Numerical modeling of strain localization and interface damage in cement based materials

In this paper, the interface damage and strain localization within the matrix are modeled for a representative volume element (RVE) of concrete. The development of displacement discontinuities along interfaces is simulated using the Extended Finite Element Method (XFEM). A new cohesive interface damage model is proposed to describe the progressive debonding process. For modeling the strain localization (microcrack growth) in cement paste matrix, a homogenized elastic-crack model is used. The macroscopic behavior is controlled by the properties of the matrix and the plastic deformation along the crack. Various numerical simulations at the level of REV are performed. The obtained results clearly show that the failure in concrete is initiated by interface debonding and is followed by crack propagation (strain localization) inside the cement paste. The interface damage plays an important role in the macroscopic failure process of concrete. The failure mode depends on the spatial distribution and size of aggregates.