FORE WORD 

This report presents several example case studies of the application of a set of guidelines 

developed for the evaluation of materials-related distress (MRD) in concrete pavements. 

The performance of concrete pavements can be adversely affected by the concrete's 

inability to resist the environment in which it is placed. This lack of durability can acw 

even when the structural design of the pavement is adequate. The distresses that result 

from this lack of durability are referred to herein as MRD. The guidelines developed 

cover three major areas of MRD: field distress surveys, pavement sampling, and sample 

handling; laboratory testing, data analysis, and Interpretation; and treatment, 

rehabilitation, and prevention of MRD. This report is Volume 3 of a three-volume set and 

documents the application of the guidelines to several concrete pavements. Volume P is 

the Final Report, which documents the work conducted in the study. Volume 2 is the 

Guidelines for the Detection, Analysis, and Treatment of Materials-Related Distress in 

Concrete Pavements, and documents the guidelines developed and their use. 

These guidelines were prepared with the practitioner in mind, and therefore this report 

will be of interest to those involved in evaluating concrete distress arid performance, as 

well as those involved in the design and construction of concrete pavements. Sufiicient 

copies are being distributed to provide 10 copies to each FHWA Resource Center, 5 

copies to each FHWA Division, and 5 copies to each State highway agency. Direct 

distribution is being made to the FHWA Division Offices. Additional copies may be 

purchased from the National Technical Information Service (NTIS), 5285 Port Royal 

Road, Springfield, Virginia 22 16 1. 

Director, Office of In&hstructure 

Research and Development 

NOTICE 

This document is disseminated under the sponsorship of the Department of 

Transportation in the interest of information exchange. The United States Government 

assumes no liability for its contents or use thereof. This report does not constitute a 

standard, specification, or regulation. 

The United States Government does not endorse products or manufacturers. Trade and 

manufacturer's names appear in this report only because they are considered essential to 

the object of the document. 


'Teclmical Report Documentation Page 

1 I 

4. Tltle and Subtitle 5. n~nnrt Date 

GUIDELINES FOR DETECTION, ANALYSIS, AND I August 2002 

1. Report No. 

FHWA-RD-01- 165 

TREATMENT OF MATERIALS-RELATED DISTRESS IN 

CONCRETE PAVEMENTS - Volume 3: Case Studies Using 

the Guidelines 

7. Author(s) L. L. Sutter, K. R. Peterson, T. J. Van Dam, K. D. 

Smith, M. J. Wade 

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

Federal Highway Administration, Research Technology and Final Report 1996-2002 

Development; 6300 Georgetown Pike 

McLean, Virginia 22 10 1-2296 C 14. Sponsoring Agency Code 

- 

6 Performing Organization Code 

8. Performing Organization Report No. 

9. Performing Organization Name and Address 

Michigan Technological University 

Department of Civil and Environmental Engineering 

1400 Townsend Drive 

Houghton, MI 4993 1 

15. Supplementary Notes: FHWA Contracting Officer's Technical Representative (COTR): Dr. Stephen W. Forster 

Special thanks are given to the following hghway agencies for their assistance in the conduct of this study: Minnesota, 

California, Iowa, South Dakota, and North Carolina. 

2. Government Accession No. 

10. Work Unit No. (TRAIS) 

I I. Contract or Grant No. 

DTFH6 1 -96-C-00073 

16. Abstract 

The performance of concrete pavements can be adversely affected by the concrete's inability to resist the environment in 

which it is placed. This lack of durability can occur even when the structural design of the pavement is adequate. The 

distresses that result from this lack of durability are referred to herein as materials-related distress (MRD). This report 

documents the investigation of MRD in concrete pavements and the development of a set of systematic guidelipes for the 

evaluation of MRD. The guidelines developed cover three major areas of MRD: field distress surveys, pavement 

sampling, and sample handling; laboratory testing, data analysis, and interpretation; and treatment, rehabilitation, and 

prevention. 

3. Recipient's Catalog No. 

This report is Volume 3 of a three-volume set, and documents the results of the use of the guidelines on in-service concrete 

pavements. The other two reports are: 

FHWA-RD-01- 163, Volume 1 : Final Report 

FHWA-RD-01- 164, Volume 2: Guidelines Description and Use 

I 

17. Key Word 

concrete materials; concrete pavements; concrete durability; concrete 

distress; concrete evaluation; petrographic examination; concrete 

mixture design. 

I 

18. Distribution Statement 

No restrictions. This document is 

available through the National 

Technical Information Service; 

Springfield, Viginia 22 16 1. 

19. Security Classif. (of this report) 

Unclassified 

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

20. Security Classif (of this page) 

Unclassified 

2 1. No. of Pages 

127 

22. Price 
APPROXIMATE CONVERSIONS TO SI UNITS 

Symbol When You Know Multiply By To Flnd Symbol 

in 

ft 

Yd 

mi 

in2 

ft= 

Y@ 

ac 

mi2 

fl 02 

gal 

fP 

Y@ 

NOTE: 

02 

Ib 

T 

"F 

fc 

fl 

Ibf 

Ibf/ln2 

LENGTH 

inches 25.4 millimeters 

feet 0.305 meters 

yards 0.91 4 meters 

miles 1.61 kilometers 

AREA 

square inches 

square feet 

square yards 

acres 

square miles 

fluid ounces 

gallons 

cubic feet 

cubic yards 

645.2 

0.093 

0.836 

0.005 

2.59 

VOLUME 

29.57 

3.785 

0.028 

0.765 

square millimeters 

square meters 

square meters 

hectares 

square kilometers 

milliliters 

liters 

cubic meters 

cubic meters 

Volumes greater than 1000 1 shall be shown in m3. 

MASS 

ountes 28.35 grams 

pounds 0.454 kilograms 

short tons (2000 Ib) 0.907 megagrams 

(or 'metric ton") 

TEMPERATURE (exact) 

Fahrenheit 5(F-32)/9 Celcius 

temperature or (F-32)/1.8 temperature 

ILLUMINATION 

footcandles 10.76 lux 

foot-lam berts 3.426 candela/m2 

FORCE and PRESSURE or STRESS 

poundforce 4.45 newtons 

poundforce per 6.89 kilopascals 

square inch 

mm 

m 

m 

km 

mm2 

m2 

m2 

ha 

kmz 

m L 

L 

m3 

m3 

9 

kg 

Mg 

(or -r) 

"C 

Ix 

dm2 

N 

kPa 

SI is the symbol for the International System of Units. Appropriate 

rounding should be made to comply with Section 4 of ASTM E380. 

APPROXIMATE CONVERSIONS FROM SI UNITS 

Symbol When You Know Multiply By To Flnd Symbol 

mm 

m 

m 

km 

mm2 

m2 

m2 

ha 

km2 

m L 

L 

m3 

m3 

9 

k9 

Mg 

(or 'tR) 

"C 

IX 

cdlm2 

N 

kPa 

LENGTH 

millimeters 0.039 inches 

meters 3.28 feet 

meters 1.09 yards 

kilometers 0.621 miles 

AREA 

square millimeters 0.0016 square inches 

square meters 10.764 square feet 

square meters 1.195 square yards 

hectares 2.47 aaes 

square kilometers 0.386 square miles 

VOLUME 

milliliters 0.034 fluid ounces 

liters 0.264 gallons 

cubic meters 35.71 cubic feet 

cubic meters 1.307 cubic yards 

MASS 

grams 0.035 ounces 

kilograms 2 202 pounds 

megagrams 1.103 short tons (2000 Ib) T 

(or "metric ton") 

TEMPERATURE (exact) 

Celcius 1.8C + 32 Fahrenheit OF 

temperature temperature 

ILLUMINATION 

IUX 0.0929 foot-candles fc 

candela.Jm2 0.2919 foot-Lamberts fl 

FORCE and PRESSURE or STRESS 

newtons 0.225 poundforce Ibf 

kilopascals 0.145 poundforce per lbfhi 

square inch 
Detection. Analysis. and Treatment of Materials-Related Distress in Concrete Pavements 

TABLE OF CONTENTS 

Chapter Pane 

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

CHAPTER 2 . PRIMARY CASE STUDIES .............................................................................. 5 

2.1 1-90 NEAR SPEARFISH. SOUTH DAKOTA (SD-090-019) ................................................... 5 

Project Description ................................................................................................................ 5 

Field Evaluation ...................................................................................................................... 6 

MRD Field Characterization ............................................................................................... 6 

Laboratory Analysis .............................................................................................................. 10 

Core SelectionNisual Inspection ...................................................................................... 10 

Stereo Optical Microscopy ................................................................................................ 11 

Staining Tests ................................................................................................................. 13 

Petrographic Optical Microscopy ...................................................................................... 16 

Scanning Electron Microscopy (SEM) .......................................................................... 19 

Chemical Laboratory Tests ............................................................................................... 21 

Interpretation and Diagnosis ................................................................................................ 21 

Recommended Treatment/Rehabilitation Alternatives .......................................................... 22 

Recommended Prevention Strategies .................................................................................... 28 

2.2 TH 65 nu MORA, MINNESOTA (MN-065-064) ............................................................... 29 

Project Description ............................................................................................................... 29 

Distress Survey Results ........................................................................................................ 30 

MRD Field Characterization ............................................................................................. 31 

Laboratory Analysis .............................................................................................................. 33 

Core SelectionNisual Inspection ...................................................................................... 33 

Stereo Optical MicroscopyIStaining Tests ........................................................................ 34 

Petrographic Optical Microscopy ...................................................................................... 36 

Scanning Electron Microscopy (SEM) ............................................................................. 46 

Interpretation and Diagnosis ................................................................................................ 48 

Recommended Treatment/Rehabilitation Alternatives .......................................................... 55 

Recommended Prevention Strategies .................................................................................... 56 

2.3 NEAR RALEIGH, NORTH CAROLINA (NC-440-0 15) ....................................................... 56 

Project Description .............................................................................................................. 56 

Distress Survey Results ......................................................................................................... 56 

MRD Field Characterization ........................................................................................... 59 

Laboratory Analysis .............................................................................................................. 61 

Core SelectionNisual Inspection ...................................................................................... 61 

Stereo Optical Microscopy ................................................................................................ 61 

Staining Tests .................................................................................................................. 63 

Petrographic Optical Microscopy ................................................................................... 63 

Scanning Electron Microscopy ......................................................................................... 65 

Interpretation and Diagnosis ................................................................................................ 66 

Recommended Treatment/Rehabilitation Alternatives .......................................................... 73 

Recommended Prevention Strategies .................................................................................... 74 

Volume 3 . Case Studies Using the Guidelines 

i i i 
Detection. Analysis. and Treatment of Materials-Related Distress in Concrete Pavements 

TABLE OF CONTENTS 

Chapter Paffe 

2.4 SR 58 NEAR BORON. CALIFORNLA (CA-058- 141) ......................................................... 74 

Project Description ............................................................................................................... 74 

Distress Survey Results .................................................................................................. 75 

MRD Field Characterization ............................................................................................. 76 

Laboratory Analysis .............................................................................................................. 77 

Core SelectionNisual Inspection ...................................................................................... 77 

Stereo Optical Microscopy ................................................................................................ 79 

Staining Tests .................................................................................................................... 79 

Petrographic Optical Microscopy ...................................................................................... 80 

Scanning Electron Microscopy ......................................................................................... 80 

Interpretation and Diagnosis ................................................................................................ 84 

Recommended Treatment/Rehabilitation Alternatives .......................................................... 84 

Recommended Prevention Strategies .................................................................................... 90 

CHAPTER 3 . SECONDARY CASE STUDIES .............................................................. 93 

3.1 NEAR MOJAVE. CALIFORNIA (CA-014-01 1) .................................................................. 93 

Project Description ............................................................................................................ 93 

Distress Survey Results .................................................................................................... 94 

MRD Field Characterization ............................................................................................. 95 

Laboratory Analysis .............................................................................................................. 96 

Core selectionNisua1 Inspection ....................................................................................... 96 

Stereo Optical Microscopy .................................................................................................... 96 

Staining Tests ................................................................................................................... 99 

Interpretation and Diagnosis ................................................................................................ 99 

3.2 SR 2 NEAR IOWA-NEBRASKA BORDER (IA-002-002) .................................................. 102 

Project Description ............................................................................................................. 102 

Distress Survey Results ....................................................................................................... 103 

MRD Field Characterization ........................................................................................... 104 

Laboratory Analysis ............................................................................................................ 104 

Core SelectionNisual Inspection .................................................................................... 104 

Stereo Optical Microscopy .............................................................................................. 104 

Petrographic Optical Microscopy .................................................................................... 109 .............................................................................................. Interpretation and Diagnosis 110 

CHAPTER 4 . CONCLUSIONS .............................................................................................. 119 

CHAPTER 5 . REFERENCES ........................................*.........***.........*..................*....*......... 121 

Volume 3 -- Case Studies Using the Guidelines i v 
Detection. Analysis. and Treatment of Materials-Related Distress in Concrete Pavements 

LIST OF FIGURES 

Figure 

3.1 . General location of projects included in study ................................................................... 3 

3.2 . Typical distress manifestation observed on SD.090.019.002 .............................................. 9 

3.3 . Typical distress manifestation observed on SD.090.019, Sections 1 and 2 ......................... 9 

3.4 . Typical distress manifestation observed on SD.090.019.002. ........................................... 10 

3.5 . Core specimens from SD.090.019 ..................................................................................... 11 

3.6 . Stereo optical micrographs of typical cracking pattern associated with porous 

siltstone aggregate SD.090.019 .......................................................................................... 12 

3.7 . Stereo optical micrograph showing gel deposits jn SD-090-019 aggregates ..................... 12 

3.8 . Slab 1B stained with sodium cobaltinitritelrhodamine B from SD-090-0 19.001 .............. 13 

3.9 . Slab 1B stained with sodium cobaltinitrite/rhodarnine B from SD-090-0 19-00 1 .............. 14 

3.10 . Slab 2B stained with sodium cobaltinitritelrhodamine B from SD.090.019.002 .............. 15 

3-1 1 . Stereo optical micrographs of air voids filled with sulfate minerals stained 

with potassium permanganate (note differences clue to polishing) .................................... 16 

3.12 . Core SD.090.019.001B, thin-section micrographs of same rhyolite aggregate 

that was stained with sodium cobaltinitrite ........................................................................ 17 

3- 13 . Core SD-090-019-00 lB, thin-section micrographs of same volcanic aggregate 

that was stained with sodium cobaltinitrite ........................................................................ 18 

3.14 . Ettringite (a) and hydrocalurnite (b) infilling in void and crack, respectively ................... 19 

3- 15 . Ternary diagram showing the probable range of composition for the hydrocalumite 

deposits analyzed from SD-090-0 19 ................................................................................ 21 

3.16 . Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to the Spearfish, South Dakota site ................................................... 23 

3.17 . Flowchart for assessing genera1 concrete propertiles based on visual examination as 

applied to the Spearfish, South Dakota site ...................................................................... 24 

3- 18 . Flowchart for assessing the condition of the concrete paste as applied to the Speafish, 

South Dakota site ................................................................................................................ 25 

3.19 . Flowchart for assessing the condition of the concrete aggregates as applied to the 

Spearfish, South Dakota site . ......................................................................................... 26 

3.20 . Flowchart for identifying infilling materials in cracks and voids as applied to the 

Spedish, South Dakota site ............................................................................................... 27 

3.21 . Typical distress manifestations observed at MN4365.064 ................................................. 33 

3.22 . Cores evaluated for MN.065.064 ........................ .,, ............................................................ 35 

3.23 . Stereo optical micrographs showing sulfate minerals filling air voids ............................... 36 

3.24 . Histogram of 16 fluorescence measurements from calibration thin section 

composed of quartz sand in a dyed epoxy matrix ............................................................... 38 

3.25 . Histogram of 30 fluorescence measurements from 0.38 w/c standard ............................... 39 

3.26 . Histogram of 30 fluorescence measurements from 0.41 w/c standard ............................... 39 

3.27 . Histogram of 30 fluorescence measurements from 0.42 w/c standard ............................... 40 

3.28 . Histogram of 30 fluorescence measurements from 0.52 w/c standard .............................. -40 

3.29 . Histogram of 30 fluorescence measurements from 0.56 w/c standard ............................... 41 

3.30 . Histogram of 30 fluorescence measurements from 0.74 w/c standard ............................... 41 

3-3 1 Histogram of . 30 fluorescence measurements from 0.80 w/c standard ............................... 42 

Volume 3 . Case Studies Using the Guidelines 

v 
Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

LIST OF FIGURES (CONTINUED) 

Figure Paae 

3-32. Average cement paste fluorescence measurements versus w/c. Error bars represent . . one standard devlation. ....................................................................................................... 43 

3-33. Histogram of fluorescence measurements from 1950 concrete from mid-panel 

of the left-turn lane of site MN-065-064-001. .................................................................... 43 

3-34. Histogram of fluorescence measurements from 1990 concrete from mid-panel of the 

traffic lane of site MN-065-064-001 ................................................................................... 44 

3-35. Distribution of the w/c values from the 1950 concrete from mid-panel of the 

left-turn lane of site MN-065-064-001. .............................................................................. 44 

3-36. Distribution of the w/c values from the 1990 concrete from mid-panel of the 

traffic lane of site MN-065-064-001 ................................................................................... 45 

3-37. The w/c values versus depth from the 1950 concrete from mid-panel of the 

left-turn lane of site MN-065-064-001. .............................................................................. 45 

3-38. The w/c values versus depth from the 1990 concrete from mid-panel of the 

traffic lane of site MN-065-064-001 ................................................................................... 46 

3-39. Typical SEM micrograph and x-ray analysis for ettringite infilling air void. .................... 47 

3-40. Typical SEM micrograph and x-ray analysis for hydrocalumite infilling air void. ........... 47 

3-41. Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to MN-065-064. ................................................................................ 50 

3-42. Flowchart for assessing general concrete properties based on visual examination as 

applied to MN-065-064. . . . ... .. . . ... .. . .... .. . .... ..... , .....,. . . ... ... ... .... ... ... . .. ... .... ... . .. ... ... ... ... ... 5 1 

3-43. Flowchart for assessing the condition of the concrete paste as applied to MN-065-064. .. 52 

3-44. Flowchart for assessing the condition of the concrete aggregates as applied 

to MN-065-064. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 

3-45. Flowchart for identifying infilling materials in cracks and voids as applied 

to MN-065-064. . . .... . . . ... . . . ..... . . ... .. . .... . . . ... ... . . . . . . . . . . ... ... . ...... .. ....... ... . ............... .54 

