Research, Development, and Technology

Turner-Fairbank Highway Research Center

6300 Georgetown Pike

McLean, VA 22101-2296

Identifying Incompatible 

Combinations of Concrete Materials: 

Volume II—Test Protocol

PUBLICATION NO. FHWA-HRT-06-080 AUGUST 2006
FOREWORD 

Unexpected interactions between otherwise acceptable ingredients in portland cement concrete 

are becoming increasingly common as cementitious systems become more complex and 

demands on the systems are more rigorous. Such incompatibilities are exhibited as early 

stiffening or excessive retardation, potential for uncontrolled early-age cracking, and unstable or 

unacceptable air void systems. 

The protocol in this volume was developed to allow product manufacturers, concrete producers, 

contractors, and owners to monitor their materials and concrete systems. The protocol has two 

phases: relatively simple field tests to provide early warnings of potential problems, and central 

laboratory tests to support and confirm the field work. Tests conducted before construction 

begins help users to plan for materials and environment changes. By monitoring materials with 

relatively simple field tests during construction, the users can detect when significant changes 

have occurred, indicating potential construction problems. 

 Gary Henderson 

 Director, Office of Infrastructure 

 Research and Development 

Notice 

This document is disseminated under the sponsorship of the U.S. Department of Transportation 

in the interest of information exchange. The U.S. Government assumes no liability for the use of 

the information contained in this document. This report does not constitute a standard, 

specification, or regulation. 

The U.S. Government does not endorse products or manufacturers. Trademarks or 

manufacturers' names appear in this report only because they are considered essential to the 

objective of the document. 

Quality Assurance Statement 

The Federal Highway Administration (FHWA) provides high-quality information to serve 

Government, industry, and the public in a manner that promotes public understanding. Standards 

and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its 

information. FHWA periodically reviews quality issues and adjusts its programs and processes to 

ensure continuous quality improvement. 
Technical Report Documentation Page

1. Report No. 

HRT-06-080 

2. Government 

Accession No 

3. Recipient’s Catalog No. 

 

4. Title and Subtitle 5. Report Date 

August 2006 

6. Performing Organization code: 

Identifying Incompatible Combinations of Concrete 

Materials: Volume II—Test Protocol 

7. Author(s) 8. Performing Organization Report No. 

Peter C. Taylor Vagn C. Johansen 

Luis A. Graf Ronald L. Kozikowski 

Jerzy Z. Zemajtis Chiara F. Ferraris 

9. Performing Organization Name and Address 10. Work Unit No. 

11. Contract or Grant No. 

CTLGroup 

5400 Old Orchard Road 

Skokie, IL 60077 DTFH61-03-X-00102 

12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered 

14. Sponsoring Agency Code 

FHWA, and 

Portland Cement Association 

5420 Old Orchard Road 

Skokie, IL 60077 

15. Supplementary Notes 

Collaboration with Chiara F. Ferraris of NIST was secured under separate contract to FHWA. 

The Contract Officer’s Technical Representative was Peter Kopac, HRDI-12. 

16. Abstract 

Unexpected interactions between otherwise acceptable ingredients in portland cement 

concrete are becoming increasingly common as cementitious systems become more complex 

and demands on the systems are more rigorous. Examples of incompatibilities are early 

stiffening or excessive retardation, potential for uncontrolled early-age cracking, and unstable 

or unacceptable air void systems. Several test methods have been reviewed to assess their 

usefulness in early detection of incompatibility, and thus prevent pavement field problems. A 

protocol has been developed to allow product manufacturers, concrete producers, contractors, 

and owners to monitor materials and concrete systems. The protocol has two phases: 

relatively simple field tests to provide early warnings of potential problems and central 

laboratory tests to support and confirm the field work. 

17. Key Words 18. Distribution Statement 

Cement, fly ash, slag, 

incompatibility, admixture, early 

stiffening, cracking, air void 

system 

19. Security Classif. (of this 

report) 

20. Security Classif. (of this 

Page) 

21. No of 

Pages 

23. Price 

 83 

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

SI* (MODERN METRIC) CONVERSION FACTORS 

APPROXIMATE CONVERSIONS TO SI UNITS

Symbol When You Know Multiply By To Find Symbol 

LENGTH 

in inches 25.4 millimeters mm 

ft feet 0.305 meters m 

yd yards 0.914 meters m 

mi miles 1.61 kilometers km 

AREA 

in2 square inches 645.2 square millimeters mm2

ft2 square feet 0.093 square meters m2

yd2 square yard 0.836 square meters m2

ac acres 0.405 hectares ha

mi2 square miles 2.59 square kilometers km2

VOLUME 

fl oz fluid ounces 29.57 milliliters mL 

gal gallons 3.785 liters L 

ft3 cubic feet 0.028 cubic meters m3 

yd3 cubic yards 0.765 cubic meters m3 

NOTE: volumes greater than 1000 L shall be shown in m3

MASS 

oz ounces 28.35 grams g

lb pounds 0.454 kilograms kg

T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t") 

TEMPERATURE (exact degrees) o

F Fahrenheit 5 (F-32)/9 Celsius oC 

or (F-32)/1.8 

ILLUMINATION 

fc foot-candles 10.76 lux lx

fl foot-Lamberts 3.426 candela/m2 cd/m2

FORCE and PRESSURE or STRESS 

lbf poundforce 4.45 newtons N 

lbf/in2 poundforce per square inch 6.89 kilopascals kPa 

APPROXIMATE CONVERSIONS FROM SI UNITS 

Symbol When You Know Multiply By To Find Symbol 

LENGTH

mm millimeters 0.039 inches in 

m meters 3.28 feet ft 

m meters 1.09 yards yd 

km kilometers 0.621 miles mi 

AREA mm2

 square millimeters 0.0016 square inches in2 

m2 square meters 10.764 square feet ft2 

m2 square meters 1.195 square yards yd2 

ha hectares 2.47 acres ac

km2 square kilometers 0.386 square miles mi2 

VOLUME 

mL milliliters 0.034 fluid ounces fl oz 

L liters 0.264 gallons gal 

m3 cubic meters 35.314 cubic feet ft3 

m3 cubic meters 1.307 cubic yards yd3 

MASS 

g grams 0.035 ounces oz

kg kilograms 2.202 pounds lb

Mg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T 

TEMPERATURE (exact degrees) o

C Celsius 1.8C+32 Fahrenheit oF 

ILLUMINATION 

lx lux 0.0929 foot-candles fc 

cd/m2 candela/m2 0.2919 foot-Lamberts fl

FORCE and PRESSURE or STRESS 

N newtons 0.225 poundforce lbf 

kPa kilopascals 0.145 poundforce per square inch lbf/in2

*SI is the symbol for th International System of Units. Approp e riate rounding should be made to comply with Section 4 of ASTM E380. 

(Revised March 2003)
iii 

TABLE OF CONTENTS 

CHAPTER 1. INTRODUCTION................................................................................................ 1

Philosophy................................................................................................................................... 2 

CHAPTER 2. SUMMARY OF MECHANISMS ....................................................................... 3

Early Setting and Excessive Retardation .................................................................................... 3 

Dimensional Stability and Cracking ........................................................................................... 6 

Air Void System.......................................................................................................................... 7 

CHAPTER 3. PRECONSTRUCTION TEST PROTOCOL .................................................... 9

Materials...................................................................................................................................... 9 

Chemistry .................................................................................................................................... 9 

Stiffening and Setting................................................................................................................ 10 

Cracking .................................................................................................................................... 11 

Air Void System........................................................................................................................ 11 

CHAPTER 4. DURING CONSTRUCTION TEST PROTOCOL......................................... 13

Chemistry .................................................................................................................................. 13 

Stiffening and Setting—Field Tests .......................................................................................... 13 

Cracking .................................................................................................................................... 13 

Air Void System........................................................................................................................ 14 

CHAPTER 5. INTERPRETING DATA................................................................................... 15

Chemistry .................................................................................................................................. 15 

Stiffening (ASTM C 359) ......................................................................................................... 16 

Time of Setting.......................................................................................................................... 16 

Calorimetry................................................................................................................................ 17 

Minislump ................................................................................................................................. 17 

Rheology ................................................................................................................................... 17 

Slump Loss................................................................................................................................ 17 

Semiadiabatic Temperature Measurement ................................................................................ 18 

Ring Test ................................................................................................................................... 18 

Air Content................................................................................................................................ 18 

Foam Index Test........................................................................................................................ 18 

Foam Drainage Test .................................................................................................................. 18 

Air Void Clustering................................................................................................................... 19 

Air Void Analyzer..................................................................................................................... 19 

Hardened Air Content ............................................................................................................... 19 

CHAPTER 6. TEST METHODS .............................................................................................. 21
iv 

CHAPTER 7. EXAMPLE: PRECONSTRUCTION MATERIALS ANALYSIS................. 25

Preconstruction.......................................................................................................................... 25 

During Construction.................................................................................................................. 26 

ACKNOWLEDGEMENTS ....................................................................................................... 29

Disclaimer ................................................................................................................................. 29 

Matching Funds......................................................................................................................... 29 

APPENDIX A: DRAFT STANDARD TEST METHOD FOR MEASUREMENT OF 

CEMENT PASTE SETTING TIME USING A PARALLEL PLATE RHEOMETER ...... 31

APPENDIX B: DRAFT STANDARD TEST METHOD FOR MEASUREMENT OF 

CEMENT PASTE INTERACTIONS USING A MINISLUMP CONE ................................ 39

APPENDIX C: DRAFT STANDARD TEST METHOD FOR MEASUREMENT OF TIME 

OF SET OF CONCRETE USING WAVE VELOCITY METHOD...................................... 47

APPENDIX D: DRAFT STANDARD TEST METHOD FOR SEMIABIDIATIC 

TEMPERATURE MEASUREMENT ...................................................................................... 55

APPENDIX E: DRAFT STANDARD TEST METHOD FOR DETERMINING FOAM 

INDEX OF CEMENTITIOUS PASTE MIXURES................................................................. 61

APPENDIX F: DRAFT STANDARD TEST METHOD FOR FOAM DRAINAGE 

ANALYSIS METHOD ............................................................................................................... 69

REPORT REFERENCE ............................................................................................................ 77
v 

LIST OF TABLES 

Table 1. Compounds of Calcium Sulfate in Cement ...................................................................... 4 

Table 2. Protocol Test Methods.................................................................................................... 21 

Table 3. Cementitious Materials Analysis.................................................................................... 25 

LIST OF FIGURES 

Figure 1. Reactions that occur in hydrating cement, the times they occur, the heat they generate, 

and the effects on stiffening and setting. ........................................................................................ 4 

Figure 2. Protocol flow chart, preconstruction stage. ................................................................... 22 

Figure 3. Protocol flow chart, construction stage. ........................................................................ 23 

1 

CHAPTER 1. INTRODUCTION 

The purpose of this protocol is to help users assess combinations of materials used for making 

concrete for pavements and their likeliness of exhibiting incompatibility under a given 

environment. 

