Finished Patch Depth _______ mm (B3)

Expected Total Volume of Finished Patches

[(B1 × B2 × B3 × A) ÷ 109] _______ m3(C) 

MATERIAL COSTS (e.g., cold mix, cement, aggregate, sand, bonding

agent, joint bond breaker, curing agent, etc.)

Material 1 = ________________________

Material 1 Purchase Cost _______ $/__ (D1)

Expected Material 1 Needs _______ ____ (E1)

Material 1 Shipping Cost _______ $ (F1) 

Total Material 1 Cost [(D1 × E1) + F1] _______ $ (G1)

Material 2 = ________________________

Material 2 Purchase Cost _______ $/__ (D2)

Expected Material 2 Needs _______ ____ (E2)

Material 2 Shipping Cost _______ $ (F2) 

Total Material 2 Cost [(D2 × E2) + F2] _______ $ (G2)

Material 3 = ________________________

Material 3 Purchase Cost _______ $/__ (D3)

Expected Material 3 Needs _______ ____ (E3)

Material 3 Shipping Cost _______ $ (F3) 

Total Material 3 Cost [(D3 × E3) + F3] _______ $ (G3)

Material 4 = ________________________

Material 4 Purchase Cost _______ $/__ (D4)

Expected Material 4 Needs _______ ____ (E4)

Material 4 Shipping Cost _______ $ (F4) 

Total Material 4 Cost [(D4 x E4) + F4] _______ $ (G4)

Figure 8. Cost-effectiveness worksheet.
44

LABOR COSTS

amount units

Number in Repair Crew _______ (H) 

Average Daily Wage per Person _______ $/day (I) 

Number in Traffic Control Crew _______ (J) 

Average Daily Wage per Person _______ $/day (K) 

Supervisor Daily Wage _______ $/day (L) 

EQUIPMENT COSTS

Material Truck _______ $/day (M)

Traffic Control Truck and Signs _______ $/day (N)

Patch Preparation Equipment

(e.g., concrete saw, jackhammer, _______ $/day (O1)

milling machine, waterblaster) _______ $/day (O2)

Cleaning Equipment _______ $/day (P1)

(e.g., sandblaster, airblaster) _______ $/day (P2)

Mixing Equipment _______ $/day (Q1)

(e.g., mortar mixer, Jiffy mixer) _______ $/day (Q2)

Consolidation/Compaction Equipment

(e.g., pencil vibrator, vibrating 

screed, vibratory roller) _______ $/day (R) 

Extra Equipment Truck _______ $/day (S) 

Miscellaneous Equipment _______ $/day (T1)

(e.g., spray-injection machine, _______ $/day (T2)

joint sealing equipment, etc.)

Figure 8. Cost-effectiveness worksheet (continued).
45

SUMMARY COSTS

amount units

Total Material Cost

(G1 + G2 + G3 + G4 + ...) _______ $ (U)

Total Daily Labor Cost

[(H × I) + (J × K) + L] _______ $/day (V)

Total Equipment Cost

[M + N + (O1 + O2 + ...) + 

(P1 + P2 + ...) + (Q1 + Q2 + ...) + 

R + S + (T1 + T2 + ...)] _______ $/day (W)

User Delay Costs _______ $/day (X)

Average Daily Productivity _______ patches/day (Y)

Estimated Number of Days

for Patching Operation (A ÷ Y) _______ days (Z)

Total Patching Operation Cost

[U + {Z × (V + W + X)}] _______ $ (AA)

Expected Mean Life for Partial-Depth

Patches1 (Duration may vary) _______ months (BB)

Time to Pavement Rehabilitation _______ months (CC)

Effective Patching Cost Over Time

[AA × (CC/BB)] _______ $ (DD)

1 Until expected mean life values have been determined, agency experience

should be applied. See Appendix B for calculation examples.

Figure 8. Cost-effectiveness worksheet (continued).
46

(B2) Average Finished Patch Width–The expected

average width of the finished patches, in millimeters.

This value could be based either on data from the

previous season or on a field survey where several

patches throughout the project are sounded to

determine the dimensions of the deteriorated area. 

This value is helpful in estimating the amount of

repair materials needed in the project (e.g., bonding

agent, curing compound, joint bond breaker, etc.)

(B3) Average Finished Patch Depth–The expected

average depth of the finished patches, in millimeters. 

This value could be based either on data from the

previous season or on a field survey where several

patches in the project are sounded and cored to

determine the depth of the deteriorated area. This

value is helpful in estimating the necessary depth of

the joint bond breaker or fiberboard.

(C) Expected Total Volume of Finished Patches–The

estimated total in-place volume of material needed to

fill the patches, in cubic meters, based on the

estimated average length (B1), width (B2), and depth

(B3). This value could be based either on the

previous season's data or on the results of a field

survey. This value is helpful in estimating the

amount of material components needed for the

project (e.g., cold mix, cement, aggregate, sand,

etc.)

Material Cost Variables

(Dn) Material Purchase Cost–The cost of purchasing

each material used to repair the partial-depth spalls. 

Materials will include the patching material, and

possibly a material such as a bonding agent, joint
47

bond breaker, or curing compound. This cost does

not include shipping costs. The amount should be

entered in dollars per metric ton, cubic meter, liter,

meter, etc., as appropriate for each material. If there

are more than four materials, the worksheet can be

duplicated.

(En) Expected Material Needs–The amount of each

material needed for the project, such as the amount

of the patching material, bonding agent, joint bond

breaker, or curing compound, taking into

consideration a wastage factor of 10 to 20 percent. 

The amount should be entered in units of metric ton,

cubic meter, liter, meter, etc., as appropriate for

each material.

(Fn) Material Shipping Cost–The cost of shipping each

material from the site of production to the site of

storage during the project, in dollars.

(Gn) Total Material Cost–The total cost of each

material, including shipping, in dollars.

Labor and Equipment Costs Worksheet Variables

(H) Number in Repair Crew–The number of workers

who will be performing the partial-depth patching

operation, not including traffic control personnel.

(I) Average Daily Wage per Person–The average

wage paid to the members of the repair crew, in

dollars per day. By multiplying this figure by (H),

the total labor costs for the workers doing the

patching can be obtained.
48

(J) Number in Traffic Control Crew–The number of

workers required to set up and conduct the traffic

control operation. When the repair crew sets up

signs and cones before the repair operation, the

number of traffic control workers would be zero, so

that the workers are not counted twice.

(K) Average Daily Wage per Person–The average

wage paid to the members of the traffic control

crew, in dollars per day. By multiplying this number

by (J), the total labor costs for the workers doing the

traffic control can be obtained.

(L) Supervisor Daily Wage–The wage paid to the

supervisor who oversees the repair operation, in

dollars per day.

(M) Material Truck–The operating charge associated

with the truck carrying the repair materials

(excluding the driver's wages), in dollars per day. 

Only trucks carrying the repair material should be

included.

(N) Traffic Control Truck and Signs–The cost

associated with all traffic control, including the cost

of arrow boards, attenuator trucks, etc., in dollars

per day. If vehicles are used to set up traffic control

and then are used for other activities during the day,

a fraction of the daily cost should be used to

approximate the time spent setting up traffic control

for the repair operation. The amount entered should

not include the cost of labor.

(On) Patch Preparation Equipment–The cost

associated with each piece of equipment that is used

to saw the patch boundaries and/or to remove the
49

deteriorated concrete (e.g., concrete saw,

jackhammers, milling machine, waterblasting

machine, etc.), in dollars per day.

(Pn) Cleaning Equipment–The cost associated with

each piece of equipment used to clean the repair hole

after the deteriorated concrete has been removed, in

dollars per day. If a spray-injection machine's air

hose is used to clean the repair hole, this value

should be zero.

(Qn) Mixing Equipment–The cost associated with each

piece of equipment used to mix the repair

material(s), in dollars per day.

(R) Consolidation/Compaction Equipment–The cost

associated with the equipment used to consolidate

or compact the patches, in dollars per day.

(S) Extra Equipment Truck–The cost associated with

any equipment used to transport preparation,

cleaning, mixing, consolidation, or compaction

equipment to the site, in dollars per day.

(Tn) Miscellaneous Equipment–The cost associated

with each piece of any other equipment used in the

partial-depth spall repair process that was not

included in (M) through (S) (e.g., spray-injection

machine, joint-sealing equipment, etc.), in dollars per

day.

Summary Costs

(U) Total Material Cost–The cost of all materials used

in the partial-depth spall repair process, in dollars.
50

(V) Total Daily Labor Cost–The cost per day of all

labor used in the partial-depth spall repair process, in

dollars per day.

(W) Total Equipment Cost–The cost per day of all

equipment used in the partial-depth spall repair

process, in dollars per day.

(X) User Costs–The costs to the highway user per day

due to the delay associated with the repair operation,

in dollars per day. This value is fairly difficult to

calculate; the agency may rely on its experience.

(Y) Average Daily Productivity–The rate at which the

partial-depth spall repair patching can be done by the

patching crew, in patches per day. This amount

should reflect the size and experience of the crew

specified above.

(Z) Estimated Number of Days for Patching

Operation–An estimate of the number of days

required to perform the partial-depth spall repairs.

(AA) Total Patching Operation Cost–The total initial

cost of the entire partial-depth repair process, in

dollars. It does not take into account the expected

life of the partial-depth patches. To compare the

cost-effectiveness of different material and

procedure combinations without knowing the

expected life of the patches, the total cost per

project can be compared.

(BB) Expected Mean Life–An estimate of how long the

patches will survive. The amount entered should be

in months.
51

(CC) Time to Rehabilitation–An estimate as to the

amount of time remaining before rehabilitation will

be performed on the pavement surface. The amount

should be entered in months.

(DD) Effective Patching Cost–The cost of partial-depth

patching, in dollars, adjusted to reflect the expected

life of the partial-depth patches and the expected

time until rehabilitation.

3.8.2 Determining Cost-Effectiveness Inputs

The cost-effectiveness analysis requires an evaluation of the

maintenance crew, their past efficiency, their current salary

levels, and the availability of equipment. The costs of materials,

shipping, and rental equipment may be obtained from

manufacturers and dealers such as those listed in Appendix E. 

It is difficult to obtain accurate user costs and partial-depth

patch survival rate for a given material and procedure. 

Pavement condition, material quality, climatic conditions, and

crew ability all factor into these values. Guidelines for

calculating expected mean life for patches are given in chapter

5; examples of cost-effectiveness calculations are included in

Appendix B.
 
53

4.0 Construction

The most frequent construction-related causes of partial-depth

patch failure include the following:

! Failure to square the hole.

! Failure to remove all deteriorated material.

! Inadequate cleaning.

