Foamed Warm Mix Asphalt Design Issues

Warm Mix Asphalt (WMA) has quickly become a popular topic in the asphalt industry, and the Federal Highway Administration (FHWA) is actively encouraging implementation of WMA in all states. While a fair assessment plan has been developed with regard to mix design for WMA technologies using additives (TRC-1004), a number of questions remain as to the most appropriate method for assessing plant-foamed WMA. There are currently three devices available for simulating the plant-foaming technique in the laboratory, though no data is yet available to determine whether these devices provide a suitable representation of field produced mixtures. Data from Project TRC-1004 suggests that a WMA design should not be developed by simply altering a Hot Mix Asphalt (HMA) design by 'plugging in' a WMA additive. Thus, it is reasonable that the same would be true of the plant-foaming techniques. The Arkansas Highway and Transportation Department (AHTD) does not currently have a laboratory foamer, and as a result, has no mechanism for approving WMA mix designs that are intended to be generated by a plant-foaming technique. However, the majority of warm mix in Arkansas is produced using a plant-foaming technique. The results of the recently completed NCHRP project 9-43 indicate that a laboratory foamer is necessary for all WMA mix designs that will utilize plant-foaming techniques. In addition, recommendations have been made to append AASHTO R35 to require a laboratory foamer for the design of such mixes. Thus, an evaluation is necessary to determine how a laboratory foamer could or should be used for the purpose of WMA mix design approval in Arkansas. Additional investigations of WMA and RAP/RAS combinations in laboratory-foamed mixes will also be studied.

    Language

    • English

    Project

    • Status: Completed
    • Funding: $343626.00
    • Contract Numbers:

      TRC-1304

    • Sponsor Organizations:

      Arkansas State Highway and Transportation Department

      P.O. Box 2261
      Little Rock, AR  United States  72203
    • Project Managers:

      Tamayo, Sarah

    • Performing Organizations:

      University of Arkansas, Fayetteville

      Board of Trustees
      Fayetteville, AR  United States 
    • Principal Investigators:

      Braham, Andrew

      Williams, Stacy

    • Start Date: 20120701
    • Expected Completion Date: 0
    • Actual Completion Date: 20140630
    • Source Data: RiP Project 32769

    Subject/Index Terms

    Filing Info

    • Accession Number: 01542995
    • Record Type: Research project
    • Source Agency: Arkansas State Highway and Transportation Department
    • Contract Numbers: TRC-1304
    • Files: RiP
    • Created Date: Nov 1 2014 1:41AM