A loading rate dependent cohesive model for concrete fracture

A time dependent cohesive model to account for the influence of loading rate on concrete fracture is addressed. Viscous-cohesive parameters are introduced in the fictitious crack model to represent a time dependent stress-crack opening zone in an elastic solid. A computational implementation has been performed, simulating the cohesive stress-crack opening and rate dependence in a smeared crack tip framework. The model has been validated with results from three-point-bend notched specimens of high strength concrete, tested at five different loading rates. Numerical results show that the approach reflects the experimentally documented dependence of crack propagation in cementitious materials on the loading rate.