Rate Dependence of Confined Recycled Aggregate Concrete

Twenty-seven groups of short reinforced recycled aggregate concrete (RAC) columns are tested under a series of typically controlled strain rates (10(-5)/s to 10(-2)/s). The rate dependence on the mechanical behaviors of confined recycled aggregate concrete is estimated experimentally. Under dynamic loading conditions with different RCA replacement ratios (0, 30, and 100%), the ascending portions of the stress-strain curves are basically consistent with each other, while the descending branches are distinctly different and change in an inconspicuously steepening trend with the increasing replacement ratio. The influences of strain rate and lateral confinement on the mechanical behaviors of RAC are also investigated. Based on the experimental results, rate-dependent constitutive equations of URAC and CRAC under the quasi-static and dynamic loading conditions are proposed, respectively. The effects of the replacement ratio, strain rate, and lateral confinement are taken into account in the suggested constitutive equations.