Performance evaluation of recycled aggregate concrete under multiaxial compression

This paper presents the results of an experimental study of the failure criteria and mechanical behavior of recycled aggregate concrete (RAC) under uniaxial and triaxial compression. Three parameters: the recycled coarse aggregate (RCA) replacement percentage (gamma), lateral confining pressure (sigma 3) and the age of concrete from which the RCA was obtained were considered in the tests. The effects of these parameters on the failure behavior of RAC and the compressive strength, elastic modulus and stress-strain curves of RAC are discussed. The results show that RCA replacement percentage has a very little effect on the compressive strength of RAC under uniaxial and triaxial compression; the lateral confinement significantly affects the failure pattern and the stress-strain behavior of RAC, with the increase of lateral confining pressure, the failure pattern changes from vertical fracturing to oblique fracturing. Based on the experimental observations and test results, the Mohr-Coulomb failure criterion, shear stress failure criterion and failure on the compression meridian plane are extended to describe the behavior of RAC under multiaxial compression. For analysis and design purposes, empirical models are proposed to predict the stress-strain relationship of RAC under multiaxial compression. (C) 2019 Elsevier Ltd. All rights reserved.