Flexural performance of reinforced concrete beams repaired with BFRP grid-TSUHDC

Due to the influence of time, load, and external environmental factors, many reinforced concrete beams have been damaged and require repair. Tailings are waste generated during mineral production, resulting in substantial environmental pollution and economic losses due to the excessive generation of tailings and low comprehensive utilization. In the UHDC, tailings replaced quartz sand, while BFRP grids itself is an environmentally friendly material. Two repair methods were evaluated in this study, Tailings Sand Ultra-High Ductile Concrete (TSUHDC) and Basalt Fiber Reinforced Polymer (BFRP) grid-TSUHDC, grounded in the principles of green and sustainable development. Five reinforced concrete beam specimens were designed and fabricated for bending performance tests and finite element simulations. The effects of different repair methods and levels of damage on the flexural performance of reinforced concrete beams were investigated. The results reveal that, compared to untreated reinforced concrete beams, both TSUHDC and BFRP grid-TSUHDC repair methods enhanced bending load-bearing capacity. However, the stiffness of specimens repaired with TSUHDC decreased when subjected to 80% of the pre-applied failure load. When the pre-applied failure load is less than 80%, the recommended repair approach is the use of TSUHDC for repair. For cases where the pre-applied failure load exceeds 80%, BFRP grid-TSUHDC is the preferable option. The flexural bearing capacity formula for this type of repair method was derived by improving existing formulas, yielding prediction results in close alignment with the experimental results.