Cost-effectiveness of crack sealing materials and techniques for asphalt pavements

2004·3.2 MB·English

by  Cuelho, Eli

C -E C S M
OST FFECTIVENESS OF RACK EALING ATERIALS
T A P
AND ECHNIQUES FOR SPHALT AVEMENTS

Final Report

By

Eli Cuelho

of the

Western Transportation Institute
College of Engineering
Montana State University – Bozeman

and

Reed B. Freeman

of the

U.S. Army Engineer Waterways Experiment Station
Airfields and Pavements Division

Prepared for the

STATE OF MONTANA
DEPARTMENT OF TRANSPORTATION
RESEARCH SECTION

in cooperation with the

U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION

April 2004
TECHNICAL REPORT DOCUMENTATION PAGE

1. Report No. 2. Government Access No. 3. Recipient’s Catalog No.
FHWA/MT-04-006/8127

4. Title and Subtitle 5. Report Date
Cost-Effectiveness of Crack Sealing Materials and Techniques for April 2004
Asphalt Pavements

6. Performing Organization Code

7. Author(s) 8. Performing Organization Report Code
Eli Cuelho and Reed Freeman

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

PO Box 174250 11. Contract or Grant No.
Montana State University - Bozeman MSU G&C #429800
Bozeman, Montana 59717 MDT Project #8127

12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered
Montana Department of Transportation Final Report
2701 Prospect Avenue October 1995 – December 2003
Helena, Montana 59620-1001

14. Sponsoring Agency Code
5401

15. Supplementary Notes
Research performed in cooperation with the Montana Department of Transportation and the U.S. Department of Transportation, Federal
Highway Administration. This report can be found at: http://www.mdt.state.mt.us/research/docs/research_proj/crackseal/final_report.pdf

16. Abstract
Sealing or filling cracked asphalt pavements to prevent the intrusion of water into the pavement structure has long been an accepted
practice of the Montana Department of Transportation (MDT). The goals of this research are to establish the most economical and effective
method of sealing pavement cracks for Montana; and to better determine the role of crack sealing within Montana’s pavement management
system (PvMS). This study has involved the construction of four experimental test sites within larger crack sealing projects. These test sites
have included combinations of eleven sealant materials and six sealing techniques. Monitoring of the test sites includes visual inspections
(for all of the sites) and nondestructive structural readings and surface distress identification under Montana’s PvMS (for one test location).
An estimate of the useful life of each crack sealing method has been determined from these investigations.
This report presents information on project history, the project methodology used for evaluating and analyzing the performance of sealed
cracks, and the results of the cost-effectiveness analysis. Final results are presented for the four test sites: Conrad, Dutton, Tarkio, and Helena
(Seiben). Results show that similar performance has been observed for all materials with ASTM D 5329 cone penetrations in excess of 90. In
general, routing of transverse cracks improved the performance of the sealants. Routing does not appear necessary for centerline longitudinal
cracks. Notably, router operators seem to prefer the shallow reservoir configuration as compared to square reservoirs.
The test site established near Helena provided the most reliable and useful data. As such, a detailed review of the final performance from
four and a half years of service is summarized. In general, the highest failure rates occur during the coldest period of the year, and much of
this distress exhibits a tendency to “heal” after exposure to the summer heat and traffic. An eclectic forecasting model has proven useful in
predicting the life of crack sealing operations for those methods that did not show complete failure during the evaluation period. Structural
evaluations using a Falling Weight Deflectometer did not prove an advantage for any particular sealing technique or sealing material nor did
they prove the benefit of sealing cracks in asphalt pavements. Therefore, conducting a life-cycle cost analysis was impractical because no
structural or ride benefit was proven at this site, however, a cost-effectiveness analysis was performed and the averaged results showed that,
overall, Crafco 522 was the most cost-effective material and the Shallow and Flush was the most cost-effective fill technique. However, the
crack sealing approach that has the highest cost-effectiveness as calculated herein (defined as the ratio of effectiveness to cost) may not offer
the best value, if this effectiveness is in excess of that required to protect the pavement from premature damage. Therefore, even though the
most cost-effective material and techniques have been determined, more research is necessary to substantiate the need for higher performance

materials and techniques.

17. Key Words 18. Distribution Statement
Montana, crack sealing, sealant, routing, capped, band-aid, No restrictions. This document is
reservoir, flush, recess, cost-effectiveness analysis, IRI, FWD, available to the public through NTIS,
structural monitoring Springfield, Virginia 22161.