3-46. Typical cracking pattern at NC-444-015. Note distress over entire slab length with . . spalling occuring at joints. ................................................................................................. 60 

3-47. Cores and specimens evaluated from NC-440-015. .. ... ... ... .... ....... ... ... . ........ ... . ....... ... .... ... -6 1 

3-48. Stereo optical micrographs of ASR gel and reactive coarse aggregate from 

NC-440-0 1 5. . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62 

3-49. Typical stereo optical micrographs of stained concrete. Note that the broad banding 

occurs from the montage process to create a single image ................................................. 63 

3-50. Petrographic micrographs from spall obtained from NC-440-015 showing ettringite 

filled entrained air voids. Ettringite growths are unusually dense ...................................... 64 

3-5 1. Petrogrpahic micrograph of a tan to red coating observed on some of the fine 

aggregates that appears to undergo ASR from spall obtained from NC-440-0 15. ..... ........ 64 

3-52. Petrographic micrograph of ettringite and "ASR gel blob" from spall obtained 

from NC-440-015. . ,. . . , . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , , . . . . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . , . . . . ...... . . . . ....... 64 

3-53. Petrographic micrograph of ettringite intermixed with ASR gel ........................................ 65 

3-54. Petrographic micrograph of ASR gel in crack within coarse aggregate ............................. 65 

3-55. SEM micrograph of ettringite filling air voids and crack, ................................................ 66 

3-56. SEM micrograph of ettringite and ASR reaction product. ....................................... .. ....... 66 

3-57. Typical spectra for ettringite and ASR reaction product. ................................................... 67 

3-58. Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to Nc-440-0 15. ... .. . .... .. .... . ... ... . ..... .. ... ... ... , ... . ... . ... .... ... ... ... ... ... ... ... .... 68 

Volume 3 - Case Studies Using the Guidelines 
Detection. Analysis. and Treatment of Materials-Related Distress in Concrete Pavements 

LIST OF FIGURES (CONTINUED) 

Figure Paae 

3.59 . Flowchart for assessing general concrete properties based on visual examination as 

applied to NC-440-0 15 ....................................................................................................... 69 

3.60 . Flowchart for assessing the condition of the concrete paste as applied to NC.440.015 .... 70 

3.61 . Flowchart for assessing the condition of the concrete aggregates as applied to 

NC-440-0 15 ...................................................................................................................... 71 

3.62 . Flowchart for identifying infilling materials in cracks and voids as applied to 

NC-440-0 15 ....................................................................................................................... 72 

3.63 . Typical conditions at CA.058.141 .................................................................................... 78 

3.64 . Photographs of core specimens analyzed from CA-058- 141 ............................................. 78 

3.65 . Stereo optical micrographs showing staining observed in core CA-058-141-00 1C .......... 80 

3.66 . Petrographic micrograph of core CA-058- 14 1-001 E ........................................................ 81 

3.67 . Petrographic micrograph of core CA.058.141.001E ......................................................... 82 

3.68 . SEM spectra and micrograph from CA-058-141 ................................................................ 83 

3.69 . Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to CA.058.141 .............................................................................. 85 

3.70 . Flowchart for assessing general concrete properties based on visuaI examination as 

applied to CA.058.141 ....................................................................................................... 86 

3.71 . Flowchart for assessing the condition of the concrete paste as applied to CA.058.141 .... 87 

3.72 . Flowchart for assessing the condition of the concrete aggregates as applied to 

CA.058.141 ........................................................................................................................ 88 

3.73 . Flowchart for identifying infilling materials in cracks and voids as applied to 

CA-058- 14 1 ................................................................................................................. 89 

3.74 . Typical conditions at CA.014.011 .................................................................................. 95 

3.75 . Map cracking pattern on core CA-014-Ol l-OOlE, emphasized by wetting down the 

surface ................................................................................................................................ 96 

3.76 . Inverse image of polished cross section of core CA~014~011~001E .................................. 97 

3.77 . Same area of core CA-058-011-001E as shown in figure 3.78 .......................................... 98 

3.78 . Results of staining test applied to core CA.058.011.001E ................................................ 99 

3.79 . Phenolphthalein stained polished slab, showing carbonation along plastic shrinkage 

crack ................................................................................................................................. 100 

3.80 . Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to CA.014.011 ................................................................................ 101 

3-8 1 Site conditions at IA.002.002 .......................................................................................... 107 

3.82 . Closeup view of longitudinal hairline cracks ................................................................... 107 

3.83 . Polished slab from core IA~002~002~001A .................................................................. 108 

3.84 . Stereo micrograph showing air void structure of IA-002-002-001A ............................... 109 

3.85 . Reactive fine aggregate particle with alkali-silica gel filled air voids as viewed in 

thin section ...................................................................................................................... 110 

3.86 . Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as appIied to IA-002-002 .................................................................................. 112 

3.87 . Flowchart for assessing general concrete properties based on visual examination as 

applied to IA.002.002 ................................................................................................ 1 13 

Volume 3 . Case Studies Using the Guidelines vi S 
Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

LIST OF FIGURES (CONTINUED) 

Figure Page 

3-88. Flowchart for assessing the condition of the concrete paste as applied to 

LA-0020002 ....................................................................................................................... 1 14 

3-89. Flowchart for assessing the condition of the concrete aggregates as applied to 

IA-002-002. ...................................................................................................................... 1 15 

3-90. Flowchart for identifying infilling materials in cracks and voids as applied to 

IA-002-002. ...................................................................................................................... 1 16 

Volume 3 - Case Studies Using the Guidelines 

Viii 
Detection. Analysis. and Treatment of Materials-Related Distress in Concrete Pavements 

LIST OF TABLES 

Table . Pagg 

Primary and secondary test sites included in study ................................................................ 2 

Summary of design features for SD.090.019 ........................................................................ 5 

Summary of pavement condition surveys for SD.090.019.001 ............................................ 7 

Summary of pavement condition surveys for SD.090.019.002 ............................................ 8 

Summary of MRD characterization for SD.090.019 ............................................................. 8 

Results of ASTM C 457 for concrete from SD.090.019 ..................................................... 12 

Summary of 10 analyses from ettringite deposits, compared to a calculated 

composition for dehydrated ettringite .................................................................................. 20 

Summary of 13 analyses from hydrocalumite deposits ....................................................... 20 

Identified diagnostic features along with their associated MRD type and 

significance as related to SD.090.019 ................................................................................. 28 

3-10 . Summary of design features for MN-065-064 ..................................................................... 30 

3-1 1 . Summary of pavement condition surveys for MN-065-064-001 ......................................... 31 

3-12 . Summary of pavement condition surveys for MN-065-064-002 ......................................... 32 

3-13 . Summary of MRD characterization for MN-065-064 ..................................................... 33 

3-14 . Results of ASTM C 457 on concrete from MN-065-064-001 ............................................. 34 

3-15 . Quantitative results from single spectrum collected from ettringite deposit, 

compared to a calculated composition for dehydrated ettringite ......................................... 48 

3- 16 . Summary of 10 analyses and theoretical composition of hydrocalumite deposits .............. 49 

3-17 . Diagnostic features identified along with their associated MRD type and 

significance as related to MN-065-064 ................................................................................ 55 

3-18 . Summary of design features for NC-440-015 ...................................................................... 57 

3- 19 . Summary of pavement condition surveys for NC-440-0 15-00 1 .......................................... 58 

3-20 . Summary of pavement condition surveys for NC-440-015-002 .......................................... 59 

3-2 1 . Summary of MRD characterization for NC-440-015 .......................................................... 60 

3-22 . Results of ASTM C 457 on concrete from NC-440-015 ..................................................... 62 

3-23 . Diagnostic features identified along with their associated MRD type and 

significance as related to NC-440-0 15 ................................................................................. 73 

3-24 . Summary of design features for CA-058-141 ...................................................................... 75 

3-25 . Summary of pavement condition surveys for CA-058- 14 1-00 1 .......................................... 76 

3-26 . Summary of MRD characterization for CA-058-141 ......................................................... 77 

3-27 . Results of ASTM C 457 on concrete from CA-058-141 .................................................... 79 

3-28 . Summary of 12 analyses of ASR gel deposit shown in figure 3-68 .................................... 83 

3-29 . Diagnostic features identified along with their associated MRD type and . . s~gnificance as related to this pavement ........................................................................... 90 

3-30 . Summary of design features for CA-0 14-0 1 1 ...................................................................... 93 

3-31 . Summary of pavement condition surveys for CA-014-011-001 .......................................... 94 

3-32 . Summary of MRD characterization for CA-014-011 .......................................................... 95 

3-33 . Diagnostic features identified along with their associated MRD type and 

significance as related to CA-014-001 ............................................................................... 102 

3-34 . Summary of design features for IA-002-002 ..................................................................... 103 

3-35 . Summary of pavement condition surveys for IA-002-002-001 ......................................... 105 

3-36 . Summary of pavement condition surveys for IA-002-002-002 ......................................... 106 

Volume 3 . Case Studies Using the Guidelines 
Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

LIST OF TABLES (CONTINUED) 

Table & 

3-37. Summary of MRD characterization for LA-002-002. ......................................................... 106 

3-38. Air-void characteristics of core IA-002-002-001A as determined by ASTM C457 .......... 108 

3-39. Diagnostic features identified along with their associated MRD type and significance as 

related to this pavement .................................................................................................. 117 

Volume 3 - Case Studies Using the Guidelines X 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

CHAPTER 1. INTRODUCTION 

The objective of this research, conducted under FHWA Contract DTFH61-96-C-00073, was 

to develop guidelines to provide pavement engineers and field and laboratory personnel with a 

systematic procedure for the identification, evaluation, treatment, and prevention of materialsrelated distresses (MRD) in portland cement concrete (PCC) pavements. 

This report, Volume 3: Case Studies Using the Guidelines, presents the six case studies that were 

conducted as part of this study. The other two reports are: 

Volume I: Final Report 

Volume 2: Guidelines Description and Use 

Each of these in-service concrete pavements appeared to be exhibiting MRD, and were subjected 

to a coordinated series of field-testing and laboratory evaluation activities. In this way, the 

usefulness and applicability of the guidelines were evaluated under actual field conditions, 

thereby providing feedback on what areas of the guidelines worked well and what areas required 

modification or refinement. The results of these case studies were directly used to establish the 

final version of the guidelines as published in Volume 2: Guidelines Description and Use. 

In this volume, the field and laboratory testing activities that were conducted under this project 

are presented. A general summary of the data collection and analysis procedures conducted on 

each pavement case study is provided. This is followed by a summary of the condition survey, 

field sampling, and laboratory analysis results obtained for each of the case studies, leading up to 

the identification of the most likely MRD type present in the pavement. Finally, remediation 

strategies for each pavement examined are presented. 

The case studies have already been briefly introduced in Volume I: Final Report. As described, 

two sets of test sites were established: 

Primary Test Sites-Four test sites exhibiting MRD that are located in each Strategic 

Highway Reseach Program (SHRP) Long-Term Pavement Performance (LTPP) climatic 

region. Each of these pavement test sites are subjected to the full battery of field and 

laboratory tests. 

Secondary Test Sites-Two test sites exhibiting MRD that provide an alternative site in a 

particular climatic region. These pavement test sites are subjected to the same level of field 

testing as the primary sites, but are subjected to less intensive laboratory testing. 

The primary and secondary test sites included in the study are summarized in table 3-1. Again, 

the primary test sites represent each of the four SHRP LTPP climatic regions, and also include a 

range of other factors including age, pavement design, and type of distress manifestation. The 

secondary sites are included to provide additional sections for assessing the guidelines. The 

general location of these projects is shown in figure 3-1. 

The case studies included in the study were subjected to a detailed field condition survey, and 

core samples were retrieved from prescribed locations for laboratory testing and evaluation. All 

Volume 3 - Case Studies Using the Guidelines 1 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

of these activities were performed in accordance with the systematic procedures outlined in the 

guidelines. 

Chapter 2 of this volume presents the primary case studies and chapter 3 presents the secondary 

case studies. Chapter 4 provides a brief conclusion. Due to the vast amount of data collected in 

the course of this study, it is not practical to present it all in printed format, Thus a web-based 

appendix is used to provide this detailed information. 

Table 3-1. Primary and secondary test sites included in study. 

I1 California 

I Minnesota w TH 65, Mora Wet-Freeze 

I North Carolina I-440, Raleigh 1 Nz:eze 

1) South Dakota 1 

11 Secondary Sites 

I I 

1-90, Spearfish 

1 California 1 SR 14, Mojave I N2iLe,e 

Dry-Freeze 

I Iowa 1 SR '7 Nebraska / ~et-rreeze City 

230 mm JPCP 

4.0-5.8-5.5-3.7-m joint spacing 197 1 

No dowels 

No dowels 

200 mm JPCP 

200 mrn JPCP 

4.0-4.6-5.2-04.6-111 joint spacing 

7.6-7.0-5.8-5.5 m joint spacing 

1989 

32-mm dowels 

200 mm JRCP 

12.3-m joint spacing 

25-mm dowels 

215 mm JPCP 

3.7-4.0-5.8-5.5-m joint spacing 1972 

No dowels 

240 mm JPCP 

6.1-m joint spacing 1986 

32-mm dowels 

Volume 3 - Case Studies Using t& Guidelines 2 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Volume 3 - Case Studies Using the Guidelines 3 

Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

CHAPTER 2. PRIMARY CASE STUDIES 

2.1 1-90 NEAR SPEARFISH, SOUTH DAKOTA (SD-090-019) 

Project Description 

The South Dakota Department of Transportation (SDDOT) provided this project as a pavement 

with a history of durability problems. In particular, the pavement is experiencing surface or map 

cracking over the entire pavement surface. This project represents the primary case study site in 

the dry-freeze climatic region. The area receives approximately 400 mm of precipitation each 

year and has a freezing index of 684 "C-days. 

This 14-km-long project is located on 1-90 near Spearfish, South Dakota and extends from 

milepost 19.8 to milepost 28.5 in both directions. Table 3-2 provides a summary of the specific 

design features for this project. 

Table 3-2. Summary of design features for SD-090-019. 

Category - 

General 

Information 

I Number of lanes 

I Direction I Eastbound/westbound I 

Construction date 1 1968 

Cumulative ESALs 1 -2.250.000 , , I 

Pavement type JRCP 

Pavement PCC slab thickness 200 mm 

Cross Section Base 75-mm lime-treated gravel 

Subbase 1 SO-mm lime-treated suberade 

11 ( Subgrade type 

Transverse 

Joint Load transfer 

Inner Surface type I Shoulder Width 

Climatic 

Conditions ! 

Red clay 

12.3 m I 

None I 

25-mm dowels I 

Silicone 

* Climatic data are for Rapid City, South Dakota. 

Volume 3 - Case Studies Using the Guidelines 5 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavenzents 

The project is at four-lane divided highway, and the same design was placed in both the 

and westbound lanes. It is a jointed reinforced concrete pavement (JRCP) containing 

reinforcement. The joints are spaced at 12.3-m intervals and contain 25-mm dowel 

bars. The lolzgitudinal centerline joint is sealed with a hot-pour asphalt sealant, whereas the 

transverse joints are sealed with a silicone sealant. The pavement structure consists of a 200-mm 

JRCP, a 75-mm Ilme-treated gravel base, and a 150-mm lime-treated subgrade. The subgrade is 

a red clayey soil. There are n provisions for subsurface drainage. The inside and outside 

shoulders are AC-surfaced an are 1.2 and 3.0 m wide, respectively. 

After an initial investigation, the survey team selected two sections-one each in the inside and 

e traffic lanes-to be surveyed in order to evaluate the differences between lanes. Section 

001 is located in the eastbound, inside traffic lane beginning at milepost 23.1. This section was 

constructed in a cut section of approximately 10 m. Section 002 is also located in the eastbound 

direction but in the outside traffic lane and begins at milepost 24.5. This section was constructed 

on approxinrately 3 m of fill material. 

A summary of the distress survey results is provided in tables 3-3 and 3-4 for Sections 001 and 

002, respectively. Overall, Section 001 appears to be in better structural condition than Section 

002, as would be expected due to the lower traffic volumes on the inside traffic lane. Section 

081 colltainns some low-severity transverse cracks, which are expected to occur on JRCP. 

occurs at 6 of the 14 transverse joints but only 1 has progressed to medium severity. 

ling appears to be due to the progression of MRD. Three small rigid patches, each of 

along a transverse joint, are also present. Faulting is virtually nonexistent, 

d 0.7 mm measured at distances of 0.30 and 0.75 m from the slab edge. 

Section 002 exhibits more distress and greater deterioration. Although low-severity transverse 

cracks are expected on JRCP, there are considerably more cracks as compared to Section 001. In 

addition, Section 002 also exhibits two medium-severity cracks and two high-severity cracks. 

Faulting is also much more significant, averaging 3.7 and 4.2 mm at 0.30 and 0.75 m from the 

slab edge. Another distress that. is more significant on Section 002 is patching. A high-severity 

flexible patch is observed, as are 10 low-severity and 2 moderate-severity rigid patches. Some of 

the rigid patches are full-depth patches at transverse joints, indicating that the joints were likely 

badly deteriorated at one time. Five of the 14 transverse joints exhibit spalling, including 2 that 

have progressed to moderate severity. 

During the field surveys, the attributes of the MRD were characterized. Although a definitive 

diagnosis cannot be made in the field, it is important to evaluate the attributes of the MRD as 

effect these distresses have on pavement performance. A summary of the MRD 

zahn for both sections is provided in table 3-5. Figures 3-2 through 3-4 show some 

itions observed on the two test sections. 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-3. Summary of pavement condition surveys for SD-090-019-001. 

--- - - - - -- 

Volume 3 - Case Studies Using the Guidelines 7 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-4. Summary of pavement condition surveys for SD-090-019-002. 

Table 3-5. Summary of MRD characterization for SD-090-019. 

Volume 3 - Case Studies Using the Guidelines 
Guidelinesfor Detection, Analysis, and Treatment of Materials-Reluted Distress in Concrete Pavements 

(a) Section 002 (b) Section 002 

Figure 3-2. Typical distress manifestation observed on SD-090-019-002. 

(a) Section 002 (b) Section 00 1 

Figure 3-3. Typical distress manifestation observed on SD-090-019, Sections 1 and 2. 

Volume 3 - Case Studies Using the Guidelines 9 
Guidelines for Detection, Analysis, and Treatment ofMatericels-Related Distress in Concrete Pavements 

Figure 3-4. Typical distress manifestation observed on SD-090-019-002. 

