The simulation of time dependent behaviour of cement bound materials with a micro-mechanical model

An approach is described for simulating the behaviour of concrete, and other cementitious composites materials, using micro mechanics. The basic mechanical material model is that presented by Mihai and Jefferson 1 which employs micromechanical solutions of a two-phase composite comprising a matrix phase, spherical inclusions, circular microcracks distributed in the matrix and potentially combining these with a rough crack contact component. The primary focus of the paper is on the enhancement of the model to allow for the future inclusion of time dependent behaviour. This is accomplished by the addition of inelastic strains in the matrix phase. These inelastic strains can be included at the fundamental micromechanical level of the homogenisation process by being included in the compatibility equations and embedded mechanistically into the constitutive equations