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages: 313 22. Price
Unclassified Unclassified
Western Transportation Institute ii
ACKNOWLEDGMENTS
The authors would like to extend their appreciation to the Montana Department of Transportation
(MDT) for their sponsorship and participation in this project. The following groups within MDT
provided essential technical assistance: the Research Section, the project technical panel, the
Non-Destructive Testing Unit, the Pavement Management Unit, technicians in the Sealant
Testing Laboratory, and field personnel from the Maintenance Division.
In addition, the authors would like to thank David Johnson for being involved with this project
since its inception, remaining faithful to its vision, and bringing the continuity necessary to make
the project valuable throughout its duration. His attention to detail during the construction and
evaluation, and his hard work collecting the bulk of the data have been invaluable to the project.
DISCLAIMER
This document is disseminated under the sponsorship of the Montana Department of
Transportation and the United States Department of Transportation in the interest of information
exchange. The State of Montana and the United States Government assume no liability of its
contents or use thereof.
The contents of this report reflect the views of the authors, who are responsible for the facts and
accuracy of the data presented herein. The contents do not necessarily reflect the official policies
of the Montana Department of Transportation or the United States Department of Transportation.
The State of Montana and the United States Government do not endorse products of
manufacturers. Trademarks or manufacturers’ names appear herein only because they are
considered essential to the object of this document.
This report does not constitute a standard, specification, or regulation.
ALTERNATIVE FORMAT STATEMENT
The Montana Department of Transportation attempts to provide reasonable accommodations for
any known disability that may interfere with a person participating in any service, program, or
activity of the Department. Alternative accessible formats of this document will be provided
upon request. For further information, call [phone] or TTY [phone].
NOTICE
The authors, the State of Montana, and the Federal Highway Administration do not endorse
products or manufacturers. Trade and manufacturers names appear herein solely because they
are considered essential to the objective of this report.
Western Transportation Institute iii
ABSTRACT
ABSTRACT
Sealing or filling cracked asphalt pavements to prevent the intrusion of water into the pavement
structure has long been an accepted practice of the Montana Department of Transportation
(MDT). The goals of this research are to establish the most economical and effective method of
sealing pavement cracks for Montana; and to better determine the role of crack sealing within
Montana’s pavement management system (PvMS). This study has involved the construction of
four experimental test sites within larger crack sealing projects. These test sites have included
combinations of eleven sealant materials and six sealing techniques. Monitoring of the test sites
includes visual inspections (for all of the sites) and nondestructive structural readings and surface
distress identification under Montana’s PvMS (for one test location). An estimate of the useful
life of each crack sealing method has been determined from these investigations.
This report presents information on project history, the project methodology used for evaluating
and analyzing the performance of sealed cracks, and the results of the cost-effectiveness analysis.
Final results are presented for the four test sites: Conrad, Dutton, Tarkio, and Helena (Seiben).
Results show that similar performance has been observed for all materials with ASTM D 5329
cone penetrations in excess of 90. In general, routing of transverse cracks improved the
performance of the sealants. Routing does not appear necessary for centerline longitudinal
cracks. Notably, router operators seem to prefer the shallow reservoir configuration as compared
to square reservoirs.
The test site established near Helena provided the most reliable and useful data. As such, a
detailed review of the final performance from four and a half years of service is summarized. In
general, the highest failure rates occur during the coldest period of the year, and much of this
distress exhibits a tendency to “heal” after exposure to the summer heat and traffic. An eclectic
forecasting model has proven useful in predicting the life of crack sealing operations for those
methods that did not show complete failure during the evaluation period. Structural evaluations
using a Falling Weight Deflectometer did not prove an advantage for any particular sealing
technique or sealing material nor did they prove the benefit of sealing cracks in asphalt
pavements. Therefore, conducting a life-cycle cost analysis was impractical because no
structural or ride benefit was proven at this site, however, a cost-effectiveness analysis was
performed and the averaged results showed that, overall, Crafco 522 was the most cost-effective
material and the Shallow and Flush was the most cost-effective fill technique. However, the
crack sealing approach that has the highest cost-effectiveness as calculated herein (defined as the
ratio of effectiveness to cost) may not offer the best value, if this effectiveness is in excess of that
required to protect the pavement from premature damage. Therefore, even though the most cost-
effective material and techniques have been determined, more research is necessary to
substantiate the need for higher performance materials and techniques.
Western Transportation Institute iv
CONTENTS
TABLE OF CONTENTS
1 Experimental Setup.......................................................................................................................1
1.1 Test Sites..............................................................................................................................1
1.2 Materials...............................................................................................................................2
1.3 Sealing Techniques..............................................................................................................4
1.4 Construction of Test Sites....................................................................................................5
2 Evaluation Methodology.............................................................................................................10
3 Results.........................................................................................................................................13
3.1 Crack Inventory..................................................................................................................13
3.2 Coin Test Results...............................................................................................................15
3.3 Pavement Movement..........................................................................................................15
