A carbon-fibre FRP showed modest but noticeable degradation. This indicates the need for further study - even for FRPs made of carbon fibres, which are known for their high resistance to chemical degradation. Specially made FRP specimens have been exposed to air, water and aqueous solutions of salt and alkali at various temperatures. Further tests of one-year duration have since been set up at IRC to provide more information about the causes and mechanisms of FRP deterioration. Results obtained so far show physical damage in the form of cracking and etching of the surface, and the exposure of some fibres.
Some tests also indicate the onset of chemical degradation.
However, the trends observed still need to be confirmed by test results following exposure for a year. The next step will be to subject the materials to accelerated-aging tests. The results of these tests, together with the monitoring of actual FRP applications over a longer period of time, will help researchers formulate a mathematical model to predict the service life of FRP-reinforced concrete structures. IRC researchers are collaborating with researchers from the University of Sherbrooke and the Japanese Public Works Research Institute on such tests. The knowledge gained from these investigations will eventually be integrated into the existing CCMC Technical Guide for the evaluation of FRPs as concrete reinforcement.