Simulation of bending fracture test process for asphalt concrete beam based on heterogeneous state

To analyze the crack propagation behavior of bending fracture of asphalt concrete beam, RFPA (Realistic Failure Process. Analysis) was selected to conduct a numerical simulation of bending fracture test of asphalt concrete beam specimens under the heterogeneous state. Physical tests were performed on AC-13C to simulate the process of bending fracture. Research results showed that the direction of crack extended along the stochastic distributed 'basic element,' the heterogeneity of 'basic element' only changes the direction of crack growth locally, it will not change the trend of crack propagation. Affected by the stochastic distribution of heterogeneous element, the stress distribution presents multiple peaks in specimen split process. The crack propagation gradually changed from the initial mode I-II to mode I. At the beginning of the loading procedure, tensile, compressive, and shear stresses reached the minimum at about 65 mm away from the middle of the beam. Once the distribution process completed and no element fracture happened, the tensile and shear stresses increased rapidly to 1.4-1.6 times. When element fracture occurred, the stress at the initial point of crack quickly dropped to 0. The location of fracture starting point deviated from midspan by about 3-5 mm. The crack distribution tends to discrete with the decrease of the homogeneity degree, but when the homogeneity degree is high, the crack distribution will be relatively straight and regular. The deflection analyzed under different conditions is about 1.9 mm, which is consistent with the deflection 1.7 mm tested in the laboratory. With lower tensile strength under the same homogeneous degree, the crack in specimen has multiple paths extending from the bottom to upward, as long as the tensile strength grows, the crack extends upward while only one path occurs. (C) 2017 Elsevier Ltd. All rights reserved.