Fracture criteria and initiation mechanism of concrete based on material configurational mechanics

In this study, the interaction force between an in-plane elliptical inclusion and a crack is evaluated using the Eshelby equivalent inclusion and material configurational force method. The toughening effect of coarse aggregates on concrete is investigated. The fracture criteria for mixed-mode cracks based on the characteristics of the crack-tip plastic zone assessed by the principal configurational stress difference are proposed and verified by experimental results in the literature. The fracture probability is then used to improve the fracture criteria, and the dimensionless factor associated with stress intensity factors is introduced to determine the fracture probability. Additionally, the volume fraction of coarse aggregates, the age and fatigue life of concrete are considered in the present fracture criteria. Theoretical studies show that the interaction between a crack and a hard or soft inclusion exhibits mutual repulsion and attraction. The size and shape of the crack-tip plastic zones assessed by the Mises stress and the principal configurational stress difference are essentially the same. The fracture load envelopes increase with the increase in the volume fraction of coarse aggregates and the age of concrete and shrink with the increase in the life ratio. The interaction force between a crack and an elliptical inclusion and toughening effect of coarse aggregates on concrete are evaluated. Fracture criteria based on the characteristics of the crack-tip plastic zone by the principal configurational stress difference for mixed-mode cracks are proposed. The fracture probability is introduced to elucidate the fracture mechanism of concrete. The impacts of the volume fraction of coarse aggregates, the age, and fatigue life on concrete fracture are investigated.