Finite element cohesive fracture modeling of asphalt mixture based on the semi-circular bending (SCB) test and self-affine fractal cracks at low temperatures

摘要

Thermal cracking is one of the most common distresses for asphalt pavement constructed in the cold regions. In order to address this issue, the combined use of fracture mechanics-based tests and simulation is a solid option. First, asphalt mixture samples are prepared based on the German standard and the low temperature strength are measured by Semi-Circular Bending (SCB) test and the Uniaxial Creep (UC) test at three different temperatures: -6, -12 and -18 degrees C. Next, experimental test results are used to perform the cohesive zone (CZ) modeling by using a two-dimensional finite element (FE) simulation. As a new approach, the CZ is modeled along a self-affine crack path, which allows performing a simulation closer to reality. The FE results provide a comprehensive understanding of the mechanism of crack initiation and propagation while keeping the computational time within a reasonable level.