Flexural strength of reinforced concrete members strengthened by fabric reinforced cementitious matrix considering bond characteristics

Fabric-reinforced cementitious matrix (FRCM) is used to strengthen the structural performance of deteriorated reinforced concrete members. Unlike fiber-reinforced polymer (FRP) strengthening, the fabrics are embedded inside the cement matrix to prevent performance degradation owing to exposure to high temperatures and ultraviolet radiation. In exterior strengthening methods, the integrity of the strengthening material and concrete substrates plays an important role in determining the strengthening performance. This study aimed to evaluate the strength of FRCM-strengthened flexural members by considering the bond mechanism that reflects the failure mode of FRCM between the cement matrix and fabrics. In particular, the previously proposed FRCM bond behavior evaluation model was applied to flexural specimens based on the relationship between the maximum bond strength and effective bond length, and the flexural strength of specimens strengthened by FRCM from the existing literature was evaluated. As evaluated by a bond behavior model that takes into account the number of fabrics, spacing between fabrics, and the effect of the direct stress transfer between the cement matrix filled in the grid of fabrics, the mean, standard deviation, and coefficient of variation of the experimental results for the calculated results were 1.216, 0.185, and 0.152, respectively.