! Lack of bond.

! Failure to re-establish the joint (compression failure).

! Variability of the repair material.

! Insufficient consolidation.

This chapter provides guidelines for each step in the

construction process to help eliminate these causes of failure. 

The topics covered include: traffic control, safety precautions,

materials testing, joint preparation, patch preparation, mixing

the repair materials, placing the repair materials, consolidating

and compacting, screeding and finishing, curing, joint sealing,

cleaning up, opening to traffic, and inspection of the

construction process.

4.1 Traffic Control

Whenever any partial-depth patching operation is performed, it

is very important to provide adequate traffic control. This

ensures a safe working environment for the maintenance crew

and safe travel for vehicles in the construction area. Traffic

control operations should cause the least possible amount of

disturbance in the flow of traffic. While the actual traffic

control requirements for each construction site will vary, every

maintenance agency has the responsibility of ensuring that all

necessary steps are taken to maintain safety.
54

4.2 Safety Precautions

Many rapid-setting materials require special safety precautions,

both to protect the maintenance workers using them and to

protect the environment. It is extremely important that

highway agencies follow all instructions regarding worker

protection and repair material disposal. These instructions

are available from the manufacturer in the form of

MSDS’s.

In addition, the agency should follow safety instructions for

worker protection and material disposal for any other accessory

material or substance used (e.g., solvents, bonding agents, joint

bond breakers, admixtures, curing compounds, etc.), as well as

for all equipment that is used in the partial-depth spall repair

process.

Some common-sense safety precautions for using materials and

equipment in the partial-depth spall repair process are included

in Appendix C.

4.3 Material Testing

Material testing during the construction phase of a partial-depth

spall repair project involves daily quality control. A program of

testing samples of the repair mix for slump, air, compressive

strength, or flexural strength should be conducted, as

appropriate, for each type of cementitious repair material. 

Testing of bituminous and flexible polymer repair materials

must be done before their use in the field. Appendix A outlines

suggested pre-construction material testing specifications.
55

4.4 Initial Joint Preparation

The most frequent cause of failure of partial-depth spall repairs

is high compressive stress. Nonflexible partial-depth patches

placed directly against transverse joints and cracks will be

crushed by the compressive forces created when there is not

enough room for thermal expansion of the slabs. Patches may

also fail if, during placement, the repair material is allowed to

flow into the joint or crack opening below the bottom of the

patch. When cured, the material will prevent the crack or joint

from working and will keep the slabs from moving. These

failures must be prevented by using proper joint preparation

methods. 

4.4.1 Removing Old Sealant

If a nonflexible patching material is used, the old sealant in the

adjacent joint and 75 mm to 100 mm beyond the patch must be

removed for placement of a joint bond breaker. If a flexible

polymer material is used, the old sealant should still be

removed, and the area adjacent to the patch should be cleaned

thoroughly. Bituminous materials do not need any special

cleaning.

Most spall repair materials are nonflexible. However, some

materials (e.g., some polymers, cold mixes, spray-injection

mixes) are flexible and do not need a joint sealant or a joint

bond breaker. The material manufacturer should be consulted

to determine if joint sealant or bond breakers are necessary.

4.4.2 Joint Sawing

When a joint bond breaker is needed, the existing transverse

and longitudinal joints next to the repair should be resawn using

a double-bladed concrete saw. The depth of the cut should be

at least 25 mm deeper than the depth of the repair. The saw cut
56

should extend 50 to 75 mm beyond the repair area in each

direction. This sawing is usually done before removing the

deteriorated concrete, and must be done before cleaning the

repair area. Figure 9 shows the proper dimensions of the saw

cut. Water-wash equipment should be used to remove all

sawing slurry from the repair area before it dries.

Joint sawing may not be needed if flexible materials, such as

Percol FL and Penatron R/M-3003, are used. Joint sawing is

not used in either the clean-and-patch procedure because of

adverse conditions or when UPM High-Performance Cold Mix

and spray-injection mix (e.g., AMZ, Rosco) are used.

Repairs can be constructed without transverse joint bond

breakers by sawing the transverse joint to full depth as soon as

the patch has gained sufficient strength. However, if the joint

closes before sawing, the patch will fracture. This operation is

not recommended because timing is critical.

4.4.3 Sawing Out Joint Inserts

Spalls caused by metal or plastic joint inserts usually start at the

bottom fin of the insert, about 64 mm below the surface. When

repairing this type of spall, the joint insert should be sawed out

along the entire length of the joint to prevent further

deterioration. The joint can then be repaired and resealed. This

is normally done using a double-bladed concrete saw before

removing the deteriorated concrete.
57

Figure 9. Dimensions of joint saw cut.

4.5 Removing the Deteriorated Concrete

Partial-depth removal of the deteriorated concrete may be done

using several methods. The most frequently used method, the

saw-and-patch procedure, uses a wheel saw to cut the patch

boundaries, and jackhammers to remove the concrete inside the
58

boundaries. Small handheld saws are occasionally used, but

wheel saws are more common. Other methods include

chiseling without sawing the patch boundaries, cold milling,

waterblasting, and using handtools (under adverse conditions).

4.5.1 Saw and Patch

In the saw-and-patch procedure, a single-bladed concrete saw is

used to cut the boundaries of the patch and to make removing

the deteriorated concrete easier, as shown in figure 10. The

saw cut should be 25 mm to 50 mm deep and usually extends

50 mm to 75 mm beyond the patch boundaries to obtain that

depth for the entire length and width of the patch. The cut

boundary should have straight, vertical faces and square

corners. Vertical boundaries reduce the spalling associated

with thin or feathered concrete along the repair perimeter. The

recommended dimensions of the repair boundaries are shown in

figures 3 through 6. For large areas of repair, the area to be

removed may be sawed in a shallow crisscross or waffle pattern

to facilitate concrete removal, as shown in figure 11. Waterwash equipment should be used to remove sawing slurry from

the repair area before it dries.

After sawing, jackhammers are used to remove the unsound

concrete. Initially, hammers weighing less than 6.8 kg are used,

but hammers weighing up to a maximum of 13.6 kg may be

allowed. Removal should begin near the center of the spall and

proceed toward (but not to) the patch boundary. Care must be

taken not to fracture the sound concrete below the repair or to

overcut the repair boundaries.

Removal near the repair boundaries must be completed with

4.6-kg to 6.8-kg hammers fitted with spade bits, because gouge

bits can damage sound concrete. Spade bits are shown in figure

12. Jackhammers and mechanical chipping tools should be
59

Figure 11. Sawing pattern for large repair areas.

Figure 10. Sawing patch boundaries with a small

handheld saw.
60

Figure 12. Spade bits.

operated at an angle less than 45 degrees from vertical as

shown in figure 13.

Finally, the repair area must be tested again for soundness after

removing the deteriorated concrete as shown in figure 14. Any

additional unsound concrete must be removed by continued

chipping. A full-depth repair must be used if the deterioration

is found to be deeper than the top third of the pavement slab, or

if reinforcing bars or mesh are reached.
61

45

profile

Figure 14. Sounding repair area with a steel rod.

Figure 13. Using a jackhammer.
62

 Figure 15. Scalloped edge and 25-mm vertical edge.

4.5.2 Chip and Patch

The chip-and-patch procedure is the same as the saw-and-patch

procedure, except that the patch boundaries are not sawed. 

Cutting boundaries with jackhammers may result in scalloped

boundaries. Therefore, a 25-mm vertical edge must be

specified when using a repair material that does not perform

well when feathered. A scalloped edge and a 25-mm vertical

edge are shown in figure 15.

Finally, the repair area must be tested again for soundness, as

shown in figure 14. Any additional unsound concrete must be

removed by continued chipping. A full-depth repair must be

used if the deterioration is found to be deeper than the top third

of the pavement slab, or if reinforcing bars or mesh are reached.
63

4.5.3 Mill and Patch

In the mill-and-patch procedure, all unsound concrete within

the marked area is removed to a minimum depth of 50 mm

using a carbide-tipped milling machine. The small amount of

material that remains at the patch corners must be removed by

light jackhammering or sawing. Whenever possible, the milling

machine should be oriented such that the rounded edges of the

hole it produces are parallel to the direction of traffic. The

proper orientation of the rounded edges of the milled patch is

shown in figure 7. If this orientation is not possible, the

rounded edges should be made vertical using a light

jackhammer.

Finally, the repair area must be tested again for soundness, as

previously shown in figure 14. Any additional unsound

concrete must be removed by continued milling. A full-depth

repair must be used if the deterioration is found to be deeper

than the top third of the pavement slab, or if reinforcing bars or

mesh are reached.

4.5.4 Waterblast and Patch

The first step in the waterblast-and-patch procedure is to build

a shield around the repair area if there is any traffic passing in

the next lane, as shown in figure 16. Two trial areas, one of

sound concrete and one of deteriorated concrete, are then used

to determine the appropriate waterblasting operating

parameters. These parameters include speed, pressure, and the

number of overlapping passes. Using trial and error in the test

areas, the waterblaster must be programmed to remove all

unsound concrete without removing sound concrete

unnecessarily.

Once properly calibrated, the operating parameters should not

be changed while waterblasting the rest of the spalls, unless
64

Figure 16. Protective shield around waterblasting operation.

the concrete changes (for example, a harder aggregate has been

used in one section of the highway). If the concrete does

change, the waterblasting machine must be recalibrated using

two new trial areas in the section of the highway with the

different concrete.

All unsound concrete within a marked spalled area should be

removed to a minimum depth of 50 mm with neat vertical faces. 

Then the repair area must be tested again for soundness. Any

additional unsound concrete must be removed by continued

waterblasting. A full-depth repair must be used if the

deterioration is found to be deeper than the top third of the

pavement slab, or if reinforcing bars or mesh are reached.

The debris and slurry that result from the waterblasting

operation must be removed using a low-pressure water stream

before the slurry dries and hardens on the surface of the hole. If

this is not done, the repair area may have to be refaced. Once

dried, sandblasting may or may not be able to remove the dried
65

slurry residue. Some moisture-sensitive materials may require

the repair area be completely dry before placing the material.

4.5.5 Clean and Patch

Under adverse conditions, handpicks and shovels should be

used to remove loose material. A light jackhammer may

sometimes be used for larger areas.

4.6 Cleaning the Repair Area

After all unsound concrete has been removed, the surface of the

repair area must be cleaned. Sandblasting, airblasting, and

sweeping normally provide a clean, rough surface for the

development of a good bond between the patch and the

pavement. High-pressure water may also be used to remove

dirt, dust, and other contaminants, but sandblasting usually

produces better results.

