Anisotropic nonlinear elastoviscoplastic model for rutting of asphalt mixtures

Rutting, one of the primary distresses in asphalt pavement, is influenced by the nonlinear deformation of its constituents and their microstructural features such as the directional distribution of aggregates and cracks. This study develops a nonlinear elastoviscoplastic model to systematically account for the aggregate directional distribution and damage propagation during the accumulation of permanent deformation. This is accomplished by incorporating a fabric tensor for aggregates and a direction-dependent damage parameter into the yield and potential functions and by the use of Perzyna's viscoplastic formulation. The comparison of indirect tensile test results with the predictions from the model show that the model captures the permanent deformation of asphalt mixtures well.