Analysis of Dual-G Criterion for Post-fire Concrete

Abstract:

Based on the linear elastic fracture mechanics (LEFM) and the cohesive stress on the fictitious crack, the dual-G criterion characterizing the fracture behaviour of crack propagation in post-fire concrete is proposed, where, G is in terms of the energy release rate. Two important parameters, the initial fracture toughness GICini,T and the unstable fracture toughness GICun,T, are included to describe the crack extension at various stages. The quantitative relationship between GICini,T and GICun,T is established by introducing the cohesive fracture toughness GICc,T, which is conformed by the wedge-splitting experiments on the post-fire concrete specemens. Furthermore, the fracture toughness determined by energy-based method (dual-G) and stress intensity factor (SIF) is compared, and the two parameters show a good coincide with each other.