Numerous mechanisms and effects contribute to so-called incompatibility of materials, which 

may be manifest as a number of different problems including unusual stiffening and setting, 

increased risk of cracking, and unacceptable air void systems. Many of these mechanisms are 

complex and interrelated, which means there is no simple way to reliably measure the risk of 

incompatibility. Some test methods are suitable for indicating risk problems in the first 30 

minutes (min) because of aluminate and sulfate imbalances; other test methods are suitable for 

detecting later silicate hydration problems; and yet other methods are useful for assessing signs 

of distress. No single method is ideal for measuring all potential mechanisms. 

Some tests are low cost and more appropriate for field use, but they tend to be less sensitive than 

more precise laboratory-based tests. Many of these tests take a long time to conduct, which is 

problematic for field applications where an answer may be required in a few hours. 

It also has been observed that in many of the tests, no threshold clearly indicates incompatibility 

with any given system; therefore, the greatest value of many of the field tests is in monitoring the 

uniformity of a system over time, such as using control charts. A marked change in a test result 

would indicate potential problems and necessitate investigation by other means. Such tracking 

would need to be based on knowing the acceptable ranges of that system for the environment 

where it is used. 

This protocol has been developed on the premise of obtaining as much information as possible 

during a preconstruction phase. This work would include calibrating the more sensitive central 

laboratory tests with the equivalent field tests, using materials that are likely to be used in the 

field and environments similar to field conditions. This protocol also includes preparing 

alternative mix proportions and practices to accommodate changes in environment or in 

materials sources. Field tests developed for this protocol would be more rugged and conducted 

regularly, primarily to monitor the uniformity of the materials and the final mixture. 

While most of the tests in this protocol are valuable, the extent of preconstruction and field 

testing depends on the availability of equipment and the relative cost of testing compared to the 

cost and risk of failures. A typical example is in selecting a method to determine setting time. 

Setting time can be measured by up to six different techniques, any of which is acceptable. Test 

selection depends on contractor requirements, equipment availability, and site conditions. 

A relatively simple suite of field tests conducted regularly, listed as follows, will provide much 

of the needed reassurance that a concrete mixture will perform satisfactorily: 

• Foam index. 

• Foam drainage. 

• Unit weight. 
2 

• Slump loss. 

• Semiadiabatic temperature monitoring. 

• Setting time. 

• Chemistry of reactive materials. 

It may be problematic to obtain information about the materials chemistry in the detail required 

for individual batches. For a large project that has significant cost associated with failure, 

however, negotiations may be made with the suppliers to conduct the reviews as part of the 

existing quality control and to provide certification that a set of critical parameters such as 

tricalcium aluminate (C3A) content has not changed by more than an agreed amount between 

loads. 

PHILOSOPHY 

The testing protocol seeks to detect three potential problems: 

• Unexpected stiffening and setting (accelerated or retarded). 

• Unexpected cracking. 

• Unexpected air void system characteristics. 

The protocol has been designed to test materials at mix in the preconstruction stage and at the 

batch plant when sources of materials are changed and delivered. 

The protocol is set up so that some tests can be conducted in a batch plant laboratory or field 

trailer. If these tests indicate potential problems, or if they are inconclusive, then materials could 

be sent to a central laboratory for more sophisticated tests. 

Flow charts summarizing tests in the protocol appear as figures 2 and 3 later in this volume. 
3 

CHAPTER 2. SUMMARY OF MECHANISMS 

As indicated in volume I, there are a large number of mechanisms and effects that contribute to 

incompatibility. Many of these are complex and interrelated, which means there is no simple way 

to reliably measure the risk of incompatibility. This section summarizes some of the mechanisms 

as background to the test protocol. 

Many of the tests discussed in the protocol have no observable threshold that clearly indicates 

whether any given system was incompatible or not. A result that may be considered poor for one 

system may be considered acceptable for another; therefore, the greatest value of many of these 

tests is in monitoring the uniformity of a system over time. A marked change in a test result 

would indicate potential problems and a need for investigation by another means. Tracking test 

results would have to be based on knowing the acceptable ranges for that system and the 

environment in which it is used. 

EARLY SETTING AND EXCESSIVE RETARDATION 

Hydraulic cementitious systems stiffen, set, and harden by a process called hydration—a series 

of nonreversible chemical reactions with water. This process is complex and is still the subject of 

extensive research. The broad principles are discussed below. 

Cement Chemistry—Portland cement and cementitious materials are in the same family of 

chemical elements known as oxides, which can be detected by chemical analyses with X-ray 

fluorescence. In the following paragraphs, for convenience of discussion only, these elements are 

referred to as “oxides”; however, it is not likely all chemical elements are pure oxides. 

Calcium oxide normally comprises 60 to 65 percent of cement by mass, while silica normally 

contributes about 20 percent. These combine to form the so-called “silicates,” belite (C2S) and 

alite (C3S). The hydration products (the compounds formed when they react with water) of C2S 

and C3S are similar to each other, albeit in different proportions. Hydration of silicates also 

produces some heat (figure 1). Calcium silicate hydrate (CSH) is the primary compound that 

gives hydrated cement paste the strength and impermeability that makes concrete useful in 

construction. Calcium hydroxide (CH) forms hexagonal crystals that do not contribute 

significantly to strength, but which can be readily dissolved by acids and soft water. 

C3S, also known as alite, is the compound that contributes to setting and early strength 

development of concrete. The contribution normally begins a few hours after mixing. C2S, also 

known as belite, is the primary compound that contributes to later strength development of 

concrete. The contribution is considered to begin about a week after mixing. Portland cements 

currently contain approximately 60 percent C3S and 20 percent C2S. 
4 

Figure 1. Reactions that occur in hydrating cement, the times they occur, the heat they 

generate, and the effects on stiffening and setting. 

Alumina is included in the mixture introduced into a cement kiln because it helps reduce the 

burning temperatures required to make cement. Normally, iron oxide is also present in the raw 

materials. Alumina combines with calcium and iron oxide to form two aluminate compounds: 

C3A and C4AF. Typical portland cements contain approximately 5 to 8 percent C3A and 8 to 12 

percent C4AF. C4AF reactions do not contribute significantly to the properties of concrete, 

except for its gray color. C3A reacts very rapidly when mixed with water, and it generates a large 

amount of heat (figure 1) unless the reaction is controlled by the presence of calcium and sulfate. 

Calcium sulfate is added to clinker during grinding at about 5 percent dosage to control the initial 

reaction of C3A. The dosage is carefully optimized because cement strength is influenced by the 

amount of sulfate, and incompatibility (including uncontrolled stiffening and setting) can occur if 

the amounts of C3A and sulfate are out of balance. Calcium sulfate normally is present in three 

forms, depending on the amount of water tied to the compounds. These calcium sulfate forms are 

described in table 1. 

Table 1. Calcium Sulfate Compounds in Cement 

Compound Shorthand Notation 

Anhydrous calcium sulfate (anhydrite) CS ̄

Calcium sulfate dihydrate (gypsum) CS ̄H2

Calcium sulfate hemihydrate (“plaster” or bassanite) CS ̄H1⁄2

Troubleshooting presentations

Gypsum

CS ? Gypsum deposition (False set)

Gypsum depletion

Aluminate reactions

C3A + CH + 12H ? C4AH13 ** Hopefully never (flash set)

C3A + 3CS + 26H ? C3A•3CS•H32 (Ettringite) **

2C3A + C3A•3CS•H32 + 4H ? 4(C 3A•CS•H12 ) (Monosulfate)

Silicate reactions

2C3S + 6H ? CSH + 3CH *

2C2S + 4H ? CSH + CH * Later

* Retarded by sugar / lignin

** Accelerated by sugar / lignin

0

5

10

15

20

25

0:00 6:00 12:00 18:00 0:00

Time of hydration (h)

J/g/h

Working time

Initial set

Final set

"Sulfate depletion"

(ettringite to monosulfate

conversion)

Strength 

development

1 J/g/h (joule/gram/hour) = 0.008 calories/ounce/hour
5 

The reaction products of C3A and sulfate are complex, and they change with time from mainly 

amorphous hydrates to form more crystalline hydrates such as ettringite and monosulfoaluminate 

hydrate (figure 1). The formation of syngenite also appears to be a potentially significant factor. 

Hydration Reactions and Development of Microstructure—Hydration begins as soon as the 

cementitious materials come in contact with water. The particles partially dissolve and the 

components start to react at various rates. 

There is no single mechanism behind the wide range of effects that occur. Many of the 

mechanisms are complex and interactive, and they may require expert evaluation if they occur in 

the field. The following paragraph discusses some of the chemical reactions that occur. 

Cement hydration in the first 15 min is a delicate balance between the C3A in the cement and the 

sulfate in solution, slowing the C3A reaction (figure 1). If there is insufficient sulfate in solution, 

the C3A begins to react immediately to form calcium aluminate hydrate, which can cause 

immediate and permanent flash set if it is not controlled. C3A hydrates at a more controlled rate 

in the presence of sulfate to form ettringite while there is sulfate in solution. When the sulfate is 

consumed, ettringite continues to react to form monosulfate (figure 1). On the other hand, too 

much sulfate in solution may precipitate out as gypsum, causing false (temporary) set. These 

reactions are the basis of many incompatibility problems. 

The amount of sulfate in solution depends not only on the amount of sulfate in the cement, but 

also the form in which it occurs. Cement that has overheated in the mill can contain excess 

amounts of relatively fast dissolving plaster (CaSO4·1⁄2H2O). Cement manufacturers normally 

target a balance of plaster and gypsum (CaSO4·2H2O) suitable for the reactivity of a given 

clinker type and cement fineness, and optimize the sulfate content to balance the concrete setting 

time. 

Addition of a supplementary cementitious material (SCM) that contains calcium aluminates 

(typically high calcium fly ash) can mean compromising the aluminate and sulfate balance, 

causing incompatibility problems. 

The fineness of the cement also can influence the reaction rates: the finer the cement, the greater 

the risk of uncontrolled C3A reactions with other ingredients in the concrete. 

Some chemical admixtures will interfere with C3A hydration and the solubility of calcium and 

sulfate in the pore solution; thus chemical admixtures may significantly affect the workability of 

the concrete in the first few minutes. Type A water reducers tend to accelerate aluminate 

hydration and retard silicate hydration. Some chemical admixtures may reduce early slump when 

used with some cementitious combinations. 

Temperature strongly influences the solubility and reactivity of all of the chemical element 

compounds. Higher temperatures generally increase solubility and accelerate reaction rates. 

These changes can affect the balance of the system and change stiffening rates and setting times. 

After a dormant period of 1 to 3 hours, the silicates (C3S and later the C2S) start to hydrate, 

forming fibrous CSH that gradually spreads and merges with the growth from other cement 

particles or adheres to aggregate particles. This buildup of new solid compounds results in 
6 

progressive stiffening, hardening, and strength development. This reaction proceeds as long as 

the system contains water, which explains the need for curing. 

Increasing alkali content and cement fineness, along with increasing temperature, will increase 

reactivity of the silicate components and decrease setting times. Increasing reactivity will also 

tend to increase the rate of gain of stiffness, which may in turn increase the risk of cracking. 

The presence of some chemical admixtures affects reaction rates, often retarding setting. Type A 

water-reducing admixtures may retard silicate hydration. 