On both pavement sections, map cracking was observed throughout the entire area. On Section 

001, the cracks appear to be confined to the upper 50 mm at the pavement surface. The majority 

of cracks run perpendicular to the centerline, but there are some cracks that run parallel to the 

centerline. The combination of cracks forms a criss-cross pattern on the surface. Although the 

cracking pattern is similar on Section 002, the transverse cracks on Section 001 are more 

pronounced and some are opened at the surface. 

On Section 001, the area around the joints is discolored, showing a brownish-gray staining. 

However, the cracking pattern around the joints is similar to the slab interior. The MRD has 

progressed at a few of the slab corners and spalling has occurred. There is no exudate from the 

cracks on this section. 

Section 002 exhibits a different cracking pattern along the joints. The cracking and staining form 

a semi-circular pattern, widening at the slab corners. A dark gray staining is observed around 

both the longitudinal and transverse joints. Unlike Section 001, exudate is observed at some 

cracks, particularly cracks located near a joint. The exudate is either a dark gray or white 

substance. 

Laboratory Analysis 

Core SelectionNisual Inspection 

Based upon the field survey, distress was detected at joints and near slab corners. Photos of 

typical distresses are shown in figure 3-5. To Icok at concrete from more than one slab, Cores B 

and D were selected from Section 001 and Cores A, B, and C were selected from Section 002. 

All cores were cut to produce slabs for examination with stains. 

-- 

VoIume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(a) Section 00 1, Core B (b) Section 002, Core A (c) Section 002, Core C 

Figure 3-5. Core specimens from SD-090-019. 

Mix proportions were estimated by inspecting the cores visually before and after slicing. In this 

case, detailed construction records were unavailable to verify the mix design. The concrete was 

well consolidated with no apparent segregation or parallelism of the aggregates. No scaling or 

sub-parallel cracking was apparent on these sites. The embedded steel was at a sufficient depth 

to prevent corrosion and no entrapped water voids were seen under aggregates or embedded 

steel. Surface cracking was apparent that was not related to plastic shrinkage cracking. 

Stereo Optical Microsco~v 

The stereo optical microscope was used to first examine polished slabs cut from each core to 

assess the general condition of the concrete. Typical micrographs of interesting features are 

presented in figures 3-6 and 3-7. The aggregate type was determined to be a natural gravel with 

a varied lithology including limestone, siltstone, dolomite, and rhyolite as the main rock types 

for the coarse aggregate. Many of the rhyolite particles had small feldspar inclusions. The fine 

aggregates contained the same rock types seen in the coarse aggregate in addition to shale, 

sandstone quartzite, and granite. Cracks passing through the paste also passed through 

aggregates. Reaction rims were visible along with secondary infilling in cracks and air voids. A 

yellow to white "soft" crumbly siltstone constituent of the coarse aggregate natural gravel is 

frequently cracked, with the cracks extending into the surrounding cement paste, and occasional 

white deposits in cracks. Aggregate particles that were volcanics or rhyolites appear to be 

reactive. 

Volume 3 - Cuse Studies Using the Guidelines 11 
Guidelinesfor Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(a) Siltstone aggregate (b) Siltstone and rhyolite aggregate 

Figure 3-6. Stereo optical micrographs of typical! cracking pattern associated with porous 

siltstone aggregate SD-090-0 19. 

(a) Metamorphic aggregate (b) Siltstone aggregate 

Figure 3-7. Stereo optical micrograph showing gel egosits in SD-090-019 aggregates. 

The stereo microscope was also used to erforrn a modified point count in accordance with 

ASTM C 457. As part of the modified point count, the volume fractions of paste and aggregate 

were also detennined to confirm mix vohmetrics. The results of this analysis are given in table 

3-6. 

C 457 for concrete from SD-090-019. 

- 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Staining Tests 

The sodium cobaltinitritelrhodarnine B staining tests were applied and a number of aggregates 

were identified as being susceptible to alkali-silica reactivity (ASR). The phenolphthalein 

staining method was used to determine the depth of carbonation on freshly cut surfaces. Slabs 

cut from the analyzed cores were tested for depth of carbonation with no core having a depth of 

carbonation greater than 2 mm below the road surface. Barium chloridelpotassium 

permanganate stain was used to identify sulfate minerals. Examples of the stained slabs are 

presented in figures 3-8 through 3- 1 1. 

(b) Stereo optical micrograph of reactive 

(a) Stained slab (c) Stereo optical micrograph of reactive 

volcanic particle 

Figure 3-8. Slab 1B stained with sodium cobaltinitritelrhodarnine B from SD-090-019-001. 

Volume 3 - Case Studies Using the Guidelines 13 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(b) Stereo optical micrograph of reactive 

rhvolite particle 

* Volume Volume 

titho Type (ml) % 

limestone 5 30 35.8 

siltstone 

dolomite 

rhyolite/volcanics 

chert 

gneiss/schist/phyllite 

sandstone 

shale 

grdnitdpegmatite 

quartzite 

total 

* Determined by H20 displacement from 

sample gathered at nearby river. 

(a) Stained slab 

Figure 3-9. Slab 1B stained with sodium cobaltinitrite/rhodarnine B from SD-090-019-001. 

Volume 3 - Case Studies Using the Guidelines 14 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Puvements 

Figure 3-10. Slab fI3 stained with sodium cobaltinitrite/rhodamine B from SD-090-019-002. 

(b) Reactive aggregate particle 

(c) ASR gel filled void (d) Reactive aggregate particle 

-- - -- - 

Volume 3 - Case Studies Using the Guidelines 
Guidelinesfor Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(a) Ettringite filled voids on polished 

surface 

surface 

(b) Ettringite filled voids on polished 

(d) Ettringite filled voids on unpolished 

surface 

igure 3- 1 1. Stereo optical micrographs of air voids filled with sulfate minerals stained with 

potassium permanganate (note differences due to polishing). 

Petrographic Optical Microscopv 

upon stereo microscope observations and staining, thin sections were prepared from the 

selected cores. Surfaces were sectioned from the core adjacent to stained sections to avoid 

csntmination from the stains. The reactive coarse aggregates were primarily the siltstones and 

rhyolites, although others were noted as reactive. The shale was commonly associated with ASR 

e. In addition to cracking associated with ASR, other cracking of non-reacted 

ates was noted. The siltstone aggregates had a very porous microstructure as 

These aggregates may be susceptible to aggregate freeze-thaw deterioration, 

e cracking seen in the concrete. In addition to possible ASR and aggregate 

rioration, evidence of alkali-carbonate reactivity (ACR) was noted where 

gions or "halos'with a large amount of calcite were seen surrounding dolomite 

(Spry et d. 1996). Secondary deposits within cracks and voids were 

cific phases identified (e.g., ASR gel, calcite), etlringite was 

sit. In addition to these diagnostic features, hydrocalumite 

sits were found. Given the high chloride concentration needed to 

wmite, this is taken as a diagnostic feature of deicer attack. Petrographic 

sented in figures 3- 12 and 3-1 3. 

VoEurne 3 - Gme Srudies Using the Guidelines 16 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress irz Concrete Pavements 

Figure 3-12. Core SD-090-019- 

00 1B, thin-section micrographs 

of same rhyolite aggregate that 

was stained with sodium 

cobaltinitrite ASR stain as 

shown in figure 3-9 (b). 

From top to bottom: transmitted 

plane polarized light, 

epifluorescent mode, and 

transmitted cross polarized 

light. Ettringite can be seen 

filling the entrained air void, 

ASR gel can be seen in the 

crack within the aggregate, and 

hydrocalumite can be seen in 

the crack along the contact 

between the aggregate and the 

cement paste. This same area 

was analyzed with the SEM to 

collect quantitative chemical 

information about the gel, 

ettringite, and hydrocalumite. 

90x magnification 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3- 13. Core SD-090-0 19- 

00 1B, thin-section micrographs 

of same volcanic aggregate that 

was stained with sodium 

cobaltinitrite ASR stain as 

shown in figure 3-8 (c). 

From top to bottom: transmitted 

plane polarized light, 

epi fluorescent mode, and 

transmitted cross polarized 

light. Ettringite can be seen 

filling the entrained air void, 

ASR gel can be seen in the 

crack within the aggregate, and 

hydrocalumite can be seen in 

the small entrained air void in 

the lower right hand corner. 

This same area was analyzed 

with the SEM to collect 

quantitative chemical 

information about the gel, 

ettringite, and hydrocalurnite. 

90x magnification 

Volume 3 - Case Studies Using the Guidelines 18 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Scanning; Electron Microscopv GEM) 

A conventional SEM was used to identify secondary deposits seen in the petrographic 

microscope examination to confirm those observations. Figure 3-14 contains a backscattered 

electron image showing an ettringite filled void, a crack filled with hydrocalumite, and 

characteristic x-ray spectra from each phase illustrating their compositions. The SEM analysis 

confirmed the petrographic analysis with regards to the composition of the secondary deposits. 

The phase identified as hydrocalurnite was confirmed, as were the presence of ettringite and the 

composition of various ASR reaction products. The results of x-ray microanalyses of the 

ettringite and the hyrocalumite phases are presented in tables 3-7 and 3-8, respectively. Figure 

3-15 presents the ternary diagram showing the probable range of composition for the 

hydrocalumite deposits. 

Window : Be 

100s Remaining: 0s 

FS= 8K 

MEN1: ettri ngi tt 

X-RAV: 0 - 20 ke Window : Be 

Live: l00rPr ~Remaining: 0s 

Real: 118s 

3.61 

FS= 8K 

MEMl: hydrocalumi te? 

C 

a 

keU 8.8 > 

ch 14V= 7569 cts 

Figure 3-14. Ettringite (a) and hydrocalurnite (b) infilling in void and crack, respectively. 

Example spectra from each phase are shown in (c) and (d), respectively. 

Volume 3 - Case Studies Using the Guidelines 19 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-7. Summary of 10 analyses from ettringite deposits, compared to a calculated 

composition for dehydrated ettringite. 

Table 3-8. Summary of 13 analyses from hydrocalumite deposits, compared to calculated 

compositions for the 3 dehydrated end members of the hydrocalumite solid solution series. 

Volume 3 - Case Studies Using the Guidelines 20 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete PavemenEs 

Ca2AI(OH), [CI] . 2H,O 

1-\ for hydrocalumite from analyses 

I 

Figure 3-15. Ternary diagram showing the probable range of composition for the hyc 

deposits analyzed from SD-090-019. 

Chemical Laboratory Tests 

Ion chromatography was used to analyze the sulfate content of soil samples taken from the grade 

below the individual core holes. The complete analysis is presented in the final report. To 

summarize, the soil base below the test sites would be classified as a negligible sulfate exposure 

using the criteria set forth in ACI 201.2R-92 Guides to Durable Concrete. 

Interpretation and Diagnosis 

Having performed the described laboratory analyses and applied the diagnostic flowcharts as 

shown in figures 3-16 through 3-20, several possible MRDs were identified in SD-090-019-001, 

including ASR, ACR, aggregate freeze-thaw, and deicer attack. This is consistent with the visual 

observations of the distress reported from the field where mixtures of diagnostic features were 

apparent. To finalize the diagnosis, the diagnostic tables were consulted. The diagnostic 

features identified in the analysis processes are listed below in table 3-9 along with their 

associated MRD type and significance as related to this pavement. A brief discussion follows of 

each possible MRD identified in the laboratory analysis: 

ASR - This MRD seems to be the most dominant given its extent in the sections sampled. From 

the standpoint of the guidelines, all diagnostic features of ASR were present with the exception 

of known poor performance for the aggregate used. 

ACR - This MRD was identified as a possible but in the final analysis is not listed as pmb 

a major contributor. Although there was strong evidence of the reactivity of some dolomite 

aggregates, the extent and magnitude of this reaction was not great. 

Aggregate Freeze-Thaw - Like ASR, this appeared to be a dominant distress in terms of extent. 

The likelihood or certainty of diagnosis is also very high given that, with the exception of 

Volume 3 - Case Studies Using the Guidelines 2 1 
Guidelinesfor Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

erfomaance for the aggregate used, 75 percent of all diagnostic features for aggregate 

freeze-thaw were present. 

Deicer Aeeack - This ly the most difficult to diagnose as it can often be present 

diagnostic feature that ma s deicer attack probable is the 

occurrence of hydroealumike as an irlfilling material in cracks a 

As stared previously, it as rmt rare to find a pavement with diagnostic features representative of 

In most of these cases, as with this one, the failure of 

icular cause. However, in this case some general 

ggregate freeze-thaw, and potential ACR distresses 

lity aggregate source w used. As is most often the case, 

sible aggregate source economic feasible but in some locations, 

. The other distress mechanism 

as deicers are clearly required on this portion of the 

ratio fwk) would likely reduce the concrete 

of a recurrence of this distress. 

eline III in Volume 2: Guidelines Description and Uses, 

alternatives were selected. The two most significant MRD 

eeze-thaw deterioration and ASR. Because the two 

s difficult to rate the severity of each independently, but the 

transverse joints indicates that the severity level is likely a 

medium to high in Section 082. The extent was at both 

result, feasible treatmentlrehabilitation alternatives 

include: 

Sealing less det rated joints and crx 

Q Partial- and ful 

The applicatio ht methacrylate (WMWM). 

Overlay. 

e use of patching is still feasible even though ASR was observed since most deterioration is 

vicinity sf joints and s. Further, lithium compounds are not suggested since 

::live in delaying a freeze-thaw damage. 

Ultinmdy, as the paverne=r.it continues to deeefiorate, a reconstmction/recycling option becomes 

ore wable. Tf recycling it, t be taken to avoid aggregate freeze- 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Records Survey 

Yes 

I - 

I 

I 

0 Cracking Present? 

Yes 

I 

Concentrated at and Q arallel to joints? 

Cracking 

exudate? 

I 

I 

Is there 

progressive map 

cracking? 

I 

I 

Joint Deficiency? 

-NO+ 

Yes 

Staining or 

Exudate? 

Yes NO 

Progressive 

i 

1 

I 

1 

I 

Scaling? 

-NO+ 

I Possible MRD 

Yes 

4 

Perform Visual Inspection anq 

Examine Paste and Aggregate 

Exudate or 

Staining? 

4 Progressive 

Scaling? 

Excesswe 

Popouts? 

CI23 Probably not an MRD 

Figure 3-16. Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to the Spearfish, South Dakota site. 

Volume 3 - Case Studies Using the Guidelines 23 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

0 Perform a Visual inspection 

- - r Carbonation at Depths > 5-10 mm I Yes I No I See Recommended Literature 1 

Is the concrete 

well consolidated? 

Mix Design andlor 

Segregation or 

parallelism of the 

I I 

Yes No 

concrete cover 

I 

No Yes 

Poss~ble Poor Poss~ble Poor 

Steel Placement F~nishmg/Curlng 

Possible High wlc ryes- 

-- 

depths? 

Examine the Paste u and Aggregate 

Figure 3-17. Flowchart for assessing general concrete properties based on visual examination as 

applied to the Spearfish, South Dakota site. 

Volume 3 - Case Studies Using the Guidelines 24 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

and Alr Vold System 

I 

freeze-(haw 

occur? 

I 

I 

arr void system Paste Freeze-Thaw 

Paste Freeze-Thaw 

POS~I~I~ Paste 

~reeze-maw 

Cracb 

Posslble 

aggregates intu Aggregate Freeze-Thaw 

paste? 

I 

Are the gap AIIed? 

1 

I Examne the Aggregstes ------- Possible Sulfate Anack 

Figure 3-18. Flowchart for assessing the condition of the concrete paste as applied to the 

Spearfish, South Dakota site. 

Volume 3 - Case Studies Using the Guidelines 25 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Possible Distress I Present I Additional lofnslation 

Natural Cracking of Aggregate I Yes I No 1 See Recommended Literature - -- Sample Preparation Cracks 1 Yes I No / See Recwmmended Literature ] 

Examine the Coarse and 

Fine Aggregate Structure 

Determine the coarse u and fine aggregate type 

yes 1- 

I 

PosGble Aggregate 

Yar . -- I 

Identify the 

In-Filling Material 

Yes 

ldemify the 

In-Filling Material 

Examne the Paste 1- 4-I 

Figure 3-19. Flowchart for assessing the condition of the concrete aggregates as applied to the Spearfish, South Dakota site. 

Volume 3 - Case Studies Using the Guidelines 26 
Guidelines for Detection, Anulysis, and Treatment of Materials-Related Distress in Concrete Pavements 

I Wbk Distm ) Present I Additional Inlormation 

Sulfate Attack I Yes I No 1 Table 11-4 

1 Deicer Attack 1 Yes I No 1 Table 11-5 1 Alkali Silkd Reactism 1 Yes I No I Tdhle I1 6 

AlkaltCark~ndteRexti~~n I Yes I No I 'Table 11-7 

C'om~slon of F.mheckliil Steel I Yes I No I Tabk 11-1 

/ Staining TBchniques 1 

Perogtaph'ic Microscope I ~orSEt4Analylr I 

Yea Yes 

Verify the Presence/ 

Diagnostic Features 

+ PossiMe ACR Possb!e ASR 

I 

I 

Verily me Prerencel Verily the Presed 

Absence d Other 

Diagnoslk Fealures Diagnostic Feawres 

of Embedded Steel. 

I verify me Presence/ 

Absence of Other 

Diagne Feah~es t-l Absence of Other 

Digrootic Features 

1 Establish a Cause and I 

Figure 3-20. Howchart for identifying infilling materials in cracks and voids as applied to the Spearfish, South Dakota site. 

Volume 3 - Case Studies Using the Guidelines 2 7 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

- 

Table 3-9. Identified diagnostic features along with their associated MRD type and significance 

as related to SD-090-019. 

filling air voids attack, ASR, ACR, Sulfate 

Staining at joints or 

cracks 

Secondary deposits of . - 

chloroaluminates 

Cracking near 

Staining/Spalling 

Cracks through nonreactive coarse 

aggregates 

Deicer attack 

Field evaluation 

Field evl 

Visual ins~ection 

Stereo oIG Aggregate freeze-thaw 

Petrographic OM 

Petrographic OM >I 

LVSEM 

Map Cracking with Visual inspection 

exudate 

ASR reaction product Stereo OM 

Reaction rims on ASR 

crackedaggregate SEM 

Map Cracking Field evaluation 

Significant sulfate 

deposits in cracks and 

voids 

Staining 

Stereo OM 

Petrographic OM 

Sulfate attack 

Recommended Prevention Strategies 

For the distresses noted, the best preventative strategy is to use a different source of 

aggregate. Testing in accordance with the guidelines should show that the current source 

would be unacceptable without mitigation. Mitigation strategies for aggregate freeze-thaw 

deterioration that could be used if current aggregate source is all that is available include: 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

-- - 

Heavy media separation. 

