Numerical simulation of mechanical behaviour of asphalt mix

The present paper attempts to develop a numerical model for predicting the mechanical behavior of asphalt mixes. In this work asphalt mix samples are modeled with the finite element method incorporating irregular as well as for random elliptical aggregates. The irregular shaped aggregates are obtained by tracing out the original aggregate shapes from cross-sectional images of asphalt mix samples and detecting the aggregate boundaries by image processing techniques. The elliptical aggregate samples are prepared by generating non-overlapping ellipses of random shapes and orientations. The asphalt binder, air voids and small sized aggregates together are assumed to behave like a viscoelastic material idealized by a Prony series and its properties are determined from relaxation tests performed in the laboratory on such a mix. The cylindrical asphalt mix samples are subjected to a line load at constant displacement rate and its response is studied for variations in constituent proportions and morphology. Similar conditions are simulated in the finite element model. The overall behavior of the asphalt mix in terms of displacement at failure and location of crack initiation exhibit good match between experimental and computational results.