عنوان مقاله [English]
Fiber-reinforced polymer (FRP) composites have been considered as a practical and easy-to-use method for the rehabilitation and strengthening of concrete structures. They are being increasingly used as an alternative to steel for reinforcing and strengthening purposes. The main reasons for the increasingly vast interest in application of FRPs for the repair and strengthening of concrete members are: high strength, high modulus, corrosion resistance property, low weight and ease of use. Nevertheless, the debonding of FRP laminates from concrete substrate is a major problem, leading to a decrease in the expected capacity of the strengthened concrete member. To postpone the debonding of the laminates, surface preparation of the substrate is considered a necessity. The purpose of surface preparation is to remove contamination and weak surface layers, to change the substrate surface roughness and to apply new surface chemical groups to promote the bond between FRP composites and concrete. However, conventional surface preparation is not so easy, in some cases, due to the high cost of preparation, non-access to the member surface, and environmental pollution, etc. In this paper, a new method, named; the Grooving Method (GM), is introduced, to promote the performance of FRP laminates from a debonding point of view. The method includes making longitudinal grooves on the concrete surface and filling the grooves with suitable epoxies. The experimental results of the surface preparation effect, and substitute methods to surface preparation, are presented. The results showed that making longitudinal grooves is a very good alternative to surface preparation to postpone the debonding failure of FRP strengthened concrete beams.