A comparison between the bond behavior of SRP and SRG strengthening systems applied to a masonry substrate

Strengthening and rehabilitation of existing masonry buildings is a topic that attracts the interest of the scientific community worldwide. Fiber reinforced polymer (FRP) composites have been largely employed for structural rehabilitation of masonry structures due to their ease of installation and their high strength-to-weight ratio, since the end of the previous century. Recently, fiber reinforced cementitious matrix (FRCM) composites have become an appealing alternative to traditional FRPs, because they employ an inorganic matrix to embed the fibers, which provides a better vapor compatibility with masonry substrate and better resistance to high temperatures than FRPs. To reduce the cost of carbon and glass fibers, the use of new types of fibers, such as high strength steel cords, has been explored. Steel reinforced polymer (SRP) and steel reinforced grout (SRG) are still moving their first steps in the world of structural rehabilitation, but they have shown potentials to become a suitable alternative to other FRP and FRCM composites, respectively. In this work, SRP and SRG composites are bonded to masonry blocks and tested using a direct single-lap shear test set-up to investigate the debonding phenomenon. Two different types of mortar grout are employed for the SRG. A comparison between SRP and SRG composites is presented in terms of debonding capacity and failure modes.