Bond behavior between carbon fabric reinforced cementitious matrix (FRCM) composites with added short fibers and concrete substrates

Fabric reinforced cementitious matrix (FRCM) composites show an innovative solution for strengthening existing concrete structural elements to solve the drawbacks of organic resins in fiber-reinforced polymers (FRP) system. However, the brittle fracture of the cementitious matrix significantly reduces the efficiency of the fabric. Hence, the incorporation of short fibers into the matrix is proposed to increase the fabric efficiency. For externally bonded FRCM composites to structural element surfaces, it is a crucial issue to investigate the bond behavior at the fabric-matrix and matrix-substrate interfaces, where the effect of short fibers is non-negligible and requires further investigation. In this study, a single-lap direct shear test was used to investigate the bond behavior between carbon FRCM composites with added short fibers and concrete substrates. 36 specimens were tested and discussed by considering the effects of bond length, volume content of short fibers, type of short fibers, and bond width. The experimental results were discussed in terms of failure mode, load-slip curve, and characteristic parameters. Subsequently, the contribution of weft yarns was studied and accounted for in the developed bondslip model, which additionally takes into account the effects of the volume content of the short fibers, the type of short fibers, and the bond width.