Flexural performance of steel-reinforced recycled concrete beams

A new method of mixture proportioning is used to investigate the flexural performance of reinforced concrete beams made with coarse recycled concrete aggregate (RCA). In this method, RCA is treated as a two-phase material comprising residual mortar and natural aggregate; therefore, when proportioning the mixture, the relative amount and properties of each phase are considered separately. Several reinforced concrete beams are built and tested using concrete mixtures designed by the new method and their deflection; cracking, yielding, and ultimate moments; crack spacing; cracking patterns; and failure modes are studied. The results show that at both the serviceability and ultimate limit states, the flexural performance of beams made of RCA-concrete proportioned by the new method is comparable to that of beams made of conventional natural aggregate concrete; and the general flexural theory and current code provisions for flexural design are applicable, without alteration, to the reinforced recycled concrete beams. © 2009, American Concrete Institute.