A Bending Test Set-Up for the Investigation of the Bond Properties of FRCM Strengthenings Applied to Masonry Substrates

Abstract

Existing masonry and reinforced concrete structures are characterized by a wide use of structural and non-structural masonry members such as structural walls, infill walls, arches, vaults etc. All these members are characterized by high vulnerability when subjected to seismic events, since unreinforced masonry has a negligible tensile strength. The use of fiber reinforced polymers (FRP) composites has become a common practice and it represents a light-weight, easy, fast, and non-invasive solution for rehabilitation of existing masonry structures. Fabric reinforced cementitious matrix (FRCM) are relatively newly developed composite materials, representing a valid alternative to FRP in strengthening and retrofitting of existing reinforced concrete and masonry structures. Despite of the numerous advantages guaranteed by the inorganic matrix, the bond-behavior between the fibers and the embedding matrix is still under investigation. Different set-ups have been proposed in the literature to study the bond behavior of FRCM composites. Among them, single-and double-lap shear tests are the most commonly used. In this paper, the bond behavior of a polyparaphenylene benzobisoxazole (PBO) FRCM composite applied to masonry elements is studied using a bending and a single-lap shear test set-up. The bond capacities obtained by the two set-ups are analyzed and discussed.