The saturation of calcium can also affect the hydration of C3S, which in turn is influenced by the 

reactions in early stages of hydration discussed earlier. Insufficient calcium in solution (i.e., if it 

has been consumed in early C3A hydration) will slow or stop silicate hydration, leading to 

retardation of the concrete or its failure to set. 

DIMENSIONAL STABILITY AND CRACKING 

Concrete, and all of the components in it, tends to grow or shrink with changing temperatures, 

moisture conditions, and, in some cases, with chemical reactions. By nature of its composition, 

concrete is mixed with water, some of which is consumed in hydration, and some of which may 

leave the system by bleeding or evaporation as the concrete is allowed to dry. All of the materials 

in concrete expand and shrink with changing temperature and moisture content. 

The space occupied by the reagents of cement hydration is less than that of the hydrated system. 

This results in chemical shrinkage and autogenous shrinkage (the amount of chemical shrinkage 

that can be measured). This phenomenon is greatest in systems with low water-to-cementitiousmaterials ratios. Other chemical reactions, including alkali aggregate reactions and sulfate attack, 

can cause changes in the physical dimensions of the concrete, which are outside the scope of this 

protocol. 

The consequences of these dimensional changes are a function of other properties of the concrete 

including restraint, stiffness, strength, and creep. A freestanding object that is not restrained 

internally or externally will shrink without damage; however, external restraint is almost always 

applied to concrete elements through their support systems and connections to adjacent elements. 

Internal restraint is also imposed by different components such as aggregates and pastes that 

have different stiffness values, which likely results in different amounts of dimensional 

movement. Such restraint will result in cracking. 

The amount of stress set up in a shrinking, restrained material is a direct function of its stiffness 

(modulus of elasticity); stiffer materials result in higher stresses. Creep helps to mitigate the 

amount of stress. The risk of cracking is governed by the balance of imposed stress and the 

material strength. 

Adding to the complexity of dimensional change is that all of these properties (including strength 

and stiffness) change with time as the concrete hydrates. The changes occur rapidly at earlier 

ages and slow with time. Furthermore, the changes occur at different rates for different 

properties. The rate of hydration can be influenced by temperature and the chemistry of the 

reactive materials. The rate of drying (and associated shrinkage) also can be influenced by 
7 

temperature and the environment the concrete is exposed to. The rates and amounts of 

temperature change are governed by the dimensions of the element, the environment, and the 

chemistry and degree of hydration. 

Computer models are available to assess the risk of cracking in concrete pavements. Part of the 

work conducted in this project has been to determine the relative rates of change of strength and 

stiffness of the concrete mixtures tested. 

The current standard test for concrete shrinkage (American Society for Testing and Materials 

(ASTM) C 157) does not provide information about dimensional changes in the concrete for the 

first 24 hours after mixing. It provides limited information before drying can start. Such 

information is required if early-age cracking is to be better understood and prevented. The ring 

shrinkage test provides a controlled method of tracking shrinkage-related stresses in concrete 

under restraint from the time the concrete is placed in the mold. 

AIR VOID SYSTEM 

To protect concrete from frost damage, it is important that it has a proper air void system. Such a 

system may be considered as a uniform distribution of a large number of small air bubbles, The 

critical variable in air void systems is the maximum distance from any point in the paste to the 

nearest bubble. 

The quality of an air void system is strongly influenced by the chemistry of the cementitious 

materials, particularly the carbon content of fly ash if present. Different air-entraining admixtures 

also can produce different air void systems; some materials are strongly influenced by the 

presence of other chemical admixtures SCMs. Other influences are the grading of fine aggregate 

and the amount of mixing energy provided. It is easier to entrain air in a mixture with a higher 

slump than in one with a lower slump. The air void system of concrete will also change with 

continued handling, placing, and compacting. 

It is desirable that spacing be determined in concrete, particularly in the fresh state, to allow early 

decisions regarding the concrete’s acceptability. It may be beneficial to test the concrete in its 

final position to evaluate the effects of handling; however, at present no proven method is 

available to make this measurement, making it important to correlate the final spacing factor 

with other, more easily measured parameters such as total air content, which is measured using a 

pressure meter. 

9 

CHAPTER 3. PRECONSTRUCTION TEST PROTOCOL 

The purpose of conducting preconstruction tests is to evaluate the sensitivity of proposed 

materials to variations in composition and environment. If problems are observed in the field, 

this preconstruction evaluation allows selection of alternative materials before action plans are 

implemented. The work also provides calibration between field-based tests and laboratory-based 

tests and will give guidance on the limits appropriate for the materials to be used and conditions 

likely to be encountered. 

MATERIALS 

Representative samples of all materials likely to be used in the planned project, including 

substitutes that may be required, should be acquired and tested for compliance with their 

respective specifications. Expertise and experience aid in interpreting test result data. 

CHEMISTRY 

Chemical analyses of the reactive materials such as cements, SCMs, and chemical admixtures 

should include the following materials and characteristics: 

• C3A amount. 

• Alkali content. 

• Sulfate content. 

• C3A and sulfate contents balance. 

• Fineness. 

• Sulfate form (if available). 

Fly ashes and slags should be examined for the following characteristics: 

• Loss-on-ignition (LOI) 

• Calcium content. 

• Alkali content. 

• Sulfate content. 

• Glass content, (if available). 

• Fineness (ultrafines) (if available). 

Water-reducing admixtures should be identified for the following contents: 

• Lignosulfonate. 

• Triethanolamine (TEA). 

• Sugar. 

• Polycarboxylate. 

The solids content of chemical admixtures also should be determined. 
10 

Air-entraining admixtures should be identified for the following contents: 

• Vinsol resin. 

• Resin and rosin. 

• Alpha sulfonate. 

• Benzene sulfonate. 

• Tall oil. 

• Fatty acid. 

Guidelines for interpreting the data are given at the end of the protocol. Any of the examined 

chemical balances that indicate potential problems should be followed up with appropriate tests. 

It may be advisable to conduct all of the tests below (under “Stiffening and Setting,” “Cracking,” 

and “Air Void System) to provide a baseline for comparison with tests that are conducted later 

during construction. 

STIFFENING AND SETTING 

Paste, mortar, and concrete tests should be conducted at 21 °C (70 °F) and at the maximum and 

minimum temperatures likely to be encountered during construction. Tests should be conducted 

at the extremes of likely SCM and chemical admixture dosages. If any of the tests indicate 

potential problems, adjustments should be made to the system, and then tests should be 

conducted again to see if the issue is resolved. Note that in general, paste and mortar tests are 

more sensitive than concrete tests, meaning that a system that is marginal in a paste or mortar test 

may still be satisfactory in a concrete test. 

Conduct any or all of the following tests on paste and mortar: 

• Time of setting (ASTM C 191, paste) and stiffening (ASTM C 359, mortar). 

• Conduction calorimetry (paste or mortar). 

• Minislump (paste or mortar). 

• Rheology (paste or mortar). 

If potential problems are indicated, then conduct any or all of the following tests on concrete: 

• Slump loss. 

• Time of setting. 

• Ultrasonic P-wave. 

• Semiadiabatic temperature measurement. 

Any method of determining time of setting may be appropriate, as long as it is applied 

consistently. Different methods may yield slightly different results. The minislump test may not 

be necessary if a rheology test is conducted. 

It is particularly helpful to repeat the testing after changing a single parameter (e.g., fly ash 

dosage or order of batching) to assess the sensitivity of the system to these changes. An example 

would be temperature change. Raising the temperature from 27 °C to 32 °C (80 °F to 90 °F) has 

been known to change the stiffening rate of concrete from satisfactory to unsatisfactory. 
11 

The cure to problem systems is often one or a combination of the following factors: 

• Change in fly ash (source, type, or dosage). 

• Change in chemical admixture (type or dosage). 

• Change in batching sequence. 

• Change in concrete temperature (e.g., through planning to work at night). 

• Addition of a set retarder (only recommended if system is in sulfate balance, which can be 

determined by calorimetry). 

• Information from the cement supplier informing of a change in the sulfate form. 

CRACKING 

Tests should be conducted at 21 °C (70 °F) and at the maximum and minimum temperatures 

likely to be encountered during construction. Tests should be conducted at the extremes of likely 

SCM and chemical admixture dosages. If any of the tests indicate potential problems, 

adjustments should be made to the system and followup tests should then be conducted to see if 

the issue is resolved. 

Conduct any or all of the following tests: 

• Time of setting (ASTM C 403). 

• Strength and modulus development. 

• Ring test (ASTM C 1581). 

• Semiadiabatic temperature measurement or isothermal calorimetry. 

Use computer models such as HIPERPAV® to assess the risk of cracking for the system and 

environment expected. 

The cure to problem systems is often one or a combination of the following changes: 

• SCM (type or source). 

• SCM proportions. 

• Retarding or accelerating admixtures; dosage may need to be optimized. 

• Concrete temperature. 

• Cement with a different chemistry. 

AIR VOID SYSTEM 

Tests should be conducted at 21 °C (70 °F) and at the maximum and minimum temperatures 

likely to be encountered during construction. Tests should be conducted at the extremes of likely 

SCM and chemical admixture dosages. If any of the tests indicate potential problems, 

adjustments should be made to the system and followup tests should be conducted to see if the 

issue is resolved. 
12 

Conduct any or all of the following tests: 

• Foam index test (paste). 

• Foam drainage test (paste). 

• Air content (ASTM C 231) (concrete). 

• Air void analyzer (concrete). 

• Hardened air content (ASTM C 457). 

• Clustering rating of hardened concrete. 

The cure to problem systems is often one or a combination of the following changes: 

• Air-entraining admixture (type or dosage). 

• Chemical admixture (type, formulation, or dosage). 

• Batching sequence. 

• Refrain from adding water after initial mixing. 

• SCM. 

• SCM dosage. 

• Cement with a different chemistry. 

• Concrete temperature. 
13 

CHAPTER 4. DURING CONSTRUCTION TEST PROTOCOL 

This portion of the protocol describes testing for prequalified systems to evaluate the risk of 

problems occurring because of changes in materials from load to load or changes in source or 

environment. If changes are noted, then the previously developed plans can be implemented; if 

these actions do not address the problem, then samples can be sent back to the laboratory for 

more detailed evaluation. More detailed laboratory tests will be those described for the 

preconstruction stage above. 

Ideally, field tests should provide results in a short time; however, but this may not always be 

practical. The results of rapid tests (less than 24 hours) may indicate potential problems, but firm 

decisions on the acceptability of a given material may need to be delayed until after further 

testing. If the information can be used to change mixture proportions or practices to sidestep 

problems, then the protocol may be considered successful. 

CHEMISTRY 

To detect significant changes in composition or proportions, it is a good idea to track mill 

certificates and supplier’s data sheets for changes in chemistry of all the reactive systems, which 

could indicate potential problems. Pay special attention to variations in reported sulfur trioxide 

(SO3), C3A, C3S, fineness, setting time, and equivalent alkali content (Na2Oeq). 

STIFFENING AND SETTING—FIELD TESTS 

Conduct any or all of the following concrete stiffening and setting field tests: 

• Slump loss. 

• Time of setting (ASTM C 403). 

• Ultrasonic P-wave. 

• Semiadiabatic temperature measurement. 

