Performance of WMA Technologies: Stage I--Moisture Susceptibility

Recently, interest in warm mix asphalt (WMA) has dramatically increased. WMA is now seen as an alternative to hot mix asphalt (HMA) offering the potential to lower energy demand during production and construction, reduce emissions at the plant and the paver, and increase allowable haul distances. However, there are still questions about the long-term performance and durability of WMA pavements. One key issue is the moisture susceptibility of WMA pavements. Concerns about WMA moisture susceptibility include the possibility that aggregates will be inadequately dried at lower production temperatures and the fact that several WMA technologies introduce additional moisture in the production process. The moisture susceptibility of HMA is evaluated by a variety of standard laboratory tests. The results of these tests on WMA indicate that WMA may be more susceptible to moisture damage than HMA. However, more limited data suggest that the resistance of WMA to moisture damage improves with time and may ultimately be equivalent to that of HMA. In some situations, anti-strip agents are added to WMA to address the issue of moisture susceptibility. However, as is the case with HMA, anti-strip agents may not always be compatible or work effectively with WMA. The objectives of this research are to (1) assess whether WMA technologies adversely affect the moisture susceptibility of flexible pavements and (2) develop guidelines for identifying and limiting moisture susceptibility in WMA pavements.


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  • Status: Completed
  • Funding: $450000.00
  • Contract Numbers:

    Project 9-49

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Harrigan, Edward

  • Performing Organizations:

    Texas A&M Transportation Institute, College Station

    Texas A&M University System
    3135 TAMU
    College Station, TX  United States  77843-3135
  • Principal Investigators:

    Martin, Amy

  • Start Date: 20100726
  • Expected Completion Date: 20100726
  • Actual Completion Date: 20130930
  • Source Data: RiP Project 22350

Subject/Index Terms

Filing Info

  • Accession Number: 01464202
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 9-49
  • Files: TRB, RiP, USDOT
  • Created Date: Jan 3 2013 2:38PM