Experimental investigation of the corrosion effect and repair effectiveness for an RC beam with the corroded stirrups

To investigate the effectiveness of selected repair materials and reinforcement methods on the shear strength of reinforced concrete (RC) beams with corroded stirrups, 14 RC beam specimens were designed with corroded stirrups exhibiting weight loss rates of 10% and 17%. Additionally, control specimens without repairs were included to assess the impact of pre-corroded stirrups on strength development. A three-point bending test was conducted to evaluate the shear strength of the specimens under various repair and reinforcement scenarios. Epoxy mortar, cement mortar, and non-shrinkage cement mortar were selected as repair materials, while spot-welded steel wire mesh (WWM) and carbon fiber-reinforced plastics (CFRP) were used to enhance repair effectiveness. The results indicate that, for the specimens with corroded stirrups showing weight loss rates of 10% and 17%, their shear strengths decreased by up to 17% and 21%, respectively, compared to specimens without any corrosion. Additionally, the shear strengths of the specimens repaired using epoxy mortar were slightly increased by reinforcing with WWM and CFRP. However, the shear strengths of most specimens with repair and reinforcement were lower than their original shear strengths. For practical design applications, this work introduces a novel approach to quantifying the effectiveness of repair materials in conjunction with reinforcement methods, based on the softened strut-and-tie model (SST), which was verified using experimental data.