3.4 Condition Survey Results...................................................................................................15
3.4.1 Conrad Condition Survey Results..............................................................................17
3.4.2 Dutton Condition Survey Results...............................................................................19
3.4.3 Tarkio Condition Survey Results...............................................................................21
3.4.4 Helena Condition Survey Results..............................................................................22
3.4.5 Summary of Condition Survey Results......................................................................33
3.5 Structural Condition Monitoring of Helena Test Site........................................................35
3.5.1 FWD Testing Methodology.......................................................................................35
3.5.2 Structural Condition Monitoring – Results................................................................36
3.5.3 Structural Condition Monitoring – Conclusions........................................................52
3.6 Pavement Roughness.........................................................................................................52
4 Cost-Effectiveness Analysis.......................................................................................................55
4.1 Cost Information................................................................................................................56
4.2 Overall Cost of Installing Crack Sealant............................................................................56
4.3 Material Costs....................................................................................................................57
4.4 Cost-Effectiveness Analysis..............................................................................................58
5 Conclusions.................................................................................................................................64
6 References...................................................................................................................................67
Appendix A: Weather Data.........................................................................................................A-1
Appendix B: Crack Inventory for the Conrad Site......................................................................B-1
Appendix C: Crack Inventory for the Dutton Site.......................................................................C-1
Appendix D: Crack Inventory for the Tarkio Site......................................................................D-1
Appendix E: Crack Inventory for the Helena Site.......................................................................E-1
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CONTENTS
Appendix F: Coin Tests...............................................................................................................F-1
Appendix G: Pavement Movement Measurements....................................................................G-1
Appendix H: Condition Survey Results for the Conrad Site......................................................H-1
Appendix I: Condition Survey Results for the Dutton Site..........................................................I-1
Appendix J: Condition Survey Results for the Tarkio Site...........................................................J-1
Appendix K: Condition Survey Results for the Helena Site.......................................................K-1
Appendix L: Structural Condition Data for the Helena Site........................................................L-1
Appendix M: Eclectic Forecasting Results for the Helena Site..................................................M-1
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CONTENTS
LIST OF TABLES
Table 1: Summary of Traffic Volumes...........................................................................................2
Table 2: Average Annual Weather Statistics..................................................................................2
Table 3: Properties for the Cold-Pour Materials as Advertised on the Manufacturer Data
Sheet..............................................................................................................................3
Table 4: Properties for Hot-Pour Materials as Advertised on Manufacturer Data Sheets..............3
Table 5: Crack Sealing Experiment - Interstate 15 North of Conrad, MT.....................................6
Table 6: Crack Sealing Experiment - Interstate 15 North of Dutton, MT......................................7
Table 7: Crack Sealing Experiment - Interstate 90 West of Tarkio, MT........................................8
Table 8: Crack Sealing Experiment - Interstate 15 North of Helena, MT......................................9
Table 9: Qualitative Ratings for Failure Percentages...................................................................10
Table 10: History of Crack Inventory and Condition Surveys of the Four Test Sites..................12
Table 11: Summary of Abbreviations for Test Site Descriptions and Distress Information........16
Table 12: Final Summary of Average Distress for Transverse Cracks at the Conrad Site
Five Years after Construction......................................................................................18
Table 13: Final Summary of Average Distress for Longitudinal Centerline Cracks at the
Conrad Site Five Years after Construction..................................................................19
Table 14: Final Summary of Average Distress for Transverse Cracks at the Dutton Site
Four Years after Construction.....................................................................................20
Table 15: Final Summary of Average Distress for Transverse Cracks at the Tarkio Site
Three Years after Construction...................................................................................21
Table 16: Final Summary of Average Distress for Longitudinal Cracks at the Tarkio Site
Three Years after Construction...................................................................................22
Table 17: Summary of Average Distress for Transverse Cracks at the Helena Site as of
February 1999 – Six Months after Construction.........................................................23
Table 18: Summary of Average Distress for Transverse Cracks at the Helena Site as of
April 2001 – Thirty-Two Months after Construction..................................................24
Table 19: Summary of Average Distress for Transverse Cracks at the Helena Site as of
February 2002 – Forty-Two Months following Construction.....................................26
Table 20: Summary of Average Distress for Transverse Cracks at the Helena Site as of
May 2003 – Fifty-Seven Months following Construction..........................................27
Table 21: Evaluation Results with Forecasted Life Expectancies for the Helena Test Site.........32