Blending with non-susceptible aggregates. 

Crushing to a non-susceptible size (potentially blending with larger non-susceptible 

aggregates). 

To address the potential for ASR, the following strategies can be employed to reduce the 

reactivity of the aggregate: 

Heavy media separation. 

Blending with non-susceptible aggregates. 

Washing, 

If aggregate benefaction is not feasible or cost effective, other strategies can also be employed 

including: 

Reducing the total mixture alkalinity to less than 3 kg/m3. 

Using a blended cement containing a pozzolan or ground slag. 

Through supplementation or addition, use pozzolans or ground slag in the mixture. 

Add lithium nitrate. 

Regardless of the approach, the design PCC mixture must be tested to ensure that the aggregate 

freeze-thaw deterioration and ASR have been mitigated. 

2.2 TH 65 IN MOM, MINNESOTA (MN-065-064) 

Project Description 

The Minnesota DOT provided several candidate projects with durability problems. One of the 

projects-located on TH 65 in downtown Mora-was experiencing severe durability problems 

concentrated at the transverse joints. This project was selected as the primary case study site for 

the wet-freeze climatic region. This area receives approximately 660 mm of annual precipitation 

and has a freezing index of 1030 "C-days. 

Table 3-10 presents a summary of the design information for this project. This project extends 

from milepost 64.2 to 65.0 and is located in both the northbound and southbound lanes. It is a 

four-lane divided roadway separated by a concrete median; some sections also include an 

additional lane for left-turn traffic. The pavement, which was constructed in 1989, consists of a 

200-mm jointed plain concrete pavement (JPCP) with a 75-mm granular base and a 305-mrn 

granular subbase. The transverse joints are skewed and have a variable joint spacing pattern of 

4.0-4.6-5.2-4.6 m. Load transfer is provided by aggregate interlock only; no additional load 

transfer devices have been employed. The only variation in the two sections is the transverse 

joint sealant-Section 001 uses silicone sealant and Section 002 uses hot-pour sealant. The 

longitudinal joints are not sealed. A 2.4-m-wide AC shoulder is placed at the outer edge; there is 

no inside shoulder due to the concrete median. 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Climatic ( 

Table 3-10. Summary of design features for MN-065-064. 

Highway type 1 Divided 

General Number of lanes 14 I 

Information t Direction 1 Northbound/southbound I 

Construction date 1989 

Cumulative ESALs -300,000 

Cross Section 

Transverse 

Joint 

Longitudinal I Load transfer 1 I 

Climatic 

Conditions 

Inner 

Shoulder 

-- 

Jata are for Minneapolis, Minnesota. 

Distress Survey Results 

Surface type 

Width 

Although the design and construction details are the same, the initial investigation revealed that 

the southbound lanes were in better condition than the northbound lanes. Thus, two sections 

were selected for survey, one in each direction- Section 001 is located in the northbound outer 

lane beginning at milepost 64.6, and Section 002 is located in the southbound outer lane 

beginning at milepost 64.4. Both sections are constructed at grade. Tables 3-1 1 and 3-12 

provide a summary of the distress survey results for Sections 001 and 002, respectively. 

n/a 

n/a 

As previously mentioned, Section 001 is exhibiting the worst performance, with most of the 

deterioration limited to the transverse joints. Joint spaling and bituminous patching are 

predominant along the transverse joints. The spalling appears to be materials-related and 

progressed to medium severity in most cases. In some cases, the surface has scaled off and 

aggregate particles have been exposed. Every transverse joint has been patched over a portion of 

its length to help address the spalling problem. In fact, the transverse joints were so deteriorated 

that faulting could not be measured. In addition, maintenance forces on hand during the surveys 

indicated that removal of the material during the patching operation often extended through the 

entire depth of the slab. The only other distress noted was a longitudinal crack that extended the 

length of one slab. 

Volume 3 - Case Studies Using the Guidelines 30 
Guidehesfor Detection, Analysis, and Treatment of Maferials-Related Distress in Concrete Pavements - 

Table 3- 1 1. Summary of pavement condition surveys for MN-065-064-001. 

Sealant 

P!" 

I I Width 

Scaling 

I Blowups 

Flexible Patches 

B - 

d. Rigid Patches 

Pum in /Bleedin I I==== 

percent of slabs 1 I 

! fair to good condition silicone sealant 

number 1 I 7 I u 

linear meters I 0.4 2.7 0 1 I 

millimeters n/a 

millimeters n/al I 

millimeters 9.4 

I Faulting could not be measured due to deterioration at transverse joints. 

Section 002 is in better overall condition but still exhibits some deterioration at the transverse 

joints. Medium-severity spalling is observed at 6 of the 33 joints (18 percent) and bituminous 

patches are observed at 12 of the 33 joints (36 percent). However, the deterioration at the 

affected joints is less severe than that observed on Section 001. Faulting could be measured on 

this section and averaged 2.0 and 1.7 mm at 0.30 and 0.75 m from the outer slab edge. The only 

other distresses include a single transverse crack and a single longitudinal crack. 

MRD Field Characterization 

A more detailed evaluation of the attributes of the MRDs was also conducted in the field. Table 

3-13 provides the results of this characterization. Figure 3-21 shows some typical distress 

manifestations. Although a definitive diagnosis should not be drawn from this evaluation, it does 

provide information that can help diagnose the distress in conjunction with the laboratory results. 

Volume 3 - Case Studies Using the Guidelines 31 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

-- 

Table 3-12. Summary of pavement condition surveys for MN-065-064-002. 

On both pavement sections, the MRD is confined to the transverse joints; it is not exhibited over 

the entire slab. The distress is exhibited as hairline cracks that typically run parallel to the 

transverse joint. The cracking appears to initiate at the transverse joint and progresses outward. 

As the deterioration progresses, scaling occurs at the surface and exposes the aggregate particles. 

For the most part, the cracking and deterioration is confined to 150 mm on either side of the 

joint. The cracks do not have any staining or exudate in or around the cracks. 

Knterestingly, adjacent to Section 001 was a left-turn lane that was part of the original road 

constructed in the 1950's. This turn-lane appeared to be in excellent condition and it was decided 

that the turn-lane should also be sampled, thereby providing an insight into a concrete pavement 

from the same environment, made from similar materials that performed well. 

Volume 3 - Case Studies Using the Guidelines 32 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

-- 

Table 3- 13, Summary of MRD characterization for MN-065-064. 

-- I Location I Joints 

Parallel to 

Cracking 

Extent ioint I -- - 

Crack size I Hairline 

Location I None Staining Color I n/a 

Extent nla 

Location None 

Scaling Area of surface n/a 

I Discolored I n/a 

( Change in texture I n/a 

joints 

Within 150 mm of I 

joint I 

Hairline 

n/a I 

None 

None 1 

n/a I 

None 

(a) (b) 

Figure 3-2 1. Typical distress manifestations observed at MN-065-064. 

Laboratory Analysis 

Core SelectionNisual Inspection 

Based on the field survey and site inspection by researchers, the distress was determined to be 

concentrated at the transverse joints. In addition, the northbound turning lane was recognized as 

being in good condition even though it was approximately 40 years older than the badly 

distressed northbound Section 001. The guidelines for sampling were applied and four cores 

were retrieved from each section. Also, one mid-panel core (core D in standard pattern) was 

retrieved from the northbound (Section 001) left-turn lane. The cores selected for laboratory 

analysis were A from Section 002, cores B and D from Section 001, and core D from the leftturn lane. Pictures of these cores are shown in figure 3-22. 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Inspecting the cores visually before and after slicing, mix proportions were only noted. If 

required to understand the distress, an estimate of the relative phase abundance is obtained 

simultaneously with determination of the hardened air content. The concrete was well 

consolidated with no apparent segregation or parallelism of the aggregates. Scaling was present 

in the deteriorated areas but not on the cores examined. Also, no evidence of sub-parallel 

cracking was apparent on these cores, no entrapped water voids were seen under aggregates, and 

no surface cracking was seen in the cores. In the rnid-panel core D from Section 001, abundant 

infilling of the entrained air voids was seen and the paste appeared "soft." The mid-panel core 

from the left-turn lane also had abundant air void infilling but had a much harder paste. Also, the 

turn-lane concrete had a coarse aggregate that was not crushed and had a larger (25.4 mm) top 

size. This is in contrast to the concrete in Section 001, which used a crushed aggregate with a 

19-mm top size. The concrete at the joint and in contact with the subbase had a depth of 

carbonation of 5-10 mm. This indicates some deterioration of the paste at those locations. 

Stereo Optical Microscouv/S taininrr Tests 

The rock type for the coarse aggregate was characterized as varying, but was dominantly mafic 

rock types typical of the Superior Lobe. The fine aggregate was the same, but with more quartz. 

No unusual alteration of the aggregate was observed. For this study, the most useful role for the 

stereo microscope was for observing stained specimens and determination of the hardened air 

content. The barium chloride/potassium permanganate stain described in Guideline II colors 

sulfate minerals a brilliant pink to purple hue as shown in figure 3-23. 

Hardened Air-Void Analysis According to ASTM C 457 

The hardened air-void content was determined in accordance with ASTM C 457. For the work 

performed in this study, the modified point count method was used for analysis and the required 

software was written in house using the free image analysis program from NIST Image 1.62. 

The results of the analysis are presented in table 3-14. 

Table 3-14. Results of ASTM C 457 on concrete from MN-065-064-001. 

As can be seen, the original air-void system and the existing air-void system (after infilling) are 

both inadequate in terms of the Power's spacing factor for each. This indicates a cement paste 

that is not adequately protected from the cyclic stresses of freezing and thawing. This usually 

results in cracking of the paste that is then susceptible to ingress of water and deicers. 

I 

Volume 3 - Case Studies Using the Guidelines 34 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-22. Cores evaluated for MN-065-064. 

Volume 3 - Case Studies Using the Guidelines 35 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-23. Stereo optical micrographs showing sulfate minerals filling air voids. 

Petrographic Optical Microscopy 

Petrographic microscopy was used to further examine the infilling material present in the air 

voids. In addition to ettringite, which was common, hydrocalumite (Friedel's Salt) was also 

identified. The hydrocalumite was most common in the concrete in contact with the subbase. 

There appeared to be little difference between the cores from the joint and from the mid-panel of 

Section 001. In general, there was extensive infilling of voids and the cement paste appeared to 

be very porous and soft. Therefore, in addition to identifying infilling material within voids and 

cracks, epifluorescent techniques were used for examining the cement paste in the mid-panel 

cores from Section 001 and the left-turn lane of the northbound section. This analysis leads to an 

estimate of the w/c ratio for the concrete. 

The technique used is commonly known as the UV dye method for determining w/c and uses a 

fluorescent dye epoxy impregnation preparation and microscopic observation using UV 

illumination. This method of w/c determination relies upon the relationship between 

measurements of cement paste fluorescence and the w/c values of known concrete standards 

(Mayfield 1990; Elsen et al. 1995; Jakobsen et al. 1997). To determine the w/c of a sample of 

concrete, fluorescence measurements are made from the cement paste, and related back to 

fluorescence measurements from the concrete standards. The intensity of the fluorescence 

measurements depends upon the amount of dyed epoxy absorbed by the cement paste. Cement 

pastes of higher w/c absorb more of the dyed epoxy because they possess a larger volume of 

capillary porosity than do cement pastes of lower w/c. 

To measure the fluorescence of the cement paste, a concrete thin section is illuminated from 

above with blue light. The blue light causes the dyed epoxy to fluoresce yellow-green. A 

blocking filter is used remove the blue light reflected from the surface, allowing only the yellowgreen fluorescence to reach the camera (Walker 1992). The camera generates a video signal, 

which is converted to an RGB digital image on a computer monitor. In the image, each pixel is 

assigned a 0-255 intensity, where 0 represents pure white (high intensity) and 255 represents 

pure black (low intensity). The G band of the image contains the most information about the 

fluorescence, and is used to make the cement paste fluorescence measurement. 

Volume 3 - Case Studies Using the Guidelines 36 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

To ensure that the illumination of the blue light and the performance of the camera are constant, 

a method of calibration is needed. Prior to collecting any measurements, a thin section 

composed of quartz sand in a matrix of dyed epoxy is used to calibrate the system. A digital 

image of the calibration slide is collected. In the image, the quartz sand appears dark, and the 

dyed epoxy matrix appears bright. If a histogram is plotted of the image, two distinct peaks are 

present, one for the quartz sand, and the other for the dyed epoxy matrix. It is important that the 

positions of the peaks on the x-axis do not shift in order to ensure consistent measurements. 

Figure 3-24 shows a summary of histograms collected from our calibration thin section. If the 

peak positions are out of alignment, then adjustments need to be made, either in the illumination, 

shutter speed of the camera, or gain and offset of the digital capture card. It has been reported 

that the fluorescence of the dyed epoxy decreases under constant illumination, but recovers to its 

initial fluorescence if allowed to sit in darkness for a period of 2 hours (Jakobsen et al. 1995). 

Furthermore, the drop-off in fluorescence is most dramatic within the first 2 minutes, so it is 

important not to pause too long over any given area before collecting a fluorescence 

measurement. 

Another set of parameters that can affect the fluorescence measurements is consistency in 

thickness of the thin sections, uniformity of impregnation by the dyed epoxy, and the consistency 

in dosage of dye. It is imperative that the thin sections used are of high quality (Elsen et al. 

1995; Jakobsen et al. 1997). 

Since concrete is a combination of cement paste, aggregate, and air bubbles, it is necessary to 

distinguish between the cement paste fluorescence and the fluorescence from aggregates and air 

bubbles. Generally, the aggregates are less porous than the cement paste, and therefore fluoresce 

at lower intensity levels, although this may not always be the case, especially when porous 

aggregates are used. At the other extreme, total porosity, the air bubbles fluoresce at a higher 

intensity level than the cement paste. At intermediate intensity values, most of the fluorescence 

can be attributed to the cement paste. Although this is a good approximation, intensity level 

alone is not enough to determine whether any given pixel represents cement paste, aggregate, or 

air bubble. Rigorous schemes have been proposed to ensure that the pixels used to make the 

cement paste fluorescence measurements do not include air bubbles or aggregate, but they were 

not employed here (Elsen et al. 1995; Gerold 2000). Instead, the distinction between cement 

paste, aggregate, or air bubble was based solely on fluorescence intensity. 

Figures 3-25 through 3-3 1 summarize the fluorescence measurements from the different 

standards. Three thin sections were prepared from each w/c standard, and 10 fluorescence 

measurements were made from different locations on each thin section for a total of 30 

measurements per w/c standard. Each fluorescence measurement represents a 2.493-mm x 

1.870-mm region on the thin section; therefore, a total area of ahout 140 mm2 was measured per 

W/C standard. Each measurement consists of a 640 x 480 pixel image, so a total of 9.216 million 

pixels were collected per w/c standard. Regions containing coarse aggregates were avoided 

during the sampling. The regions sampled were chosen by the operator, which may introduce 

bias. 

Volume 3 - Case Studies Using the Guidelines 3 7 
Guidelinesfor Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Number of Pixels 

""1 

Fluorescence Intensity 

Figure 3-24. Histogram of 16 fluorescence measurements from calibration thin section 

composed of quartz sand in a dyed epoxy matrix. The peak on the left represents the dyed epoxy 

matrix, and the peak on the right represents the quartz sand. 

It is clear from figures 3-25 through 3-3 1 that there is considerable variability within the 

individual standards, although the three distinct fluorescence levels attributed to air bubbles, 

cement paste, and aggregate can be distinguished in each of the standards. Assuming that the 

intermediate intensity levels represent the cement paste, channels 75 through 175 were used to 

quantify the cement paste fluorescence of the standards, The choice of channels 75 through 175, 

however, does not ensure that the pixels included in the measurement exclusively represent 

cement paste, nor does it ensure that some pixels that represent cement paste are not omitted. 

One concern is that the choice of channels 75 to 175 may exclude unhydrated cement grains, 

which appear as dark specks against the background of cement hydration products and capillary 

porosity. The overall fluorescence of the cement paste is related to both the capillary porosity as 

well as the quantity of unhydrated cement grains. In these measurements, variations in capillary 

porosity alone seem sufficient to distinguish variations in w/c (see figure 3-32). However, with 

the inclusion of unhydrated cement grains, the variation in intensity versus w/c would perhaps be 

more pronounced. 

There is no doubt thdt it would be advantageous to employ a more rigorous method to ensure that 

only those pixels that represent cement paste are used in the measurements, but the simple 

ernployed here performed adequately. The major weakness in the strict use of channels 

75 to 175 is that the fluorescence of the cement paste and aggregates are both influenced to some 

degree by the fluorescence of the surrounding phases. For instance, the cement paste 

surrounding air bubbles often appears brighter than the rest of the cement paste due to the 

Volume 3 - Case Studies Using the Guidelines 
GuideEines.for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Percentage of 

Pixels 

0 25 50 75 100 125 150 175 200 225 250 

Fluorescence Intensity 

Figure 3-25. Histogram of 30 fluorescence measurements fram 0.38 w/c standard. 

Percentage of 

Pixels 

0 25 50 75 100 125 150 175 200 225 250 

Fluorescence Intensity 

Figure 3-26. Histogram of 30 fluorescence measurements from 0.41 w/c standard. 

---- - 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Percentage of 

Pixels 

0 25 50 75 100 125 150 175 200 225 250 

Fluorescence Intensity 

Figure 3-27. Histogram of 30 fluorescence measurements from 0.42 w/c standard. 

Percentage of 

Pixels 

0 25 50 75 100 125 150 175 200 225 250 

Fluorescence Intensity 

Figure 3-28. Histogram of 30 fluorescence measurements from 0.52 w/c standard. 

I 

Volume 3 - Case Studies Using the Guidelines 40 I 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Percentage of 

Pixels 

0 25 50 75 100 125 150 175 200 225 250 

Fluorescence Intensity 

Figure 3-29. Histogram of 30 fluorescence measurements from 0.56 w/c standard. 

Percentage of 

Pixels 

0 25 50 75 100 125 150 175 200 225 250 

Fluorescence Intensity 

Figure 3-30. Histogram of 30 fluorescence measurements from 0.74 w/c standard. 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Percentage of 

Pixels 

Fluorescence Intensity 

Figure 3-3 1. Histogram of 30 fluorescence measurements from 0.80 w/c standard. 

proximity to the air bubbles. For this reason, some researchers exclude cement paste that 

neighbors air bubbles from recorded fluorescence measurements (Elsen et al. 1995). Similarly, 

translucent aggregates, such as quartz, may appear brighter if surrounded by brightly fluorescing 

cement paste. Depending on the appearance of a series of images, it may be necessary to 

interactively change the interval of channels that is used to represent the fluorescence of the 

cement paste. However, this would require the operator to repeatedly make decisions that could 

introduce bias to the measurements, hence the rigid choice of channels 75 to 175 used here. 

