Fracture simulation of asphalt concrete with randomly generated aggregate microstructure

This paper investigated fracture behaviour of asphalt concrete in a semi-circular bending test using randomly generated aggregate microstructure. Asphalt concrete was modelled as heterogeneous material with coarse aggregate and fine aggregate matrix (FAM). The extended finite element method was used to model crack propagation with different microstructures. The model predictions were validated with experimental results reported in the literature. The fracture behaviour of asphalt mixture is affected by the loading rate and temperature due to the viscoelastic nature of FAM. The results show that increasing fracture strength and energy of FAM significantly improves fracture resistance of asphalt concrete. The spatial distribution, angularity, and gradation/size of coarse aggregate have influences on crack propagation path and possibly global fracture parameters. The computational modelling approach provides an effective way to investigate the effect of an individual component. Although a relatively simple microstructure with coarse aggregates is considered in the current model, the results indicate that the fracture behaviour of asphalt concrete can be effectively predicted as consistent with findings reported in experimental studies.