Flexural performance of basalt FRP reinforced concrete beams with and without discrete basalt fibers

Steel corrosion in reinforced concrete has driven the search for alternative materials. This study investigates the flexural behavior of Basalt Fiber Reinforced Polymer (BFRP) reinforced concrete (RC) beams, including the effect of basalt fibers on crack control and deflection. Three beams made with M30 grade concrete, one with BFRP bars only and two with added basalt fibers (0.35% volume, 12 mm and 24 mm lengths), were tested and compared to steel reinforced concrete beams with similar configurations: one with steel reinforcement only and two with steel reinforcement and added basalt fibers (0.35% volume, 12 mm and 24 mm lengths). All beams were evaluated to assess their ultimate moment capacities. RC beams with BFRP rebars are designed according to ACI 440.1R-15, whereas steel RC beams are designed as per IS 456 and ACI 318 code guidelines. The BFRP beams demonstrated comparable ultimate moment capacities to steel, with only a 3 to 5% reduction, and showed up to 24% improvement in post-crack stiffness due to the fibers. While theoretical models underestimated the cracking moment by approximately 43 to 49%, they closely matched the ultimate moment capacities. The results highlight the potential of BFRP and basalt fibers to replace conventional steel reinforcement in concrete structures; however, the brittle failure mode associated with BFRP reinforced beams remains a concern.