Influence of Tire-Pavement Contact Stress Distribution on Development of Distress Mechanisms in Pavements

Abstract

It is demonstrated that accurate characterization of tire-pavement contact stress distribution is important for the correct prediction of distress evolution in flexible pavements. First, an analysis of tire imprints and measured tire-pavement contact stress distribution leads to the conclusion that the shape of the contact area depends on the load and tire pressure and that the contact stress distribution is nonuniform. Second, software for a linear-layered elastic medium contrasts the stress distribution in a pavement due to two loads: a uniformly distributed pressure on a circular area and a distribution reported earlier by de Beer and Fisher. The analysis herein demonstrates that nonuniform contact stress distribution leads to considerably larger stresses in the pavement relative to the uniform stress distribution case. Consequently, both rut and crack evolution prediction would be different if they were based on true distribution rather than on the uniform distribution assumption. It is also shown that for overloaded tires, the contact area is rectangular, where the width of the contact is a tire property independent of the applied load. Therefore, approximating the load as a uniformly distributed stress over a circular area may lead to erroneous prediction regarding the transverse or longitudinal orientation of cracks.