Experimental and analytical study on flexural behavior of corroded RC beams strengthened with CFRP rods and UHPC

Recent research confirms that concurrent use of Ultra-High Performance Concrete (UHPC) and Carbon Fiber Reinforced Polymer (CFRP) yields superior strengthening effects on RC structures compared to individual applications. However, this combined strategy is underutilized in research on corroded structure strengthening. This study investigates the flexural behavior of corroded RC beams strengthened with UHPC and CFRP rods through experimental and numerical analyses. A total of 13 RC beams were designed with different corrosion levels (0 %−20 %) and strengthening forms (U-strengthened, T-strengthened). The four-point bending test results indicate a substantial increase in peak moments for the strengthened beams, with U-strengthened beams exhibiting higher bearing capacity than T-strengthened ones. Additionally, the failure mode of the strengthened beams tends to be brittle. Sectional analysis results demonstrate that before the longitudinal reinforcement yield, it mainly governs the sectional moment, while after yielding, CFRP rods control the moment. Moreover, UHPC tensile stress makes a non-negligible contribution to the moment.