Constitutive Response and Failure Mechanism of Porous Cement-Based Materials Under Triaxial Stress States

Abstract

The constitutive response and failure mechanism of a highly porous cement-based material are generally controlled by the competition of the shear failure and pore collapse. These micromechanical processes are mainly dependent on the stress state. In this study, the pore-structure of the material is explicitly described by the discrete element modelling (DEM), the cohesive-frictional model and spherical particles are ultilised to model the mortar phase at the meso-scale. Numerical simulations of true triaxial tests are conducted on porous specimens with various stress paths. The mechanical data show that the transition, from brittle failure into cataclastic flow, is heavily dependent on the confining stress level. The insight into pore deformation and shear failure development is discussed. In addition, the octahedral section of yield surface of a typical highly porous material is presented in the paper. This feasible study demonstrates the potential of the DEM modelling in investigating the failure mechanism of the porous cement-based material under multi-axial tress state.