Experimental and numerical study on the effect of fibers on shear strength of basalt FRP-reinforced concrete beams without stirrup

The relatively low shear strength, low ductility, and weak post-cracking performance of FRP-reinforced concrete (RC) members caused by low elastic modulus and low transverse strength of FRP rebars can be significantly improved through the use of fiber concrete; this issue has not been extensively investigated yet, therefore, this investigation was motivated. This study presents the experimental and numerical analysis of basalt FRP-RC members with different types of fiber and without shear reinforcement. Seven beams with the same geometry, flexural reinforcement ratio, and shear span-to-depth ratio were cast and tested under four-point loading to fail in shear. The test variables are the type of fiber (hooked steel fiber, smooth steel fiber, and polypropylene fiber) and fiber volume fraction (0.75% and 1.5%). The experimental results indicate that the inclusion of fibers significantly improves the crack pattern, ductility, post-cracking shear resistance, and ultimate shear strength; hence, it is alleviated, either partially or completely, the reduction in ductility and shear strength caused by using FRP bars as a substitute to steel bars. The presence of fibers with ratios of 0.75% and 1.5% increased the ratio of shear strength with respect to the reference beam to about 1.55 and 1.93, 1.51 and 1.68, and 1.37 and 1.46 for Steel fiber type-1, steel fiber type-2, and polypropene fiber, respectively. Finally, the standardized finite-element simulation for beams with various types and volume ratios showed an influential capability in pretending the tested beams regarding the failure load, load–deflection relationship, and crack pattern. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.