Degradation Behavior and Mechanism of HMA Aggregate

    Volume 40, Issue 5 (September 2012)

    ISSN: 0090-3973

    CODEN: JTEOAD

    Published Online: 1 August 2012

    Page Count: 11


    Ma, Tao
    School of Transportation, Southeast Univ., Nanjing,

    Huang, Xiaoming
    School of Transportation, Southeast Univ., Nanjing,

    Zhao, Yongli
    School of Transportation, Southeast Univ., Nanjing,

    Yuan, Hao
    Engineer Division, Jiangsu Shanshui Co. Ltd., Jurong,

    Ma, Xin
    China Academy of Transportation Sciences, Beijing,

    (Received 13 March 2012; accepted 11 May 2012)

    Abstract

    The degradation behavior and mechanism of aggregate used for hot mix asphalt (HMA) mixtures has been investigated in this study. Laboratory tests, including the crushing test, Marshall compactor test, and Superpave gyratory compactor test, were used to evaluate the degradation behavior of single-size aggregate and/or graded aggregates. In order to verify the laboratory test results, the degradation of field HMA materials extracted from asphalt pavements after long-time service was also evaluated. The stress-transfer model for an aggregate skeleton was analyzed in order to provide a fundamental understanding of the stress distribution and degradation mechanism of the aggregate system. The results indicate that the degradation of the aggregate gradation is not random and has a fixed internal trend. The 4.75 mm aggregate proved to be the demarcation point between coarse and fine aggregate. During the degradation process, coarse aggregate tends to break into graded aggregate to form a well-balanced skeleton to bear an external load, and the 4.75 mm aggregate plays a key role in the graded aggregate. The crushing test and Superpave gyratory compactor test proved to be easily done and promising for capturing the degradation of aggregate and the gradation of HMA. The variation in the retained percentage of 4.75 mm aggregate and the breakdown ratio of the original aggregate and/or gradation can quantitatively depict the degradation of HMA aggregate.


    Paper ID: JTE20120057

    DOI: 10.1520/JTE20120057

    ASTM International is a member of CrossRef.

    Author
    Title Degradation Behavior and Mechanism of HMA Aggregate
    Symposium , 0000-00-00
    Committee D04