Effect of fine recycled concrete aggregate on the mechanical behavior of self-compacting concrete

Abstract

The high flowability of Self-Compacting Concrete (SCC) is achieved by adding large amounts of fine aggregate. Therefore, the addition of fine Recycled Concrete Aggregate (RCA) in this type of concrete can very noticeably change its behavior. SCCs with different percentages of fine RCA (0%, 25%, 50%, 75%, and 100%) and 100% coarse RCA were manufactured in this study, to evaluate their performance, and to analyze the effect of fine RCA in an SCC when a high amount of coarse RCA is also added. Both the fresh properties (flowability, density, and air content) and their mechanical behavior (strengths, non-destructive tests, stress–strain curves, and Poisson coefficient) at different curing ages were studied. These mechanical properties were compared with the values calculated using the formulas from two of the most common structural design standards. High values of strength and modulus of elasticity were obtained up to a fine RCA content of 50%. Additionally, any increase in fine RCA increased flowability and elastic and plastic deformability of the SCC. The theoretical values overestimated the experimental ones by around 25%. From the mechanical point of view, SCC with up to 50% fine RCA could be used for structural applications, although service requirements regarding deformability recommend that its content should be limited to 25%.