Mesoscopic simulation of the dynamic tensile behaviour of concrete based on a rate-dependent cohesive model

• A meso-scale numerical model is developed to investigate the dynamic tensile behaviour of concrete in spall tests.
• The dynamic fracture process of concrete is successfully captured by the proposed rate-dependent cohesive model.
• The micro cracking process in the meso structure is explicitly represented.
• The influences of fracture properties in different constituents and mesostructure are discussed.
• The results show good agreement with the experimental data over a wide range of strain rates.

We present a two-dimensional meso-scale finite element model for simulating the dynamic tensile behaviour of concrete. Aggregate, mortar and interface transition zone (ITZ) are explicitly modelled at the meso-scale. Rate-dependent cohesive elements, which take into account the effects of the viscosity occurring in the fracture process, are dispersedly pre-inserted to simulate the nucleation, coalescence, and propagation of cracks. The proposed model is validated by comparing with the experimental data of spall tests. The evolution of microcracks of concrete under dynamic loading is presented. The influences of the fracture parameters and the mesostructure on the dynamic tensile strength are investigated. The results suggest that the property of ITZ plays an important role on the dynamic tensile behaviour of concrete. The tensile strength and dissipated fracture energy under dynamic loading are affected by the mesostructure of concrete as well.