The first step in quantifying the fluorescence for each individual measurement was to normalize 

the number of pixels contained in channels 75 through 175 to 100. This step is necessary to 

account for differences in the volumes of cement paste between standards. For instance, the low 

W/C standards contained a higher volume of cement paste in order to maintain the workability of 

the plastic concrete. Next, an average intensity value was determined from the normalized 

number of pixels in channels 75 through 175. The average intensity value was used as a 

measurement of cement paste fluorescence. Figure 3-32 plots the average fluorescence intensity 

values versus the w/c of the standards, along with a best-fit line. The equation for the best-fit 

line from figure 3-32 can then be used to convert average fluorescence intensity measurements 

from unknown concrete samples to values for w/c. 

The concrete samples analyzed here are from mid-panel of the traffic lane and from mid-panel of 

a left-turn lane. Thin sections were prepared from the cores at different depths to make cement 

paste fluorescence measurements. Figures 3-33 through 3-38 summarize the measurements from 

the old concrete and the new concrete. 

- - - 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Fluorescence 

Intensity 

- Individual 

Measurements 

Average of 30 

measurements 

Figure 3-32. Average cement paste fluorescence measurements versus wk. Error bars represent 

one standard deviation. 

Percentage of 

Pixels 

Fluorescence Intensity 

Figure 3-33. Histogram of fluorescence measurements from 1950 concrete from mid-panel of the 

left-turn lane of site MN-065-064-001. 

. - 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Percentage of 

0 25 50 75 100 125 150 175 200 225 250 

Fluorescence Intensity 

Figure 3-34. Histogram of fluorescence measurements from 1990 concrete from mid-panel of the 

traffic lane of site MN-065-064-001. 

Number of 

Measurements 

0.30 0.38 0.46 0.54 0.62 0.70 0.78 0.86 

W/C equivalent 

Figure 3-35. Distribution of the w/c values from the 1950 concrete from mid-panel of the leftturn lane of site MN-065-064-001. 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Number of 

Measurements 

0.3 0.38 0.46 0.54 0.62 0.7 0.78 0.86 

W/C equivalent 

Figure 3-36. Distribution of the w/c values from the 1990 concrete from mid-panel of the traffic 

lane of site MN-065-064-001. 

W/C Equivalent - Individual Measurement 

Figure 3-37. The w/c values versus depth from the 1950 concrete from mid-panel of the left-turn 

lane of site MN-065-064-001. 

0.30 -. 

Volume 3 - Case Studies Using the Guidelines 45 

I I 8 I 

0 5 10 15 20 

Depth (cm) 
I 

I Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

I 

I 

W/C Equivalent - Individual Measurement 

0.30 ! a I I t 

0 5 10 15 20 

Depth (cm) 

Figure 3-38. The w/c values versus depth from the 1990 concrete from mid-panel of the traffic 

lane of site MN-065-064-001. 

When using the fluorescent method of w/c determination, it is important to realize that the 

capillary porosity is not solely a function of the w/c. As both proponents and critics of the 

technique are quick to point out, the capillary porosity is influenced by a number of different 

parameters. For example, the degree of hydration, the use of cementitious additives such as fly 

ash, and the amount of weathering or leaching of the cement paste all influence the capillary 

porosity, just to name a few (Jakobsen et al. 1997; Neville 1999). Certainly, to make an accurate 

estimation of w/c, appropriate standards of similar hydration and composition should be used. 

Since it would be difficult to produce suitable standards for every situation, another approach 

would be to refer to the fluorescence measurement of w/c as an "equivalent w/cn. This makes it 

clear that the w/c value determined for a sample of concrete is expressed in terms of an 

equivalent w/c as compared to the standards. In the case of site MN-065-064-001, the w/c 

standards came from concrete that had cured for 65 days. The concrete from the 1950's has had 

a long time to hydrate, and it might not be appropriate to directly compare it to the 65-day cure 

standards. The concrete from 1990 may have undergone some leaching and weathering, so 

again, it might not be appropriate to directly compare it to the standards as a measure of 

constructed w/c. However, if it is understood that the w/c measurement is an equivalent to the 

65-day cured laboratory standards, then the results are not as misleading. 

Scanning Electron Microscov~ (SEMI 

SEM was used to identify infilling material in voids and cracks. As indicated earlier, the 

principal materials idenlified were ettringite and hydrocalumite as shown in the typical SEM 

micrographs and x-ray analyses presented in figures 3-39 and 3-40. 

Volume 3 - Case Studies Using the Clridelines 46 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrefe Pavements 

1%-RAYS 0 - 20 Kd Mi ndow : Be 

.ive: 100s Preset: 100s Remaining: 01 

!rail 120s 17:: Dead 

3.686 keU 8.8 : 

FS= 8K ch 19% 7232 cti 

MEB1:ettringi te 

(b) X-ray analysis 

Figure 3-39.Typical SEM micrograph and x-ray analysis for ettringite infilling air void. 

(a) Hydrocalumite in air void, 

magnified 7 16x 

-RAY: O - 20 keU Window : Be 

ive: 100s Preset: 100s Remaining: 0s 

eal: 118s t5%Qead 

3.686 KeU 8.8 > 

FS= 8K ch 19Y= 7!%9 ctr 

BEfl1: hydracaIuni te? 

(b) Typical spectrum from 

hydrocalumite deposit 

Figure 3-40. Typical SEM micrograph and x-ray analysis for hydrocalumite infilling air void. 

Volume 3 - Case Studies Using the Guidelines 4 7 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3- 15 presents the quantitative results from a single spectrum collected from an ettringite 

deposit, compared to a calculated composition for dehydrated ettringite. Table 3-16 is a 

summary of 10 analyses of hydrocalumite deposits, compared to calculated compositions for the 

3 dehydrated end members of the hydrocalumite solid solution series. The ternary diagram 

presented previously in figure 3- 15 shows the probable range of composition for the 

hydrocaIurnite deposits analyzed from the pavement. Hydrocalumite describes a solid solution 

series with 3 end-member compositions and a range in substitutions between C1-, OH-, and ~0~~' 

. The hydrocalumite analyses were low in chlorine as compared to the pure Cl- hydrocalumite 

end member shown above. Oxygen and carbon were not analyzed so the true composition of the 

hydrocalumite cannot be determined. 

Table 3-15. Quantitative results from single spectrum collected from ettringite deposit, compared 

to a calculated composition for dehydrated ettringite. 

(1 Element I Results I ~ttrin~ite 1 

This test site illustrates a key point with the laboratory analysis of MRD. Namely, standard 

procedures will provide adequate data for diagnosing the majority of MRD cases. But in some 

cases, a more in-depth or "unique" analysis must be conducted to fully understand the MRD 

mechanisms identified. In this case, a more in-depth investigation of the effective w/c led to a 

better insight into why the distresses observed were occurring. 

1 

In the context of a guideline, it is impossible to design an analytical approach that will identify 

dl possible types of MRD in every situation. For more difficult or complex cases of MRD, a 

State highway agency (SHA) may have to contract with outside labs for petrographic services if 

such services are not available within the organization. Even if an outside contract is required, 

the guidelines still assist the analyst or engineer in refining the questions that you want the 

external petrographer to answer. 

Volume 3 - Caw Studies Using the Guidelines 48 

0 

H 

Not Measured 

Not Measured 

- --- 

48.8 

1.5 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-16. Summary of 10 analyses and theoretical composition of hydrocalumite deposits. 

Having performed the described laboratory analyses and applied the diagnostic flowcharts 

reproduced in figures 3-41 to 3-45, two possible MRDs were identified in MN-065-064-001, 

including paste freeze-thaw and deicer attack. To finalize the diagnosis, the diagnostic tables 

were consulted. The diagnostic features identified in the analysis processes are listed below in 

table 3-17 along with their associated MRD type and significance as related to this pavement. A 

brief discussion follows of each possible MRD identified in the laboratory analysis: 

A 

Paste Freeze-Thaw - Clearly, there were two distinguishing features of this distressed concrete. 

The first was the softness and high effective w/c for this concrete. The porous paste was evident 

even in the mid panel when compared to the passing lane constructed with similar aggregates but 

approximately 40 years before the failed concrete. Of course, changes in cement characteristics 

and other factors may be contributors to the observed paste characteristics. However, it is 

unlikely that these factors would result in a difference of the magnitude seen in these pavement 

sections. It is most probable that a high w/c contributed to the observed distress. In addition, the 

original air system was marginal and once infilling occurred; the hardened air system became 

inadequate to protect the weakened paste. 

Deicer Attack - This MRD may be opportunistic or it may be a contributor. Given the degree of 

distress seen near the joint, it is reasonable to infer that deicer attack was a factor. Also, the 

presence of hydrocalumite is an indicator that this concrete was exposed to a high chloride 

environment, given the necessary high chloride concentration required for this phase to 

precipitate. 

C 

0 

Volume 3 - Case Studies Using the Guidelines 49 

Not Measured 

Not Measured 

0.0 

39.2 

0.0 

45.9 

2.8 

44.6 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

0' Cracking Present? 

Cracking 

exudate? 

No 

- -No- Scaling? 

Yes 

Yes 

I 

I 

Evidence of 

Expansion? Popouts? 

I 

I 

Perform Visual Inspection and Possible MRD Examine Paste and Aggregate 0 Probably not an MRD 

Figure 3-4 1. Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to MN-065-064. 

-- 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

L=' Perform a Visual Inspection 

vdumetrics as -Yes- - well consolidated? -Yes- - 

Possible Error in Mix 

I water voids 

under aggregate at over steel? 

I 

I 

Na . .- Yes + 

Possible Poor Possible Poor Possible Poor 

PlacmenVFinishing Steel Placement Finishinfluring 

Possible High wlc ryes- 

- carbonation at 

> 510 mm 

depths? 

Examine the Paste 

and Aggregate 

Figure 3-42. Flowchart for assessing general concrete properties based on visual examination as 

applied to MN-065-064. 

Volume 3 - Case Studies Using the Guidelines 51 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Examine the Paste 

Yes. 'A I 

Possible 

I I 

I Possible Pasta 

Freeze-Thaw 

I 

I 

aggrepatss into Aggregate Freeze-Thaw I 

I 

Calcium 

r - -yes- hydroxide 

I pin@? 

u A Are there gsps - - - - - -No- around he 

I 

I 

identify me 

I 

I 

Figure 3-43. Flowchart for assessing the condition of the concrete paste as applied to MN-065- 

064. 

Volume 3 - Case Studies Using the Guidelines 52 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Examine the Coarse and 

Fine Aggregate Struclure 

Determine the coarse 

and fine aggregate type 

cracked? 

F-T climate 

oyes<-l 

Are the Possible Sample 

Preparation Artifact 

Identify the 

In-Filling Material 

Yes 

Identify the 

In-Filling Material 

Passibk Distrea I FTesenl I Additiod lnformatim 

Natural Crackme of Agp@le I Yes I No I See Rec~mmndd Literature 

Are reaction 

Yes 

In-Filling Material 

Are the 

aggregates 

softening? -6 No I aggregate? susceptible ACR 

I 

I I 

Yes 

m Possible ACR 

I 

L Examine the Paste Condition 

Rgure 3-44. Flowchart for assessing the condition of the concrete aggregates as applied to MN-065-064. 

Volume 3 - Case Studies Using the Guidelines 53 
I 

i Guidelines for Detection, Analysis, and Treaant of Mutericals-Related Distress in Concrete Puvemen~s 

I Diagnostic Features 1 

Alkali-Carbonae Reaction I Yes 1 No I Table 11-7 

Table 11- I 1 

Yes I 

Diagnostic Features 

Yes 

Diagnostic Features 

Figure 3-45. Flowchart for identifying infilling materials in cracks and voids as applied to Md-065-064. 

Volume 3 - Case Studies Using the Guidelines 54 
Guidelinesfor Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-17. Diagnostic features identified along with their associated MRD type and 

significance as related to MN-065-064. 

Diagnostic 

Feature 

Secondary deposits 

filling air voids and 

cracks 

Surface scaling or 

Sub-parallel cracking 

Inadequate air-void 

system 

Scaling of slab 

surface 

Secondary deposits of 

chloroaluminates 

Secondary deposits of 

ettringite in air voids 

and cracks 

Method of 

Characterization 

Visual 

Stereo OM 

Petrographic OM 

SEM 

Field evaluation 

- Visual 

Visual 

Stereo OM 

Associated with MRD Type Significance 

Paste freeze-thaw, deicer 

attack, sulfate attack (both 

internal and external) 

Low 

Paste freeze-thaw 

Field evaluation 

Visual 

Stereo OM 

Petrographic OM 

SEM 

Petrographic OM 

SEM 

I Medium 

Deicer attack 

Sulfate attack 

(both internal and external) 

In summary, a combination of heavy deicer use, an inadequate air-void system, and a weak paste 

resulting from a high w/c all combined to cause the distress in this pavement. With care in 

batching future concrete mixes and possibly alternative deicers, this type of distress may be 

minimized in future construction. 

Recommended Treatment/Rehabilitation Alternatives 

The application of the procedures presented in Guideline I11 in Volume 2: Guidelines Description 

and Uses is not straightforward in this case since the high w/c is a major factor in the observed 

failure, yet it is not considered a common MRD. Even so, the guideline can be used to select 

feasible treatment and rehabilitation alternatives for paste freeze-thaw deterioration and deicer 

attack. Based on the visual assessment, Section 001 is clearly suffering high-severity distress in 

the vicinity of joints, with patching observed at every joint. Section 002 is in slightly better 

condition, but still would be considered high severity based on the depth of spalling and the 

number of patches observed. It was also noted by maintenance crews that the deterioration 

extended through the full depth of the slab. Based on this assessment, the following 

treatmenthehabilitation options are available: 

Full-depth repairs 

Reconstructiodrecycling 

The use of full-depth patching is still feasible, although it should only be used as a stop-gap 

measure with the full realization that deterioration will likely continue at the patch boundary. 

Ultimately, as the pavement continues to deteriorate, a reconstructiodrecycling option becomes 

more viable. 

Volume 3 - Case Studies Using the Guidelines 55 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

-- 

Recommended Prevention Strategies 

For the distresses noted, the best preventative strategy is to ensure that the concrete specified is 

constructed. It seems evident that the w/c as constructed was well in excess of that specified and 

that the as-constructed air-void system was inadequate to protect against paste freeze-thaw 

damage. Further, the deicer attack was also a result of these two factors. If this concrete was 

constructed as specified, it is unlikely that deterioration would have occurred. Thus, the use of a 

W/C equal to or less than 0.45 and the addition of an effective air entraining admixture at a dosage 

sufficient to create an adequate air-void system would be all that was needed to address the 

observed MRD. 

2.3 NEAR RALEIGH, NORTH CAROLINA (NC-440-015) 

Project Description 

Pavements with durability problems in the wet-nonfreeze climatic region were not as easy to 

locate. However, the North Carolina DOT did provide a viable section that was selected as the 

primary site for the wet-nonfreeze region (this area receives approximately 1070 mm of annual 

precipitation and has a freezing index of 58°C-days). The section is located on 1-440 near 

Raleigh and exhibits surface cracking over the entire slab area. The project extends 

approximately 3 krn from Pool Road to Raleigh Boulevard in both directions. The highway is a 

divided roadway with a minimum of three and in some cases up to five lanes in each direction. 

The project was constructed in 1982 and consists of a 250-mm JPCP and a 100-mm cementtreated base. A 25-mm AC separator layer is located between the PCC slab and the base course. 

The transverse joints are doweled, sealed with silicone, and employ a variable joint spacing 

pattern of 7.6-7.0-5.8-5.5 m. The longitudinal joints were formed using a plastic joint insert and 

have not been sealed. AC shoulders are located along the inside and outside edge and are 1.8 

and 3.0 m wide, respectively. The design information is summarized in table 3-18. 

Distress Survey Results 

An initial windshield survey was conducted over the entire project. Following this cursory 

survey, two sections-one in each direction-were selected for more detailed surveys. Both 

sections are located in the outer traffic lane. Table 3-19 presents a summary of the distress 

survey results for Section 001; the results for Section 002 are summarized in table 3-20. 

Both sections are in similar condition. The predominant distress is map cracking over the entire 

pavement surface. Several flexible patches (low to medium severity) have also been placed on 

each section. Faulting is not to the extent where it is creating any reduction in ride quality. The 

only observed difference is the presence of two transverse cracks on Section 002. Due to the 

surface cracking, these cracks have begun to deteriorate and have been patched with AC. The 

transverse joints, which have been sealed with a silicone sealant, are in fair condition. However, 

it appears that as this MRD continues to progress, it could result in problems in the future. 

Volume 3 - Case Studies Using the Guidelines 56 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-18. Summary of design features for NC-440-015. 

I Highway type I Divided 

General Number of lanes 6 

Information Direction Eastbound/westbound 

Construction date 1982 

Cumulative ESALs 

Pavement type JPCP 

PCC slab thickness 250 mm 

Pavement Base 100-mm cement-treated base 

Cross Section I I (CTB)' 

I Subbase I 

I Subnrade tv~e I 

I Joint svacine: 1 7.6-7.0-5.8-5.5 m 

Transverse Joint skew I None 

Joint Load transfer I Dowels 

I Sealant tv~e I Silicone 

Longitudinal Load transfer 

Joint Sealant tv~e I None 

Outer Surface type I AC 

Shoulder Width 1 3.0 m 

Inner Surface type I AC 

Shoulder Width I 1.8m 

Also includes 25-rnm AC separator layer between the CTB and PCC slab. 

Volume 3 - Case Studies Using the Guidelines 5 7 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3- 19. Summary of pavement condition surveys for NC-440-015-001. 

Volume 3 - Case Studies Using the Guidelines 58 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-20. Summary of pavement condition surveys for NC-440-015-002. 

- MRD Field Characterization 

An evaluation of the MRDs is a key component of this project, so they are thus examined closely 

in the field. This detailed investigation, along with the comprehensive laboratory investigation, 

will help diagnose the type and cause of the distresses. The findings from this evaluation are 

summarized in table 3-21 and typical photos are shown in figure 3-46. 

