Prediction of tire pavement contact stresses and analysis of asphalt pavement responses: A decoupled approach

This paper discusses the distribution of contact stress at the tire-pavement interface and how to quantify its impact on viscoelastic pavement responses using a decoupled modeling approach. The authors developed a tire-pavement interaction model to predict the three-dimensional (3-D) contact stresses under various loads and inflation pressures. In this model, an air-inflated radial-ply ribbed tire was loaded on a non-deformable pavement surface. The predicted contact stresses are consistent with previous measurements and validate the non-uniformity of vertical contact stresses and localized tangential contact stresses at the tire-pavement interface. The load primarily affects the vertical contact stress at the edge of the tire contact area and the longitudinal contact stress; while the inflation pressure primarily controls the vertical contact stress in the center region of the tire contact area and the transverse contact stress. Statistical models were developed to predict the 3-D contact stresses at each rib under various loads and inflation pressures. Utilizing the realistic contact stress distribution at the tire-pavement interface, a 3-D finite element (FE) model was built to analyze the critical pavement responses under moving tire loading. The FE model simulated the asphalt mixture layer as a linear viscoelastic material and considered the cross-anisotropic stress-dependent modulus for the unbound base layer. The authors concluded that when 3-D tire contact stresses are used in the analysis, the longitudinal fatigue cracking, primary rutting, and secondary rutting potential in thin asphalt pavement are increased, compared to when uniform contact stress distribution is applied. The heavy load causes increased responses in the base layer and subgrade, while high tire pressure causes increased response impact in the asphalt mixture layer, especially the shear stress at high temperature. The results of the analysis illustrate the importance of considering the realistic contact stress distribution when analyzing pavement responses under various loading and tire pressure conditions.