Shear Strength of Circular Beams Made of Geopolymer Concrete and Reinforced with GFRP Rebars

Traditional steel reinforcing rebars are susceptible to corrosion as they are exposed to weather conditions. This vulnerability creates a limit to its effectiveness as a reinforcement within concrete structures. Corrosion of steel reinforcement can lead to damage and deterioration of reinforcement in concrete structures, as well as put the overall structure at risk of accumulated damage and ultimately failure. This paper involves an alternative material to longitudinal and spiral reinforcements consisting of Glass Fiber Reinforced Polymer (GFRP). The paper explores the shear strength of circular concrete beams reinforced with GFRP rebars. A total of four full-scale concrete beams with a total length of 2500 mm and a diameter of 260 mm were tested to failure in four-point loading setup. The investigated parameters were the type of longitudinal reinforcement (steel vs GFRP), number of longitudinal rebars, and the pitch of spirals. The performance of the GFRP beams is compared to their steel beams counterparts. The comparison involved: failure load, load-deformation behavior, and failure mode. It was observed that flexural cracking patterns are initially manifested, and ultimately shear cracking patterns emerge. The GFRP beams provided significantly higher strengths and impeccable protection against corrosion than their steel counterparts. The steel-reinforced beams, however, provide superior ductility and deformation city.