Comparative analysis of shear behavior in continuous low-strength RC beams strengthened with BFRP and CFRP: An experimental and numerical investigation

Abstract

The integration of Basalt Fiber-Reinforced Polymer (BFRP) materials marks a significant advancement in sustainable construction. This study evaluates the impact of externally bonded BFRP and Carbon Fiber-Reinforced Polymer (CFRP) sheets and laminates on the shear strength of reinforced concrete (RC) beams with a compressive strength of 20 MPa. Seven full-scale, two-span RC beams, each four meters in length, were tested, with identical strengthening patterns applied to both BFRP and CFRP sheets to allow for a direct comparison. One beam served as a control sample to assess the effectiveness of the strengthening techniques. Results showed that CFRP improved the shear capacity of the beams by 38.3 % to 46.6 %, while BFRP provided an increase of 9.7 % to 32.5 %, demonstrating substantial gains in load-carrying capacity for both materials, though CFRP showed a higher performance boost while BFRP materials are an economical alternative for CFRP materials, and the most effective strengthening configuration for both fiber types is full side coverage, as it offers superior confinement of the concrete. These findings were well-aligned with Finite Element Modeling predictions and theoretical expectations, closely matching ACI 440.2R-08 guidelines.