Chloride-ion induced corrosion of galvanized and ordinary steel reinforcement in high-performance concrete

Abstract

An experimental investigation has been carried out to assess the effectiveness of the use of high-performance concrete (HPC) and galvanized steel in reducing reinforcement corrosion. Two normal strength concrete (NSC) mixtures with 28-day compressive strengths of 30 and 40 MPa and two high strength concrete (HSC) mixtures with compressive strengths of 50 and 80 MPa were used for this study. The rapid chloride ion penetration test was used to study the ion penetration and the results are compared with the results of long-term immersion tests in 4% NaCl solution over a period of 1 year. No correlation between the results of these two tests could be established. Half-cell potential measurements were used to monitor the initiation of corrosion. The pH of HPC pastes and mortars were monitored for 90 days to study the effect of silica fume on pH of concrete and corrosion initiation. The results showed that HPC reduced chloride ion penetration significantly. Silica fume at 10% replacement level reduced the pH of concrete from 14.00 to 12.8 over a period of 90 days.