Effect of high temperature on bond strength of near-surface mounted FRP reinforcement

This paper presents results from an experimental study on the effect of temperature on bond strength and modulus of near-surface mounted (NSM) fiber-reinforced polymer (FRP) strengthened concrete. 36 NSM FRP specimens, fabricated using different types of epoxy adhesive and FRP reinforcement, were tested to evaluate bond strength in 20–400 °C temperature range. Results from these tests indicate that bond strength and modulus decrease significantly in 20–200 °C temperature range, and only retain 20–30% of their original values at 200 °C. NSM FRP strips and rods possess negligible bond strength beyond 400 °C. Data from tests also indicates that NSM FRP system exhibits similar bond stress–slip response at both room and high temperatures. However, the peak value (bond strength) and the slope (bond modulus) are much lower at high temperatures. Data from the tests is utilized to propose empirical relations for variation of bond strength and modulus of NSM FRP strengthening system with temperature.