Meso-scale behavior of fracture process zone in quasi-brittle materials induced by micro-crack interactions

The formation of a fracture process zone (FPZ) often observed at meso-scale structures of quasi-brittle materials such as concrete and other cementitious materials is simulated with a discrete fracture analysis method to clarify the underlying mechanism that characterizes the corresponding macro-scale behavior. After formulating the discrete fracture analysis method, which we have developed to simulate the softening behavior of concrete with the help of the cohesive crack model, we explain the numerical modeling of micro-crack behavior in consideration of material inhomogeneity at meso-scale together with energy-based fracture mechanics. Two representative numerical examples are presented to demonstrate that the interactions of crack nucleation, coalescence, opening and closing eventually leads to a crack in the meso-scale FPZ and that the macro-scale fracture toughness is characterized by the distributions of multiple micro-cracks.