Digital image correlation measurement of the bond–slip relationship between fiber-reinforced polymer sheets and concrete substrate

Abstract

Due to the difficulties and the limitations of traditional measurements, it is extremely challenging to obtain an accurate bond–slip relationship for a fiber-reinforced polymer (FRP) sheets to concrete interface. This paper presents experimental studies aimed at accurately measuring the bond–slip relationship of the FRP sheets to concrete interface using a digital image correlation (DIC) measurement. Double-lap shear specimens were tested with different layers and sequences of carbon or basalt FRP sheets attached to the concrete substrate. The fitting procedures for determining the bond–slip relationship from the DIC results were proposed and validated. The test results show that more comprehensive information during the debonding process can be recorded through the DIC measurement. Error reductions and more accurate bond–slip relationships can be achieved by using the fitting procedures. In addition, the type of FRP sheets and their sequence attached to the concrete surface have a significant influence on the bond behavior between FRP sheets and concrete substrate.