Abstract：In this paper, regular octagon coarse aggregates with AC-16 gradation and sizes greater than 2.36 mm were generated by utilizing the random aggregate generation and packing algorithm, and fine aggregates were combined with asphalt in the matrix. As a result, some two-dimensional heterogeneous asphalt mixture beam models with two phases, namely coarse aggregates and matrix, were built. The enrichment functions were added into the standard finite element approximation in the extended finite element method so that fracture could step across the continuous finite elements. With the aid of ABAQUS software, the extended finite element simulations of three-point bending fracture were performed on the beam models with prenotches at the midspan, the 20 mm offset and the 40 mm offset, respectively. The bilinear damage evolution model and the maximum tensile stress criterion were employed to simulate micro-crack initiation and evolution as well as macro-fracture onset. Three groups of experiments were carried out, and some model parameters were obtained by the comparison between the simulations and the experimental results. The influences of prenotch location on the crack path and the load vs. displacement curve were analyzed. It was shown that the farther is the prenotch away from the midspan, the larger is the deflection angle between the crack propagation and the extension line of prenotch. It was also found that a specimen with a prenotch farther away from the midspan has a greater peak load, which means that a pernotch farther away from the midspan weakens the carrying capacity of asphalt mixture beam more gently. The qualitative consistency between experiments and simulations indicated that the extended finite element method is suitable for simulating the fracture behavior of asphalt mixture.
2017, Vol. 38 
