3D mesoscale fracture analysis of concrete under complex loading

Analyzing mechanical behavior at the mesoscale level should be a powerful tool for higher heterogeneous materials like concrete. In this study, the mechanical and damage analysis of concrete were investigated using a 3D mesoscale model under complex loading. A less timeconsuming method was proposed for constructing the realistic mesostructure of concrete. The finite element simulation showed good agreements with the uniaxial and biaxial experimental results. Then complex loading conditions such as compression-compression (C-C), tension-tension (T-T), and compression-tension (C-T) were simulated. The computation showed that damage failure under biaxial loading was completely different from that under uniaxial compression. Under T-T conditions, the tensile strength decreased and an oblique crack formed perpendicular to the free plane. Finally, the obtained numerical failure envelope agreed relatively well with the corresponding experiment. The mesoscale model provided an effective way to understand the damage mechanism of concrete especially under muti-axial stress condition.