Mechanical properties of recycled aggregate concrete under compression-shear stress state

Abstract

Mechanical properties including failure mode, strength, and stress–strain relation of recycled concrete specimens are tested under compression-shear stress state. Replacement ratio of recycled coarse aggregate (RCA), stress ratio of applied compression (σ/ƒcu) and reinforcement ratio (ρv) are designed as the main factors which affect mechanical properties of concrete. The results show that the failure mode is mainly affected by σ/ƒcu, both ρv and σ/ƒcu take an effect on shear strength, the strength value increases with the ρv and σ/ƒcu goes up. RCA replacement ratio gives a negative effect on shear strength due to the initial damage initiated in crushing process, the strength value decreases with RCA replacement ratio increases. Appropriate formula has been selected to describe the change of shear strength combined with σ/ƒcu and ρv under different RCA replacement ratios, and the predicted strength curves match well with the experimental data based on regression analysis. The shear stress–strain curve of the plain concrete is influenced by both σ/ƒcu and RCA replacement ratio, the initial slope and the whole shape of the curve are effected by the two factors, a fitting equation is proposed to describe the shear stress–strain relationship of plain concrete under compression-shear composite stress state.