Volume 41, Issue 6 (November 2013)
    Volume 41, Issue 6 (November 2013)

    Mechanistic Evaluation of the Effect of WMA Additives on Wettability and Moisture Susceptibility Properties of Asphalt Mixes

    (Received 31 October 2012; accepted 28 March 2013)

    (Received 31 October 2012; accepted 28 March 2013)

    Published Online: 2013

    CODEN: JTEOAD

    Published Online: 2013

    CODEN: JTEOAD

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    Abstract

    This study used a mechanistic framework (i.e., surface free energy) to evaluate the moisture susceptibility of warm mix asphalt (WMA) with three different WMA additives, namely, Sasobit, Advera, and Evotherm. The surface free energy (SFE) components of modified PG64-22 asphalt binder with different percentages of WMA additives and selected aggregates were measured in the laboratory. The wettability, the work of adhesion, the work of debonding, and energy ratios were estimated in order to assess the moisture-induced damage potential of combinations of modified asphalt binders and different aggregates. The results indicate that Sasobit and Advera are able to reduce the moisture susceptibility potential of the mixes, but their use is not recommended with highly acidic aggregates such as granite. Evotherm resulted in the highest increases in wettability, total surface free energy, and increased work of adhesion and a reduction in the work of debonding, resulting in a better possible aggregate coating with asphalt binder and lower moisture susceptibility with all types of tested aggregates relative to those of other WMA additives. Furthermore, tensile strength ratio (TSR) tests were conducted on Advera and Evotherm-modified and neat (unmodified) asphalt mixes, and the results were compared with those from the SFE test. It was found that the SFE approach is a better indicator of moisture susceptibility than the traditional TSR test. The findings of the present study would help the highway engineers and agencies to better understand the moisture damage potential of flexible pavements constructed with WMA technologies.


    Author Information:

    Ghabchi, Rouzbeh
    Doctoral Candidate, School of Civil Engineering and Environmental Science, Univ. of Oklahoma, Norman, OK

    Singh, Dharamveer
    Assistant Professor, Dept. of Civil Engineering, Indian Institute of Technology (IIT), Bombay,

    Zaman, Musharraf
    David Ross Boyd Professor and Aaron Alexander Professor of Civil Engineering, Professor of Petroleum and Geological Engineering, Associate Dean for Research and Graduate Programs, College of Engineering, Univ. of Oklahoma, Norman, OK

    Tian, Qingyan
    Former Visiting Scholar, School of Civil Engineering and Environmental Science, Univ. of Oklahoma, Norman, OK


    Stock #: JTE20120317

    ISSN: 0090-3973

    DOI: 10.1520/JTE20120317

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    Author
    Title Mechanistic Evaluation of the Effect of WMA Additives on Wettability and Moisture Susceptibility Properties of Asphalt Mixes
    Symposium , 0000-00-00
    Committee D04