Monitor the results of these tests from batch to batch because changes can indicate potential 

problems. Either further laboratory testing is indicated or a change in the cementitious system or 

procedures. 

CRACKING 

No field tests are completely accurate for detecting risk of cracking in a concrete system; 

however, the tests can monitor changes in system chemistry and proportions by using computer 

models such as HIPERPAV to assess the risk of cracking. Monitoring test results of the 

semiadiabatic temperature measurement may provide a signal that hydration rates of the 

cementitious system are changing, thus pointing to potential problems. 
14 

If unexpected cracking occurs, then work should stop until the causes are identified and rectified. 

Concrete microscopy often can reveal underlying mixing, mixture proportion, or curing 

problems that can contribute to cracking. 

AIR VOID SYSTEM 

Use any or all of the following field tests to assess air void systems: 

• Foam index test (paste). 

• Foam drainage test (paste). 

• Air content (ASTM C 231) (concrete). 

• Air void analyzer (concrete). 

Monitor the results of these tests from batch to batch Changes in results as indicated below will 

indicate potential problems requiring more detailed laboratory tests, or change the cementitious 

system or procedures. 
15 

CHAPTER 5. INTERPRETING DATA 

CHEMISTRY 

The chemical reactions in cement hydration, and the interactions with other added materials, are 

extremely complex. The following recommendations are intended as guidelines on data that may 

indicate potential problems. Values outside these limits should act as early warnings that indicate 

the need for further assessment, and the results should not necessarily be taken as definitive. 

Portland Cement— The C3A content of a cement is not of direct concern; however, high C3A 

cements (>8 percent) are more likely prone to aluminate/sulfate imbalances. Likewise, it is not 

the total sulfate content that is of concern, but materials with low sulfate content (<3 percent) are 

more likely to be problematic. The form of the sulfate is important if the data on that 

characteristic are available. Approximately half of the sulfate should be in the form of gypsum 

(CaSO4·2H2O) and the remainder as plaster (CaSO4·1⁄2H2O). Greater amounts of plaster are likely 

to be problematic. This balance should be monitored between batches, and changes should warn 

of likely variations in the performance of the material. 

Cements with high alkali contents (>0.8 percent) are generally more reactive, and therefore, they 

may be more prone to unexpected or imbalanced reactions including greater risk of cracking and 

air void system problems. 

The finer the cement, the greater the risk of uncontrolled C3A reactions with other ingredients in 

the concrete. 

Supplementary Cementing Material—Increasing calcium contents will accelerate initial 

hydration but, if it is in the form of C3A (typically high-calcium fly ash), it can cause the 

system’s C3A /sulfate balance to be compromised, resulting in unexpected stiffening early in the 

hydration process. Materials containing more than 10 percent CaO should be reviewed. Any C3A 

detected indicates that the material should be evaluated with the intended cement. 

Increasing alkali contents will increase the reactivity of all supplementary cementing materials. 

Increasing LOI contents will increase the amount of air-entraining admixture required to achieve 

a given air content, and it also will increase the variability in this amount. LOI greater than 4 

percent may indicate potential problems. 

Supplementary cementing materials will change the propensity of a system to crack, sometimes 

for the better by reducing stiffness and heat generation at early ages, and sometimes for the 

worse by reducing strength at early ages. The overall effect of such materials is specific to the 

material, environment, and application. 

Chemical Admixtures—Some chemical admixtures will interfere with C3A hydration and the 

solubility of calcium and sulfate in the pore solution, and thus, it may significantly affect the 

workability of the concrete in the first few minutes. Tests have shown that some chemical 
16 

admixtures (particularly those containing TEA, lignin, and sugar) actually reduce slump when 

used with some cementitious combinations. 

As with supplementary cementing materials, chemical admixtures can modify the risk of 

cracking by modifying the setting time, shrinkage, strength development, and heat development 

of a mixture, sometimes beneficially and sometimes detrimentally. 

Air-entraining admixtures based on materials other than Vinsol® may require additional 

evaluation. 

STIFFENING (ASTM C 359) 

This test for stiffening is used to indicate if a system stiffens quickly and whether workability is 

recovered after remixing some time later. Either of these findings can be significant. A marked 

increase in mortar temperature indicates that uncontrolled C3A hydration is occurring, which 

may lead to flash set or rapid stiffening. 

TIME OF SETTING 

Initial set and final set in paste and concrete are defined as the times when a given penetration 

resistance is achieved as the mixtures hydrate. Initial set is associated with the beginning of the 

silicate reactions that give cementitious systems their hardness and strength. Final set is slightly 

more arbitrary, as defined in ASTM C 403, but it can be correlated loosely with the time when 

initial silicate reactions start to slow. 

Time of setting can be determined in several ways: 

• In paste, by using a vicat needle (ASTM C 191). 

• In concrete, by using a penetrometer (ASTM C 403). Initial set is when a pressure of 

3.5 megapascals (MPa) (500 pounds per square inch (psi)) is required to penetrate a 

plunger 1 inch into mortar sieved from the concrete. Final set is when a pressure of 

27.6 MPa (4,000 psi) is required to penetrate the mortar. 

• In examining the output of calorimetry or semiadiabatic temperature measurement 

tests, initial set corresponds reasonably with the time when the heat plot starts to rise 

at the end of the dormant period. Present test methods cannot determine final set. 

• Likewise, a plot of the output from an ultrasonic P-wave plot shows the initial set 

when the curve starts to rise and final set when the curve starts to flatten off. 

• Initial set can be observed in the output from a parallel-plate rheology test as the time 

when the torque that is required to shear the sample starts to increase. 

Changes between batches of materials of more than 60 min for initial set, determined using any 

of these test techniques, can indicate potential problems. 
17 

CALORIMETRY 

Following is a list of possible observations from a plot of heat versus time: 

• Time of setting when the heat starts to increase: changes of more than 60 min are 

significant. 

• Time of maximum heat generation: changes of more than 60 min are significant. 

• Maximum rate of heat generation (silicate peak): changes of more than 2.5 joules per 

gram per hour (J/g/h) (0.021 calories per ounce per hour) (cal/oz/h) are significant. 

• Movement of the sulfate depletion peak without a change in the sulfate content of the 

system indicates a potential problem. The presence of chemical admixtures can 

change the timing of the sulfate depletion peak. This is usually not a problem as long 

as the sulfate depletion peak occurs after the main alite hydration peak. 

MINISLUMP 

Comparison of the relative areas of paste mixture pats formed over time can provide useful 

information regarding the potential problems from C3A hydration or gypsum deposition. 

Changes in the concrete can be predicted by marked differences in the area of the pat made at 5 

min after mixing because of changing temperature, changes in material batches, types, sources, 

or changing proportions of materials. The smaller the pat, the greater the likelihood that the 

workability of the associated concrete will be reduced. A change of 20 percent in pat area 

between batches should be considered significant. 

An increase in pat area with increasing time is an indication of undesirable reactions occurring, 

probably because of gypsum deposition that results in a false set. If the ratio of pat area at 5 min 

over the 2-min pat area is 1.3 or greater, the system may be problematic. 

A marked reduction in pat area in the first 30 min may indicate excessive stiffening, probably 

because of insufficiently controlled C3A hydration. If the ratio of pat area at 5 min over the 30-

min pat area is 0.8 or less, the system may be problematic. 

RHEOLOGY 

Changes in setting times as recorded in the rheology plots can be used to interpret the output. 

Changes of more than 60 min between comparable points are significant. 

SLUMP LOSS 

Monitoring the slump of concrete over a period of time will provide a clear indication of the 

potential performance of the concrete. 

A slump loss of 50 millimeters (mm) (2 inches) or more during the first 60 min may be 

considered significant. 
18 

SEMIADIABATIC TEMPERATURE MEASUREMENT 

The output from a semiadiabatic temperature measurement test can be interpreted in much the 

same way as data from calorimetry can be. Changes in the setting time, the time and magnitude 

of the temperature peak, and an observation of any secondary peak, all can help indicate 

problems. 

Changes in timing from batch to batch of more than 30 min are significant, just as a change in 

peak temperature of more than 6 °C (10 °F) is significant, Development of a secondary peak 

often is associated with the presence of SCMs, and changes in the magnitude or position of such 

a peak should be considered an indication that something significant has changed in the concrete 

composition. 

RING TEST 

The ring test can be used to observe stress development in a system and indicate when cracking 

may occur. Guides for interpreting the results appear in ASTM C 1581. 

AIR CONTENT 

A change of 30 percent in the amount of air-entraining admixture required to achieve a given air 

content can indicate significant changes in the system. 

FOAM INDEX TEST 

A change in the amount of air-entraining admixture required to achieve a full coverage of foam 

of more than 30 percent from previous tests is considered significant and indicates a change in 

the properties of the materials in the system. 

FOAM DRAINAGE TEST 

The foam drainage test indicates the stability of a foam that has generated in a paste system. The 

test indicates clear differences between chemical admixtures and its effects in combination with 

supplementary cementing materials; however, the limited concrete test program did not exhibit 

the same sensitivity. A system that appears problematic in the laboratory test may still perform 

satisfactorily in the field; on the other hand, if the system performs well in the laboratory, 

problems in the field are unlikely. It should be noted that the foam drainage test may indicate a 

property—such as stability with continued handling—that was not investigated in the concrete 

tests. 

A value of 100 or less for the parameter –1/k (the output from the test method) may indicate a 

potential problem. A change of 300 or more between samples for –1/k also could indicate 

significant changes in the system. 
19 

AIR VOID CLUSTERING 

If a rating for observed clustering of 1 or greater is determined for a mixture, using the method 

described by Kozikowski, then a significant loss of compressive strength may be expected in the 

concrete.(1) 

AIR VOID ANALYZER 

The air void analyzer (AVA) is marketed as an instrument that provides data on the air void 

system in hardened concrete. Correlation with total air content is reportedly poor, but satisfactory 

correlation with spacing factor has been reported. The data collected in this project indicated 

poor correlation with either parameter. 

Field reports indicate that the system is sensitive to mounting stability, and that vibration of the 

platform (e.g., a trailer) can interfere with the output. Temperature also has been described as a 

critical control parameter. 

It is possible a system calibrated to a single mix can provide useful data on potential variability 

between batches. The intended application of this test is to determine the air void system in 

concrete that has been placed and compacted, without needing to wait for days for a hardened 

air-content analysis. 

Pass/fail limits could be based on the same values used in the hardened air content test, discussed 

in the next paragraphs. 

HARDENED AIR CONTENT 

Most authorities consider the following air void characteristics as representative of a system with 

adequate freeze-thaw resistance: 

• Calculated spacing factor (an index related to the distance between bubbles but not the actual 

average spacing in the system)—less than 0.2 mm (0.008 inch). 

• Specific surface, α, (surface area of the air voids)—24 mm2

/mm3 (600 in2/in3) of air void 

volume, or greater. 

21 

CHAPTER 6. TEST METHODS 

Table 2 lists the test methods referred to in the protocol flow charts presented in figures 2 and 3. 

Copies of nonstandard methods are included in appendix A for reference. 

Table 2. Protocol test methods. 