4.6.1 Sandblasting

Sandblasting, shown in figure 17, is highly recommended for

cleaning the surface. It removes dirt, oil, thin layers of unsound

concrete, and laitance. Sandblasting equipment consists of a

compressed air unit, a sand dispenser, hoses, and a wand with a

venturi-type nozzle. The compressed air must be free of oil and

water, since a contaminated surface will prevent bonding. The

air quality can be checked by placing a cloth over the air

compressor nozzle and visually inspecting for oil. Sandblasting

is generally not used under adverse conditions.
66

Figure 17. Sandblasting.

4.6.2 Airblasting

After sandblasting, high-pressure airblasting should be used to

remove any remaining dust, debris, and loosened concrete

fragments. Debris must be blown out and away from the patch

so that wind or passing traffic cannot carry it back into the

patch. The cleanliness of the repair area must be checked using

a black glove or cloth. If the glove or cloth picks up material

(dust, asphalt, slurry) when rubbed across the prepared surface,

the surface should be cleaned again or poor bonding will result. 

If there is a delay between cleaning and patch placement, the

surface may have to be cleaned again. Airblasting is generally

not used with the clean-and-patch procedure under adverse

conditions.

Either trailer-mounted air compressors or portable backpack

blowers may be used. Backpack blowers need only one laborer

and are very mobile. However, trailer-mounted air compressors
67

are recommended because they provide a higher pressure

(greater than 670 kPa). The compressed air unit should have

oil and moisture filters; otherwise, it may blow oil or moisture

into the repair area and prevent the patch from bonding. When

patching with a spray-injection machine (e.g., AMZ, Rosco),

the hole may be cleaned with its blower.

4.6.3 Sweeping

Sweeping is most commonly used to clean the repair area when

patching under adverse conditions. Under better conditions,

sandblasting and airblasting should be used.

4.7 Final Joint Preparation

If a nonflexible repair material is used, a compressible joint

bond breaker must be installed as the last step of joint

preparation. The type of joint (i.e., transverse, centerline, or

lane-shoulder) will determine the type of bond breaker to use. 

Some flexible materials may not need a bond breaker.

Polystyrene or polyethylene joint bond breakers are placed flush

with the pavement surface, between the new (nonflexible)

concrete and the adjacent slab to reduce the risk of

compression-related failure. They also protect the patch from

damage caused by deflection under traffic.

The bond breaker should have a scored top strip as shown in

figure 2. It should extend 25 mm below and 75 mm beyond the

repair boundaries, as shown in figure 18a. The extension will

prevent the repair material from flowing into the joint during

placement. Figure 18b shows a bond breaker installed

improperly, as there is not enough length to extend beyond the

repair boundary along the top (longitudinal) edge of the repair

area. The bond breaker should be slightly wider than the joint
68

Figure 18a. Correct dimensions of joint bond

breaker placement at one joint.

Figure 18b. Incorrectly installed bond

breaker at two joints.
69

Figure 19. Joint bond breaker that has been stacked

and caulked.

so that it is slightly compressed when installed. The scored top

strip must later be torn off and the resulting joint reservoir filled

with an appropriate joint sealant. Consult the Materials and

Procedures for Repair of Joint Seals in Concrete Pavements–

Manual of Practice for more information on selecting

appropriate dimensions for the joint reservoir and joint bond

breaker, and for appropriate joint sealing materials and methods

(Evans and Romine, 1993b).

4.7.1 Preparing Transverse Joints

A straight joint line should be maintained during bond breaker

placement at transverse joints. This may be difficult with back-
70

to-back patches. Bond breakers of different heights may be

installed in patches of different depths. Alternatively, the bond

breaker may be stacked to the needed depth, which may be

difficult. Latex caulking may be used to seal any gaps between

layers of bond breaker or between the bond breaker and the

joint opening, as illustrated in figure 19. This will prevent the

repair material from flowing into the joint or a crack opening

below the bottom of the patch.

4.7.2 Preparing Centerline Joints

Partial-depth patches placed at the centerline joint often spall

because of curling stresses. To prevent this, a polyethylene

strip (or other thin bond-breaker material) must be placed along

the centerline joint to prevent the patch from contacting the

adjacent lane, as described in section 4.7.1.

4.7.3 Preparing Lane-Shoulder Joints

The joint must be formed using a piece of fiberboard if the

repair is at the lane-shoulder joint. Fiberboard is stiffer than a

polyethylene or polystyrene joint bond breaker, and it provides

the support needed at the lane-shoulder joint when placing the

repair material. Like more flexible bond breakers, fiberboard

will prevent the repair material from flowing into the shoulder

during material placement. If the repair material flows into the

lane-shoulder joint, it will restrict longitudinal movement of the

slab and damage the repair. Fiberboard must be placed to the

same dimensions as the more flexible bond breaker, as shown in

figure 18.

4.7.4 Using Flexible Repair Materials

Some proprietary flexible repair materials, such as Percol FL

and Penatron R/M-3003, and some bituminous materials, such

as UPM High-Performance Cold Mix and spray-injection mix
71

(e.g., AMZ, Rosco), may have enough compressibility to allow

joints to move without needing a joint bond breaker. The

manufacturer should be consulted for the appropriate joint

treatment when using a flexible spall repair material.

4.8 Pre-Placement Inspection of the Repair Area

After cleaning, the repair area should be inspected to determine

if there is any more unsound concrete. If there is, it should be

removed, and the repair area should be cleaned again. 

Sandblasting should never be used to remove unsound material.

If the repair area is sound, it should then be inspected for clean,

dry, freshly exposed concrete. Any dust remaining on the

pavement surface around the repair area should be removed by

sweeping, especially on windy days or when traffic passes

alongside the repair. If there is a delay between cleaning and

placing the material, the repair area must be inspected again at

the time of placement, and must be cleaned again by airblowing

if dirt has blown into it.

4.9 Mixing the Bonding Agent

Some partial-depth patching materials require epoxy or

proprietary bonding agents. Epoxy bonding agents should be

mixed carefully according to the manufacturer's instructions. 

An electric drill with a Jiffy mixer may be used to mix the two

epoxy components for the required time.

Some spall repair materials, such as SikaPronto 11, specify a

proprietary bonding agent. The manufacturer's mixing

instructions should be followed exactly to ensure good patch

performance.
72

4.10 Mixing the Repair Material

The volume of material required for a partial-depth repair is

usually small (0.014 m3 to 0.057 m3). Ready-mix trucks and

other large equipment cannot efficiently produce small

quantities. Small drum or paddle-type mixers with capacities of

0.17 m3 to 0.23 m3 and Jiffy mixers are often used. Based on

trial batches, repair materials may be weighed and bagged in

advance to make the batching process easier. Prebagged

cement may also be used; aggregate may be weighed using a

precalibrated volume method (i.e., a bucket can be marked by

volume for the appropriate weight). Continuous-feed mixers

are also widely used.

Mixing times and water content must be carefully observed for

prepackaged rapid-setting materials. Mixing for a longer time

than needed for good blending reduces the already short time

available for placing and finishing rapid-setting materials. 

Additional water may significantly reduce the strength of the

patch.

4.10.1 Cementitious Concretes

Rapid-setting cementitious materials used in partial-depth spall

repair, such as Type III PCC, gypsum-based concrete (e.g.,

Duracal), magnesium phosphate concrete (e.g., Set-45), and

high alumina concrete (e.g., Five Star HP), generally are mixed

with small drum or mortar mixers, as shown in figure 20.

The proportions of water, aggregate, and cement depend on the

type of material selected. A rapid-setting Type III PCC mix

generally includes an air-entraining agent, an accelerating agent,

and a superplasticizer. In addition to the cement itself, rapidsetting cementitious materials need clean water and a

manufacturer-specified gradation of aggregate. Some

proprietary materials (e.g., Duracal) also need sand. Most 
73

Figure 20. Adding carefully measured components to a

drum mixer.

cementitious materials require that the water be added to the

running mixer, followed by the aggregate, and then the cement. 

Warm water may be needed at air temperatures below 13oC,

while ice water may be needed at higher temperatures. The

manufacturer's recommendations for proportions, mixing

sequence, and mixing times for each component should be

followed exactly.

4.10.2 Polymer Concretes

Polymer concretes, such as epoxies (e.g., MC-64), methyl

methacrylates (e.g., SikaPronto 11), and polyurethanes (e.g.,

Percol FL, Penatron R/M-3003), are generally mixed with a
74

Jiffy mixer or a mortar mixer, as specified by the material

manufacturer.

The materials usually consist of two or more premeasured

liquid components, or a liquid component and cementitious

components. The different components are generally mixed

separately and then in combination. Mortar mixers are used for

mixing large batches of liquid components and for mixing

cementitious components with aggregate. Jiffy mixers are used

for mixing small batches of liquid components, as shown in

figure 21. Liquid mixtures are either mixed with or poured

over a specified gradation of oven-dried aggregate. The

manufacturer's recommendations for mixing sequence,

component amounts, and mixing times should be followed

exactly.

4.10.3 Bituminous Materials

Bituminous cold mixes (e.g., UPM High-Performance Cold

Mix) are generally mixed at a local plant using the

manufacturer's mix design. They may also come premixed in

drums, buckets, or bags. When patching spalls with a sprayinjection machine (e.g., AMZ, Rosco), the machine mixes

asphalt emulsion heated to approximately 57oC and aggregate. 

An experienced operator should carefully control the volume of

each component. The asphalt and aggregate are sprayed out

under pressure. Care should be taken not to overfill or to spill

material outside of the repair area.
75

Figure 21. Using a jiffy mixer.

4.11 Applying the Bonding Agent

A bonding agent should be applied after cleaning the repair area

and just before placing PCC repair materials. The

manufacturer's directions must be closely followed when using

epoxies or other manufactured grouts. The bottom and sides of

the repair area must be thoroughly coated by brushing the grout

or epoxy onto the concrete as shown in figure 22. Spraying

may be appropriate for large repair areas. Excess bonding

agent should not be allowed to collect in pockets. The

placement of the bonding agent should be timed so that it is

tacky when the repair material is placed.
76

Figure 22. Applying bonding agent.

4.12 Placing the Repair Material

For materials that will be consolidated or compacted, the

placement procedure begins by slightly overfilling the repair

hole to allow for the reduction in volume. Materials that

contain aggregate must be placed with a shovel. Segregation

will occur if these materials are dumped from a bucket or

wheelbarrow.

4.12.1 Cementitious Concretes

PCC and most of the rapid-setting proprietary patching

materials should not be placed when the air or pavement
77

temperature is below 4oC. Insulating covers and longer cure

times may be needed at temperatures below 13oC. The repair

area must be sprayed with water to enhance bonding before

placing many cementitious materials (e.g., Duracal, Five Star

HP, Pyrament 505). Vibration may be needed during placement

to improve workability.

