Numerical simulation of crack paths in asphalt mixture using ordinary state-based peridynamics

Cracking creates major distress in asphalt pavements. Because of mathematical complications, existing simulation efforts are incapable of simulating the crack branching and crack coalescence in asphalt mixtures. To overcome this deficiency, this paper developed a two-dimensional (2D) ordinary state-based peridynamics (OSB-PD) method to simulate the entire crack propagation phase, which includes crack propagation, crack branching and crack coalescence. The 2D asphalt mixture digital image was acquired via the X-ray computed tomography method. The Prony series coefficients of the fine aggregate mixture (FAM) were obtained from the dynamic modulus test. The fracture energy of the FAM was determined from the semicircular bending (SCB) test. The measured mixture properties were then input into the 2D OSB-PD numerical method to simulate the crack paths under the SCB test and the three-point bending (TPB) test conditions. The simulated crack paths matched well with those observed from the experiments (at 5% level of significance), thus validating the accuracy of the proposed 2D numerical simulation method. The validated method was finally implemented into the simulation of the crack paths in the laboratory-used asphalt mixture and subjected to compressive loading. The simulation results indicated that the diagonal crack exists when the crack propagates in an asphalt mixture. The diagonal crack then continues to branch and coalesce through the following possible paths until the failure of the asphalt mixture: (a) penetrating through the aggregate; (b) branching along the surface of aggregate in different directions; and (c) coalescing with each other.