Evaluation on Fatigue Life of Expressway Asphalt Pavement Based on Tire-Pavement-Subgrade Coupling Model

Abstract

The fatigue failure has become one of the main failure modes in asphalt pavement of expressway. However, due to the material nonlinear of the tire, pavement and subgrade, the contact nonlinear of tire-pavement and the influence factors, such as the tire inflation pressure, rotation speed, wheel load, the values and distributions of contact stress between tire and pavement are extremely complex and affect the tensile stress and tensile strain, as well as affect the wear, deformation and fatigue life of pavement. The three dimensional (hereinafter referred to as 3D) finite element model of tire-subgrade-pavement structure was established, and the steady-stable rolling of tire and stress-dependent dynamic resilient modulus of subgrade soil were considered in the model．Based on the mixed Euler-Lagrange describtion, the steady-state finite element analysis were carried to indicate the mechanism of fatigue cracking of asphalt pavement, the influences of rolling resistance of wheel, friction coefficient, axle load, tire pressure and running velocity on fatigue lives were discussed based on the tensile strain fatigue prediction model. The results show that the fatigue life of pavement decreases with the increasing rolling resistance of wheel, friction coefficient, wheel load and tire pressure, and it does not obvisouly depend on the running velocity. The study could provide a reference for the design of the flexible asphalt pavement structure and the evaluation of pavement fatigue life.