Test Method Comment 

Chemistry XRF – ASTM C 114 

XRD 

DSC 

Refer to manufacturers operating 

manuals. 

Conduction calorimetry – Measurement procedure is in 

development at ASTM. 

Rheology – *(A) 

Minislump – *(B) 

Time of setting—vicat ASTM C 191 – 

Time of setting—penetrometer ASTM C 403 – 

Ultrasonic P-wave – *(C) 

Semiadiabatic temperature 

measurement – *(D) 

Slump loss—concrete ASTM C 143 – 

Slump loss—mortar ASTM C 1437 – 

Ring test ASTM C 1581 – 

Foam index – *(E) 

Foam drainage – *(F) 

Hardened air content ASTM C 457 – 

Clustering – ** 

Air void analyzer – Refer to manufacturers operating 

manual. 

Stiffening (mortar) ASTM C 359 A revised version is in 

development at ASTM. 

* See letter-designated appendix. 

** See reference at end of report. 
22 

Figure 2. Protocol flow chart, preconstruction stage. 

Review Chemistry of Reactive Materials 

Cement: C3A and alkali content, fineness 

SCM: calcium and alkali content, LOI 

Chemical admixtures: composition 

Select Tests: 

• Setting time. • Temperature development. 

• Minislump/concrete slump loss. • Rheology. • Stiffening (ASTM C 359). 

Select Tests: 

• Setting time. • Strength development. • Ring test. • Temperature development. 

Sele

• Foam index. • Foam drainag• Air void analy• Hardened air. • Clustering. 

• Change fly ash (source, type or dosage). • Change chemical admixture (type or dosage). 

• Change batching sequence. • Change concrete temperature (e.g., through 

planning to work at night). 

• Use a set retarder. 

• Contact the cement supplier regarding the 

sulfate form in the system. 

Stiffening Cracking Air Vo

• Change supplementary cementitious material 

(type or source). 

• Change SCM proportions. • Use retarding/accelerating admixtures; dosage 

may have to be optimized. 

• Change concrete temperature. • Select a cement with a different chemistry. 

• Change air-entrai

dosage). 

• Change chemical 

formulation, or do

• Change batching • Refrain from add

mixing. 

• Change suppleme

material. 

• Change SCM dos

• Select a cement w

• Change concrete 

Vary the following to assess risks of problems and potential mitigating methods.

Potential Problems?

Provide guidelines on actions to take if temperature changes, materials change, or problems 
23 

Figure 3. Protocol flow chart, construction stage. 

NOTES: • Tests should be selected on the basis of what is available locally, the value of the project, and the risk or con

occurring. 

• Setting time may be monitored using any one of a number of techniques including vicat, penetrometer, calor

monitoring, and P-wave.

Monitor Chemistry of Reactive Materials 

Cement: C3A and alkali content, fineness 

SCM: calcium and alkali content, loss-on-ignition 

Chemical admixtures: composition 

Select Tests: 

• Slump loss. • Setting time. 

• Temperature development. 

Select Tests: 

• Hiperpav. • Temperature development. 

Sele

• Foam index. • Foam drainag• Air content. • AVA. 

Stiffening Cracking Air Vo

Significant changes noted or problems occur? 

Institute actions developed during preconstruction tests. 

If problems continue, refer back to the laboratory. 

25 

CHAPTER 7. EXAMPLE: PRECONSTRUCTION MATERIALS ANALYSIS 

Following is an example to illustrate the protocol steps that should be followed and the 

observations that are likely to be noted. The example starts out with the preconstruction analysis 

of cementitious materials shown in table 3. 

PRECONSTRUCTION 

Materials 

Table 3. Cementitious materials analysis. 

Mass Percentage Analyte Cement Fly Ash Combined (75/25)

SiO2 26.91 33.83 28.64 

Al2O3 6.46 17.99 9.34 

Fe2O3 1.86 6.08 2.92 

CaO 54.45 26.11 47.37 

MgO 5.67 6.12 5.78 

SO3 2.64 2.17 2.52 

Na2O 0.24 2.14 0.72 

K2O 0.49 0.39 0.47 

TiO2 0.33 1.46 0.61 

P2O5 0.23 1.33 0.51 

Mn2O3 0.23 0.03 0.18 

SrO 0.05 0.36 0.13 

Cr2O3 <.01 0.02 0.01 

ZnO 0.03 0.02 0.03 

L.O.I. (950 oC) 0.03 0.38 0.07 

Total 99.56 98.39 – 

Alkalies as Na2O 0.56 2.39 1.02 

C3S 57 – – 

C2S 15 – – 

C3A 7 18 9.75 

C4AF 12 – – 

Moisture – 0.09 – 

SiO2+Al2O3+Fe2O3 – 57.90 – 

Fineness, kg/m2 423 – – 

Fineness, % passing #325 sieve – 10.3 – 

• Fly ash dosage: 25 percent. 

• Water reducing admixture: unknown composition. 

• Air entraining admixtures: Vinsol. 

• Environment: maximum temperature = 32 °C (90 °F). 
26 

Interpretation 

• C3A of system = 9.75%, combined with sulfate content of system = 2.52% and alkali content 

of system = 1.02%, indicates a risk of stiffening and cracking problems. 

• Sulfate form is unknown. 

• Unknown admixture type is a concern. 

Therefore, evaluate mixtures for performance for stiffening and cracking. 

Tests 

Tests on the original mix design at 32 °C (90 °F) indicated the following: 

• ASTM C 359: indicated severe flash set problems. 

• Calorimetry and temperature monitoring showed large initial heat generation, 

followed by no silicate hydration for 48 hours. 

• Slump went from 50 mm to 0 mm (2 inch to 0 inch) in first 5 min. 

• System did not set until 3 days after mixing. 

• Ring test indicated high risk of cracking. 

This system is at high risk of exhibiting problems in the field. Solutions include changing 

chemical admixtures and reducing the fly ash content to 10 percent. 

Revised interpretation: 

• C3A of system = 8.1, sulfate content of system = 2.59 percent, and alkali content of system = 

0.74 percent, indicates reduced risk of stiffening and cracking problems. 

• Lignin-based admixture substituted. 

Tests on the revised mix design at 32 °C (90 °F) indicated the following: 

• ASTM C 359: clear. 

• Calorimetry and temperature monitoring showed normal trends. 

• Slump went from 50 mm to 25 mm (2 in to 1 in) in first 30 min. 

• Concrete system set at 5 hours and 45 min. 

• Ring test indicated moderate risk of cracking. 

Recommendations 

The original mix may be acceptable at moderate temperatures, but above 29 °C (84 °F) the 

revised mix proportions should be used. 

DURING CONSTRUCTION 

It was noted on control charts that the CaO content of the fly ash increased from 47 percent to 55 

percent. Analysis of the C3A content of the fly ash was not available, but knowing that increasing 
27 

CaO is often associated with increasing C3A, it was decided to institute the modified asset of mix 

proportions immediately even though the temperature was at 27 °C (81 °F). 

No stiffening issues were noted on site. The amount of cracking was observed to decrease with 

the modified mix.

29 

ACKNOWLEDGEMENTS 

The authors wish to acknowledge the work of the following people in completing the work 

described in this report: 

From the CLT Group: 

Katie Amelio 

Pat Berry 

Barb Betke 

Javed Bhatty 

Fred Blaul 

Phil Brindisi 

Roberto Celestin 

Luis Duval 

Ken MacLeod 

Greg Miller 

Mohamad Nagi 

Agata Pyc 

Brian Szczerowski 

Shiraz Tayabji 

From Braun Intertec: 

Rachel Detwiler 

From NIST: 

Max Peltz 

John Winpigler 

DISCLAIMER 

Commercial equipment, instruments, and materials mentioned in this paper are identified to 

foster understanding. Such identification does not imply recommendation or endorsement by the 

authors or NIST, nor does it imply that the materials or equipment identified are necessarily the 

best available for the purpose. 

MATCHING FUNDS 

CTLGroup was required to provide a minimum of a 20 percent match of the Federal funding 

toward the project. The matching funds were obtained by reaching agreement with the Portland 

Cement Association. No specific task was solely funded by PCA, but rather, a proportion of 

every payment due through the duration of the project was invoiced to PCA. PCA’s total 

contribution was $110,000 of the total estimated project cost of $451,245. 

31 

APPENDIX A: DRAFT STANDARD TEST METHOD FOR MEASUREMENT OF 

CEMENT PASTE SETTING TIME USING A PARALLEL PLATE RHEOMETER 
32 

Draft Standard Test Method for 

Measurement of Cement Paste Setting Time Using a Parallel 

Plate Rheometer 

______________________________________________________________________________ 

1. SCOPE 

1.1 This test method covers the determination of cement paste yield stress using a parallel 

plate rheometer. It is intended for use in monitoring setting time of cement paste. 

1.2 The values stated in SI units are to be regarded as the standard. 

1.3 This standard does not purport to address all of the safety problems, if any, associated 

with its use. It is the responsibility of the user of this standard to establish appropriate 

safety and health practices and determine the applicability of regulatory limitations prior 

to use. 

______________________________________________________________________________ 

2. REFERENCED DOCUMENTS 

______________________________________________________________________________ 

3. SUMMARY OF TEST METHOD 

3.1 This test method uses the stress growth procedure. The cement paste is sheared at a very 

low shear rate (the lowest possible with the rheometer used) and the shear stress is 

measured. The shear stress increases linearly with time until the yield stress is reached. 

At that point, the shear stress reaches a peak, and then it decreases. The linear portion is 

caused by the elastic response of the viscoelastic material. After the yield stress is 

reached, the material flows, and the reduction in shear stress is measured. The plot of the 

yield stress versus the time will gradually increase until initial setting is reached. After 

initial setting is reached, the shear stress will increase very fast until the rheometer can no 

longer measure flow because the shear stress is too high. . 
33 

______________________________________________________________________________ 

4. SIGNIFICANCE AND USE 

4.1. To determine early stiffening of cement paste resulting from incompatibility between the 

various constituents such as supplementary cementitious materials, chemical admixtures, 

and the cement, it is important to monitor and track changes in the setting times of the 

cement paste. 

4.2. The standard test to measure the evolution of setting time uses a vicat needle, but this 

method provides measurement of only initial set and final set. It does not monitor the 

evolution of setting before the initial set. This method based on the measurement of 

rheological properties allows the monitoring of the evolution before initial set. Two 

parameters can be measured before initial set: the initial yield stress and the slope of the 

yield stress versus time. It is possible that a higher initial yield stress and a higher slope 

could lead to a low workable mixture. 

4.3. The vicat needle initial setting time corresponds to the point in the stress versus time 

curve where the cement paste yield stress starts to increase more rapidly until final set. 

______________________________________________________________________________ 

5. INTERFERENCES 

5.1 Slippage—If the water/cement ratio selected is too high, and sedimentation/bleeding 

occurs during the measurements, the shear stress measured would be artificially low, 

which can be detected by observing the cement paste left in the vacuum bottle for 

bleeding or performing a bleeding test using a small graduate cylinder filled with cement 

paste and covered with plastic. 

