Compressive loading helps to confirm the rutting of the load-induced distresses found in Clay-asphalt trays. Interestingly, the mechanism of rutting is associated with shear deformation rather than densification. Recently, uniaxial cracking and its propagation is probably attributed to shear failure. Clearly, shear stress is one of the critical factors affecting clay-asphalt performance. Conventionally, laminar design methodologies assume the compressive machine stress is equivalent to tire inflation pressure under loading and uniformly distributed over a circular contact area. In fact, the compressive loading pressure is non- circular and contact pressure is not uniform and the same as tire inflation pressure. This study evaluates the shear stress in asphalt mixture layers produced by non-uniform stresses applied to the laminar surface, in a simulation of field conditions. Then a concrete analysis is carried out for a Clay- asphalt laminar. The calculated results indicate the maximum shear stress occurs at a point approximately 50 mm under the compressive loading. The loading distinctly affects shear stress. Bonding at the interface between the asphalt mixture layer and the clay-base course obviously affects shear stress as well.
