Bond behaviour between hybrid fiber reinforced polymer sheets and concrete

Fiber reinforced polymer (FRP) have been widely used for strengthening and retrofitting the existing structures. Debonding has been identified as one of the most common failure modes of such composite structures. Numerous studies have been conducted to investigate the bond behavior between FRP and concrete. Hybrid FRP, which is made of combinations of different types of fibers, has shown their excellent performance in strengthening structures. However, only limited studies have been conducted on the bond behaviour between hybrid FRPs and concrete. This study investigates the interfacial behaviour between hybrid FRP (carbon/basalt) and concrete blocks by using the single-lap shear testing method. The digital image correlation (2D-DIC) technique is used to measure the full fields of displacements and strain of the specimens. The effects of FRP stacking order and the mechanical properties of FRP on the bond behavior are evaluated. The experimental results show that the FRP stacking order has obvious influences on the debonding load and the bond-slip relationship. The effect of FRP stacking order on the fracture energy is also examined. The existing models are recalibrated with consideration of stiffness variations and the predictions of the modified models agree better with the experimental results. (C) 2019 Elsevier Ltd. All rights reserved.