Study on corrosion and anticorrosion of rebar in magnesium oxychloride cement concrete

In order to solve the rapid corrosion problem associated with rebar in magnesium oxychloride cement concrete, an experiment on the corrosion and anticorrosion of rebar is designed. The corrosion and anticorrosion effects of rebar are evaluated through the corrosion current density. A time-varying model of rebar corrosion in magnesium chloride cement concrete is proposed. Based on the time-varying model for rebar corrosion, the initial cracking time with magnesium oxychloride cement concrete is calculated. The results show that the test environment has little effect on exposed-rebar corrosion. The corrosion current density of the coated rebar in a water-soaking environment is greater than that for coated rebar in an indoor natural environment. Greater concrete cover depths cause more severe rebar corrosion. All cases of exposed-rebar corrosion conform to the exponential-type time-varying model, whereas coated-rebar corrosion conforms to the logarithmic-type time-varying model. The corrosion degree of the magnesium oxychloride cement exposed-rebar concrete is much greater than that for magnesium oxychloride cement coated-rebar concrete by two orders of magnitude, showing the feasibility, long-term stability and effectiveness of using coated rebar in magnesium oxychloride cement concrete.