4.12.2 Polymer Concretes

Some polymer concretes may be installed under adverse

conditions of low temperatures and wet substrates with

reasonable success (Stingley, 1977). However, these materials

perform better when installed under more favorable conditions. 

Due to their high heat of hydration, some polymer concretes,

such as epoxies (e.g., MC-64), and methyl methacrylates (e.g.,

SikaPronto 11) are placed in lifts no more than 38 to 50 mm

deep. The time between lifts should be that recommended by

the manufacturer. These materials have also been placed in one

lift during partial-depth spall repair with no adverse effects.

When placing polyurethane concretes, such as Percol FL and

Penatron R/M-3003, the repair area is first filled to grade with

washed, oven-dried, and crushed stone of the type and

gradation specified by the manufacturer. The polymer is then

poured (as in the case of Penatron R/M-3003) or pumped (as in

the case of Percol FL) directly over and through the preplaced

aggregate until all the aggregate is encased in the concrete and

the material is flush with the pavement surface, as shown in

figure 23. If specified by the manufacturer, aggregate may then

be broadcast over the top of the repair as a friction layer.
78

Figure 23. Pumping polymer into a patch that was prefilled

with aggregate (cover aggregate also being placed).

4.12.3 Bituminous Materials

Some bituminous mixes may be installed under adverse

conditions of low temperatures and wet substrates with

reasonable success (Stingley, 1977). However, these materials

perform better when installed under more favorable conditions. 

Bituminous cold mixes, such as UPM High-Performance Cold

Mix, must be placed by shovel. When patching using a sprayinjection machine (e.g., AMZ, Rosco), a coating of emulsified

asphalt should be sprayed into the hole and onto the edges of

the pavement around the repair. A mixture of emulsified

asphalt and aggregate should then be sprayed directly into the

hole. The repair should be filled slightly above level with the

pavement surface, and a coating of chip stone should be

sprayed onto the patch to prevent tracking.
79

4.13 Consolidating and Compacting

Cementitious repair materials must be consolidated by vibration

during placement to release trapped air from the fresh mix. 

Failure to do so may result in poor durability, spalling, and

rapid deterioration. Voids between the repair material and

pavement can cause total debonding and loss of repair material. 

Percol FL, MC-64, Penatron R/M-3003, and bituminous cold

mixes (e.g., UPM High-Performance Cold Mix, spray-injection

mixes) do not need vibration.

Three common methods of consolidation are:

! Using internal vibrators with small heads (less than 25

mm in diameter).

! Using vibrating screeds.

! Rodding or tamping and cutting with a trowel or other

handtools.

The internal vibrator, shown in figure 24, and the vibrating

screed give the best results. However, partial-depth patches are

usually too small to use a vibrating screed. Internal pencil

vibrators are recommended. Very small repairs may be

consolidated using handtools. Cutting with a trowel seems to

give better results than rodding or tamping. The tools used

should be small enough to work easily in the repair area.
80

Figure 24. Using an internal vibrator.

The vibrator should be held at 15 degrees to 30 degrees from

the vertical, as shown in figure 24, and should be moved

through the patch until the entire repair has been vibrated. It

should be lifted up and down, but not moved horizontally in the

patch. The vibrator should not be used to relocate material

within the repair as this may cause segregation. The mix is

adequately consolidated when it stops settling, air bubbles no

longer emerge, and a smooth layer of mortar appears at the

surface. 

Bituminous patching materials, such as UPM High-Performance

Cold Mix, are generally compacted using a vibratory roller or

plate until level with the pavement. The patches should be

compacted with three to eight passes. The roller or plate must

not bridge the patch.
81

4.14 Screeding and Finishing

The surface of the patch should be troweled flush with the

pavement surface. Vibration may be needed to make the work

finishable if the mix is too stiff. Partial-depth repairs are usually

small enough that a stiff board resting on the adjacent pavement

can be used as a screed. The material should be worked toward

the edges of the patch to establish contact and enhance bonding

to the pavement, as shown in figure 25. At least two passes

should be made to ensure a smooth surface.

The repair surface must be hand-troweled to remove any

remaining minor irregularities, as shown in figure 26. The edge

of a repair located next to a transverse joint should be tooled to

provide a good reservoir for joint sealing. Extra mortar from

troweling can be used to fill any saw overcuts at the patch

corners. Extra epoxy may also be used, or the saw overcuts

may be filled with joint sealant during the joint sealing process.

Partial-depth repairs typically cover only a small portion of the

pavement surface and have little effect on skid resistance. 

However, the finished surface of the repair should match that of

the pavement as closely as possible.

4.15 Curing

Curing is as important for partial-depth repairs as it is for

full-depth repairs. Since partial-depth repairs often have large

surface areas in relation to their volumes, moisture can be lost

quickly. Improper curing can result in shrinkage cracks that

may cause the repair to fail prematurely.
82

Figure 25. Screeding the patch.

Figure 26. Finishing the patch.
83

4.15.1 PCC Patching Materials

The most effective curing method when patching with PCC

materials in hot weather is to apply a white-pigmented curing

compound as soon as water has evaporated from the repair

surface. The compound will reflect radiant heat while allowing

the heat of hydration to escape and will provide protection for

several days. Moist burlap and polyethylene sheeting can also

be used, but must be removed when the roadway is opened to

traffic. In cold weather, insulating blankets or tarps can be used

to provide more rapid curing and to allow an earlier opening to

traffic. The required curing time should be stated in the project

plans and specifications.

4.15.2 Proprietary Patching Materials

Some proprietary materials may require some form of moist

curing after the mix has stiffened (e.g., Five Star HP). Others

require the application of a curing compound (e.g., Pyrament

505). Some proprietary repair materials may be air-cured (e.g.,

SikaPronto 11). Epoxy and proprietary repair materials should

be cured as recommended by their manufacturers.

4.16 Joint Sealing

The final step in partial-depth spall repair is restoring the joints. 

When the recommended scored bond breaker has been used,

the tear-off top strip should be removed, as shown in figure 27,

and the selected sealant applied (see section 3.4.4). If a scored

bond breaker has not been used, joint restoration is

accomplished by resawing the joint to a new shape factor,

sandblasting and airblasting both faces of the joint, inserting a

closed-cell backer rod, and applying the sealer. A minimum 1-

week cure time should be allowed before joint sealing. Consult
84

Figure 27. Removing the tear-off top

strip of a joint bond breaker.

the Materials and Procedures for Repair of Joint Seals in

Concrete Pavements–Manual of Practice for more information

on proper joint sealing practices (Evans and Romine, 1993b).

4.17 Cleanup Requirements

The material manufacturer's instructions should be consulted for

information on cleaning equipment that has been used to mix,

place, and finish their material. The cleaning solvent for most

cementitious materials is simply potable water. Some

proprietary materials may require a special solvent; table 5

shows which of several rapid-setting repair materials require a

special cleaning solvent. Equipment must be cleaned
85

immediately after use so it will not contaminate the next

material it contacts.

4.18 Opening to Traffic

Compressive strength requirements for paving concrete are

generally specified at 20,700 kPa at 28 days. The repair

concrete should develop an equal or greater strength by the

time it receives traffic loadings. However, to minimize lane

closures, traffic loadings may be allowed on a patched area

when the repair concrete has attained the minimum strength

needed to ensure its structural integrity. The compressive

strength required for the opening of partial-depth patches to

traffic may be lowered because of their lateral confinement and

shallow depth.

The specifications of rapid-setting proprietary mixes should be

checked for recommended opening times. Cylinders or beams

can be tested for strength to determine what opening time will

allow the repair material to develop enough strength. The time

to opening to traffic at 21oC for several rapid-setting partialdepth spall repair materials is shown in table 1.

4.19 Inspection

Quality control and inspection of the entire construction

process is crucial to the success of the repair. Field experience

has shown that each step in the partial-depth spall repair

process requires careful supervision and inspection. An

inspector must continually observe the various operations to

ensure that proper procedures are being followed. Appendix D

contains detailed checklists for each step of the inspection

process.
 
87

5.0 Evaluating Partial-Depth Patch

Performance

It is good practice to monitor the performance of partial-depth

patches. By doing so, patch performance factors can be

determined and used in comparing cost-effectiveness of

different material-procedure patch treatments. One method for

calculating a performance factor is described in this chapter.

5.1 Data Required

To determine the effectiveness of a given patch type (materialprocedure combination), field surveys must be conducted

periodically. The highway agency must record the survival life

for all patches placed so that the mean service life can be

calculated for the patch type. The main emphasis for the field

survey is to verify the continued survival of the patches, to

document those that have failed, and to note distresses evident

in the surviving patches, which may indicate the failure mode of

the patch.

For calculating the cost-effectiveness of a partial-depth spall

repair patching operation, it is necessary to estimate the

expected mean repair life of the patches. Table 8 shows one

alternative for documenting survival information and generating

a mean repair life value for a situation when the time until repair

is to be approximately 48 months. For a situation where the

time until repair would be approximately 24 months, the

maximum service life recorded for each individual repair would

be 24 months.
88

Table 8. Sample patch performance data.

Patch

No.

Survival at Month No. Life at Month No.

1 3 6 12 18 24 36 48 24 36 48

1 U U U U U U U U 24 36 48

2 U U U U U U 24 24 24

3 U U U U U U U U 24 36 48

4 U U U U U U U U 24 36 48

5 U U U U U 18 18 18

6 U U U U U U U U 24 36 48

7 U U U U U U U U 24 36 48

8 U U U U U U U U 24 36 48

9 U U U U U U U U 24 36 48

10 U U U U 12 12 12

11 U U U U U U U U 24 36 48

12 U U U U U U U U 24 36 48

13 U U U U U 18 18 18

14 U U U U U U U U 24 36 48

15 U U U U U U 24 24 24

16 U U U U U 18 18 18

17 0 0 0

18 U U U U U U U 24 36 36

19 U U U U U 18 18 18

20 U U U U U 18 18 18

Mean Service Life 21 27 33
89

5.2 Calculations

The mean patch service life is calculated simply by averaging

the individual service life values recorded for each patch being

monitored. The true mean service life cannot be determined

until all of the repairs have failed.

The mean service life for the example shown in table 8 is 33

months. This value is valid for calculating cost-effectiveness

for situations where the time until rehabilitation will be

approximately 48 months. For situations where the time until

rehabilitation will be 24 or 36 months, the mean service life for

the data shown in table 8 would be 21 or 27 months,

respectively.
 
91

Appendix A

Material Testing Specifications

The following specifications for partial-depth spall repair

materials are given as a guideline only and should be modified

to reflect the conditions and requirements of a particular

climatic region or roadway classification.

