Mesoscale modeling based numerical study on size effect of concrete compressive strength

Concrete is composed of cement, aggregates, and the interface. A three-phase mesoscale model is adopted to analyze the size effect of concrete compressive strength and failure mechanism. The random distribution of coarse aggregate is considered during the establishment of the model. By assigning each phase its own damaged plasticity property and introducing initial defects, this mesoscale model can successfully simulate the propagation of the blunt crack band. Comparing with experimental data, the simulation makes a well prediction in the size effect of concrete compressive strength. The research results show that the size of the defect exerts a significant influence on the ultimate compressive capacity of concrete columns, while the strength grade of concrete and the location of defect present weak impacts. Finally, it is found through the analysis of failure mechanism that the size effect theory based on energy dissipation can perfectly account for the failure process and the simulation results.