Bond analysis of FRCM strengthened masonry subjected to salt attack

Externally bonded reinforcement of masonry structures with Fiber Reinforced Cementitious Matrix (FRCM) composites has received increasingly attention in the last years. Notwithstanding the vast literature on short-term behavior and structural performance of these systems, very little is known about their durability. During their life-time, masonry buildings are affected by weathering processes due to, among the others, environmental causes such as rising damp and salt attack. Thus, the assessment of the mechanical characteristics of strengthened masonries in on-site conditions is fundamental for evaluating their real structural performance. To this aim, masonry blocks strengthened by steel FRCM composites were built and subjected to weathering cycles constituted by a wetting phase and a drying phase. The cycles aim at reproducing the on-site conditions of masonry, usually subjected to daily and seasonal climatic changes. After conditioning, the FRCM-masonry joints were subjected to direct shear tests in order to investigate the effects of the cycles on the interfacial bond between composite and masonry substrate. Further, materials characterization on constituent materials was conducted in order to interpret the results from direct shear tests.