Quantifying corrosion caused by extreme weathering between carbon fibre reinforced polymers (CFRP) and steel

Research into carbon fibre reinforced polymers (CFRP)'s application to steel as a retrofitting technique has shown very positive results for increasing mechanical properties. However, the limitation of these materials in a corrosion inducing environment has been widely overlooked. In this study, the possible interaction of CFRP and steel in extreme weather conditions in causing localized corrosion (e.g., pitting) was investigated, with the primary aim of quantifying the pit depth and density caused by the galvanic corrosion process between the two materials. Steel tiles patched in direct contact with different varieties of CFRP were exposed to 5% NaCl solutions at two temperatures for different durations. After removal, the pit depth and pit density were analysed to determine whether galvanic conditions could indeed generate pits, which are known to initiate fatigue cracks in steels. It was observed, in this initial work, that after 4 weeks of exposure to NaCl, the pits formed from the CFRP patched specimens were not exceedingly different or critical compared to that of the control steel tiles.