______________________________________________________________________________ 

6. APPARATUS 

6.1 Blender—A blade mixer with a 1 L (.3 gallon (gal)) capacity that is connected to a speed 

controller and a temperature controlled water bath. 
34 

6.2 Speed Controller—A device capable of maintaining blade speed at a preset rate. 

6.3 Water bath—A controlled-temperature bath capable of maintaining a desired 

temperature. 

6.4 Rheometer—A parallel-plate rheometer has a 35 mm diameter with two serrated test 

plates, which are separated by a gap of 1mm (0.04 inch). 

6.5 Syringe—A disposable syringe without a needle used for measuring 2 mL (0.07 fluid 

ounce (fl oz)) of cement paste. 

6.6 Vacuum Bottle—A hermetically sealed vacuum stainless steel bottle for storing cement 

paste between measurements. 

6.7 Blender Vane—A system capable of mixing the cement paste directly into the vacuum 

bottle. 

6.8 Balance—A device used to measure materials for the mixture. 

______________________________________________________________________________ 

7. REAGENTS, MATERIALS 

7.1 Cement—Tested cement. 

7.2 Cementitious Materials—Tested materials in the cement paste. 

7.3 Water—An ingredient required for making cement paste with specified water-to-cement 

ratios. 
35 

_____________________________________________________________________________ 

8. TEST SPECIMENS 

8.1 Single test specimen for use in this test should consist of 2 mL (.07 fl oz) of fresh cement 

paste per rheometer measurement. To obtain a uniform cement paste mixture, about 300 

grams (g) (10.6 ounces (oz)) of dry material (cement and supplementary cementitious 

materials) should be used in the blender. (Mixing procedure described in section 8.3). 

8.2 Cement paste for this test should be prepared as cement (cementitious) and water mix 

with desired water-cement ratios. 

8.3 Mixing procedure for cement paste should be the following: 

• Add water to mixer. 

• Set the blade speed at about 419 radians per second (rad/s) (4,000 revolutions per 

minute (rpm)). 

• Introduce cement into the mixer in a 30 s period. 

• Increase the blade speed to 1,047 rad/s (10,000 rpm) and mix for 30 s. 

• Stop the mixer and scrape the walls. 

• After 2.5 min, turn the mixer on for 30 s at the speed of 1,047 rad/s (10,000 rpm). 

• Measure the temperature of cement paste. 

8.4 Remove the cement paste and place it in the vacuum bottle. 

______________________________________________________________________________ 

9. CONDITIONING 

9.1 Between measurements, store tested cement paste in a hermetically sealed vacuum bottle. 

9.2 Before testing the remaining cement paste in the storage jar, use the blender to remix the 

cement paste for 10 s. 
36 

_____________________________________________________________________________ 

10. PROCEDURE 

10.1 Using a disposable syringe, transfer 2 mL (0.07 fl oz) of fresh cement paste to the lower 

plate of the rheometer. 

10.2 Record the shear stress versus time for 5 min at constant shear rate. 

Note 1—Select the minimum shear rate possible with the rheometer in use; shear rate ≤

0.01 s-1 is recommended. 

Note 2—Shorter measurement time is possible in most cases; usually 3 min are 

sufficient. 

10.3 Clean the rheometer and prepare it for the next measurement. 

10.4 Just before the next measurement, use the blender to remix the remaining cement paste in 

the vacuum bottle and repeat from section 10.1. 

______________________________________________________________________________ 

11. CALCULATION AND INTERPRETATION OF RESULTS 

11.1 The shear stress increases linearly with time until the yield stress is reached (figure 1). At 

that point, the shear stress reaches a peak and then decreases. The shear stress at point B 

(figure 1) is taken as the yield stress at the time the measurement was made. 

11.2 For each time measurement, record the yield stress and plot it versus time. 

Note 3—It is recommended a measurement be taken every 15 to 20 min for at least the 

first 2 to 4 h. 

11.3 Interpretation of the measurements: The plot of yield stress versus the time gradually 

increases until initial setting is reached. After initial setting is reached, the shear stress 

increases very fast, lasting until the rheometer can no longer measure flow because the 

shear stress is too high. 
37 

_____________________________________________________________________________ 

12. REPORT 

12.1 Reporting includes (1) cement paste proportion and water-cement (cementitious) ratio as 

determined in section 8.2, and (2) initial setting times for tested cement mixes obtained 

from plots as described in section 11.3. 

12.2 Optional information could also report the initial yield stress as determined in section 

11.3 and the initial slope before setting time. 

______________________________________________________________________________ 

13. PRECISION AND BIAS 

13.1 The precision of initial setting time by this method depends on the number of data points 

that are available around the initial set data point. 

13.2 Bias could be determined as comparison with the vicat needle measurements because it is 

the only other test for determining setting time. The error is about 30 min between the two 

methods. 

______________________________________________________________________________ 

14. KEYWORDS 

Rheology, cement paste, initial setting 

______________________________________________________________________________ 

15. REFERENCES 

R.A. Helmuth, L.M. Hills, D.A. Whitting, S. Bhattacharja, “Abnormal Concrete Performance in 

Presence of Admixtures.” PCA serial number 2006. 1995. 

C.F. Ferraris, “Measurements of the Rheological Properties of Cement Paste: A New Approach.” 

Conference on Role of Admixtures in High Performance Concrete sponsored by 
38 

Cementos Mexicanos, S.A. (CEMEX), March 21–26, 1999. Monterey, Mexico. Rilem 

Publications S.A.R.L.. Cabrera, J.G., Rivera-Villarreal, R.R., Editors, pp. 333–342, 1999. 

C.F. Ferraris, J.M. Gaidis, “The Connection Between the Rheology of Concrete and the 

Rheology of Cement Paste.” ACI Materials Journal, 88(4). pp. 388–393. 1992. 
39 

APPENDIX B: DRAFT STANDARD TEST METHOD FOR MEASUREMENT OF 

CEMENT PASTE INTERACTIONS USING A MINISLUMP CONE 
40 

Draft Standard Test Method for 

Measurement of Cement Paste Interactions Using a 

Minislump Cone 

______________________________________________________________________________ 

1. SCOPE 

1.1 This test method is used to assess the risk of flash or false set in a cementitious paste. 

1.2 The values stated in SI units are to be regarded as the standard. 

1.3 This standard does not purport to address all of the safety problems, if any, associated 

with its use. It is the responsibility of the user of this standard to establish appropriate 

safety and health practices and determine the applicability of regulatory limitations prior 

to use. 

______________________________________________________________________________ 

2. REFERENCED DOCUMENTS 

______________________________________________________________________________ 

3. SUMMARY OF TEST METHOD 

3.1 This method consists of monitoring the change in workability of cement paste over time. 

Workability is assessed by observing the size of the pat formed when a slump test is 

conducted using a scaled-down cone-shaped mold. Samples are tested at intervals 

between 2 and 60 min after mixing. 
41 

______________________________________________________________________________ 

4. SIGNIFICANCE AND USE 

4.1 The data are used to assess whether undesirable reactions are occurring in the system, 

which could indicate unexpected stiffening of concrete made with the same materials 

tested. 

______________________________________________________________________________ 

5. INTERFERENCES 

5.1 The size of slump-cone pats is influenced by the mixing effort applied to the system; 

therefore, data should be compared between laboratories only if both are using similar 

mixers. 

5.2 Temperature of the mixture influences its workability and also the results of this test. 

5.3 The speed at which the slump cone is lifted may influence the results. 

______________________________________________________________________________ 

6. APPARATUS 

6.1 A blade mixer with vibrating filler chute. 

6.2 Water temperature controller. 

6.3 Scale reporting to 0.1g with a minimum capacity of 500 g. 

6.4 Dropper graduated to 0.01 mL. 
42 

6.5 Minislump cone, 60-mm high, 20-mm top diameter, 40-mm bottom diameter. 

6.6 Scraper. 

6.7 Tamper as specified in ASTM C 109. 

6.8 Acrylic sheet at least 3 mm thick. 

6.9 Vernier calipers. 

______________________________________________________________________________ 

7. REAGENTS, MATERIALS 

7.1 Potable water. 

______________________________________________________________________________ 

8. TEST SPECIMENS 

8.1 The matrix of materials and mix proportions depends on the purpose of the test program. 

To evaluate field mixtures, use materials and proportions based on the concrete mix 

design. 

8.2 Vary the water to cementitious materials (w/cm) ratio, temperature, SCM, and chemical 

admixture selections and dosages and sequence of additions of admixtures. Varying these 

factors helps in the observation of the effects of these changes on the performance of the 

mixture. 
43 

______________________________________________________________________________ 

9. CONDITIONING 

9.1 Allow materials to stabilize at the test temperature before testing. 

______________________________________________________________________________ 

10. PROCEDURE 

10.1 Attach mixing bowl to water conditioning unit for 30 min to reach equilibrium 

temperatures. 

10.2 Weigh out cementitious materials (approximately 600 g is sufficient for a typical mix) 

and water to achieve the required w/cm. 

10.3 Measure out appropriate amount of chemical admixtures. If dosages are very low, then 

dilute the admixtures and allow for the extra water in the total water measurement. 

10.4 Pour dry materials into mixing bowl, and start mixer. 

10.5 Add water and start timer. 

10.6 Mix for 30 s and switch off mixer until 1 min 30 s on the timer. 

10.7 Restart mixer and mix for 30 s. 

10.8 Use spoon to place paste into mold on acrylic sheet in a single layer. Compact with 

tamper for 15 blows. 
44 

10.9 Lift mold quickly. 

10.10 Measure and record diameter of pat in mm across two perpendicular axes. 

10.11 Repeat steps 10.7 through 10.10 so that mold is lifted at 5, 10, and 30 mins, or at other 

intervals as necessary. Remixing may be omitted if the mixture for modeling will be 

transported in nonagitating equipment,. 

______________________________________________________________________________ 

11. CALCULATION AND INTERPRETATION OF RESULTS 

11.1 Calculate areas of pats at the measured time intervals using the following equation: 

Area = (average diameter)2 * π/4 

11.2 Calculate false set index, FSI, using the following equation: 

FSI = Area at 5 min/Area at 2 min 

11.3 Calculate stiffening index using the following equation: 

Stiffening Index = Area at 30 min/Area at 5 min 

11.4 If FSI is greater than 1.3, then the mix likely will exhibit false setting tendencies. 

11.5 If SI is less than 0.85, the mix is likely to stiffen unacceptably quickly. 

11.6 If average pat area is less than 15,000 mm2

, the mix is likely to be stiff and unworkable. 
45 

______________________________________________________________________________ 

12. REPORT 

Report the following factors: 

12.1 Materials details and proportions. 

12.2 Test temperature. 

12.3 Pat areas at times tested. 

12.4 False set index and stiffening index. 

______________________________________________________________________________ 

13. PRECISION AND BIAS 

13.1 Precision and bias have not been determined for this test. 

______________________________________________________________________________ 

14. KEYWORDS 

Paste, minislump, incompatibility, false set, flash set 
46 

______________________________________________________________________________ 

15. REFERENCE 

S. Bhattacharja and F.J. Tang. “Rheology of Cement Paste in Concrete With Different Mix 

Designs and Interlaboratory Evaluation of the Mini-Slump Cone Test.” PCA R&D Serial 

No. 2412, Portland Cement Association, Skokie, Illinois, 2000. 
47 

APPENDIX C: DRAFT STANDARD TEST METHOD FOR MEASUREMENT OF TIME 

OF SET OF CONCRETE USING WAVE VELOCITY METHOD 
48 

Draft Standard Test Method for 

Measurement of Time of Set of Concrete Using Ultrasonic 

Pulse-Wave Velocity Method 

______________________________________________________________________________ 

1. SCOPE 

1.1 This testing method covers the determination of initial and final setting times for fresh 

concrete by use of ultrasonic pulse-wave velocity. This nondestructive test is designed 

for use in either the field or laboratory. 

