Rutting prediction of asphalt concrete materials using a multi-criteria viscoplasticity model

These last few years, many efforts have been devoted to the study of rutting problems. In fact, under high traffic loadings together with the extreme environmental conditions, permanent deformations of asphalt pavements appear and become more and more severe demanding more efforts on developing suitable predictive models. In this paper, a threedimensional elasto-viscoplastic model is developed and applied to describe the behaviour of asphalt concrete materials under cyclic loadings. The model is based on a double-criteria viscoplasticity model and focuses on the coupling of a Drucker-Prager type criterion with a customized quadratic criterion. This is in order to take into account the evolution of volumetric deformations and the role of the shear strains on the establishment of permanent deformations. The kinematic hardening law is introduced following the continuum thermodynamics framework together with Koiter's evolution law for plasticity followed by an extension to viscoplasticity by using a Duvaut-Lions type formulation. The model is validated using experimental results of dynamic creep tests. A numerical method for high-cycles calculation will be presented as well.