Shear debonding of FRP plates from concrete surface: using modified single lap shear test set-up

One of the most critical issues in the strengthening of the structures with fibre reinforced polymer materials is the bond behaviour between substrate and FRP plates. During past decades, several investigations have been done to address the bondline characteristics and the effects of various parameters on the interfacial behaviour. Based on empirical, numerical models or fracture mechanics theory, numerous models have been advanced to estimate the bond behaviour using existing processing techniques. However, few researches have been carried out to modify the bond characteristics between concrete and FRP materials in order to improve the performance of these materials during loading. In this article, a new innovative processing method for application of FRP materials will be examined. In this method, fibres will be injected by resin under vacuum condition to achieve higher quality in bond. The results of single lap shear tests have been utilized to investigate the capability of this system in strengthening of concrete elements. According to sensitivity of the experiments to the small amount of error in single lap shear tests, several modifications have been done in test set-up during the experiments which led to more precise outcomes in terms of load-slip and therefore shear-slip or strain-slip of the interface.