1.2 The values stated in SI units are to be regarded as the standard. 

1.3 This standard does not purport to address all of the safety problems, if any, associated 

with its use. It is the responsibility of the user of this standard to establish appropriate 

safety and health practices and determine the applicability of regulatory limitations prior 

to use.

2. REFERENCED DOCUMENTS 

2.1 AASHTO Standards

 T 119 Slump of Hydraulic Cement Concrete 

 T 141 Sampling Freshly Mixed Concrete 

 T 152 Air Content of Freshly Mixed Concrete by the Pressure Method 

 T 196 Air Content of Freshly Mixed Concrete by the Volumetric Method 

 T 197 Time of Setting of Concrete Mixtures by Penetration Resistance 

2.2 ASTM Standards

C 670 Practice for Preparing Precision and Bias Statements for Test Methods of 

Construction Materials 
49 

E 1 Specification for ASTM Thermometers 

C 403 Time of Setting of Concrete Mixtures by Penetration Resistance 

C 597 Standard Test Method for Pulse Velocity Through Concrete 

______________________________________________________________________________ 

3. SUMMARY OF TEST METHOD 

3.1 This testing method uses ultrasonic pulse-wave velocity (UPV) transmitted through fresh 

concrete specimens to determine the initial time of set. Fresh concrete is consolidated in 

an acrylic mold and stored at a specified curing temperature. Ultrasonic transducers are 

bolted on each side of the mold, and then connected to a pulse velocity transit time 

recorder. At regular intervals, the time taken for a pulse to travel through the concrete 

specimen (ultrasonic pulse-wave velocity transit time) is recorded automatically. The 

recorded time is used to calculate the ultrasonic pulse velocity. Plot of change in pulse 

velocity as a function of the elapsed time is obtained. The data is used to determine the 

initial setting time of concrete. 

______________________________________________________________________________ 

4. SIGNIFICANCE AND USE 

4.1 The ultrasonic pulse-wave velocity method directly determines the initial setting time of 

fresh concrete. This nondestructive, simple, and reproducible testing method that can be 

used in both the field and laboratory. 

4.2 The time of setting is evaluated by monitoring the change in the rate of pulse velocity of 

concrete from the time of placement up to the final setting stage. 

______________________________________________________________________________ 

5. INTERFERENCES 

_____________________________________________________________________________ 
50 

6. APPARATUS 

6.1 A rigid, securely tightened, leakproof acrylic mold that measures 150 mm by 150 mm by 

300 mm. 

6.2 Mold fastening system of 2 steel rods and 4 nuts used to clamp mold together. 

6.3 Ultrasonic pulse velocity transit time recorder that is capable of automatic digital 

recording and storing in memory data on pulse velocity transit. 

6.4 P-wave transmitter and receiver transducers. 

6.5 Ultrasonic couplant. 

6.6 Computer software to transfer data from pulse velocity transit time recorder to a 

computer central processing unit (CPU). 

6.7 Round, straight, steel tamping rod with a rounded hemispherical tip. 

6.8 Vibrating table for concrete consolidation. 

6.9 Thermometer capable of measuring fresh concrete temperature to ± 0.5 oC (±1 oF). 

______________________________________________________________________________ 

7. REAGENTS, MATERIALS 

7.1 Cement, aggregates, admixtures, mineral admixtures, water. 
51 

_____________________________________________________________________________ 

8. TEST SPECIMENS 

8.1 For field tests, make a minimum of two specimens from each concrete batch. 

8.2 For laboratory tests, make two specimens from each concrete batch. More specimens may 

be needed, depending on the purpose of the test. 

8.3 Obtain a representative sample of the fresh concrete in accordance with AASHTO T141. 

Determine and record the slump and air content of the fresh concrete. 

______________________________________________________________________________ 

9. CONDITIONING 

9.1 The entire testing set up is to be placed in the test environment 24 hours before the test. 

9.2 Samples should be protected from drying by covering with suitable material such as a 

water impermeable sheet for the duration of the test. 

______________________________________________________________________________ 

10. PROCEDURE 

10.1 Prepare an acrylic 150 mm by 150 mm by 300 mm mold. 

10.2 Set the pulse velocity transit time recorder at a specified recording time interval (5 min is 

adequate). 

10.3 Record time when water is added to the mix. 

10.4 Place fresh concrete in the prepared mold. 
52 

10.5 Consolidate concrete mix by using a vibration table or by tamping. 

10.6 Place the test specimen in the desired curing environment within 30 min of initial mixing. 

10.7 Bolt the ultrasonic transducers on each end of the mold. Apply ultrasonic couplant 

between the transducers and the plastic mold to assure good wave transmission. 

10.8 Connect the ultrasonic transducers to the pulse velocity transit time recorder. 

10.9 Fasten the ultrasonic transducers with two steel rods and four bolts to assure constant 

pressure between the ultrasonic transducers and the acrylic mold. 

10.10 Start automatically recording the pulse velocity transit time. Continue monitoring as long 

as required. 

______________________________________________________________________________ 

11. CALCULATION AND INTERPRETATION OF RESULTS 

11.1 Transfer pulse velocity transit time data to CPU using appropriate software. 

11.2 Enter the time difference between the test starting time and the time at which initial 

contact was made between cement and mixing water. 

11.3 Calculate the ultrasonic pulse velocity by dividing the distance separating the transducer 

transmitter and receiver by the ultrasonic pulse velocity transit time, as shown in the 

following equation: 

 Ultrasonic pulse velocity = Distance between sensors/transit time 

11.4 For the test sample, prepare ultrasonic pulse velocity versus time plots. 

11.5 For each plot, determine the times of initial setting as the time corresponding to the first 

inflection in the plot. 

11.6 Record the setting time in hours and minutes. 
53 

______________________________________________________________________________ 

12. REPORT 

Report the following information: 

12.1 Details of the materials used. 

12.2 Mixture proportions. 

12.3 Mixing and curing environments. 

12.4 Plots of ultrasonic pulse velocity versus elapsed time for each time of setting test. 

12.5 Time of initial setting for each test. 

12.6 Average times of initial and final setting for each test condition. 

______________________________________________________________________________ 

13. PRECISION AND BIAS 

No precision or bias has been determined for this test. 

______________________________________________________________________________ 

14. KEYWORDS 

Setting times, ultrasonic pulse velocity (UPV) method, concrete, nondestructive testing, p-wave
54 

______________________________________________________________________________ 

15. REFERENCES 
55 

APPENDIX D: DRAFT STANDARD TEST METHOD FOR SEMIABIDIATIC 

TEMPERATURE MEASUREMENT 
56 

Draft Standard Test Method for 

Semiadiabatic Temperature Measurement 

______________________________________________________________________________ 

1. SCOPE 

1.1 This test method covers the monitoring of temperature changes of fresh concrete. It is 

intended for use in monitoring setting time and hydration characteristics of concrete 

mixtures. 

1.2 The values stated in SI units are to be regarded as the standard. 

1.3 This standard does not purport to address all of the safety problems, if any, associated 

with its use. It is the responsibility of the user of this standard to establish appropriate 

safety and health practices and determine the applicability of regulatory limitations prior 

to use.

______________________________________________________________________________ 

2. REFERENCED DOCUMENTS 

______________________________________________________________________________ 

3. SUMMARY OF TEST METHOD 

3.1 This test method monitors the change in temperature of the mortar or concrete over time. 
57 

______________________________________________________________________________ 

4. SIGNIFICANCE AND USE 

4.1 The output from a semiadiabatic temperature measurement test can be used to determine 

setting time of a mixture, as well as to observe hydration characteristics of a given 

system. 

4.2 Changes in the timing or magnitude of temperature increase indicate changes in the 

hydration of a cementitious system, possibly resulting from changes in the chemistry of 

the system or changes in the environment. 

4.3 The test can be used to identify some potential incompatibilities that may occur in 

cementitious systems. 

4.4 Samples tested may be purpose-made mortars prepared in the laboratory, or mortar field 

samples sieved from concrete at a construction site. 

______________________________________________________________________________ 

5. INTERFERENCES 

______________________________________________________________________________ 

6. APPARATUS 

6.1 Type T thermocouples. 

6.2 Data logger with multiple data channels. 

6.3 Computer software to record temperature readings over time. 

6.4 Cylinder molds or disposable foam cups. 
58 

6.5 Insulating container such as Dewar flasks or a special insulated container shaped to hold 

the cylinder molds. 

6.6 Number 4 sieve. 

______________________________________________________________________________ 

7. REAGENTS, MATERIALS 

7.1 Dry sand for reference sample. 

_____________________________________________________________________________ 

8. TEST SPECIMENS 

8.1 The selection of materials and mix proportions depends on the purpose of the experiment. 

Normally, a suite of tests with various admixtures and SCM dosages are used to 

determine their effects in a given mixture. Tests also can be conducted over a range of 

ambient temperatures to assess the sensitivity of the system to temperature. Field tests 

use proportions based on the concrete design mix to determine if the materials vary 

significantly or if the mixture is at risk of unexpected stiffening and setting behavior. 

8.2 Prepare a control specimen using sand in one of the test containers with the same volume 

as the mortar specimens to be tested. 

8.3 Prepare a mortar sample, either by mixing in a laboratory, or by sieving from a concrete 

mixture using the number 4 sieve. (Note: concrete mixtures can be tested without sieving, 

but larger specimens are required, and the sensitivity of the method decreases). 
59 

______________________________________________________________________________ 

9. CONDITIONING 

9.1 None. 

___________________________________________________________________________ 

10. PROCEDURE 

10.1 Place and compact mortar into the test containers. 

10.2 Place containers into the insulating system within 30 min of mixing. 

10.3 While the temperature of the samples is being recorded, thermocouples attached to 

containers or placed into the mortar should be used to minimize influence of the 

environment. 

10.4 Attach thermocouples to data logger and start collecting temperature readings. 

Frequency and duration of readings depend on the mixture and the application; generally, 

one reading per min is adequate. 

______________________________________________________________________________ 

11. CALCULATION AND INTERPRETATION OF RESULTS 

 

11.1 Subtract temperature recorded for sand sample (reference) from temperatures recorded 

for cement paste or mortar samples (test). 

11.2 Prepare temperature change versus time graphs for cement or mortar samples (test). 
60 

______________________________________________________________________________ 

12. REPORT 

12.1 Items to include in the report are (1) cement paste proportion and water-to-cement 

(cementitious) ratio, (2) temperature versus time graphs for every tested cement paste or 

mortar sample obtained, (3) first and second temperature peaks. 

