Experimental investigation of GFRP-RC beams with Polypropylene fibers and waste granite recycled aggregate

Nowadays, using Glass Fiber-Reinforced Polymer (GFRP) rebars has attained high attention owing to their ad-vantages, such as high tensile strength and corrosion resistance. GFRP rebars can be used in conjunction with Polypropylene (PP) fibers to alleviate reinforcing congestion in high-rebar-density areas of Reinforced Concrete (RC) beams as a substitute for shear reinforcement. This study aims to investigate the simultaneous impact of GFRP and PP fibers on improving the shear performance of High-Strength (HS) Recycled Coarse Aggregate (RCA) concrete beams. 36 RC beams were produced, and the influence of longitudinal GFRP rebars ratio, shear span-to -depth ratio, RCA, and fiber content on the shear behavior of specimens was assessed. The load-displacement behavior, maximum load-bearing capacity and deformation, maximum shear resistance, ductility, stiffness, toughness, modes of failure, and post-cracking strength of the specimens were studied. In addition, the results were compared with the available design codes for the shear resistance of RC beams. The testing results showed that with increasing the RCA content, PP fibers were more operative in enhancing the shear performance of High Strength Concrete (HSC) beams reinforced by GFRP rebars. Additionally, to provide enough ductility and to avoid a sudden shear failure, the use of PP fibers and RCA is recommended since the greatest improvement in ductility and deformability of HSC was observed when both of them were simultaneously employed.