Application of bilinear cohesive zone model in damage and cracking analysis of concrete pavement

In order to reveal the damage and cracking mechanisms and their impact on the bearing capacity of concrete pavement, the elasticity and plasticity of concrete material were considered. By using the bilinear cohesive zone model in non-linear fracture mechanics, the cohesive elements were inserted into the potential path of crack propagation based on ABAQUS finite element software, and the whole process from elastic response to damage failure was modeled for a four-point loading beam. The reliability of bilinear cohesive zone model for the analysis of concrete damage and cracking was verified. By using the bilinear cohesive zone model, the cracking characteristics and the decrease of bearing capacity after the initial damage of a concrete slab on Winkler foundation were analyzed as well. Analysis result indicates that under the entire process of loading, the stresses at the bottom of the beam experience the phases of increasing linearly, decreasing after reaching the concrete flexural strength, the maximum stress point moving upwards, and reducing to 0. The load-displacement relationship on the beam is in accordance to the existing results. For the concrete slab under the entire process of loading, the variations of stress distribution at the section are similar to those of the beam. The bearing capacity of concrete slab increases continuously, but for its supporting condition is different from that of the beam. The failure of concrete slab appears to be brittle, and shows no obvious decay. The ratio of the ultimate bearing capacity to the critical bearing capacity at the elastic phase is 1.32. Once the initial damage of concrete slab occurs, the ultimate bearing capacity will decrease at most to 87% of undamaged slab. The decay rate of ultimate bearing capacity increases with the degree of initial damage.