Chapter 24 - A Multiphase Mesostructure Mechanics Approach to the Study of the Fracture-Damage Behavior of Concrete

Abstract

A multiphase mesostructure mechanical model is proposed to study the deformation and failure of concrete considering its heterogeneity at the mesoscopic level. Concrete is a composite material of mortar matrix, aggregates and interfaces. An efficient approach to the disposition of aggregates of concrete and a state matrix method to generate mesh coordinates for aggregates are proposed. Based on nonlinear continuum damage mechanics, a mesoscale finite element model is presented with a damage-softening stress–strain relationship to describe the mechanical behavior of different concrete components. Heterogeneities of the components are considered by assuming that their material properties conform to the Weibull distribution law. Based on this multiphase mesomechanics model, a simulation analysis of fracture behavior of a rockfill concrete beam is accomplished. The study includes experimental tests to determine basic mechanical parameters of three components of rockfill concrete and four-point flexural beam tests to verify the model. The numerical model is shown to be applicable to studying failure mechanisms of concrete-type material.