Extraction of bond-slip characteristics in FRP-to-concrete joints exposed to accelerated aggressive environments

Strengthening of structurally deficient reinforced concrete elements by means of adhesively bonding fibre-reinforced polymers (FRP) is now common practice. Given the uncertainty of the long-term durability of these strengthening systems, the critical bond between the FRP and concrete has seen widespread testing of samples conditioned under accelerated aggressive environments. In order to develop a set of bond deterioration factors, a database of test results containing full range load-displacement relationships of FRP-to-concrete joints under various environmental conditions has been collected and a mechanics based approach has been shown to be able to extract bond properties across the various test set-ups, material properties and environmental exposures. Through a statistical analysis, conservative deterioration factors are determined that allow for the design of future durability bond tests that can ensure that the full range load-displacement behaviour is captured.