Crack-damage mitigation and flexural behavior of flexure-dominant reinforced concrete beams repaired with strain-hardening cement-based composite

This paper presents experimental and analytical studies on the cracking behavior and flexural performance of reinforced concrete (RC) beams repaired with strain-hardening cement-based composite (SHCC). Test results demonstrated that RC beams repaired with SHCC showed no concrete crushing or spalling until final failure, but showed a great number of hair cracks, while non-repaired RC beam failed due to crushing. It was noted that the SHCC matrix can improve crack-damage mitigation and the flexural behavior of RC beams, such as moment strength, ductility after peak load and energy dissipation capacity. In the fiber section analysis, the idealized tensile stress-strain curve for the SHCC based on a four-point model was similar to the test result, and it was confirmed that monotonic analytical moment-curvature curves were well-fitted to the experimental moment-curvature curves. Based on the parametric analysis results, it was noted that the curvature of the RC beam was more affected by the matrix ductility of the SHCC than the moment strength.