Browsing by Author "Leon, Lee"

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    Stress-Strain and Failure Modes of Asphalt Concrete in Compression Due to Geometrical Changes
    (LACCEI Inc., 2018-09) Leon, Lee; Gay, Derek; Simpson, Nicola; Edwin, Shian
    Evaluation of asphalt concrete modes of failure and stress-strain relationship were investigated using static compression loading on cylindrical and prismatic specimens. Effects of shape, height, temperature, binder and testing orientation were investigated. Cylindrical specimens had greater stiffness than prismatic. Temperature has significant influence on initial tangent modulus and fracture energy. Parameters derived can be used to simulate behavior of asphalt concrete mixtures.
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    Suitable Laboratory Ranges of Confinement Stresses for Performance Testing of Asphalt Concrete
    (LACCEI Inc., 2018-09) Leon, Lee; Gay, Derek
    Flexible pavement distress prediction is largely based on laboratory and numerical simulation. The traditional triaxial laboratory performance testing of asphalt concrete has been carried out at various confining (radial) stress states, however they vary significantly in literature and some did not appear to relate to an appropriate in-situ field condition. The behavior of a flexible pavement structure is modelled in ABAQUS using axisymmetric finite element analysis. The interface between wheel and pavement does not significantly affect vertical stress states with depth, however the horizontal stress states decreases. The proposed confining stress value for performance testing of asphalt concrete should be between ranges of 30% to 40% of the (vertical stress) applied axial loading.