Environmental Durability of FRP Bar-to-Concrete Bond: Critical Review

Although fiber-reinforced polymer (FRP) materials are considered noncorrosive, the FRP bar surface resin has been shown to deteriorate when exposed to aggressive environments and this can result in a significant loss of bond strength with the surrounding concrete. To study the durability of the FRP bar-to-concrete bond, numerous investigations utilizing the FRP bar pull-out test arrangement have been conducted. These studies have, however, largely been considered in isolation without any systematic attempt to critically analyze the ever increasing pool of results based on variable exposure regimes and differing geometric and mechanical properties. To address this limitation, and to quantify the durability of the FRP bar-to-concrete bond, this paper presents an experimental database comprising 1,244 individual test results from 35 unique studies which were critically analyzed in terms of bond performance. The analysis highlighted the large scatter that exists for experimental results between studies and attempted to explain this scatter through discussion of the impact of exposure to material properties and the importance of sound experimental design.