Cyclic Elasto-viscoplastic Model for Asphalt Concrete Materials

These last few years, many interests 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 three-dimensional elasto-viscoplasticity 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 formulation of permanent deformations. The kinematic hardening law is introduced following the classical 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 potentials are then demonstrated by numerical simulation of various loading conditions and the model itself is validated using experimental results of dynamic creep tests.