Experimental investigation and multiscale modeling of reactive powder cement pastes subject to triaxial compressive stresses

摘要

This paper presents experimental and numerical studies on the triaxial mechanical behaviors of reactive powder cement (RPC) pastes prepared with an alcohol-based shrink-reducing admixture (ASRA) and ice-replaced mixing procedure. Standard cylindrical samples were cored from three kinds of high strength RPC pastes. For each kind of RPC pastes, a series of triaxial compression tests were performed under different confining pressures. It is shown that the RPC pastes under consideration present a typical quasi-brittle behaviours, including nonlinearity of stress-strain curves, strain hardening/softening, pressure sensitivity, volumetric dilatancy, triaxial strength nonlinearity, etc. For completeness, triaxial cyclic tests with two different confining pressure were conducted to analyse the mechanical damage characteristics of RPC pastes. Based on the experimental investigations and considering the mircostructure evolution of RPC pastes, a two-step homogenization-based multiscale constitutive model was developed. The model allows to take into account the influence of porosity on elastic constants, material damage induced by mesocracking as well as plastic deformation caused by frictional sliding. There is a good agreement between numerical simulations and experimental data. (C) 2019 Elsevier Ltd. All rights reserved.