Cohesive Zone Simulation of Mode I and Mixed-Mode Crack Propagation in Asphalt Concrete

A cohesive zone model (CZM) is employed to investigate fracture behavior of asphalt concrete. The separation and traction response along the cohesive zone ahead of a crack tip is modeled by an exponential cohesive law specifically tailored to describe the cracking in asphalt pavement materials by means of a softening cohesive law. This exponential cohesive model is implemented into a user-defined element (UEL) of the ABAQUS software. Using the CZM, first, crack propagation in a mode I single-edge notched beam (SE(B)) test is simulated such that the cohesive parameters of finite material strength and fracture energy are calibrated based upon the experimental results. Then, the mixed-mode SE(B) test is simulated using the calibrated cohesive parameters. The crack trajectory of the numerical simulation is found to compare favorably with experimental results.