Bond strength of CFRP–concrete elements under freeze–thaw cycles

Bonding between the adherents represents a key point when dealing with the reinforcement of concrete structures by using FRPs. Bonding depends on mechanical and physical properties of concrete, composite and adhesive as well as on the surface treatment of the concrete substrate. A very important topic for civil engineering applications is related to the durability of the bond in harsh environments. In the present paper some specimens were first subjected to freeze–thaw cycles and then experimental debonding tests were performed in order to investigate the effects of the bonding length and environmental conditions. First, the effects of environmental conditions on bond strength is discussed. Finally, the experimental data are compared to the design formulae proposed by the Italian Recommendations CNR DT200/2004 and critical considerations are presented.