A.1 Rapid-Setting Cementitious Concretes

The cementitious rapid-setting patching materials and some

non-flexible rapid-setting polymer materials (e.g., SikaPronto

11) shall meet the following suggested guidelines for

acceptance as approved materials.

Initial set time, minimum ...................... . 15 min

Compressive strength

ASTM C 39, 3 hours ..................... . 6.9 MPa

Compressive strength

ASTM C 39, 24 hours ................... . 20.7 MPa

Bond strength of epoxy-resin systems

ASTM C 882 ........................... . 1.4 MPa

Bond strength of concrete overlay and 

patching materials, California test ............ . 1.4 MPa

Flexural strength

ASTM C 78 ............................ . 3.1 MPa

Freeze-thaw resistance

ASTM C 666, Procedure A (150 cycles) ..... . 15 grams

Scaling resistance

ASTM C 672 (100 cycles) ...................... . 5

Surface abrasion resistance

California Test T550 .................... . 25 grams
92

Thermal compatibility

ASTM C 884 .............................. . pass

A.2 Rapid-Setting Flexible Polymer Concretes

The flexible polymer materials shall meet the following

suggested guidelines for acceptance as approved materials.

Initial set time, minimum ...................... . 15 min

Bond strength of epoxy-resin systems

ASTM C 882 ........................... . 1.4 MPa

Bond strength of concrete overlay and 

patching materials, California test ............ . 1.4 MPa

Freeze-thaw resistance

ASTM C 666, Procedure A (150 cycles) ......... . 15 g

Scaling resistance

ASTM C 672 (100 cycles) ...................... . 5

Surface abrasion resistance

California Test T550 ........................ . 25 g

Thermal compatibility

ASTM C 884 .............................. . pass

A.3 Bituminous Materials

Bituminous patching materials shall meet the agency's

suggested guidelines for acceptance as approved materials. 

Tests for workability, stripping, drainage, and cohesion are

highly recommended. Additional tests suggested by other

agencies and proprietary material manufacturers may also be

used. Consult Appendix A of Materials and Procedures for

the Repair of Potholes in Asphalt Pavements–Manual of

Practice for more information on compatibility and acceptance

tests for bituminous cold mix materials (Wilson and Romine,

1993).
93

Appendix B

Sample Cost-Effectiveness Calculations

This appendix contains sample worksheets for costeffectiveness calculations. Different material and procedure

combinations illustrate the financial differences between

patching operations.

When using the examples in the following sections, it is

important to remember that crew size and productivity differ

greatly among agencies. These examples are fictitious and their

only purpose is to show how the worksheets are used when

completing them with the information relevant to a particular

agency.

Each example considers the placement of 200 partial-depth

patches with an average finished patch length of 457 mm, width

of 229 mm, and depth of 51 mm. Therefore, for all examples,

the expected total volume of the finished patches is 1.07 m3. 

The average daily wage for the maintenance worker is assumed

to be $120 in each example. Other data vary from example to

example.

Calculation of the amount of materials needed, such as a

patching material, bonding agent, joint bond breaker, or curing

compound, is not demonstrated. The examples assume that

agencies are already familiar with these calculations based on

the number, length, width, and depth of the patches, and a

typical waste factor for each material.
94

B.1 Example 1

Example 1 considers the placement of 200 material "A" patches

using the saw-and-patch procedure. Material, labor, and

equipment costs can be directly entered on the costeffectiveness worksheet. However, the average daily

productivity, the estimated number of days for the patching

operation, and the partial-depth patch survival rate require a

few advance calculations.

In calculating the average daily productivity and estimated

number of days for patching, the examples assume that the last

patch will be placed at the latest possible time and that

preparation will stop when there is enough time to place the last

patch. Therefore the patch preparation rate will control the

number of patches that can be placed per day. The example

also assumes that a crew of seven places seven patches per

hour, and that the average patch volume is 0.005 m3.

Patches prepared per hour = 7

Work hours per day = 8

Material cure time = 4 hr

Number of hours available for preparation

and placement (work hours - cure hours) = 4 hr

Average preparation rate

(7 patches/hr) × (0.006 m3/patch) = 0.042 m3/hr

Average daily productivity

4 hr × 0.042 m3/hr × (1 patch/0.006 m3) = 28 patches

Estimated number of days for patching (rounded up)

200 / 28 = 8 days

The mean patch survival life is estimated at 50 months for a

situation where a rehabilitation will be placed in approximately

60 months. Figure B-1 shows the completed cost-effectiveness

worksheet for this example.
95

ESTIMATE OF PROJECT SIZE OR SEASONAL PARTIALDEPTH PATCHING NEEDS

amount units

Expected Number of Patches 200 (A) 

Average Finished Patch Length 457 mm (B1)

Average Finished Patch Width 229 mm (B2)

Average Finished Patch Depth 51 mm (B3)

Expected Total Volume of Finished Patches

[(B1 × B2 × B3 × A) ÷ 109] 1.07 m3(C) 

MATERIAL COSTS (e.g., cold mix, cement, aggregate, sand, bonding

agent, joint bond breaker, curing agent, etc.)

Material 1 = Patching Material "A"

Material 1 Purchase Cost 172 $/m3(D1)

Expected Material 1 Needs 1.23 m3(E1)

Material 1 Shipping Cost 0 $ (F1)

Total Material 1 Cost [(D1 × E1) + F1] 211 $ (G1)

Material 2 = Bonding Agent

Material 2 Purchase Cost 12 $/L (D2)

Expected Material 2 Needs 56.2 L (E2)

Material 2 Shipping Cost 0 $ (F2)

Total Material 2 Cost [(D2 × E2) + F2] 675 $ (G2)

Material 3 = Joint Bond Breaker

Material 3 Purchase Cost 1.075 $/m (D3)

Expected Material 3 Needs 152.5 m (E3)

Material 3 Shipping Cost 0 $ (F3)

Total Material 3 Cost [(D3 × E3) + F3] 164 $ (G3)

Material 4 = Curing Compound

Material 4 Purchase Cost 2.6 $/L (D4)

Expected Material 4 Needs 7.7 L (E4)

Material 4 Shipping Cost 0 $ (F4)

Total Material 4 Cost [(D4 x E4) + F4] 20 $ (G4)

Figure B-1. Example 1 cost-effectiveness worksheet.
96

LABOR COSTS

amount units

Number in Repair Crew 9 (H) 

Average Daily Wage per Person 120 $/day (I) 

Number in Traffic Control Crew 2 (J) 

Average Daily Wage per Person 120 $/day (K) 

Supervisor Daily Wage 200 $/day (L) 

EQUIPMENT COSTS

Material Truck 20 $/day (M)

Traffic Control Trucks and Signs 150 $/day (N) 

Patch Preparation Equipment

(e.g., concrete saw, jackhammer, 225 $/day (O1)

milling machine, waterblaster) 60 $/day (O2)

Cleaning Equipment 350 $/day (P1)

(e.g., sandblaster, airblaster) 0 $/day (P2)

Mixing Equipment 35 $/day (Q1)

(e.g., mortar mixer, Jiffy mixer) 0 $/day (Q2)

Consolidation/Compaction Equipment

(e.g., pencil vibrator, vibrating 

screed, vibratory roller) 20 $/day (R) 

Extra Equipment Truck 0 $/day (S) 

Miscellaneous Equipment 0 $/day (T1)

(e.g., spray-injection machine, 0 $/day (T2)

joint sealing equipment, etc.)

Figure B-1. Example 1 cost-effectiveness worksheet

(continued).
97

SUMMARY COSTS

amount units

Total Material Cost

(G1 + G2 + G3 + G4 + ...) 1070 $ (U)

Total Daily Labor Cost

[(H × I) + (J × K) + L] 1520 $/day (V)

Total Equipment Cost

[M + N + (O1 + O2 + ...) + 

(P1 + P2 + ...) + (Q1 + Q2 + ...) + 

R + S + (T1 + T2 + ...)] 860 $/day (W)

User Delay Costs 1000 $/day (X)

Average Daily Productivity 28 patches/day (Y)

Estimated Number of Days

for Patching Operation

(A ÷ Y) 8 days (Z)

Total Patching Operation Cost

[U + {Z × (V + W + X)}] 28,110 $ (AA)

Expected Mean Life for Partial-Depth

Patches150 months (BB)

Time to Pavement Rehabilitation 60 months (CC)

Effective Patching Cost Over Time

[AA × (CC/BB)] 33,732 $ (DD)

1 Until expected mean life values have been determined, agency experience

should be applied. See chapter 5 for calculation examples.

Figure B-1. Example 1 cost-effectiveness worksheet

(continued).
98

B.2 Example 2

Example 2 considers the placement of 200 material "B" patches

using the chip-and-patch procedure. As in example 1, material,

labor, and equipment costs can be directly entered on the costeffectiveness worksheet. However, the average daily

productivity, the estimated number of days for the patching

operation, and the partial-depth patch survival rate require a

few advance calculations as well.

The same assumptions made in example 1, regarding the

calculation of the average daily productivity and estimated

number of days for patching, are made here. This example

assumes that sawing equipment will be needed to re-establish

the joints, and that the chip-and-patch preparation process will

have the same productivity as the saw-and-patch preparation

process, because the time needed for jackhammering will take

up the time not needed for sawing.

The mean patch survival life is estimated at 45 months for a

situation where a rehabilitation will be placed in approximately

60 months. Figure B-2 shows the completed cost-effectiveness

worksheet for this example.
99

ESTIMATE OF PROJECT SIZE OR SEASONAL PARTIALDEPTH PATCHING NEEDS

amount units

Expected Number of Patches 200 (A) 

Average Finished Patch Length 457 mm (B1)

Average Finished Patch Width 229 mm (B2)

Average Finished Patch Depth 51 mm (B3)

Expected Total Volume of Finished Patches

[(B1 × B2 × B3 × A) ÷ 109] 1.07 m3(C)

MATERIAL COSTS (e.g., cold mix, cement, aggregate, sand, bonding

agent, joint bond breaker, curing agent, etc.)

