The Influence of Temperature on the Debonding of Externally Bonded CFRP

Synopsis: Fiber Reinforced Polymers have proven to be effective strengthening materials in the construction industry, due to their low weight (easy to apply), noncorrosiveness and high strength. Extensive research has been carried out into the strengthening of concrete structures with externally bonded FRP. It turned out that debonding of the FRP is governing the design of most FRP strengthening applications. One of the parameters, which may affect the bond properties of the FRP-concrete joint, is the ambient temperature. Only little research into the influence of temperature on the bond behavior has been carried out so far. This paper presents the results of an exploratory experimental and numerical investigation in which the influence of temperature on the debonding behavior of externally bonded CFRP was investigated. Two different test setups were applied. Results showed that the failure load of CFRP strengthened concrete structures was affected by the temperature, but depended on the used test setup. Two types of failure were observed. For low to moderate temperatures (-10°C to +40°C), failure occurred in the concrete, leaving 1-3 mm of concrete attached to the adhesive. For elevated temperatures (50°C to 75°C), failure of the adhesive-concrete interface occurred, without leaving any concrete attached to the adhesive.