Volume 40, Issue 2 (March 2012)

    Evaluation of Air Void Distributions of Cement Asphalt Emulsion Mixes Using an X-Ray Computed Tomography Scanner

    (Received 27 March 2011; accepted 14 October 2011)

    Published Online: 2012

    CODEN: JTEOAD

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    Abstract

    Air void distributions of cement asphalt emulsion mixes are different from those of ordinary asphalt mixes. In order to evaluate a relationship between air voids and aggregate gradations, or binders of the mixes, an x-ray computed tomography (CT) scanner was used to quantify air void ratio, air void area, and air void size in the mixes. A rheometer and scanning electron microscope (SEM) were adopted to analyze viscosity and microstructures of the asphalt emulsion composites. The results indicate that larger air voids are concentrated on the top and the bottom of the mixes. The middle part of the mixes, which constitutes about 60–70 % of its thickness, has a nearly uniform size of air voids. The demarcation of air void ratio between suspended dense structure and framework dense structure is 6.0 %; and that between framework dense structure and framework void structure is 9.0 %. Adoption of ordinary Portland cement and appropriate increase of asphalt emulsion dosages are beneficial to the decrease of the air void ratio. The binders exert little effect on the increase of the air void sizes than the aggregate gradation types do. Benefits of cement addition are to generate hydrates which are helpful to decrease the air void ratios of the mixes.


    Author Information:

    Wang, Zhenjun
    School of Materials Science & Engineering and Engineering Research Central of Pavement Materials, Ministry of Education of P.R. China, Chang’an Univ., Xi’an,

    Xiao, Jingjing
    Key Laboratory of Highway Engineering in Special Regions of the Ministry of Education, Chang’an Univ., Xi’an,


    Stock #: JTE103881

    ISSN: 0090-3973

    DOI: 10.1520/JTE103881

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    Author
    Title Evaluation of Air Void Distributions of Cement Asphalt Emulsion Mixes Using an X-Ray Computed Tomography Scanner
    Symposium , 0000-00-00
    Committee D04