Revisiting the dynamic compressive behavior of concrete-like materials

This paper deals with two questions that are related to the dynamic compressive behavior of concrete-like materials: (1) whether the compressive strength enhancement of concrete-like materials with strain-rate is a material property; (2) what is the physical reason for the observed two-stage behavior of the compressive strength enhancement with increasing strain-rate in concrete-like materials. A series of 3D numerical simulations were performed. Analysis of the results indicates that the compressive strength enhancement with increased strain-rate is an indirect result of a lateral confining effect. Furthermore, comparisons between the results obtained with pressure-dependent material model and related tests, show that the lateral confinement is caused by both the lateral inertia and the interface friction between the loading apparatus and the loaded specimen. Under these two joint actions the trend of the strain-rate effect is characterized by two stages. The current study points out the role of these mechanisms in controlling the two stages. Finally, similarities between the stress–strain behaviors obtained in the current uniaxial dynamic compressive loading and in triaxial compressive static loading with a moderate level of lateral confining pressure, further prove that the lateral confinement generated during the dynamic loading process contributes to the strain-rate effect.