Connected Air Voids Content in Permeable Friction Course Mixtures

    Volume 37, Issue 3 (May 2009)

    ISSN: 0090-3973

    CODEN: JTEOAD

    Published Online: 26 February 2009

    Page Count: 10


    Alvarez, Allex E.
    Ph.D. CandidateAssistant Professor, Zachry Department of Civil Engineering, Texas A&M UniversityUniversity of Magdalena,

    Epps Martin, Amy
    Associate Professor, Zachry Department of Civil Engineering, Texas A&M University,

    Estakhri, Cindy
    Associate Research Engineer, Texas Transportation Institute,

    (Received 4 August 2008; accepted 25 January 2009)

    Abstract

    Current hot mix asphalt (HMA) mix design procedures used to determine the optimum asphalt content for permeable or porous friction course (PFC) mixtures are based primarily on total air void (AV) content. Durability and functionality of PFC mixtures are also related to the total AV content. However, the connected AV content (defined as the proportion of AV that form connected pathways for air and water transport through PFC mixtures) may provide more insight into the mixture structure in terms of the AV content directly associated with functionality and durability properties and constitute an alternative parameter to conduct PFC mix design and evaluation. This study evaluated two laboratory methodologies (vacuum and dimensional analysis) for determining water-accessible AV content and two types of analysis to compute interconnected AV content based on X-ray Computed Tomography (X-ray CT) and image analysis techniques. Although both the interconnected AV content and water-accessible AV content constitute determinations of connected AV content, different nomenclature was used to differentiate the origin of the calculation. Dimensional analysis with application of vacuum and X-ray CT and image analysis with inclusion of surface AV are recommended for determining water-accessible AV content and interconnected AV content, respectively. Future work should focus on investigating the use of connected AV content as an alternative parameter to integrate in mix design and laboratory and computational evaluation of PFC mixtures.


    Paper ID: JTE102056

    DOI: 10.1520/JTE102056

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    Author
    Title Connected Air Voids Content in Permeable Friction Course Mixtures
    Symposium , 0000-00-00
    Committee D04