Effectiveness of Fabric-Reinforced Cementitious Matrix in Strengthening Reinforced Concrete Beams

This paper reports on the efficiency of fabric-reinforced cementitious matrix (FRCM) in enhancing the flexural capacity and deformational characteristics of RC beams. In the main experimental part of the paper, 12 RC beams, 2,500 mm long, 150 mm wide, and 260 mm deep, were fabricated. The beams had two different steel reinforcement ratios, namely,ρ_s^D12=0.72% andρ_s^D16=1.27%, representing typical underreinforced beam sections. The strengthened beams utilized two FRCM types, carbon and polyparaphenylene benzobisoxazole (PBO) FRCM systems. In the second part of the work, tensile material characterization tests were performed on the FRCM coupons to determine the tensile characteristics of the FRCM composites. The beams were tested in flexure under four-point loading until failure. Two beams without FRCM strengthening were used as a benchmark. Six beams were externally strengthened using one, two, and three layers of carbon FRCM system. Four beams were strengthened with one and two layers of PBO FRCM system. Test results showed that the flexural capacity of the strengthened beams increased by 77% for the carbon FRCM system (three layers) and to 27% for the PBO FRCM system (two layers) over that of their benchmark (unstrengthened) beams.