Modelling the mechanical behaviour of asphalt concrete using the Perzyna viscoplastic theory and Drucker–Prager yield surface

Asphalt concrete has been considered one of the major pavement materials due to its advantages that are good workability, ease of repair and smoothness for vehicles travelling on it. However, its plastic and viscous behaviour causes a gradual accumulation of deformation under repeated vehicle loading, resulting in a shortage of traffic safety. This paper presents an elasto-viscoplastic model for asphalt concrete material undergoing finite strain in an effort to predict the permanent deformation of a pavement structure. The model uses the Perzyna viscoplastic theory and an ordinary Drucker–Prager yield surface. The well-known return mapping algorithm is used for numerical resolution, and tangent stiffness is derived for finite element implementation. Owing to the lack of a triaxial creep test device, the model parameters are determined on the basis of the Hamburg wheel tracking test results. Numerical examples are presented to assess the efficiency of the formulation proposed. The results show that the prediction achieves an acceptable level of accuracy in a low-velocity traffic area.