Corrosion control in RC structures using fibre reinforced concrete

摘要

Recent studies have shown that fibre reinforcement of concrete reduces its permeability to water and enhances its service life. In this study, this finding was extended to determine if fibre reinforcement can also control corrosion of reinforcing steel in traditionally reinforced concrete. Two fibre types, cellulose and polypropylene, at 0.1% and 0.3% volume fraction, were examined. Two series of tests were performed. In the first series, chloride transport characteristics were determined by using the Bulk Diffusion Test, the Silver Nitrate Spray Test and the Rapid Chloride Permeability Test. In the second series, corrosion activity in reinforcing steel was monitored in loaded RC beams with and without fibre reinforcement for a year in a simulated marine environment. Results demonstrated that while the presence of fibres increased the coefficient of chloride diffusion based on total chlorides, there was a decrease in the coefficient related to free chlorides. Fibres therefore appear to bind the chlorides and inhibit their transport through concrete. Corrosion tests further corroborated these findings and indicated that fibres delayed the onset of corrosion in RC beams as long as the applied load did not exceed a certain threshold value.