Flexural performance of reinforced concrete beams made by using recycled block aggregates and fibers

This article analyzes the flexural performance of reinforced concrete beams produced by granulated blast furnace slag (GBFS) as a substitute for cement, recycled block aggregates (RBA) as an alternate for ordinary coarse aggregate, normal steel fiber and staplers and polypropylene fibers. Ten reinforced concrete beams with a cross section. 90 mm wide, 150 mm depth and a length of 1000 mm were designed and tested. For this study, a total of 10 mixtures were prepared with different substitutes (in terms of weight) for RBA (0%, 25%, 50% and 100%) and GBFS (0%, 25%, 50% and 70%), while normal steel fiber (0%, 0.5%, 1.0% and 1.5%), 0.5% stapler pin steel fiber and 0.5% polypropylene fibers were added (in terms of volume). The compressive strength and flexural tensile strength were tested for each concrete mixture. Here, the compressive strength and flexural tensile strengths were reduced when using GBFS, RBA and fibers, and the extreme reduction of compressive strength and flexural tensile strength was 50% and 55%, respectively, for 70% GBFS, 25% RBA and 0.5% normal steel fiber. The less decreasing in compressive strength and flexural tensile strength was for a mix of 25% GBFS, 25% RBA and 0.5% stapler pin steel fiber. The role of fiber, GBFS and RBA was more promised in the behavior of reinforced concrete beams. There was an enhancement in flexural capacity for all reinforced concrete beams reaching 27.7%, furthermore when made via using 25%GBFS, 25% RBA and 1.5% normal steel fiber. According to the obtained test data, the utilization of GBFS, RBA, and fibers made the reinforced concrete beams more ductile compared with reference one.