Material 1 = Material B

Material 1 Purchase Cost 278 $/m3(D1)

Expected Material 1 Needs 1.23 m3(E1)

Material 1 Shipping Cost 0 $ (F1)

Total Material 1 Cost [(D1 × E1) + F1] 342 $ (G1)

Material 2 = Joint Bond Breaker

Material 2 Purchase Cost 1.14 $/m (D2)

Expected Material 2 Needs 152.5 m (E2)

Material 2 Shipping Cost 0 $ (F2)

Total Material 2 Cost [(D2 × E2) + F2] 174 $ (G2)

Material 3 = __________________

Material 3 Purchase Cost 0 $/___ (D3)

Expected Material 3 Needs 0 _____ (E3)

Material 3 Shipping Cost 0 $ (F3)

Total Material 3 Cost [(D3 × E3) + F3] 0 $ (G3)

Material 4 = __________________

Material 4 Purchase Cost 0 $/___ (D4)

Expected Material 4 Needs 0 _____ (E4)

Material 4 Shipping Cost 0 $ (F4)

Total Material 4 Cost [(D4 x E4) + F4] 0 $ (G4)

Figure B-2. Example 2 cost-effectiveness worksheet.
100

LABOR COSTS

amount units

Number in Repair Crew 7 (H) 

Average Daily Wage per Person 120 $/day (I) 

Number in Traffic Control Crew 2 (J) 

Average Daily Wage per Person 120 $/day (K) 

Supervisor Daily Wage 200 $/day (L) 

EQUIPMENT COSTS

Material Truck 20 $/day (M)

Traffic Control Trucks and Signs 150 $/day (N) 

Patch Preparation Equipment

(e.g., concrete saw, jackhammer, 225 $/day (O1)

milling machine, waterblaster) 60 $/day (O2)

Cleaning Equipment 350 $/day (P1)

(e.g., sandblaster, airblaster) 0 $/day (P2)

Mixing Equipment 35 $/day (Q1)

(e.g., mortar mixer, Jiffy mixer) 0 $/day (Q2)

Consolidation/Compaction Equipment

(e.g., pencil vibrator, vibrating 

screed, vibratory roller) 20 $/day (R) 

Extra Equipment Truck 0 $/day (S) 

Miscellaneous Equipment 0 $/day (T1)

(e.g., spray-injection machine, 0 $/day (T2)

joint sealing equipment, etc.)

Figure B-2. Example 2 cost-effectiveness worksheet

(continued).
101

SUMMARY COSTS

amount units

Total Material Cost

(G1 + G2 + G3 + G4 + ...) 516 $ (U)

Total Daily Labor Cost

[(H × I) + (J × K) + L] 1280 $/day (V)

Total Equipment Cost

[M + N + (O1 + O2 + ...) + 

(P1 + P2 + ...) + (Q1 + Q2 + ...) + 

R + S + (T1 + T2 + ...)] 860 $/day (W)

User Costs 1000 $/day (X)

Average Daily Productivity 28 patches/day (Y)

Estimated Number of Days

for Patching Operation

(A ÷ Y) 8 days (Z)

Total Patching Operation Cost

[U + {Z × (V + W + X)}] 25,636 $ (AA)

Expected Mean Life for Partial-Depth

Patches145 months (BB)

Time to Pavement Rehabilitation 60 months (CC)

Effective Patching Cost Over Time

[AA × (CC/BB)] 34,181 $ (DD)

1 Until expected mean life values have been determined, agency experience

should be applied. See chapter 5 for calculation examples.

Figure B-2. Example 2 cost-effectiveness worksheet

(continued).

103

Appendix C

Material and Equipment Safety

Precautions

This appendix contains some common-sense safety precautions

for using materials and equipment in the partial-depth spall

repair process. These precautions are not a complete list, nor

will they apply to all materials and equipment. It is essential

that the highway agency obtain, review, and follow safety

data sheets for all materials and all equipment. The agency

should develop a safety training program that will properly

instruct highway workers in the safe use of all materials and

equipment involved in partial-depth spall repair. 

C.1 Materials

Some common-sense precautions for the safe use of many

rapid-setting materials, admixtures, bonding agents, curing

compounds, and solvents include the following:

! To avoid skin contact during mixing, placing, and

cleaning:

ý Wear long-sleeved shirts.

ý Wear long pants.

ý Wear gloves.

ý Wear steel-toed boots.

! To avoid ingestion during mixing, placing, and cleaning:

ý Wear eye protection.

ý Wash hands (even if gloves have been worn) before

handling anything that will go into the mouth (e.g.,
104

lunch containers, silverware, food, drinks, tobacco,

gum, etc.).

ý Wash hands before touching the face, eyes, nose,

mouth, or any other part of the body.

ý Avoid inhaling fumes and vapors (use respirators if

required).

ý Use in well-ventilated areas.

! To avoid creating additional toxic vapors or fumes,

never combine any substances unless following the

specific instructions of the manufacturers of those

substances. This includes combination by mixing, by

cleaning, by adjacent placement, by contamination, etc.

C.2 Equipment

Some common-sense precautions for the safe use of typical

partial-depth spall repair equipment include the following:

! Wear eye protection, gloves, long-sleeved shirts, long

pants, and steel-toed boots during sawing,

jackhammering, sandblasting, airblasting, milling,

waterblasting, spray injection, and any other operation

that could injure the skin, eyes, limbs, etc.

! Use ear protection during sawing, jackhammering,

sandblasting, airblasting, milling, waterblasting, spray

injection, and any other operation that is loud and could

permanently damage the hearing.
105

Appendix D

Inspection Checklists for Construction

This appendix is intended for inspectors of the partial-depth

spall repair process. It contains discussions of planning,

equipment, and procedures crucial to successfully completing a

partial-depth spall repair project. Checklists pertaining to each

step of the process–including planning, equipment, material

mixing, patch preparation, material installation, and safety

precautions–are provided.

D.1 Plans and Specifications

Plans must be prepared and distributed to the inspector and the

supervisor of the installation crew. The plans must contain the

following information:

G 1. Project layout (including stationing, slab lengths,

location of spalls to be repaired, etc.).

G 2. Original pavement material type.

G 3. Location and type of any pre-patching repairs

required.

G 4. Required patch dimensions.

G 5. Required joint reservoir dimensions.

Specifications may be based either on adherence to designated

procedures or on achieving a quality end-product. They may

also combine the two. Procedure-based specifications must

contain the following information:

G 1. Delivery and storage requirements.

G 2. Equipment requirements.

G 3. Material requirements.
106

G 4. Material mixing procedure requirements.

G 5. Patch preparation procedure requirements.

G 6. Installation procedure requirements.

G 7. Weather condition limitations.

G 8. Traffic control requirements.

G 9. Material disposal requirements.

G 10. Safety requirements.

End-result specifications must contain the following

information:

G 1. Delivery and storage requirements.

G 2. Required results of mixing procedures and

acceptance-rejection criteria.

G 3. Required results of each preparation procedure

and acceptance-rejection criteria.

G 4. Required results of the installation process and

acceptance-rejection criteria.

G 5. Weather condition limitations.

G 6. Traffic control requirements.

G 7. Material disposal requirements.

G 8. Safety requirements.

Most projects combine procedure-based and end-result

specifications. The following inspection process is based on

their combination.

D.2 Equipment

All equipment must be inspected and approved before the

project begins, as well as during mixing, patch preparation,

patch installation, and sealant installation. A list of proposed

equipment should be submitted before installation for approval. 

During the pre-installation inspection, the inspector should

check all equipment, ensuring that each piece meets the project
107

specifications. Suitability of equipment for mixing and placing a

particular repair material can be confirmed by contacting the

material manufacturer.

The condition and effectiveness of each piece of equipment

should be checked at the beginning of each day of patch

preparation, mixing, and installation.

D.3 Material Quality

The inspector must confirm that the patching materials, joint

bond breaker, bonding agent, curing compound, and so on are

from the agency's "approved list" or are from a certified plant,

and that samples of the materials have been submitted to the

agency's laboratory for testing. The material manufacturer's

recommendations for storage and shelf life should also be

checked. Materials that are not stored properly or that are old

may not meet quality standards.

D.4 Field Installation

After all required slab stabilization and other prepatching

rehabilitation have been completed and approved, the partialdepth spall repair process can begin. Inspector(s) and

supervisor(s) should meet before work begins to discuss the

following subjects:

G 1. Exact locations and dimensions of all spalls to be

patched. (The boundaries should be clearly

marked.)

G 2. Traffic control requirements and lane closure

time limitations.
108

G 3. Methods for preparing and cleaning repair areas,

for mixing and placing the repair materials, and

for reinstalling a joint sealant system.

G 4. Recommended accessory materials and

instructions for their use.

G 5. Material properties and working tolerances;

G working times.

G time to traffic at the anticipated mixing and

placement temperatures.

G moisture conditions allowable during

placement.

G temperatures allowable during mixing and

placement.

G 6. Mixing times, components, proportions, and

sequences.

G 7. Criteria for approval of all cleaning and

installation equipment and processes.

G 8. Criteria for final approval of the repair work.

G 9. Any localized variations from the specified

methods.

G 10. Procedures in the event of hot, cold, and/or wet

weather.

G 11. Material disposal requirements.

G 12. Safety requirements for all equipment and

procedures and MSDS’s.

D.5 Preparing the Repair Area

Patch preparation includes removing deteriorated concrete and

old sealant in the adjacent joint, final cleaning, installing the

joint bond breaker, and applying the bonding agent. The

following inspection checklist can be used to ensure that spall

preparation is completed properly. Not all of these patch

preparation procedures are used at one time.
109

G 1. Sounding:

G a solid steel rod, chain, or ball-peen hammer

is used to sound the spalled area before and

after the deteriorated concrete is removed.

G all deteriorated concrete is removed using

the specified method until all parts of the

repair area yield a clear ringing sound when

they are sounded.

G 2. Sawing:

G the concrete saw is establishing straight,

vertical patch boundaries to the required

depth, where specified.

G the concrete saw is removing the required

amount of concrete and sealant in any

adjacent joint.

G the concrete saw is uniformly cutting to the

proper width and depth. (Depth and width

can be checked quickly using a metal

template.)

G 3. The water-wash equipment is removing all

sawing and/or waterblasting slurry from the

repair area before it dries.

G 4. Jackhammering:

G jackhammers of the specified weight are

removing all deteriorated concrete to the

specified depth, without fracturing the sound

concrete below the repair or undercutting or

spalling any sawed boundaries.

G chiseling is begun in the center of the repair

area and proceeds outward.

G only light jackhammers are used near the

patch boundaries.

G if patch boundaries have not been sawed, the

hammering is producing rough, vertical

edges (not scalloped edges into which the

repair material will have to be feathered).
110

G spade bits (not gouge bits) are being used.

G jackhammers are being operated at an angle

less than 45 degrees from the vertical.

G 5. Milling:

G the carbide-tipped milling machine is

removing all deteriorated concrete to the

specified minimum depth.

G any material that remains at the patch

corners is removed by light jackhammering

or sawing.

G whenever possible, the milling machine is

oriented such that the rounded edges of the

milling hole are parallel to the direction of

traffic.

