Three-Dimensional Simulations of Asphalt Pavement Permanent Deformation Using a Nonlinear Viscoelastic and Viscoplastic Model

The writers recently developed a nonlinear viscoelastic-viscoplastic constitutive model, in order to represent the response of asphalt mixtures under different temperatures and rates of loading. This model has been implemented in the finite-element (FE) code Abaqus via the user material subroutine UMAT, and it was verified through comparisons with experimental data of asphalt mixtures at various stress levels and temperatures. This research develops a three-dimensional FE model using Abaqus to represent a three-layer pavement structure and to simulate the viscoelastic and viscoplastic responses under repeated loading at different temperatures. The results demonstrate the capability of the model in simulating the influence of temperature on permanent deformation and in predicting viscoelastic and viscoplastic strain distributions in the asphalt layer. The simulations show that tensile viscoplastic strain accumulates at the pavement surface, a phenomenon that could be associated with cracking of asphalt pavements. In addition, the results show that at high pavement temperature (40°C), tensile viscoplastic strain develops at the sides of the applied load due to asphalt mixture heave associated with permanent deformation and dilation.