The primary distress, and the reason this section was selected as part of this project, is the 

extensive surface cracking exhibited over the entire pavement area. These hairline cracks run 

parallel to the longitudinal joints and are more prevalent near the outer edge of the slab (i.e., near 

the longitudinal joints). Some cracks are stained immediately around the cracks, which further 

highlights the presence of the cracks. The staining is typically dark gray areas around the crack; 

no exudate appears to be present in the cracks. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

-- 

Table 3-21. Summary of MRD characterization for NC-440-015. 

Figure 3-46. Typical cracking pattern at NC-444-015. Note distress over entire slab length with 

spalling occuring at joints. 

Volume 3 - Case Studies Using the Guidelines 60 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

For the most part, these surface cracks are not causing any immediate concerns or problems. At 

a few joints and at the two transverse cracks, the surface cracks have begun to deteriorate and 

create loose pieces and some large spalls were seen on the side of the road. These areas have 

been patched with AC. Otherwise, the cracks are not adversely affecting the ride quality. 

Laboratory Analysis 

Core SelectionNisual Inspection 

Based on the field survey and site inspection by researchers, the distress was determined to be 

widespread and uniform. Therefore it wasn't necessary to emphasize the joints as compared to 

the mid-panel concrete in selecting cores to analyze. As a result only two cores were examined, 

cores A and E. In addition, a large spall found by the side of Site 1 was selected for 

examination. Pictures of the cores and spall are shown in figure 3-47. 

Figure 3-47. Cores and specimens evaluated from NC-440-0 15. 

As with the other sites, mix proportions were not documented in the construction records and 

were only noted in the visual inspection as being normal. The concrete cores were 265 mm in 

depth, considerably greater than the design thickness of 250 mm. The concrete was well 

consolidated with no apparent segregation or parallelism of the aggregates. No scaling was 

present and there was no evidence of sub-parallel cracking or entrapped water voids under 

aggregates and surface cracking was seen in the cores that was thought not to be shrinkage 

cracks. Cracks extended from aggregates and through the paste. Secondary deposits were seen 

in some entrapped air voids and darkened rims were seen on coarse aggregate particles. 

Stereo Optical Microscopy 

As with the other sites, the stereo optical microscope was used to inspect the concrete in greater 

detail and perform the ASTM C 457 analysis. Infilling in cracks and voids was common with 

some entrapped air voids exhibiting large amounts of gel products. Figure 3-48 shows examples 

of infilling. The aggregate shown stained in figure 3-48 was prepared in thin section for 

additional study. Coarse aggregates in contact with the cement paste showed darkened rims. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(a) Desiccated ASR gel lining large entrapped air 

void. 

(b) Granite coarse aggregate that picked up the 

stain, especially in cracks within the aggregate. 

Matching face from this aggregate prepared in thin 

section to examine material in cracks. 

Figure 3-48. Stereo optical micrographs of ASR gel and reactive coarse aggregate from NC-440- 

015. 

The coarse aggregate type was identified as granite and the fine aggregate appeared to be the 

same rock type. The fine aggregate was very angular, further indicating it may be a crushed 

version of the coarse aggregate used. The paste was hard and varied in color from yellow on one 

site to green on the other. This was attributed to different cement types being used in different 

sections, a fact later confirmed by observation of the unhydrated cement grains in the concrete 

using the petrographic optical microscope. 

The results of ASTM C 457 are shown below in table 3-22. Both the air-void parameters and 

phase abundance results are presented. As can be seen, the value of Power's spacing factor 

measured for this concrete exceeds the maximum recommended t~ ensure freeze-thaw 

protection. In general this is not a concern for this pavement as the environment is considered a 

wetho-freeze zone. However, the fact is that some freezing does occur and there may be some 

minor contribution of paste freeze-thaw damage to the overall observed distress. 

Table 3-22. Results of ASTM C 457 on concrete from NC-440-015. 

Volume 3 - Case Studies Using the Guidelines 62 
Guidelines for Detecrion, Analysis, and Treatment of Materials-Relaled Distress in Concrete Pavements 

Staining Tests 

The results of staining indicate that both sulfate minerals and ASR gel are present as infilling 

material in cracks and voids. Figure 3-49 below shows some typical results for these tests. The 

characteristic yellow of the sodium cobaltinitrite stain is seen on the left and the brilliant purple 

color associated with the barium chloride/potassium permanganate is seen on the right. The 

phenolphthalein stain indicated a depth of carbonation of approximately 5 mrn at the road surface 

and at the bottom of the slab. 

(a) Sodium cobaltinitrite stain (b) Barium chloride/potassium 

permanganate stain 

Figure 3-49. TypicaI stereo optical micrographs of stained concrete. Note that the broad banding 

occurs from the montage process to create a single image. 

Petrogra~hic O~tical Microscopy 

The petrographic microscope further confirmed dense reaction rims on coarse aggregates in 

contact with the cement paste. Cracks within the aggregate were filled with crystalline ASR 

product and ettringite, The ettringite was generally very dense and tightly packed. In addition to 

the granite aggregates reacting, some reactive chert was seen in the fine aggregate. Also, the fine 

aggregate contained some reactive particles that were a red to tan color and occurred as a 

"coating" on other particles. The reaction seems to convert the coating to a gel product, which 

appears desiccated in thin section. Apart from consuming the tan to red coating, the reaction 

appears to cause no damage to the surrounding concrete. Some typicd petrographic optical 

micrographs of reacting aggregate and ASR gel "blobs" are shown in figures 3-50 through 3-54. 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

polarized light polarized light 

Figure 3-50. Petrographic micrographs from spall obtained from NC-440-015 showing ettringite 

filled entrained air voids. Ettringite growths are unusually dense. 

(a) Transmitted plane 

polarized light polarized light 

Figure 3-5 1. Petrogrpahic micrograph of a tan to red coating observed on some of the fine 

aggregates that appears to undergo ASR from spall obtained from NC-440-015. 

polarized light polarized light 

re 3-52. Petrographic micrograph of ettringite and "ASR gel blob" from spall obtained from 

NC-440-8115. The tern ASR gel is misleading in this example, since the reaction product is 

slightly birefringent and, therefore, crystalline. 

Volume 3 - Case Studies Using the Guidelines 64 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(a) Transmitted plane (b) Epifluorescent mode (c) Transmitted cross 

polarized light polarized light 

Figure 3-53. Petrographic micrograph of ettringite intermixed with ASR gel. As in figure 3-52, 

the ASR "gel" in this image is birefringent and crystalline. 

Figure 3-54. Petrographic micrograph of ASR gel in crack within coarse aggregate. The gel 

deposit in this image was analyzed with the SEM. Again, the ASR "gel" in this image is 

birefringent and crystalline. 

Scanning Electron Microscopy 

Using the SEM. quantitative measurements of ettringite and ASR "gel" compositions were made. 

Ettringite deposits were extensive and found both in entrained air voids and in cracks in the 

cement paste and in cracks along the contact with coarse aggregates. Measurements were made 

of the coarse aggregate ASR product pictured in figure 3-54, both within the crack in the coarse 

aggregate, and in the region where the crack comes into contact with the cement paste. 

Measurements were also made of the gel blobs associated with the fine aggregates. The presence 

of small amounts of iron in the ASR product is unusual. Figures 3-55 and 3-56 are SEM 

micrographs of ettringite and ASR reaction product. Figure 3-57 shows the typical spectra for 

ettringite and ASR reaction product. 

Volume 3 - Case Studies Using the Guidelines 65 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(a) Ettringite in entrained air void, and in crack 

along contact between cement paste and coarse 

aggregate. 

(b) Ettringite in entrained air void, and in crack 

along contact between cement paste and coarse 

aggregate. Large relict cement grain also visible. 

Figure 3-55. SEM micrograph of ettringite filling air voids and crack. 

(a) Two ettringite filled air voids connected by a (b) ASR "gel blob associated with fine aggregate. 

crack, also filled with ettringite. Spectrum shown in figure 3-57 contain data 

collected from this deposit. 

Figure 3-56. SEM micrograph of ettringite and ASR reaction product. 

Interpretation and Diagnosis 

This test site was a good example of an "obvious" MRD, if there is such a thing. The visual 

inspection indicated a classic case of ASR distress, Further examination led to no other likely 

distress other than the potential of some paste freeze-thaw damage as a result of an inadequate 

air-void system. It should be pointed that with the visuals and stereo optical microscope 

inspection alone, a diagnosis of ASR is tempting. However, to be certain of your diagnosis, all 

other avenues must be explored. In this context the guidelines proved useful in keeping the 

analysis on track and not stopping at the first MRD identified. 

Volume 3 - Case Studies Using the Guidelines 66 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

X-RAY: D - 20 keu Window : Be X-RAY: O - 20 key Window : Be 

Live: 100sPreset: 1005Remaining: 0s Live: 1OOsPreset. 100sRemaining: 0s 

Reat: 118s 154 Dead Real: 119s 16% Dead 

S 

C i 

F W F t -A . ? A. Fe . ,.- 

3.686 keu 8.8 > 3.686 keU 8.8 > 

FS= 8K ch 19+= 6699 cts FS= 8K ch 199= 3396 ets 

MEM1: exter i or gel d~posi t MEHI: i nteri or bladed "gel" deposit 

(a) Typical spectrum from ettringite deposit. (b) Typical spectrum from ASR reaction product 

deposit. 

Figure 3-57. Typical spectra for ettringite and ASR reaction product. 

Having performed the described laboratory analyses and applied the diagnostic flow charts as 

shown in figures 3-58 through 3-62, two possible MRDs were identified in NC-440-015, 

including paste freeze-thaw and ASR. To finalize the diagnosis, the diagnostic tables were 

consulted. The diagnostic features identified in the analysis processes are listed in table 3-23 

along with their associated MRD type and significance as related to this pavement. A brief 

discussion of each possible MRD identified in the laboratory analysis: 

Paste Freeze-Thaw - The probability of paste freeze-thaw damage is low. The fact that the air 

void system was inadequate and was further compromised by infilling should be noted. 

Microcracking resulting from paste freeze-thaw may have accelerated the ASR reaction by 

providing a path for water ingress into the concrete. 

ASR - This MRD was clearly dominant in terms of extent. It is most likely that the major 

contributor to the overall observed distress is ASR. 

In summary, ASR is the most likely cause of distress in this pavement. Any steps to remediate 

should focus on ASR mitigation. In future construction, more attention to the quality of the 

entrained air system may help improve performance. 

Volume 3 - Case Srudies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Yes 

I 

Yes 

I - 

I 

I r 

Ye! 

I 

I Possible MRD Perform Visual Inspection and Examine Paste and Aggregate u Probably not an MRD 

Figure 3-58. Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to NC-440-0 15. 

Volume 3 - Case Studies Using the Guidelines 68 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

a Perform a Visual Inspection 

volumetrics as -Yes- - 

Possible Error In Mix 

IS the concrete 

well consol~dated? -Yes- - 

I 

water vo~ds concrete cover under aggregate at 

I 

I 

I 

NO 

Possible Poor Powbie Poor 

PIacmenVFinlshing Steel Placement 

plastic shrinkage No. 

~=~~~~~a?). 

Possible Pwr 

Finishinwuring 

Examine the Paste I and Aggrwate I 

Figure 3-59. Flowchart for assessing general concrete properties based on visual examination as 

applied to NC-440-015. 

Volume 3 - Case Studies Using the Guidelines 
Guidelirbes for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Eximno !he Paste 

and Ak Vdd System 

Yes- 

' I 

I I I 

I I 

r assessing the condition of the concrete paste as applied 

015. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Determine the coam u and fine aggregate type 

Figure 3-61. Flowchart for assessing the condition of the concrete aggregates as applied to NC-440-015. 

Volume 3 - Case Studies Using the Guidelines 71 
-$ & g 

I 

pi I z .!4 feg 04 

2$& & 3 .m > P 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-23. Diagnostic features identified along with their associated MRD type and significance 

as related to NC-440-0 15. 

filling air voids and attack, Sulfate attack (both 

cracks internal and external) 

Paste freeze-thaw 

exudate 

ASR reaction Petrographic OM 

products in cracks SEM 

kd voids I I ASR 

Reaction rims on Petrographic OM 

Sulfate attack 

voids (both internal and external) 

-- 

Recommended TreatmentIRehabilitation Alternatives 

Using the procedures presented in Guideline I11 in Volume 2: Guidelines Description and Uses, 

feasible treatment andrehabilitation alternatives were selected. The most significant MRD 

mechanism found was ASR. The deterioration is characterized as map cracking (hairline) over 

the entire pavement surface, with some associated staining. Isolated areas of higher deterioration 

were noted, necessitating patching. The severity level would be classified as medium severity, 

with some isolated areas of high severity. As a result, feasible treatmenthehabilitation 

alternatives include: 

Application of a lithium compound. 

e The application of a HMWM. 

Overlay. 

Ultimately, as the pavement continues to deteriorate, a reconstruction/recycling option becomes 

more viable. If recycling is considered, precautions must be taken to avoid ASR in the newly 

constructed pavement. 

- 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment ofMaterials-Related Distress in Concrete Pavements 

Recommended Prevention Strategies 

For the distresses noted, the best preventative strategy is to use a source of aggregate that is not 

ASR susceptible. Testing in accordance with the guidelines should show that the current source 

would be unacceptable without mitigation. Mitigation strategies for ASR that could be used if 

the current aggregate source is all that is available include: 

e Heavy media separation 

e Blending with non-susceptible aggregates 

Washing 

If aggregate benefaction is not feasible or cost effective, other strategies can be employed 

including: 

Reducing the total mixture alkalinity to less than 3 kg/m3 

Using a blended cement containing a pozzolan or ground slag 

e Through supplementation or addition, use pozzolans or ground slag in the mixture 

Add lithium nitrate 

Regardless of the approach, the design PCC mixture must be tested to ensure that the ASR has 

been mitigated. 

2.4 SR 58 NEAR BORON, CALIFORNIA (CA-058-141) 

Project Description 

This project is located on State Route 58 near Boron, California. This particular project has been 

documented in the literature as exhibiting cracking patterns typically associated with ASR (Stark 

et al. 1993). The project was constructed in 1970 and has exhibited MRD for many years. In 

1988, the project was treated with HMWM. After an evaluation of several other possible 

projects located in California, this project was selected as the primary case study to represent the 

dry-nonfreeze climatic region. Los Angeles, which is the closest major metropolitan area, has an 

annual precipitation of about 300 mm and no degree-days below freezing. 

State Route 58 is a four-lane divided highway running east and west. However, the test project 

is located in the eastbound lanes only, extending from milepost 141.8 to milepost 142.5. A 

summary of the design information for this project is presented in table 3-24. The pavement is a 

230-mm JPCP with a variable (4.0-5.8-5.5-5.7 m) joint spacing. The transverse joints are 

skewed at a angle of 1-to-6 (longitudinal-to-transverse). No load transfer mechanisms are 

provided at the longitudinal or transverse joints. The inside and outside shoulders, both of which 

have an AC surface, are 1.2 and 3.0 m wide, respectively. 

Chemistry lab data from the construction records indicated that the soil sulfate composition at 

this site was less than 200 ppm. As a result, this test site would be classified as a moderate 

sulfate exposure in accordance with ACI 201.2R-92. 

Volume 3 - Case Studies Using the Guidelines 74 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

- 

Table 3-24. Summary of design features for CA-058- 141. 

Construction date 

Base Cross Section Subbase 

Subgrade type 

Transverse 

Joint 

Longitudinal Load transfer I Joint Sealant tv~e 

Climatic 

Conditions Freezing index 

Sand I 

Distress Survey Results 

This project is a relatively short project that exhibits significant MRD throughout its entire 

length. The section selected for detailed investigation under this study begins at milepost 14 1.8 

and extends 150 m to the east. This section was constructed on approximately 2.5 m of fill 

material. Table 3-25 presents a summary of the distress survey results for Section 001. 

Map cracking is located throughout the entire pavement area. The only other noteworthy 

distresses are spalling and patching, both of which are due to deterioration of the surface 

cracking. Five of the 33 transverse joints have joint spalling over a portion of its length (4 have 

progressed to medium severity). There are seven small AC patches, all of which are medium 

severity, that have been placed to address the spalling caused by surface cracking. Even though 

the joints do not contain any load transfer devices, faulting is not significant enough to affect ride 

quality. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-25. Summary of pavement condition surveys for CA-058-141-001. 

MRD Field Characterization 

I 

During the distress surveys, detailed information was collected to characterize the MRD. This 

information is useful, in conjunction with a laboratory investigation, to help diagnose the type 

and cause of MRD. Table 3-26 summarizes the key attributes of the MRD. 

1 Width I millimeters 

Volume 3 - Case Studies Using the Guidelines 76 

3.4 -- 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-26. Summary of MRD characterization for CA-058- 14 1. 

Exudate Color 1 White I 

Extent I Low 

Location I None I 

Scaling Area of surface 1 n/a I 

] Depth I n/a I I Visible I None .- - 

Vibrator Discolored I n/a 1 

Trails Distressed I n/a 

As described previously, the MRD on this project is characterized by map cracking over the 

entire pavement surface. The most predominant cracking at the surface runs parallel to the 

longitudinal joints. These cracks are more prevalent, wider, and more deteriorated than the 

cracks running in other directions. In more deteriorated areas, the transverse and diagonal 

surface cracks have interconnected, forming a criss-cross or honeycomb pattern. These 

interconnecting cracks have led to spalling and loose material on the pavement surface. 

A dark gray staining has occurred in the area surrounding the cracks. However, due to the 

extensive cracking, the entire pavement surface has a darker appearance. The cracks were once 

sealed with an HMWM, but that material does not appear to be performing its intended function 

at this time. Although not widespread, exudate, typically white in color, is observed at a few 

cracks. Figure 3-63 shows typical distress patterns for this site. 

Laboratory Analysis 

Core SelectionNisual Inspection 

Based upon the field survey, distress was widespread. The joints were badly deteriorated and 

coring at the transverse joint produced pieces rather than an intact core. Cores C, D, and E were 

relatively intact and were thus analyzed. Photos of these cores are shown in figure 3-64. All 

cores were cut to produce slabs for examination with stains. 

Volume 3 - Case Studies Using the Guidelines 77 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-63. Typical conditions at CA-058-141. 

Figure 3-64. Photographs of core specimens analyzed from CA-058-141. 

Volume 3 - Case Studies Using the Guidelines 78 
Guidelines for Detection, Anaiysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Mix proportions were estimated by inspecting the cores visually before and after slicing. In this 

case, construction records were unavailable to verify the mix design. The concrete was well 

consolidated with no apparent segregation or parallelism of the aggregates. No scaling or subparallel cracking was apparent on these sites. No entrapped water voids were seen under 

aggregates or embedded steel. Surface cracking was apparent that was not plastic shrinkage 

cracking. Darkened reaction rims were seen around some of the coarse aggregates. Abundant 

cracks filled with white deposits were visible with the unaided eye. The coarse aggregates used 

were a natural igneous (both intrusive and extrusive) and the natural fine aggregate used appear 

to be similar in lithology. 

