NCHRP Synthesis 20-05/Topic 51-07 [Active (Synthesis)]
Practices for Assessing and Mitigating the Moisture Susceptibility of Asphalt Pavements
[ NCHRP 20-05 (Synthesis of Information Related to Highway Practices) ]
| Project Data
|Authorization to Begin Work:
||5/1/2019 -- estimated |
||Jo Allen Gause
||Rebecca S. McDaniel|
Moisture-induced damage of asphalt pavements is a national problem; millions of dollars are spent each year on maintenance of flexible pavements. In general, moisture damage involves physical, chemical, mechanical, and thermodynamic processes, all occurring within the asphalt mixture at different magnitudes and rates. Some of the mechanisms of moisture damage include adhesion failure between asphalt and aggregate, cohesion failure within the asphalt binder, emulsification of the asphalt, freezing of entrapped water, and cohesion degradation within the aggregate.
Different agencies and research groups are continually searching for methods that can be used to identify and prevent potential moisture damage in asphalt pavements. Most of the methods adopted by state departments of transportation (DOT) focus on testing asphalt mixtures and the adhesive bond between the aggregate and the asphalt binders. Some agencies use prescriptive methods, such as requiring the use of liquid additives, hydrated lime, or materials-based specifications. Agencies are also looking into other practices to help assess moisture damage, such as the MIST device, surface free energy analyses, and asphalt chemical analyses.
The objective of this synthesis is to document current practices used by DOTs to assess and mitigate the potential for moisture-induced damage in asphalt pavements. The study will focus on asphalt mix design and acceptance.
Information to be gathered includes, but is not limited to:
• Specific tests used by DOTs to identify an asphalt mixture’s potential moisture susceptibility (e.g., AASHTO T 283, AASHTO T 324);
• Modifications of tests methods used (e.g., temperature differences, mixture conditioning);
• Specific moisture susceptibility criteria used by DOTs (e.g., tensile strength ratio, stripping inflection point);
• Prescriptive methods used by DOTs to prevent moisture damage (e.g., material-based selection, mandated use of hydrated lime or additives);
• Predictability and reliability of methods to accept materials/asphalt mixtures that prevent moisture damage; and
• Emerging technologies and procedures to assess moisture susceptibility not widely implemented by DOTs (e.g., MIST device, surface free energy analyses, and asphalt chemical analyses).
Information will be gathered through literature review, a survey of DOTs, and interviews with selected agencies for the development of case examples. The survey should be directed to DOT voting members of the AASHTO Committee on Materials and Pavements. Knowledge gaps and suggestions for research to address those gaps will be identified.
Information Sources (Partial):
- Anderson, D., Youtcheff, J., & Zupanick, M. (2000). Asphalt Binders. TRB Committee on Characteristics of Bituminous Materials, TRB Millennium Paper Series.
- Kim, Y. R., Ban, H., & Pinto, I. (2009). Moisture Sensitivity of Hot-mix Asphalt (HMA) Mixtures in Nebraska: Phase II. Nebraska Department of Roads.
- Solaimanian, M., Harvey, J., Tahmoressi, M., & Tandon, V. (2003). Test methods to predict moisture sensitivity of hot-mix asphalt pavements. In Moisture Sensitivity of Asphalt Pavements-A National Seminar.
- D'angelo, J., & Anderson, R. M. (2003). Material production, mix design, and pavement design effects on moisture damage. In Moisture Sensitivity of Asphalt Pavements-a National Seminar.
- Wei, J., Dong, F., Li, Y., & Zhang, Y. (2014). Relationship analysis between surface free energy and chemical composition of asphalt binder. Construction and Building Materials, 71, 116-123.
- Caro, S., and Rivera, C. (2017). “Moisture damage RNS: facing new challenges,” Presented at the TRB AFK 40 Committee Meeting, 2017 TRB Annual Meeting, Washington D.C. January 7-12, 2017.
Jo Allen Gause
First Panel: September 24, 2019, Washington, DC
Teleconference with Consultant: October 22, 2019, 10:00 am, ET
Second Panel: June 2, 2020, Washington, DC
Lyndi D. Blackburn, Alabama DOT
Danny Gierhart, Asphalt Institute
Steve Hefel, Wisconsin DOT
Larry Ilg, Oregon DOT
Derek J. Nener-Plante, Maine DOT
Pranshoo Solanki, Illinois State University
Timothy B. Aschenbrener, FHWA
Nelson H. Gibson, TRB