Multi-domain hybrid boundary node method for evaluating top-down crack in Asphalt pavements

Top-down crack is a type of crack that rivals the severity and prevalence of reflective crack. It significantly reduces pavement’s quality service life. The initiation of these cracks was explained by high-contact stresses induced under radial truck tires; however, the mechanism for top-down crack propagation has not been explained. A combination of multi-domain hybrid boundary node method (Hybrid BNM) and fracture mechanics was selected for physical representation and analysis of a pavement with a top-down crack. The hybrid BNM is a boundary-only, truly meshless method, which does not require a ‘boundary element mesh’, either for the purpose of interpolation of the solution variables or for the integration of ‘energy’. In order to simulate the singularity of the stress on the crack tip, enriched basis functions are used. The factors, which influence the stress intensity factor (SIF) and the expansion path, e.g. horizontal load, thickness of asphalt concrete (AC) layer and base, AC layer and base modulus, are studied through numerical results. It can be concluded that the Hybrid BNM, which has high convergence rates and high accuracy, is able to solve top-down crack problems.