Numerical modelling of fatigue cracking in asphalt mixture using cohesive elements

The fracture resistance of asphalt materials significantly influences the service life of asphalt pavements. The Cohesive Zone Modelling (CZM) is presented to model crack initiation and propagation. The heterogeneous model was developed to explicitly model the different material phases captured by X-ray Computed Tomography (CT). A Two Dimensional (2D) Finite Element (FE) model was reconstructed by X-ray CT images; the model embedded zero-thickness cohesive elements both in asphalt mortar and interfaces between mortar and aggregates, in conjunction with the viscoelastic material properties. Crack paths of asphalt mixture samples at different deformation levels in the Indirect Tensile Fatigue Test (ITFT) were compared to simulation results. The results proved that the CZM is a powerful and efficient tool that can be easily implemented in numerical simulations to model crack initiation and propagation of asphalt mixtures.