Stereo Optical Microscopy 

For this study, the stereo optical microscope was used primarily for observing stained specimens, 

selecting areas for preparing thin sections, and air void analysis. In this climate, air content is 

not an important factor in MRD unless it becomes excessive. Interestingly enough, according to 

the construction records obtained, this concrete was air entrained. As a result, only two cores 

were analyzed using ASTM C 457. A wide disparity in air content is noted but not considered 

abnormal considering the small sample size of only two cores. Also, a side benefit of performing 

the ASTM C 457 test is obtaining a measure of the relative phase abundance in the concrete. 

The results of the analysis are presented in table 3-27. 

Table 3-27. Results of ASTM C 457 on concrete from CA-058-141. 

fl Site 1 Core D f 5.7 1 0.305 1 5.7 1 0.338 1 27.2 1 44.9 22.2 I 

Staining Tests 

Cores C and D were slabbed and stained using the sodium cobaltinitrite stain for identifying 

ASR reactive aggregates and reaction products. Also, slabs were stained with the potassium 

permanganate/barium chloride stain for identifying sulfate minerals. ASR reaction product was 

seen in cracks associated with the coarse aggregate. Ettringite was common in cracks and voids, 

and actually was more common than ASR reaction product. Examples of these stains as applied 

are shown in figure 3-65. 

Volume 3 - Case Studies Using the Guidelines 79 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(a) Sodium cobaltinitrite yellow stain 

picked up in crack within felsic volcanic 

coarse aggregate 

been stained to show ettringite filled 

cracks and voids 

Figure 3-65. Stereo optical micrographs showing staining observed in core CA-058-141-001C. 

Petrographic Optical micros cop^ 

Petrographic microscopy confirmed what was seen visually and by stereo optical microscopy. 

Alkali-silica gel was present in some cracks associated with some coarse aggregate, primarily 

felsic volcanics. Ettringite was common in cracks and air voids. This is seen in figures 3-66 and 

3-67, 

Scanning Electron Microscopy 

In this case, the SEM was used simply as a means of confirming the results of the petrographic 

optical microscopy, stereo optical microscopy, and visual inspection. Using x-ray microanalysis, 

the ASR gel deposits shown in figure 3-68 were analyzed and these results are summarized in 

table 3-28. Many ettringite filled cracks were observed and an example is shown in the backscattered electron (BSE) micrograph shown in figure 3-68. 

Volume 3 - Case Studies Using the Guidelines 80 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-66. Petrographic 

micrograph of core CA058- 14 1-OOlE, thin-section 

micrographs of ASR gel 

deposit in crack along 

felsic volcanic aggregate. 

The same deposit was 

analyzed with the SEM to 

collect quantitative 

chemical information about 

the gel. From top to 

bottom: transmitted plane 

polarized light, 

epifluorescent mode, and 

transmitted cross polarized 

light (magnified 48x). 

Volume 3 - Case Studies Using the Guidelines 8 I 
Guidelines fir Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-67. Petrographic 

micrograph of core CA058- 141-OOlE, thin-section 

micrographs of ettringite 

filled crack along contact 

between coarse aggregate 

and cement paste. From 

top to bottom: transmitted 

plane polarized light, 

epifluorescent mode, and 

transmitted cross polarized 

light (magnified 188x). 

Volume 3 - Case Studies Using the Guidelines 82 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

0 - 20 keU Window : Be 

100s Preset: 100s Remaining: 0s 

121 s 17Y Dead 

3.686 keU 8.8 > 

FS= 8K ch 199= 6334 cts 

HEM1 : exteri or gel depos i t 

(a) Typical spectrum from ASR gel adjacent to 

volcanic aggregate pictured in (b). 

(b) BSE image of ettringite filling a crack **' 

along the contact between a coarse aggregate 

and the cement paste. 

Figure 3-68. SEM spectra and micrograph from CA-058- 14 1. 

Table 3-28. Summary of 12 analyses of ASR gel deposit shown in figure 3-68. 

Volume 3 - Case Studies Using the Guidelines 83 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Interpretation and Diagnosis 

Having performed the described laboratory analyses and applied the diagnostic flow charts, 

shown in figures 3-69 through 3-73, two possible MRDs were identified in CA-058-141, 

including sulfate attack and ASR, with ASR being the dominant MRD. To finalize the 

diagnosis, the diagnostic tables were consulted. In this case, the diagnostic tables were being 

used as a review to ensure that no possible MRD was overlooked. The diagnostic features 

identified in the analysis processes are listed below in table 3-29 along with their associated 

MRD type and significance as related to this pavement. A brief discussion of each distress is 

given below: 

ASR - In consulting the diagnostic tables, the only other possibility other than ASR is some form 

of sulfate attack. However, according to the construction records, Type I1 modified cement was 

specified, which should provide protection from the moderate sulfate exposure. As a result, ASR 

is the most likely cause. The reaction was extensive and clearly documented in the laboratory 

analysis. 

External Sulfate Attack - The large amounts of ettringite present are significant but may be 

opportunistic. Given the fact that Type I1 cement was used and there was no evidence of 

ettringite formation within the paste, sulfate attack is ruled out. In general, without clear 

evidence of ettringite forming within the hardened paste, sulfate attack is unlikely. 

Although many would argue that guidelines are not needed on such an "obvious" distress, the 

guidelines are useful because the analyst is not allowed to make a final judgment until all the 

data are in, In this case, construction records provided the final piece of data (i.e., the soil sulfate 

content) and without pulling all sources of data together, clues about other possible distresses 

may be missed. 

Recommended Treatment/Rehabilitation Alternatives 

Using the procedures presented in Guideline I11 in Volume 2: Guidelines Description and Uses, 

feasible treatment and rehabilitation alternatives were selected. The two most significant MRD 

mechanisms found were ASR and external sulfate attack. Because the two mechanisms are 

acting in concert, it is difficult to rate the severity of each independently. The distress is 

characterized by high severity map cracking over the entire pavement surface accompanied by 

exudates, spalling, and patching. The severity level would thus be assigned as high severity 

whether it is ASR or sulfate attack. As a result, feasible treatmenthehabilitation alternatives 

include: 

0 Rubblization/overlay. 

Recycling. 

Reconstruction. 

If recycling is considered, precautions must be taken to avoid ASR and/or sulfate attack in the 

newly constructed pavement. 

Volume 3 - Case Studies Using the Guidelines 84 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

I Perform Field and Matntenance 

Records Sutvey 1 

0 Cracking Present? 

Cracking 

exudate? 

IS there 

PYes progresswe map 

cracking? 

I 

I 

Joint Deficiency? 

-NO+ 

Staintng or 

Exudate? 

Yes 

Yes 

Excessive 

eyes+No Popouts? 

- 

Possible MRD Perform Visual inspection and 

Examine Paste and Aggregate 

Figure 3-69. Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to CA-058- 141. 

Volume 3 - Case Studies Using the Guidelines 85 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

I I Yes No 

1 

I 

ix Proportioning, Pbce 

I 

Examine the Paste I and Aggregate I 

cpwchapt for assessing general concrete properties based on visual examination as 

applied to CA-058- 14 1. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

and Air Void System 

Pdbk Distress I Present I Additlo~ul Inhrmntlom 

Shrinkage Cracks or Sample Preparation Cracks I Yes [ No I See Rrcommenclcd Literature 

Paste Freeze-Tkw 

Passe FnewThaw 

Aggregate Freeze-Thaw 

Sulfate Attack 

Deicer Attack 

Secondary Deposits 

Possible Paste cancrete near road Freeze-Thaw 

sutface? 

Are h gapslld? 

I I 

Yes 

Yes 

Yes 

Yes 

Yes 

Figure 3-71. Flowchart for assessing the condition of the concrete paste as applied to 

CA-058-141. 

Volume 3 - Case Studies Using the Guidelines 87 

No 

No 

No 

No 

No 

Table 11-2 

Table 11-3 

Table 11-4 

Table 11-5 

Figure 3-73 
.. ~~ - 

Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Examine the Coarse and 

Fine Aggwte Structure 

I 

Freeze-thaw Distress 

I 

Are the 

Preparation Artifact 

- Yes. - 4 Identity the 

In-FiIliw Material 

softening? 

I I Yes 

I 

No 

Weathering 

I 

I 

I 

I 

I 

Yes 

Identify the 

In-Filling Material 

ko Possible ACR 

Possible ASR 

I 

I 

I 

L Examine the Paste 

Condiiim 

Figure 3-72. Flowchart for assessing the condition of the concrete aggregates as applied to CA-058- 141. 

Volume 3 - Case Studies Using the Guidelines 88 
e 

Y Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

*! I 

L-J Staining Technques 

Verify the Pregence/ 

Absence of Other 

Diagnostic Features 

Yes I Yes 

Possible De-lcer Attack Poss~ble ACR 

Verify the Premel Verify tha Presence1 

Absence of Other 

Diagnostic Features Diagnostic Features 

Pdbk Dirt- I hpscnt I Additionel Inlormation 

SuKate Attack I Yes I No I Tab* 11-4 

Q7q- products? 

- -- 

Deicer Attack 

Alkali-S~iica Reanton 

Alkalt-Carbonate Reaction 

Corrosion of Embedded Steel 

Yes 

Possible ASR of Embedded Steel. 

I 

I I 

Verify the Presence1 

Diagnostic Features Digtmstbz Features 

Yes 

Yes 

Yes 

Yes 

Verily the Presence/ 

Absence of Other 

Diagnostic Features 

I Establish a Cause and 

Effect for eachlany ------------- 

Possible MRD 

I 

No 

No 

No 

No 

Figure 3-73. Flowchart for identifying infilling materials in cracks and voids as applied to CA-058-141. 

Tabk 11-5 

Tabk 11-6 

Tabk 11-7 

Table 11-1 

Volume 3 - Case Studies Using the Guidelines 89 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-29. Diagnostic features identified along with their associated MRD type and 

significance as related to this pavement. 

Diagnostic 

Feature 

Map cracking without 

exudate 

ASR reaction 

products in cracks 

and voids 

Reaction rims on 

aggregates 

Microcracking 

radiating from reacted 

aggregates 

Significant sulfate 

deposits in cracks and 

voids 

External source 

of sulfur only 

Method of 

Characterization 

Petrographic OM 

SEM 

Petrographic OM 

SEM 

Stereo OM 

Petrographic OM 

Staining 

Stereo OM 

Petrographic OM 

SEM 

Construction 

records 

Chemistry lab 

ASR I High 

Sulfate attack 

(both internal and external) 

External sulfate attack 

Recommended Prevention Strategies 

For the distresses noted, the best preventative strategy is to use a source of aggregate that is not 

ASR susceptible and a cement type and w/c combination that will not deteriorate under moderate 

sulfate conditions. Testing in accordance with the guidelines should show that the current 

aggregate source would be unacceptable without mitigation. Mitigation strategies for ASR 

include aggregate benefaction using the following strategies: 

Heavy media separation. 

Blending with non-susceptible aggregates. 

Washing. 

If aggregate benefaction is not feasible or cost effective, other strategies can also be employed 

including: 

0 Reducing the total mixture alkalinity to less than 3 kg/m3. 

Using a blended cement containing a pozzolan or ground slag. 

0 Through supplementation or addition, use pozzolans or ground slag in the mixture. 

Add lithium nitrate. 

- 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Sulfate attack is typically mitigated by using a different cement (such as Type II or V), adding 

supplementary cementitious materials such as a pozzolan or ground slag, and/or reducing the 

W/C. For moderate sulfate conditions, Type II, IP(MS), or IS(MS) cement should be used, or a 

blend of Type I cement and a GGBFS or a pozzolan that has been determined by tests to give 

equivalent sulfate resistance. Further, a maximum w/c of 0.5 is recommended. 

Volume 3 - Case Studies Using the Guidelines 91 

Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

CHAPTER 3. SECONDARY CASE STUDIES 

3.1 NEAR MO JAVE, CALIFORNIA (CA-014-011) 

Project Description 

The California DOT provided several candidate projects and this particular project was selected 

as a secondary site in the dry-nonfreeze region. The project is located on SR 14 near Mojave, 

California from MP 2 to 12 in both the northbound and southbound lanes. The project is situated 

on a four-lane divided highway. 

The key design features of this project are presented in table 3-30. The pavement was built in 

1972 and includes a 215-mm JPCP surface on a cement-treated base course. The subgrade is 

sandy material. The transverse joints are skewed and include a random joint spacing pattern of 

3.7-4.0-5.8-5.5 m. No means of load transfer (other than aggregate interlock) is provided and 

neither the transverse of longitudinal joints have been sealed. Both shoulders are paved with an 

AC surface; the inside shoulder is 1.2 m wide and the outside shoulder is 2.4 m wide. 

Table 3-30. Summary of design features for CA-014-011. 

Construction date 

Cumulative ESALs 

Pavement type 

1972 

JPCP 

Pavement 

Cross Section 

PCC slab thickness 1 215 mm 

Base 

- - I CTB I 

Transverse 

Joint 

Longitudinal 

Shoulder I Width 1 2.4 m 

Subgrade type 

Joint spacing 

Joint skew 

Load transfer 

Sealant type I None 

Load transfer 

Joint 

Outer 

Inner 1 Surface tv~e I AC 

Sand 

3.7-4.0-5.8-5.5 m 

1 :6 

None 

Shoulder I Width I 1.2m 

Sealant type 

Surface type 

I Climatic data are for Los Angeles, California. 

None 

AC 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

- -- - 

Distress Survey Results 

Due to the similar performance observed throughout the project, only one section was selected 

for detailed survey. The section begins at milepost 11.0 and extends 150 ni to the south. The 

section is located approximately at grade. 

This section exhibits an array of distresses, as summarized in table 3-3 1. First, over one-half of 

the slabs contain corner breaks, one-third of which are medium severity. The corner breaks are 

all located at the acute angle formed at the intersection of a transverse joint and the longitudinal 

centerline joint. Nearly one-third of the slabs also contain transverse cracks and again many 

have progressed to medium-severity levels. Several longitudinal cracks are present but all are 

still low severity. Many of the cracks and corner breaks have been sealed with a hot-pour sealant 

using a band-aid configuration. Faulting is also problematic, averaging 5.1 rnm and 4.0 rnrn at 

distances of 0.30 and 0.75 m from the outer slab edge, respectively. Finally, the entire surface 

area exhibits map cracking consisting of interconnecting transverse and longitudinal surface 

cracks (this distress is discussed in more detail in the next section of this report). 

Table 3-3 1. Summary of pavement condition surveys for CA-014-011-001. 

I percent of slabs I 3 1 

Sealant 1 nla I joints not sealed 

m / square meters 561 .O ( entire area aE 8 Scaling I number of slabs I 0 I CC ._I I 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

MRD Field Characterization 

A more detailed evaluation of the potential MRDs was conducted during the visual surveys. The 

key characteristics of these distresses are summarized in table 3-32. Although such an 

evaluation cannot be used to provide a definite diagnosis, it can provide useful information in 

conjunction with the laboratory investigation. 

The potential MRD is characterized by map cracking over the entire pavement surface. These 

cracks, made up of multiple interconnecting surface cracks, form a honeycomb pattern on the 

pavement surface. The cracks are generally hairline cracks but are more visible in the wheel 

paths because they are slightly more open. No staining or exudate was observed within or 

surrounding the cracks and joints. Figure 3-74 shows the typical site conditions. 

Table 3-32. Summary of MRD characterization for CA-0114-011. 

Location 

Cracking 

I Crack size 

Location Staining Color 

I Visible 

None I I 

None 1 I 

(a) Section overview (b) Close up of observed - -- -- map cracking 

Figure 3-74. Typical conditions at. CA-0 14-01 1. 

--- -- 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Laboratory Analysis 

Core selectionNisua1 Inspection 

Through visual examination, the aggregate type was determined to be granitic crushed gravel. 

The fine aggregate was the same rock type as the coarse aggregate. In examining all pavements 

in this study, the flowchart for assessing the likelihood of MRD (figure 11-14 in Guideline 11) was 

used to determine if the distress is most likely an MRD. For the previous sites, this flowchart 

always determined that an MRD was probable and it wasn'tdiscussed. For this site, figure 11-14 

yielded the answer of probably not an MRD. Although a map cracking pattern was observed on 

the pavement surface, as shown in figures 3-74(b) and 3-75, it was thought to be shrinkage 

cracks, given the nature of the cracks, the slow progression of the distress, and the age of the 

pavement (28 years). However, to be confident of our visual assessment, it was decided to 

examine core E in the laboratory since a definitive assessment of a possible MRD cannot be 

performed without examining the concrete with a stereo optical microscope. 

Figure 3-75. Map cracking pattern on core CA-014-011-001E, emphasized by wetting down the 

surface. 

Stereo Optical Microscopy 

The stereo optical microscope was used to examine the cracking and trace its path back into the 

specimen. The surface cracks pass through the paste, some go around aggregates, and some go 

through aggregates. Cracks are wide and irregular in cross-section near pavement surface, but 

narrow as the crack descends into the pavement. To image these diagnostic features, a 

conventional flatbed scanner hooked to a PC was used. The flatbed scanner is a convenient way 

to get an image that, when scanned in at high resolution (e.g., 1200-2400), can be zoomed 

digitally and viewed magnified on the computer monitor. This is a fast and easy way of 

documenting polished slabs. 

Volume 3 - Case Studies Using the Guidelines 96 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements - - - -- 

In figure 3-76, a crack is seen that runs the length of the image. It starts wide at the top and 

narrows as it goes deeper into the concrete, jogging around one large aggregate grain. That 

portion of the crack is typical of plastic shrinkage, wide and irregular at the pavement surface, 

where the paste was soft and cracked preferentially. The rest of the crack is more typical of 

drying shrinkage where much larger stresses are applied to the aggregates as the paste hardens 

with time. Stresses build to the point where the crack already started at the surface propagates 

through an aggregate and continues. Figure 3-77 is a normal scan of the same specimen. Some 

darkened rims are evident on the coarse aggregate, which is typical of ASR. 

Figure 3-76. Inverse image of polished cross section of core CA-014-011-OOlE, through 

pavement, after painting the surface black and pressing white powder into the voids and cracks 

(magnified 1 Sx). 

