Effect of freeze-thaw cycles on the bond durability between fibre reinforced polymer plate reinforcement and concrete

Abstract

Deterioration of infrastructure is one of the most pressing concerns facing today's civil engineering community. As a result, new rehabilitation techniques, such as the external bonding of fibre reinforced polymer (FRP) plates and sheets, are being developed. To apply these rehabilitation methods in Canada, the durability of the rehabilitated structures in cold regions must be assessed. This paper examines the effects of freeze-thaw cycling on the bond between FRP and concrete. An experimental investigation was conducted using both single lap pull-off and bond beam specimens. Only uniaxial carbon FRP strips were considered. The specimens were exposed to up to 300 freeze-thaw cycles consisting of 16 h of freezing and 8 h of thawing in a water bath. After exposure, the specimens were tested to failure. The development of strain along the bond length and the failure mode are presented for both types of specimens. Load deflection curves are presented for the beam specimens. The results indicate that the bond between carbon FRP strips and concrete is not significantly damaged by up to 300 freeze-thaw cycles.Key words: reinforced concrete, repair, rehabilitation, strengthening, fibre reinforced polymers, freeze-thaw, bond damage.