G if this is not possible, the rounded edges are

chipped into straight, vertical edges.

G edge spalling is minimized.

G 6. Waterblasting:

G a protective shield has been built around the

repair area before waterblasting if traffic is

passing in the next lane.

G the waterblasting equipment has been

calibrated to remove the specified depth of

concrete.

G operation parameters are not changed

throughout the remainder of the project

unless the concrete changes (e.g., the

aggregate hardness differs from one

pavement section to another).

G the waterblasting equipment is removing all

deteriorated concrete to the required depth,

and is producing neat, vertical faces at the

patch boundaries.

G waterwashing equipment is used to wash the

waterblasting slurry from the repair area

before it dries.
111

G 7. A full-depth repair is used if at any point in the

patch preparation process, the deteriorated area

of concrete is found to be deeper than the top

third of the pavement slab, or if reinforcing bars

or mesh are encountered.

G 8. Handtools and shovels are being used to

remove all loose material, when preparing the

patch under adverse conditions.

G 9. Sandblasting:

G the sandblasting equipment is uniformly

cleaning the faces of the repair area. This

typically requires that the nozzle be held 25

mm to 50 mm from the pavement and that

several passes be made.

G no old sealant, oil, or dried sawing and/or

waterblasting slurry remains in the repair

area.

G the sandblasting equipment does not

introduce oil or moisture to the repair area.

G after sandblasting, the entire surface area of

the patch hole contains freshly exposed

concrete.

G 10. Airblasting:

G the airblasting equipment is removing all dirt,

dust, old sealant, and sand from the dry

repair area.

G the airblaster does not introduce oil or

moisture to the repair area.

G after airblasting, the repair area is clean and

dry.

G 11. Compressed air is removing all old sealant,

sand, dirt, and dust from the pavement surface

so that it cannot re-enter the repair area,

especially on windy days or when traffic passes

next to the cleaned repair areas.
112

G 12. Recleaning:

G the repair area is re-checked for cleanliness

just before material placement.

G cleaned repair areas that have been

recontaminated by rain, dew, dirt, or oil are

cleaned again in a manner that restores the

original cleanliness. This may require

sandblasting and airblasting, or merely

airblasting.

G cleaned repair areas that are left overnight

are, at a minimum, airblasted again.

G 13. The repair area is allowed to dry if a moisturesensitive repair material will be used. (Water on

the surface of the repair area during material

installation may severely reduce the ability of the

material to bond to the surface, depending on

the material type. Watch for heavy dew that

may collect in the repair area and remain after

the surface is dry.)

G 14. Scored bond breaker:

G a strip of scored bond breaker is placed at

the joint-patch interface 25 mm deeper than

the repair, and extends at least 50 mm to 75

mm beyond the repair boundaries.

G the bond breaker is either of the appropriate

height or is stacked and latex-caulked when

necessary so that there are no gaps through

which the repair material can flow.

G a true, straight joint line is maintained when

installing the bond breaker.

G 15. Bonding agent:

G the bonding agent sprayer or brush is

applying a thin layer of bonding agent

uniformly over the repair area.

G the bonding agent is still tacky when the

repair material is placed.
113

G 16. Safety:

G all required operator safety equipment is in

use.

G all required safety precautions are followed.

D.6 Installing the Patch

Patch installation includes mixing, placing, and finishing the

patching material. The following inspection checklist can 

ensure that patch installation is completed properly.

D.6.1 Mixing

During the mixing of the repair materials, the following items

should be regularly checked to ensure that they meet the

requirements. Not all rapid-setting partial-depth spall repair

materials require mixing.

G 1. All mixing equipment is clean before use. 

Some material manufacturers may recommend

pre-wetting the mixer so no water is lost when

mixing the first batch.

G 2. The water used for mixing is clean.

G 3. The mixing operation results in a consistently

mixed material.

G 4. The material is not over- or undermixed.

G 5. Any spilled material is removed from the

pavement surface.

G 6. The mixing temperature is as recommended. 

Warm water or ice water is used to raise or

lower the mix temperature as needed.

G 7. Mixing time, mix components, mix

proportions, and mix sequences are carefully

followed.
114

G 8. The mixing equipment is cleaned with the

solvent specified by the material

manufacturer immediately after use.

G 9. The mixing of the bonding agent and repair

material is scheduled such that the bonding

agent is tacky when the repair material is placed.

G 10. Disposal of all wasted materials and solvents

follows the manufacturer's specifications and

State ordinances.

G 11. All required operator safety equipment is in

use.

G 12. All required safety precautions are followed.

Material that has begun to set during mixing, or material that is

too wet, should not be placed. It should be discarded, and the

mixing process begun again; a retarding agent may need to be

added. The mixing time or amount of water may also need to

be adjusted.

D.6.2 Placement

During placement, the following items should be regularly

checked to ensure that they meet the requirements. Not all

steps will be required for all materials.

G 1. The repair material is placed in a clean repair

hole, under the specified moisture conditions,

using the specified placement methods.

G 2. The bonding agent thoroughly coats the

bottom and sides of the repair area, but does not

collect in any pockets.

G 3. The material is placed when the bonding agent

is still tacky.

G 4. The repair hole is slightly overfilled with the

repair material for those materials that require

consolidation or compaction.
115

G 5. A shovel is used (not a wheelbarrow or a

bucket) to place repair materials that contain

aggregate, so that segregation does not occur.

G 6. The repair material is not placed below or

above its permissible placement temperature

range.

G 7. Deep repairs are placed in lifts to control heat

development, when specified.

G 8. A pencil vibrator or handtools are used to

release trapped air from the mix. 

G 9. The vibrator is held at 15 to 30 degrees from

the vertical, and is moved through the concrete

by lifting it up and down to vibrate the entire

area until the mix stops settling, air bubbles no

longer emerge, and a smooth layer of mortar

appears at the surface.

G 10. A bituminous cold mix patch is compacted to

release trapped air using a vibratory roller or

plate until it is level with the pavement.

G 11. Disposal of all wasted materials and solvents

follows the manufacturer's specifications and

State ordinances.

G 12. Field testing is conducted as appropriate for the

patching materials, such as testing beams or

cylinders for strength and quality control.

G 13. All required operator safety equipment is in

use.

G 14. All required safety precautions are followed.
116

D.6.3 Material Finishing and Curing

During finishing, the following items should be regularly

checked to ensure that they meet the requirements. Not all

steps will be required by all materials.

G 1. The repair material is troweled level with the

pavement before finishing.

G 2. The repair material is screeded with a stiff

board, using at least two passes.

G 3. The repair material is worked toward the patch

edges to enhance bonding with the existing slab.

G 4. The saw cuts are filled with excess mortar or

epoxy, or are filled with joint sealant during the

joint resealing process.

G 5. The patch surface is finished to match the

surface of the surrounding pavement.

G 6. Appropriate curing methods are used so that

shrinkage cracks do not develop.

G curing agents are applied uniformly to the

patch.

G the water used for curing is clean.

G insulating covers and longer cure times

are used at cooler temperatures, as specified

by the material manufacturer.

G 7. Disposal of wasted repair material, curing

compound, and cleaning solvents follows the

manufacturer's specifications and State

ordinances.

G 8. Traffic is not allowed on the pavement until the

material has developed the strength necessary to

carry traffic without being damaged.

G 9. All required operator safety equipment is in

use.

G 10. All required safety precautions are followed.
117

D.6.4 Joint Resealing

Consult the Materials and Procedures for Repair of Joint Seals

in Concrete Pavements–Manual of Practice for information

regarding the inspection of the joint resealing process (Evans

and Romine, 1993b). In addition to the inspection criteria listed

in that manual, when using a scored bond breaker, the following

criteria should be met:

G 1. Joint resealing or filling is conducted after a

minimum curing time of 1 week.

G 2. Immediately before joint resealing or filling, the

top strip is torn off of the scored bond breaker,

leaving a uniform, clean, dry reservoir.

G 3. Before resealing or filling the joints, lowpressure air cleaning is used if dust or dirt has

blown into the joints after removal of the tearaway top strip.

D.7 Final Inspection 

During installation and before approval, the partial-depth

patches should be individually inspected, ensuring that the patch

meets the highway agency's criteria, and noting the presence

and severity of any distresses. The final inspection should

include the following:

G 1. The patch is bonded firmly to the existing

pavement and has not separated from the

sidewalls.

G 2. The patch is level with the surface of the

existing pavement.

G 3. The patch contains no cracks (other than fine

hairline shrinkage cracks) or bubbles.
118

G 4. All material that has spilled on the pavement has

been removed.

G 5. No debris has been left on the pavement.

Consult the Materials and Procedures for Repair of Joint Seals

in Concrete Pavements–Manual of Practice for information

regarding final inspection of the joint sealant system (Evans and

Romine, 1993b).
119

Appendix E

Partial List of Material and Equipment

Sources

This appendix contains a partial listing of material and

equipment manufacturers. Addresses and phone numbers are

provided for manufacturers and/or suppliers who can provide

the inquirer with information regarding products, installation

practices, safety procedures, costs, and local suppliers.

MSDS’s, where applicable, should be available from all

manufacturers. Information regarding the safe use of all

materials and equipment should be carefully followed to ensure

worker safety and the safety of the traveling public.

Inclusion of a particular material, piece of equipment, or

supplier in this list does not serve as an endorsement of that

material, equipment, or supplier. Likewise, omission from this

list is not intended to carry negative connotations for the

materials, pieces of equipment, and suppliers omitted.

E.1 Partial-Depth Patching Materials

E.1.1 Manufacturers of Cementitious Concretes

Euclid Chemical Company

19218 Redwood Road

Cleveland, OH 44110-2799

(216) 531-9222

(800) 321-7628

www.euclidchemical.com
120

Five Star Highway Products, Inc.

425 Stillson Road

Fairfield, CT 06430

(203) 336-7900

Fosroc International Limited

55 Skyline Drive

Planview, NY 11802

(516) 935-9100

www.fosroc.com

Hartline Products Company, Inc.

2186 Noble Road

Cleveland, OH 44112

(216) 451-6573

L&M Construction Chemicals, Inc.

14851 Calhoun Road

Omaha, NE 68152

(402) 453-6600

Master Builders

23700 Chagrin Boulevard

Cleveland, OH 44122-5554

(800) 628-9990

www.masterbuilders.com

United States Gypsum Company 

Industrial Gypsum Division

125 South Franklin St.

Chicago, IL 60606-4678

(312) 606-4000

(800) 874-4968

www.usg.com
121

E.1.2 Manufacturers of Polymer Concretes

Accelerated Systems Technology Corporation

140 Chaparral Court

Suite 100

Anaheim, CA 92808

(714) 263-9074

HC Epoxy Company, Inc.

