Combined Effect of Moving Wheel Loading and Three-Dimensional Contact Stresses on Perpetual Pavement Responses

Tire–pavement interaction was analyzed with measured three-dimensional (3-D) tire contact stresses at various load levels (35, 44, and 53 kN) and constant tire pressure (720 kPa). The combined effect of moving wheel load and 3-D contact stresses on flexible pavement response was evaluated with a developed 3-D finite element (FE) model, which incorporated the measured 3-D tire contact stresses, hot-mix asphalt (HMA) viscoelasticity, and continuous moving load by using implicit dynamic analysis. In FE modeling, a perpetual pavement design with 254-mm HMA placed on 305-mm lime-modified subgrade was exposed to dual tire loading. The critical pavement responses under two loading conditions (uniform contact stresses and measured 3-D contact stresses) at various load levels were calculated and compared. The 3-D tire contact stresses induced greater pavement stresses and strains at the pavement near surface (shear strains and octahedral shear stresses) and at deeper depths (transverse tensile strains and compressive strains) comparable to the uniform contact stresses; these results suggest that using uniform contact stresses could underestimate pavement damage, especially near-surface cracking potential and shear flow in perpetual pavement. The transverse tangential stresses induce the outward shear flow from the tire center and shear strain concentration at the pavement near surface. Increasing the wheel load mostly increases contact stresses at the tire edge and the corresponding shear strains and octahedral shear stresses. The difference between pavement responses caused by uniform contact stresses and 3-D contact stresses decreases when wheel load increases.