Effect of elevated service temperature on bond between FRP EBR systems and concrete

The method to increase the ultimate capacity of reinforced concrete elements, by means of Fiber Reinforced Polymers bonded on their substrate with thermosetting resins, represents a technique useable worldwide. The bonding materials used, generally epoxy resins, are sensitive to a temperature increase. In fact, the curing process of epoxies leads to low glass transition temperature (Tg) values, that may cause a relevant decay of the mechanical properties of the adhesive, even under service thermal conditions. The reduction can influence the bond performance, compromising the effectiveness of the reinforcing technique. In this work the interface behaviour FRP–concrete at elevated service temperatures is analyzed. The experimental results show a relevant influence of the temperature on bond performance, in terms of type of failure of the interface, effective bond length and bond strength.