STP1375: Effect of Frequency-dependent Asphalt Concrete Layer Moduli on Pavement Response

    Chatti, K
    Assistant Professor and Graduate Student, Michigan State University, East Lansing, MI

    Kim, TK
    Assistant Professor and Graduate Student, Michigan State University, East Lansing, MI

    Pages: 18    Published: Jan 2000


    Abstract

    The viscoelastic nature of asphalt concrete (AC) renders its properties to be frequency-dependent. Static backcalculation of layer moduli from Falling Weight Deflectometer (FWD) testing does not take into account this frequency-dependence. This paper shows the effect of frequency-dependent AC properties on the horizontal strain and vertical deflection using the computer program SAPSI-M and field results. The analysis shows that the decrease in horizontal strain with increasing truck speed can be duplicated only by using frequency-dependent properties for the asphalt concrete layer. However, using a constant backcalculated AC surface layer modulus and static analysis seems to be sufficient for giving a prediction that is reasonably close to the actual tensile strain under moving loads. This is so because the backcalculated modulus value for the AC surface layer is generally higher than the creep modulus, and the horizontal tensile strain is not affected by speed when using a constant AC layer modulus.

    Keywords:

    falling weight deflectometer, frequency, backcalculation, moving load, asphalt concrete properties


    Paper ID: STP14778S

    Committee/Subcommittee: D04.39

    DOI: 10.1520/STP14778S


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