Strength of carbon fiber reinforced polymers bonded to concrete and masonry

Fiber reinforced polymers (FRPs) have gained popularity in upgrades of reinforced concrete structural elements within the last decade because of their ease of application and high strength-to-weight ratio. In the design of an effective retrofitting solution using FRP systems, the anchorage capacity has an important role. This study presents the results of 57 double shear push-out tests conducted to determine the strength of carbon fiber reinforced polymers (CFRPs) bonded to concrete prisms and hollow clay tiles that are finished with and without plaster. In the experimental program, different types of anchorage methods were tested in a double shear push-out test setup. It was observed that presence of a plaster finish adversely affects the strength of CFRPs bonded to concrete or masonry. Furthermore, it was found that strength of CFRPs bonded to hollow clay tiles are significantly lower than CFRPs bonded to concrete. The proposed embedded anchors acting as shear connector were found to significantly improve the ultimate strength of surface bonded CFRPs both in the presence and absence of plaster finishing. A simple and effective strength model, calibrated using the experimental results, is verified for FRP anchors based on the existing analytical models and experimental observations from this and other studies reported in the literature.