A Viscoelastic Displacement Discontinuity Method for Analysis of Pavements with Cracks

ABSTRACT This paper presents a development of the displacement discontinuity boundary element method for modeling the linear viscoelastic behavior of asphalt mixtures and simulating crack propagation in asphalt pavements. The viscoelastic formulation is based on the correspondence principle, involving Laplace transformation of the constitutive equations and the associated boundary conditions. The time-dependent behavior of the asphalt mixtures is characterized by the Burger's or power law model. The associated transformed problem is solved in an analogous way to using the linear-elasticity-based displacement discontinuity method. The corresponding time-dependent viscoelastic solution is obtained using an efficient and robust algorithm for numerical Laplace inversion. A substructuring approach is employed to construct the layered formulation and higher-order elements are used to capture the bending effect in the pavement structure. With incorporation of the hot mix asphalt (HMA) fracture mechanics, which is based on the concept that there is a dissipated creep strain energy (DCSE) threshold to cracking, the numerical framework can efficiently simulate crack onset and growth in asphalt pavements. Several examples are presented to verify the accuracy and efficiency of the numerical method and to demonstrate its application in modeling pavement cracking.