Micromechanical Modeling of the Nonlinear Behavior of Lightweight Concrete with Various Expanded Polystyrene Contents

Abstract

In this contribution we present a new micromechanical damage model to predict the nonlinear behavior and damage evolution in lightweight concrete with expanded polystyrene beads (EPS). The model combines the incremental mean-field homogenization approach (MFH) and the continuum damage mechanics theory, allowing to depict the influence of the EPS volume fraction on mechanical responses in either the microstructure or the macro levels. Any point of the composite sample under study is considered the center of a representative volume element (RVE) which is a two-phase composite made of concrete matrix and EPS spheroidal inclusions. An incremental Mori–Tanaka model is used to predict the phase averages of the stresses and strains inside the RVE. The behavior of the cementitious matrix is assumed to obey Mazars’s µ-damage model coupled with fracture energy regularization method. EPS inclusions are considered elastic. The proposed model is validated and evaluated against experimental data taken from literature. It is shown that the model yields satisfactory predictions of the response under uniaxial compression/tensile of composite samples with various EPS contents.