-- -- 

Volume 3 - Case Studies Using the Guidelines 
delines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

'igure 3-77. Same area of core CA-058-011-001E as shown in figure 3-78, included tc 

darkened reaction rims on some of the coarse aggregate (magnified 1.5~). 

sho 

- --- 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Staining Tests 

The sodium cobaltinitrite and barium chloride/potassium permanganate stains were applied and 

both were positive meaning ASR reaction products and sulfate minerals were present in the 

concrete. Micrographs showing ASR reactive particles and ettringite inclusions are shown 

below in figure 3-78. Also the phenolphthalein stain was used to determine the depth of 

carbonation. This slab was scanned and is shown in figure 3-79. Note the areas of deeper 

carbonation in the vicinity of the plastic shrinkage crack, indicating the increased permeability of 

the cracked surface. 

cracks associated with granitic coarse aggregate 

(b) Ettringite filled air voids that have picked up the 

purple to pink stain from the solution of barium chloride 

and potassium permanganate 

Figure 3-78. Results of staining test applied to core CA-058-011-001E. 

Interpretation and Diagnosis 

This site provides an excellent case for demonstrating the value of the guidelines. First, through 

the rigorous field inspection, it was decided that an MRD was likely not the cause of the 

observed distress. The logic for this conclusion is shown in figure 3-80. But it was believed that 

laboratory work should be conducted to verify this conclusion. As discussed in Guideline 11, to 

reach a diagnosis, the concrete must be observed using stereo microscopy. Because of this 

examination, the true nature of the surface cracking was documented, confirming the field 

evaluation. In addition, it was determined that there were diagnostic features of MRD, 

specifically ASR reaction products. Mild infilling of air voids and cracks with ettringite was also 

observed but not considered significant. 

Having performed the necessary laboratory analyses and applying the diagnostic flowcharts, no 

possible MRDs were identified in CA-058-011. To finalize the diagnosis, the diagnostic tables 

were consulted. From the tables only two possible distresses were identified, including ASR and 

sulfate attack. The diagnostic features identified in the analysis processes are listed below in 

table 3-33 along with their associated MRD type and significance as related to this pavement. A 

brief discussion follows of each possible MRD identified in the laboratory analysis: 

-- - - 

Volume 3 - Case Studies Using the Guidelines 99 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-79. Phenolphthalein stained polished slab, showing carbonation along plastic 5 

crack (magnified 1.5~). 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Yes 

I 

Yes 

Concentrated at and 

4 

4 

- 

No 

Cracking 

exudate? 

Is there 

tyw progressive map cracking? 

Exudate? 

Scaling? -1 

I 

No 

I 

Yes I 

Exudate or 

Staining? 

Yes + 

I 

It 

I 

Progressive ,Yes+ Scaling? i I 

I No------+ I 

I 

Evidence of 

Popouts? Expansum? 

Possble MRD Periom V~sual Inspection and 

Examine Pasta mnd Aggregate I 0 Probably Not an MRD 

Figure 3-80. Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to CA-014-011. 

Volume 3 - Case Studies Using the Guidelines 101 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

- -- 

ASR - ASR is certainly occurring in this pavement, but at this time there is little to no distress 

resulting from ASR. Additionally, there are no cracks associated with the ASR reaction products 

found in this concrete. These reaction products are filling adjacent voids and cracks within the 

aggregate. It is thus concluded that the ASR is not currently deleterious and is not a major 

contributor to the distress of this pavement at this time. Monitoring the pavement condition over 

time will demonstrate whether this distress is progressive, possibly helping engineers in planning 

maintenance schedules if the ASR does become deleterious. 

SuEfate Attack - This is highly unlikely as the only signs of sulfate attack was some moderate 

infilling sf air voids, perfectly normal in good quality concrete. Also, this pavement was 

constructed using Type 11 modified cement that helps to prevent sulfate attack at a moderate 

exposure level. Sulfate attack is not a major contributor to the distress of this pavement at this 

time. 

In summary, applying the guidelines as proposed provided information for engineers that can 

help establish a maintenance program for this pavement, thereby extending its life. Specifically, 

shrinkage cracks propagating with time and applied load are the most probable cause of the 

distress. As the concrete becomes more permeable as a result of the cracking, opportunistic 

MRDs occur such as ASR. Some mitigation of ASR may be appropriate. 

Table 3-33. Diagnostic features identified along with their associated MfiD type and significance 

as related to CA-014-001. 

products in voids 

Stereo OM 

Reaction rims on Visual 

ASR 

3.2 SR 2 NEAR IOWA-NEBRASKA BORDER (IA-002-002) 

This project is located on SR 2 in Iowa near the Nebraska border; the closest city to the project 

site is Nebraska City, Nebraska. The Iowa DOT indicated that the pavement surface had a slight 

map cracking pattern over about 60 percent of the pavement area. This project was thus selected 

as a secondary test site in the wet-freeze climatic region. This area receives approximately 760 

mm of precipitation er year and has a freezing index of 580 *G-days. 

ect, located in both the eastbound and westbound lanes from MP 2.09 to 3.59, is situated 

ivided highway. The project was constructed in 1986. The pavement cross 

section inclt~des a 240-mm JPCP and a 150-mm granular base course. The transverse joints are 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

skewed at a 1:6 ratio, spaced at 6.1-m intervals, and contain 32-mm dowel bars for load transfer. 

The longitudinal and transverse joints are both sealed with a hot-pour sealant. The inside and 

outside shoulders, which are surfaced with AC, are 3.0 and 1.2 m wide, respectively. Specific 

design features for the project are summarized in table 3-34. 

Table 3-34. Summary of design features for IA-002-002. 

Construction date 1986 

Cumulative ESALs > 2.500.000 

Pavement 

Cross Section 

Pavement type JPCP 

PCC slab thickness 240 mm I Base 1 150-mm granular 1 

Subbase 

Subgrade tv~e Glacial clay 

Transverse 

Joint 

Longitudinal 

Joint 

Outer Shoulder 

Inner Shoulder 

Climatic 

conditions' 

' Climatic data are 

Joint spacing I 6.1 m 

Joint skew 1 1:6 

Width 3.0 m 

Surface tvve AC 

Width 1.2 m 

Region Wet-nonfreeze 

Annual precipitation ( 760 mm 1 

3r Omaha, Nebraska. 

Distress Survey Results 

Two sections were selected for survey within this project, both of which are located in the 

westbound, outer traffic lane. Section 001 begins at Station 1513+60 and Section 002 begins at 

Station 1495+00. Both sections are located approximately at grade. 

The performance of each section is summarized in tables 3-35 and 3-36. It is observed from 

these tables that both sections are performing similarly. Section 001 contains two transverse 

cracks---one low severity and one medium severity-and Section 002 contains only one lowseverity transverse crack. Short longitudinal cracks, which appear to be more than surface 

cracks, are also present throughout both sections. These cracks are generally confined to the 

wheel paths. Spalling is exhibited on a few transverse joints but is limited to low severity. The 

ride quality is not affected by the faulting. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

MRD Field Characterization 

A characterization of potential MRD was conducted in the field to assist in the diagnosis of the 

type and cause of the distress. The potential MRD on both sections is the presence of short 

longitudinal cracks throughout the sections. These cracks are generally confined to the wheel 

paths and in many cases initiate at a transverse joint. There is some slight staining, which is 

brownish-gray in appearance, around transverse joints and in the wheel paths. There is no 

exudate observed at the cracks. Table 3-37 provides a summary of the MRD characteristics for 

this project. Figure 3-81(a) shows staining along longitudinal cracks and at the transverse joints. 

Figure 3-8 1(b) shows closeup views of the hairline cracks. Additional site conditions are shown 

in figure 3-82. 

Laboratory Analysis 

Core SelectionNisuaI Inspection 

The distresses observed at both sections were similar, and appeared to be concentrated at the 

joints. Core A was selected from Section 001 for analysis. Core A exhibited hairline cracking at 

the pavement surface, and a large crack nea the base running parallel to the subbase contact. 

Figure 3-83 shows a polished slab from core A. Other than the visible cracks, the concrete 

seemed in good condition. The coarse aggregate consisted of a blend of a quarried limestone and 

pink granite. 

Stereo Optical Microscopy 

The most striking feature of the concrete was the abundance of small, entrained air voids, as 

shown in figure 3-84. Although the concrete did contain a large percentage of air, the specific 

surface and spacing factors were within reasonable values. A summary of the Modified Point 

Count is included in table 3-38. There was moderate infilling of the void structure by secondary 

ettringite. Some isolated alkali-silica gel deposits were observed with some of the fine aggregate 

particles. The gel deposits were found filling air voids near the reactive particles, and were not 

associated with any cracking. The coarse aggregates were intact, and did not appear to be 

reactive. 

Volume 3 - Case Studies Using the Guidelines 
Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-35. Summary of pavement condition surveys for L4-002-002-001. 

- - - -- 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-36. Summary of pavement condition surveys for IA-002-002-002. 

Table 3-37. Summary of MRD characterization for IA-002-002. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

(a) Staining along longitudinal cracks (b) Staining along transverse joints 

Figure 3-81. Site conditions at L4-002-002. 

Figure 3-82. Closeup view of longitudinal hairline cracks. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-83. Polished slab from core LA-002-002-001A. The irregular surface along the lefthand side of the core is a cross-sectional view of the transverse joint texture. 

Table 3-38. Air-void characteristics of core IA-002-002-001A as determined by 

ASTM C457. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-84. Stereo micrograph showing air void structure of IA-002-002-001A, 

magnified 7.5~. 

Areas observed to contain reactive fine aggregate particles were prepared in thin section. Figure 

3-85 shows a reactive particle that has undergone dissolution, cracking, and the reaction product 

has filled some neighboring air voids. The reactive particles, which appear to be volcanic in 

origin with phenocrysts in a very fine matrix, are likely to have originated from much further 

west, and been brought to the area by the Missouri River. The air-void structure has experienced 

limited infilling by secondary ettringite. 

-- 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-85. Reactive fine aggregate particle with alkali-silica gel filled air voids as viewed in 

thin section. Top image is transmitted plane polarized light, bottom image is in epifluorescent 

mode, magnified 20x. 

Interpretation and Diagnosis 

Although the concrete exhibits signs of distress such as hairline longitudinal cracking with 

staining in addition to staining at the transverse joints, it is still performing well. Some ASR was 

present in the fine aggregate, although it did not seem to be associated with any cracking. The 

air-void content was unusually high, over 8 percent, with an abundance of small-entrained air 

voids that were sometimes coalesced into dense groupings. 

Having performed the described laboratory analyses and applied the diagnostic flowcharts, as 

shown in figures 3-86 through 3-90, three possible MRDs were identified in LA-002-002, 

including paste freeze-thaw, ASR and sulfate attack with none being dominant or extensive. To 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

finalize the diagnosis, the diagnostic tables were consulted. The diagnostic features identified in 

the analysis processes are listed below in table 3-39 along with their associated MRD type and 

significance as related to this pavement. A brief discussion of each distress is given below. 

ASR - The ASR occurring in this pavement was not extensive and did not seem to related to any 

of the observed cracking. As a result, ASR is not considered to be a major cause of the observed 

MRD. This does not rule out ASR in its early stages as being present. 

Paste Freeze-Thaw - The only diagnostic feature of paste freeze-thaw present was the marginal 

air-void system in terms of the measured Powers spacing factor. This is considered to be a 

diagnostic feature of low significance given the fact that no other diagnostic feature of paste 

freeze-thaw was seen. As a result, paste freeze-thaw is not considered to be a major cause of the 

observed distress. 

Sulfate Attack - The only diagnostic feature of sulfate attack was ettringite infilling in entrained 

air voids. This was considered a low significance diagnostic feature for a variety of reasons. 

First, ettringite deposits by themselves are not diagnostic of sulfate attack. Second, the amount 

of infilling was limited, not extensive. Finally, no other diagnostic feature of sulfate attack was 

observed. Therefore, sulfate attack is ruled out as a major cause of the observed distress. 

In summary, the exact nature of the observed distress is not known. The unusual air-void 

structure may be a contributor but the exact mechanism could not be discerned from this 

analysis. It is noted that the concrete had a very fine coarse aggregate grading, which may also 

be a contributing factor but, again, no evidence of a specific mechanism for the observed distress 

was seen related to this gradation. The guidelines do help rule out the obvious types of MRD but 

in the end, this is an exampIe of a pavement that cannot be absolutely diagnosed using the 

developed guidelines. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Yes 

I 

Exudate or 

Slaming? 

+Yes Ewdence of 

Expansion? 

Perlorrn Visual Inspection and Posstble MRD Examine Paste and Aggregate 

* 

Probably Not an MRD 

Figure 3-86. Flowchart for assessing the likelihood of MRD causing the observed distress in the 

pavement as applied to IA-002-002. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

7 Perform a Visual InJpection 

Are the mix 

votumetr~cs as 

spec~fied? 

Is the concrete 9 wtl consolidated? --t 

( Possible Error in Mix 

proportioning )-I 

Segregation or 

parallelism of the 

I I 

Yes NO 

concrete cover under aggrme at 

road surface? 

I 

I 

Yes + 

Possible Poor Possible Poor 

Steel Placement Rn~shinglCuring 

Possible High wlc ryesExamine the Paste 

and Aggregate 

Figure 3-87. Flowchart for assessing general concrete properties based on visual examination as 

applied to IA-002-002. 

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GuideIines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Figure 3-88. flowchart for assessing the condition of the concrete paste as applied to 

IA-002-002. 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

Table 3-39. Diagnostic features identified along with their associated MRD type and 

significance as related to this pavement. 

products in voids SEM ASR 

Significant sulfate Staining 

deposits in cracks and I Stereo OM I Sulfate attack 

voids ( Petrographic OM I (both internal and external) 

SEM 

Inadequate air-void Stereo OM Paste freeze-thaw 

Significance 

Low 

Low 

Low 

-- -- 

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Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

CHAPTER 4. CONCLUSIONS 

This volume of the final report, Volume 3: Case Studies, has presented six case studies in which 

the developed guidelines were applied. In the primary case studies, the guidelines were found to 

be very useful in directing and organizing the laboratory analysis and in interpreting the data 

with the purpose of making a diagnosis. One of the two secondary case studies was used to 

illustrate how the guidelines functioned when analyzing a pavement section that turned out not to 

have an MRD at work. The other secondary case study presented an example when the 

guidelines were unable to be used to draw meaningful conclusions. 

A major conclusion of this effort is that, when diagnosing a MRD using laboratory methods, data 

acquisition and interpretation must be performed simultaneously. As the data from a first set of 

tests are analyzed, new questions are posed requiring interpretation of that first set of data before 

a second set of analyses can be applied. Then, additional analyses are performed, often using 

different techniques, and the process is repeated. After the new results are interpreted, a new 

battery of tests may be required. As the laboratoqdinterpretation procedure continues, a 

diagnosis begins to form and the analyst must use caution not to stop at the first MRD identified. 

Final diagnosis comes after all necessary laboratory tests are completed and the results are 

summarized. The developed guidelines provide a systematic way of approaching this problem. 

The diagnostic flowcharts frame the questions that should be asked about the concrete, and the 

laboratory methods recommended in the guidelines provide the means of answering those 

questions. How the analyst performs the work required for each analysis is up to the individual. 

In general, the work tends to be done following the process shown in figure 11-1 in the second 

guideline where specific techniques are applied in sequence and each technique allows the 

analyst to progress incrementally through the flowcharts, answering a few more questions each 

time. How far the analyst proceeds through figure 11-1 before completing all five diagnostic 

flowcharts varies. In general, all cases of MRD analyzed require visual inspection and stereo 

optical microscopy and most progress to the level of needing petrographic optical microscopy 

and/or SEM analysis. As a result of applying the diagnostic flowcharts, a number of possible 

MRDs can be identified. Then, referring to the diagnostic tables, the list of diagnostic features 

identified in the laboratory can be compared to common diagnostic features for the various MRD 

types. All diagnostic features listed are rarely all present at one time far a given MRD. The 

analyst has to weight the significance of each diagnostic feature relative to the magnitude, extent, 

and nature of the observed MRD. It is this last step that results in final diagnosis and requires 

objectivity and sound data to perform. 

Volume 3 - Case Studies Using the Guidelines 

Guidelines for Detection, Analysis, and Treatment of Materials-Related Distress in Concrete Pavements 

CHAPTER 5. REFERENCES 

American Concrete Institute (ACI) (1992). "Guide to Durable Concrete." ACI Manual of 

Concrete Practice-Part 1. ACI 201.2R-92. American Concrete Institute, Fmington Hills, MI. 

Elsen, J., et al. (1995). "Determination of the w/c Ratio of Hardened Cement Paste and Concrete 

Samples on Thin Sections Using Automated Image Analysis Techniques." Cement and Concrete 

Research. pp. 827-834. 

Gerold, B. T. (2000). Estimation of Water-Cement Ratios Using Fluorescent Petrography and 

Extreme Value Distributions. Thesis for a degree of Masters of Science in Civil Engineering. 

Michigan Technological University, Houghton, MI. 78 pp. 

Jakobsen, U.H., V. Johansen, and N. Thaulow (1995). "Estimating the Capillary Porosity of 

Cement Paste by Fluorescence Microscopy and Image Analysis." Materials Research Society 

Symposium Proceedings. Vol370. pp. 227-236. 

Jakobsen, U.H., V. Johansen, and N. Thaulow (1997). "Optical Microscopy - A Primary Tool in 

Concrete Examination." Proceedings: 1qh International Conference on Cement Microscopy. 

Cincinnati, OH. April 27 - May 1. pp. 275-286. 

Mayfield, B. (1990). "The Quantitative Evaluation of the WaterICement Ratio Using 

Fluorescence Microscopy." Magazine of Concrete Research. Vol42. No. 150. pp. 45-49. 

Neville, A. (1999). "How Useful is the Water-Cement Ratio?Toncrete International. Volume 

21, No. 9. September. pp. 69-70. 

Spry, P.G., G. Gan, R.D. Cody, and A.M. Cody (1996). "The Formation of Rims on Dolomite 

Aggregate in Iowa Highway Concrete." 1996 Semisesquicentennial Transportation Conference 

Proceedings. Transportation Research Board, Washington, DC. 

Stark, D., B. Morgan, P. Okamoto, and S. Diamond (1993). Eliminating or Minimizing AlkaliSilica Reacrivity. SHRP-C-343. Strategic Highway Research Program, Washington, DC. 

Walker, H. N. (1992). Petrographic Methods of Examining Hardened Concrete: A Petrographic 

Manual. Report No. FHWANA-R14. Virginia Transportation Research Council, Charlottesville, 

VA. 

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