Bond Behaviour of CFRP and GFRP Laminates on Brick Masonry

In the last decade, innovative technologies have been developed using Fiber reinforced polymer (FRP) as strengthening and repair of masonry structures. Bond of FRP to substrate is crucial for the effectiveness of the technique especially to masonry substrate, which can have a wide variability. Few contributions are available concerning debonding problems on masonry. In this paper the main results of an experimental campaign on the local behaviour of externally bonded FRP, applied on clay bricks, are presented. Double-lap Push-pull Shear Tests have been performed by using carbon and glass fiber reinforcement. Experimental results, in terms of failure load, have been compared with predictive bond-strength models proposed in literature, mainly available for concrete. Based on the measured strength, interface fracture energy has been calibrated. A simplified analytical model, fitted on the experimental data, has been proposed as bond-slip law. Finally, a bilinear function, as commonly adopted by some guidelines, has been calibrated.