Improving Corrosion Resistance of RC Beams Using Epoxy Treated Chopped Carbon Fibres

Reinforced concrete (RC) has been widely used in the construction field for many years because of its stability, economy, and resiliently in extreme conditions. However, steel bar corrosion arising from contamination of chloride is still regarded as one of the most critical issues affecting the durability and stiffness/strength of RC structures. Recently, an innovative material of carbon fibre (CF) has been implemented in concrete structures for improving mechanical performance. This study investigates the possibility of using chopped carbon fibre (CCF) for mitigating corrosion of RC structures through experimental examination of the steel corrosion behaviour when using chopped CF in RC beams. CCF of 35 mm long was surface treated with epoxy to prevent a galvanic coupling between CCF and the steel bars. The effects of two CCF proportions (2.5% and 5%) by weight of cement in RC beams were studied while the beams have been exposed to a simulated marine environment with sustained loading, 3.5 wt.% NaCl solution, 6 hours of wet-dry cycle and 50oC temperature. Electrochemical measurements have been applied to detect the corrosion process. The mechanical strength of concrete specimens with two different CCF contents was also performed. The experimental results indicated that the epoxy-treated CCF can reduce the corrosion rate from the concrete cover to the steel bars which leading to longer corrosion initiation period and lower steel reinforcement corrosion rate. The decrease in rebar corrosion rate of RC beams with 2.5% CCF was found to be 20% lower comparing to th