3D mesoscale investigation on the compressive fracture of concrete with different aggregate shapes and interface transition zones

The purpose of this work is to investigate the effect of aggregate shape parameters and interface transition zone (ITZ) thickness on the mechanical properties and failure behavior of concrete under uniaxial compression. A 3D mesoscopic model including mortar, shape-alterable aggregate and thickness-controllable ITZ was established in ABAQUS software by programming. Based on the concrete damaged plasticity (CDP) method and the cohesive element approach, the simulation analysis was carried out from the aspects of macroscopic mechanical response, macroscopic failure morphology, mesoscale fracture propagation, and energy dissipation. Results indicate that polyhedral aggregate and spherical aggregate have no significant effect on the macroscopic mechanical properties of concrete. Aggregates with sharp edges and corners may cause concrete to be destroyed into more fragments. The ITZ with 0 thickness and medium thickness can predict the compressive strength of concrete, ITZ model with solid thickness is more suitable for meso-crack research. Thinner solid ITZ fits poorly with the experimental value, and the change of ITZ has little influence on polyhedral aggregates. It is proposed to establish a polyhedral aggregate and medium thickness ITZ model for mesoscale concrete numerical simulation.