______________________________________________________________________________ 

13. PRECISION AND BIAS 

13.1 Precision and bias have not been determined for this test. 

______________________________________________________________________________ 

14. KEYWORDS 

Semiadiabatic temperature measurement, cement paste, mortar, set time, calorimetry 

______________________________________________________________________________ 

15. REFERENCE 

 T. Cost and G. Knight, A Study of the Factors Influencing Incompatibility of Common Concrete 

Materials. [DRAFT.] 2005. 
61 

APPENDIX E: DRAFT STANDARD TEST METHOD FOR DETERMINING FOAM 

INDEX OF CEMENTITIOUS PASTE MIXURES 
62 

Drat Standard Test Method for 

Determining Foam Index of Cementitious Paste 

Mixtures 

______________________________________________________________________________ 

1. SCOPE 

1.1 This test method evaluates the amount of air-entraining agent required by an SCM in 

concrete. 

1.2 The values stated in SI units are to be regarded as the standard. 

1.3 This standard does not purport to address all of the safety problems, if any, associated 

with its use. It is the responsibility of the user of this standard to establish appropriate 

safety and health practices and determine the applicability of regulatory limitations prior 

to use. 

______________________________________________________________________________ 

2. REFERENCED DOCUMENTS 

______________________________________________________________________________ 

3. SUMMARY OF TEST METHOD 

3.1 This method consists of determining the amount of air-entraining admixture required to 

make stable foam for a given set of cementitious materials. A known amount of air 

entraining admixture is added to a cement, SCM, and water mixture and vigorously 

shaken. The foam produced by the system is evaluated for its stability over the next 45 s. 

The amount of air-entraining admixture is adjusted until the minimum amount required to 

make a stable foam is determined. 
63 

______________________________________________________________________________ 

4. SIGNIFICANCE AND USE 

4.1 This testing method is used to estimate the effect of supplementary cementitious 

materials on the amount of air-entraining admixture required to entrain adequate air 

content in concrete. 

4.2 This test can also be used to monitor variability of a supplementary cementitious material 

between batches or lots. 

______________________________________________________________________________ 

5. INTERFERENCES 

5.1 Changing test temperature may change the determined foam index. 

______________________________________________________________________________ 

6. APPARATUS 

6.1 Scale reading in 0.1 g increments with a minimum capacity of 50 g. 

6.2 Dropper graduated in 0.01 mL increments. 

6.3 Mixing bowl suitable for hand mixing 500 mL of powder. 

6.4 Spatula or spoon for mixing powder. 
64 

6.5 500-mL widemouthed jar with lid. 

6.6 Stop watch.

______________________________________________________________________________ 

7. REAGENTS, MATERIALS 

7.1 Potable water. 

_____________________________________________________________________________ 

8. TEST SPECIMENS 

8.1 Cement. 

8.2 Air entraining admixture. 

8.3 Supplementary cementitious material. 

______________________________________________________________________________ 

9. CONDITIONING 

9.1 Allow materials to stabilize to the test environment before testing. 
65 

______________________________________________________________________________ 

10. PROCEDURE 

10.1 Place 50 mL of water in a 500 mL widemouthed jar. 

10.2 For a control mixture, use 20 g of cement only. For test mixtures use 16 g of cement and 

4 g of supplementary cementitious material, and then hand blend them in the bowl. 

10.3 Pour the dry blend into the water in the jar. 

10.4 Cap the jar and shake vigorously for 15 s. 

10.5 Measure a quantity of air-entraining admixture using the dropper, and then add to the jar. 

10.6 Add water and start timer. 

10.7 Shake the jar for an additional 15 s. 

10.8 Place the jar in an upright position for 45 s and remove the cap. 

10.9 Observe the stability of the foam. A stable foam may be defined as the state where 

bubbles exist as continuous foam over the entire surface of the suspension in the jar. An 

unstable state is recognized by discontinuities in the foam. 

10.10 Repeat sections 10.1 through 10.9 with other dosages of air-entrained admixture and 

determine the minimum amount of air-entrained admixture required to produce a stable 

foam. 
66 

______________________________________________________________________________ 

11. CALCULATION AND INTERPRETATION OF RESULTS 

11.1 Calculate the foam index as a percentage using the following equation: 

Foam Index = 100 (amount of AEA required for test mixture) 

/(amount of AEA required for control mixture) 

11.2 A foam index greater than 100 percent indicates that more air-entraining admixture will 

be required to produce the same amount of entrained air in a concrete mixture using the 

tested supplementary cementitious material than in a similar mixture that does not contain 

the SCM. 

11.3 A change of foam index of more than 50 percent between tests of an SCM indicates a 

likely significant change in composition of the SCM. 

______________________________________________________________________________ 

12. REPORT 

Report the following information: 

12.1 Date and time of test. 

12.2 Source of materials. 

12.3 Foam index to a whole percentage point. 

______________________________________________________________________________ 

13. PRECISION AND BIAS 

13.1 Precision and bias have not been determined for this test. 
67 

______________________________________________________________________________ 

14. KEYWORDS 

Fly ash, supplementary cementitious material, air-entraining admixture, foam stability, air void 

system 

______________________________________________________________________________ 

15. REFERENCES 

V. Dodson. “Foam Index Test.” Presentation at the Transportation Research Board, Washington, 

D.C., January 1980. 

S. H. Gebler and P .Klieger. “Effect of Fly Ash on the Air-Void Stability of Concrete,” Portland 

Cement Association, Skokie, IL. Research and Development Bulletin, RD 085, 1983. 

R. Meininger, “Use of Fly Ash in Concrete—Report of Recent NSGA-NRMCA Research 

Laboratory Studies.” Presentation at NRMCA Quality Control Conference, St. Louis, 

MO. July 1980. 

69 

APPENDIX F: DRAFT STANDARD TEST METHOD FOR FOAM DRAINAGE 

ANALYSIS METHOD 
70 

Draft Standard Test Method for 

Foam Drainage Analysis Method 

______________________________________________________________________________ 

1. SCOPE 

1.1 This test method evaluates the performance of air-entraining admixtures before their 

application in concrete, determined in terms of the stability of the air-entraining system 

resulting from use in cementitious systems. 

1.2 The values stated in SI units are to be regarded as the standard. 

1.3 This standard does not purport to address all of the safety problems, if any, associated 

with its use. It is the responsibility of the user of this standard to establish appropriate 

safety and health practices and determine the applicability of regulatory limitations prior 

to use. 

______________________________________________________________________________ 

2. REFERENCED DOCUMENTS 

______________________________________________________________________________ 

3. SUMMARY OF TEST METHOD 

3.1 This method consists of recording the rate of decay of a foam system containing an airentraining admixture. Mixtures are prepared with the air-entraining admixture alone, 

mixed with cement, and, if required, mixed with other chemical admixtures and 

supplementary cementitious materials. Typically 300 mL of fluid (water and chemical 

admixtures) is blended with 10 mL air-entraining admixture and, if used, 5 g cementitious 

material for 10 s in a kitchen blender. The resulting foam is poured into a 1,000-mL 

graduated cylinder, and the level of the foam/water interface is recorded as a function of 

time. Data are collected for 1 h. 
71 

______________________________________________________________________________ 

4. SIGNIFICANCE AND USE 

4.1 The test identifies the stability air void systems made using a given air-entraining 

admixture. A stable foam will decay more slowly and retain more water than an unstable 

foam in the test. A stable foam is less likely to exhibit change in the air void system of 

concrete as it is transported and handled in the field. 

______________________________________________________________________________ 

5. INTERFERENCES 

5.1 Temperature of the mixture will influence the results collected from this method. 

______________________________________________________________________________ 

6. APPARATUS 

6.1 Kitchen blender. 

6.2 10 mL graduated measuring cylinder. 

6.3 100 mL graduated measuring cylinder. 

6.4 500 mL graduated measuring cylinder. 

6.5 1,000 mL graduated measuring cylinder. 

6.6 Scale reporting to 0.1 g with a minimum 50 g capacity. 
72 

6.7 Stop watch. 

______________________________________________________________________________ 

7. REAGENTS, MATERIALS 

7.1 Potable water. 

7.2 Chemical admixtures. 

______________________________________________________________________________ 

8. TEST SPECIMENS 

8.1 Air-entraining admixture. 

8.2 Portland cement. 

8.3 Supplementary cementitious materials. 

8.4 Chemical admixtures. 
73 

______________________________________________________________________________ 

9. CONDITIONING 

9.1 Allow materials to stabilize at the test temperature before testing. 

______________________________________________________________________________ 

10. PROCEDURE 

The test is normally conducted as a suite to evaluate the performance of a given air-entraining 

admixture alone, and in the presence of cement, supplementary cementitious materials and other 

chemical admixtures. The following procedure is repeated with different combinations of 

ingredients, as required by the experimental plan. 

10.1 Measure 300 mL of fluid (water and 50 mL of chemical admixtures if required) into the 

blender. 

10.2 Measure 10 mL air-entraining admixture and add to the blender. 

10.3 Add 5 g cementitious materials, if required. 

10.4 Turn the blender on at a medium setting for 10 s. 

10.5 Immediately pour the resulting foam into a 1,000 ml graduated cylinder. 

10.6 Record the volume of fluid at the bottom of the cylinder as a function of time, for up to 

60 min. 
74 

______________________________________________________________________________ 

11. CALCULATION AND INTERPRETATION OF RESULTS 

11.1 Determine Vd as the amount of water drained from the foam at time t for each recorded 

reading. 

11.2 Calculate 1/t for each recorded reading (where t is in min). 

11.3 Plot Vd versus 1/t.

11.4 Determine the Y-intercept and the slope of the plot based on the following equation: 

Vd = V0 – 1/(k * t) 

11.5 V0, Y-intercept, may be considered to be the amount drained from the foam at the end of 

the test (t = infinity). 

11.6 –1/k, the slope, indicates the rate of water drainage from the foam. 

11.7 The lower the value of –1/k, and the higher the value of V0, the less stable the foam. 

11.8 Some admixtures can be strongly influenced by the presence of cement, supplementary 

cementitious materials, or chemical admixtures, and they should be tested in the 

combination likely to be used in the project being considered. 

______________________________________________________________________________ 

12. REPORT 

Report the following information: 

12.1 Date and time of test. 

12.2 Combinations of materials used and dosages. 
75 

12.3 Calculated V0 and −1/k parameters. 

______________________________________________________________________________ 

13. PRECISION AND BIAS 

13.1 Precision and bias have not been determined for this test. 

______________________________________________________________________________ 

14. KEYWORDS 

Foam stability, air void system 

______________________________________________________________________________ 

15. REFERENCE 

W. Cross, E. Duke, J. Kellar, and D. Johnston, Investigation of Low Compressive Strengths of 

Concrete Paving, Precast and Structural Concrete, South Dakota Department of 

Transportation Report SD98-03-F. 2000. 

77 

REPORT REFERENCE 

1. R.L. Kozikowski, Jr., D.B. Vollmer, P.C. Taylor, and S.H. Gebler. “Factors Affecting 

the Origin of Air-Void Clustering.” PCA R&D Serial No. 2789, Portland Cement 

Association. Skokie, IL. 2005. 
HRDI-12/08-06(1M500)E 

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