EFFECT OF CURVATURE ON THE TENSILE STRENGTH OF FRCM

Abstract

Fabric reinforced cementitious matrix (FRCM) systems are promising composite materials which are increasingly used for the strengthening of reinforced concrete components. The interaction of high performance, fine-grained concretes and noncorrosive, high strength textile reinforcements combines many advantages of shotcrete linings and externally bonded fiber-reinforced polymers (FRP). For this reason, especially the retrofitting of plane concrete structures with FRCM has already been investigated appropriately. However, the application of FRCM systems in edge regions and curved areas, such as the confinement of reinforced concrete columns or shear strengthening of beams, leads to a reduction of the systems' tensile strength. This reduction is mainly caused by additional transverse pressure, cracks in the concrete matrix, and possible pre-damage due to the bent textile. As most available prediction models use static reduction factors, the dependencies of these influences have not been considered sufficiently yet. This paper presents an experimental study regarding the effects of curvature on the tensile strength of FRCM-strengthening layers. Therefore, 93 specimens with varying radii, FRCM composite materials, and numbers of applied textile layers were tested in a newly developed setup. The test results show significant dependencies on the various parameters and contrast with the static reduction factors used so far.