Table 22: Ranking of Best Material/Technique Combinations at the Helena Test Site
Based on the Eclectic Forecasting Analysis................................................................34
Table 23: Soil classifications for base course and subgrade soils at and near the Helena
site...............................................................................................................................35
Table 24: History of FWD Testing at the Helena Test Site..........................................................37
Table 25: Correlations and Comparisons between Loads 2 and 3................................................40
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CONTENTS
Table 26: Average Pavement Stiffness for Sealed Sections on the Initial Test Date (Sept.
17, 1998)......................................................................................................................51
Table 27: Average Pavement Stiffness for Sealed Sections on the Ninth Test Date (Sept.
4, 2002)........................................................................................................................51
Table 28: Average Percent Change in Pavement Stiffness for Sealed Sections from the
Initial Test Date to the Ninth Evaluation Date............................................................52
Table 29: Estimated Costs and Coverage of the Various Fill Techniques...................................56
Table 30: Material Costs as Provided by Vendors........................................................................57
Table 31: Total Cost of Installing Specific Material/Technique Combinations for the
Helena Site..................................................................................................................58
Table 32: Measured and Estimated Life Expectancy of the Helena Material/Technique
Combinations...............................................................................................................59
Table 33: Cost-Effectiveness Values of the Helena Material/Technique Combinations
using Method A...........................................................................................................61
Table 34: Cost-Effectiveness Values of the Helena Material/Technique Combinations
using Method B...........................................................................................................62
Table 35: Individual Rankings of Specific Material/Technique Combinations Based on
Their Cost-Effectiveness.............................................................................................62
Western Transportation Institute viii
CONTENTS
LIST OF FIGURES
Figure 1: Location of Experimental Crack Sealing Sites within the State of Montana..................1
Figure 2: Crack Sealing Techniques...............................................................................................4
Figure 3: Comparison of Transverse Crack Propagation..............................................................14
Figure 4: Comparison of Longitudinal Crack Propagation...........................................................14
Figure 5: Example of Double Adhesion Failure Associated with the Shallow and Flush
Technique....................................................................................................................25
Figure 6: Average Total Failure of Sealant Materials Independent of Fill Technique for
Helena..........................................................................................................................28
Figure 7: Average Total Failure of Fill Technique Independent of Sealant Materials for
Helena..........................................................................................................................29
Figure 8: Winter’s Seasonal Exponential Smoothing for Crafco 522, BA...................................30
Figure 9: Eclectic Forecasting Results for Crafco 522, BA..........................................................31
Figure 10: Deflection Basin during a Falling-Weight Deflectometer Test...................................35
Figure 11: Percent Change in Pavement Stiffness from Initial Test Date....................................38
Figure 12: Percent Change in Asphalt Concrete Modulus from Initial Test Date........................39
Figure 13: Percent Change in Base Course Modulus from Initial Test Date................................39
Figure 14: Percent Change in Subgrade Modulus from Initial Test Date.....................................40
Figure 15: Pavement Stiffness over Time for the Unsealed Control Pavement (Control
Section)........................................................................................................................41
Figure 16: AC Modulus over Time for the Unsealed Control Pavement (Control Section)........42
Figure 17: Base Course Modulus over Time for the Unsealed Control Pavement (Control
Section)........................................................................................................................42
Figure 18: Subgrade Modulus over Time for the Unsealed Control Pavement (Control
Section)........................................................................................................................43
Figure 19: Average Pavement Surface Temperatures..................................................................44
Figure 20: Pavement Stiffness over Time for the Sealed and Unsealed Test Sections................45
Figure 21: Asphalt Concrete Modulus over Time for the Sealed and Unsealed Test
Sections.......................................................................................................................45
Figure 22: Base Course Modulus over Time for the Sealed and Unsealed Test Sections............46
Figure 23: Subgrade Modulus over Time for the Sealed and Unsealed Test Sections.................46
Figure 24: Variability in Pavement Stiffness between Tests within Test Sections......................48
Figure 25: Variability in Asphalt Concrete Modulus between Tests within Test Sections..........48
Figure 26: Variability in Base Course Modulus between Tests within Test Sections..................49
Figure 27: Variability in Subgrade Modulus between Tests within Test Sections.......................49
Figure 28: Average IRI of the Driving Lane for the Helena Test Sections..................................54
Figure 29: Average IRI of the Passing Lane for the Helena Test Sections..................................54
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CONTENTS
Figure 30: Method of Determining Individual Bid Prices for All Material/Technique
Combinations...............................................................................................................58
Figure 31: Example of Assumed Crack Sealant Performance Curve (Method A).......................59
Figure 32: Example of Performance Curve for Crack Sealant Lasting Greater Than 84
Months.........................................................................................................................60
Figure 33: Example of Actual Crack Sealant Performance Curve (Method B)...........................61

Western Transportation Institute x