862 East 19th Street

Tucson, AZ 85719

(602) 624-7929

GeoChem, Inc.

P.O. Box 838

Renton, WA 98057-0838

(425) 227-9312

www.geocheminc.com

Pyrament/Lone Star Industries, Inc.

340 North Sam Houston Parkway, East

Houston, TX 77060

(800) 633-6121

Sika Corporation

201 Polito Avenue

Lyndhurst, NJ 07071

(201) 933-8800

www.sika.com

The Burke Company

P.O. Box 5818

San Mateo, CA 94402

(415) 349-7600

(800) 423-9140
122

Thoro System Products

Department PWM

7800 N.W. 38th Street

Miami, FL 33166

E.1.3 Manufacturers of Bituminous Materials

Unique Paving Materials Corporation

3993 E. 93rd Street

Cleveland, Ohio 44105-4096

(800) 441-4881

www.upm.com

E.1.4 Manufacturers of Bonding Agents

Master Builders

23700 Chagrin Boulevard

Cleveland, OH 44122-5554

(800) 628-9990

www.masterbuilders.com

The Burke Company

6433 East 30th Street

Indianapolis, IN 46219

(317) 543-4475

E.2 Partial-Depth Patching Equipment

E.2.1 Manufacturers of Sawing Equipment

Cimline, Inc.

2601 Niagara Lane

Minneapolis, MN 55447

(800) 328-3874

www.cimline.com
123

Target Products Division

4320 Clary Boulevard

Kansas City, MO 64130

(816) 923-5040

Vermeer Manufacturing Company

Route 2

P.O. Box 200

Pella, IA 50219

(515) 628-3141

E.2.2 Manufacturers of Spray-Injection Equipment

Zimmerman Equipment Corporation

1000 South Thompson Lane

P.O. Box 110098

Nashville, TN 37211

(615) 833-5705

Wildcat Manufacturing Company, Inc.

Highway 81

P.O. Box 523

Freeman, SD 57029

(605) 925-4512

Rosco Manufacturing Company

1001 S.W. First St.

P.O. Box B

Madison, SD 57042

(605) 256-0240

Duraco Industries, Inc.

P.O. Box 6127

Jackson, MS 39288-6127

(601) 932-2100
124

E.2.3 Manufacturers of Waterblasting Equipment

FLOW Services

23500 64th Street

Kent, WA 98032

(800) 446-3569, Ext. 900

E.2.4 Manufacturers of Milling Equipment

Cedarapids, Inc.

916 16th Street, N.E.

Cedar Rapids, IA 52402

(319) 363-3511

Vermeer Manufacturing Company

Route 2

P.O. Box 200

Pella, IA 50219

(515) 628-3141

E.2.5 Manufacturers of Jackhammers

Atlas Copco Berema, Inc.

161 Lower Westfield Road

Holyoke, MA 01040

(800) 284-2373

(413) 536-0600

E.2.6 Manufacturers of Compacting Equipment

Stone Construction Equipment, Inc.

Corporate Offices/Northern Manufacturing Plant

32 East Main Street

P.O. Box 150

Honeoye, NY 14471-0150

(800) 888-9926
125

Glossary

Admixture–A substance added to a mixture during mixing.

Adverse patching conditions–Climatic conditions in which the

air temperature is below 40oF (4oC) and the repair area is

saturated with surface moisture.

Bonding agent–A substance that promotes good bonding

between the pavement surface and a repair material placed on

the surface.

Breaking and seating–The breaking and compaction of a

continuously-reinforced concrete pavement, reducing the

amount of reflective cracking in the overlay.

Calcium aluminate concrete–A high alumina (Al2O3)

cementitious concrete.

Chemical conversion–A chemical process that results in a

change in the nature, structure, or properties of a substance.

Compact–To release trapped air and reduce volume using

compression.

Compression failure–The crushing of a repair due to the

expansion of the surrounding pavement during freeze-thaw

cycles.

Compression recovery–The property of being able to regain

original shape and volume after being compressed.

Compressive strength–The maximum compressive stress a

material can withstand before failure.
126

Compressive stress–A stress that causes an elastic body to

shorten in the direction of the applied force and that causes an

inelastic body to rupture.

Consolidate–To release trapped air from fresh concrete mix by

using vibration.

Cracking and seating–The breaking and compacting of a plain

concrete pavement, reducing the amount of reflective cracking

in the overlay.

D-cracking–Durability cracking; a pattern of cracks running

parallel and close to a joint or linear crack caused by freezethaw expansion of large, nondurable aggregate.

Debonding–The partial or complete loss of bond between two

materials, such as between a patch and a slab.

Diamond grinding–A surface restoration in which patterns are

cut into hardened concrete with closely spaced diamond saw

blades to correct surface distresses.

Epoxy concrete–A polymer concrete containing epoxy resin (a

flexible, thermosetting resin made by polymerization of an

epoxy compound).

Feathering–The thin placement of patching materials because

of curved or angled patch edges that do not allow adequate

depth of placement.

Free sulfate–A chemical group containing sulfur and oxygen

(-SO4) that is free to react chemically with other chemical

groups.
127

Full-depth spall repair–The removal of an area of deteriorated

concrete the entire depth of a pavement slab, and its

replacement with a repair material along with the restoration of

load transfer devices.

Full lane-width patch–A patch that extends the entire width of

a lane.

Gouge bit–A curved chisel tip used in jackhammering that is

not recommended for partial-depth spall repair.

Gypsum-based concrete–A cementitious concrete that contains

gypsum, a common sulfite mineral.

Heat of hydration–The heat given off when molecular water is

incorporated into a complex molecule with molecules such as

those found in cementitious mixes.

High alumina concrete–A cementitious concrete that contains

a higher amount of alumina (the native form of aluminum

oxide) than regular concrete.

High early-strength materials–Patching materials that gain

high strength levels early in their curing period.

High molecular weight methacrylate concrete–A cementitious

concrete containing high molecular weight methacrylate, an

acrylic resin or plastic made from a derivative of methacrylic

acid (C4H6O2).

Hydration rate–The rate at which molecular water is

incorporated into a complex molecule with molecules such as

those found in cementitious mixes.

Incompressible–A material that resists compression, such as

stones, sand, or dirt, in a crack or joint reservoir that is closing.
128

Joint bond breaker–A strip of polyurethane, polyethylene, or

fiberboard that is placed in a joint to prevent a patch placed at

that joint from bonding to the adjacent slab.

Joint insert–A metal or plastic strip inserted into fresh concrete

to form a weakened plane and induce cracking at a desired

location.

Joint sealant system–All components that function to seal

joints, including the sealant material, surrounding concrete, and

the sealant-concrete interface.

Laitance–A residue left on a surface, such as the dried residue

left on pavement after a wet-sawing operation.

Lateral confinement–Being held in place from the sides.

Latex caulking–The filling and water sealing of a space with a

latex material.

Load transfer devices–Devices such as dowel bars that transfer

the traffic load from one slab across a joint to the adjacent slab

and that reduce the relative deflection across that joint.

Magnesium phosphate concrete–A cementitious concrete that

contains magnesium phosphate, a metallic element (Mg) bound

to a phosphate group (-PO4).

Methyl methacrylate concrete–Cementitious concrete

containing methyl methacrylate (C5H8O2), a volatile, flammable

liquid that readily polymerizes.

Opaque–Not transparent to rays of light.

Operating parameters–Equipment settings, such as speed,

pressure, and number of overlapping passes.
129

Partial-depth spall–An area of deteriorated concrete that is

limited to the top third of a concrete pavement slab.

Polymer–A chemical compound or mixture of compounds

formed by polymerization and consisting of repeating structural

units; a substance made of giant molecules formed by the union

of simple molecules.

Polymer resin–A resin that is a polymer; see polymer and resin.

Polyurethane concrete–A concrete consisting of aggregate

mixed with a two-part polyurethane resin, a resin of repeating

structural units of urethane (C3H7NO2).

Preformed compression seal–A preformed seal, generally

made from neoprene, that can be compressed and inserted into

concrete joints for sealing purposes.

Proprietary–Something that is used, produced, or marketed

under the exclusive legal right of the inventor or maker.

Radiant heat–Heat that radiates from the sun.

Rapid-setting materials–In the context of this manual, patching

materials that set within 30 minutes of mixing.

Resin–Any of a class of solid or semi-solid organic products of

natural or synthetic origin with no definite melting point,

generally of high molecular weight. Most resins are polymers.

Retarding agent–A substance added to a cementitious material

mixture that initially slows down the rate of hydration, allowing

a longer period of workability.
130

Rubblization–The breaking of a concrete pavement into pieces

smaller than 304.8 mm in diameter and its compaction, reducing

the amount of reflective cracking in the overlay.

Saturated–Full of moisture; having voids filled with water.

Scalloped–Having a series of curves in its edges.

Segregation–The separation of cement and aggregate.

Set initiator–An admixture that triggers the setting of a

material.

Shape factor–The ratio of the width to depth of a sealant.

Shrinkage cracks–Fine hairline cracks that develop as a result

of water loss and volume reduction during curing.

Skid resistance–The resistance of a pavement to tires sliding

over its surface; generally a function of the macro- and microtexture of the pavement surface.

Slab jacking–The lifting of a slab at a low point to restore it to

its original elevation and rideability.

Slurry–The mixture of water, concrete dust, old sealant, and

dirt that results from re-sawing a joint in concrete pavement.

Spade bit–A flat, spade-shaped chisel tip used in

jackhammering that is recommended for partial-depth spall

repair.

Spalling–The cracking, breaking, or chipping away of concrete

fragments in a pavement.
131

Spall–A small broken or chipped segment of concrete normally

occurring along a joint or crack.

Substrate–A base layer, such as the repair surface, upon which

a material is applied or placed.

Thermal compatibility–Compatibility between the thermal

properties of two materials, such as similar amounts of thermal

expansion resulting from a given temperature increase in the

two materials.

Thermal expansion–The increase in volume of materials due to

an increase in temperature.

Undersealing–Filling voids beneath a concrete pavement using

a pressurized slurry or hot asphalt material.

Vibrating screed–A leveling device drawn over freshly poured

concrete that is vibrated to allow consolidation of the material.

Waterblasting machine–A machine controlled by a mobile

robot that produces a high-pressure water jet capable of

removing deteriorated concrete.

Weight and volume stability–Structural strength due to

sufficient patch weight and volume.
 
133

References

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Evans, L.D., et al. 1991. Innovative Materials and

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Evans, L.D., et al. 1993a. Innovative Materials Development

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Krauss, P. 1985. New Materials and Techniques for the

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