Effect of cement type on the corrosion of reinforcing steel bars exposed to acidic media using electrochemical techniques

The effect of different percentages of cement components (tricalcium aluminate C3A) on the corrosion of embedded reinforcing steel bars was studied in presence of 5% NaCl or 5% MgSO4 solutions. Different electrochemical techniques namely; half-cell potential measurement, impressed voltage method and impressed current method were used. The C3A in cement reduced greatly the corrosion of steel bars embedded in concrete subjected to chloride or sulphate solutions. In chloride solution, as the percent of C3A increased in cement from 2% to 10% the steel corrosion decreased proportionally. The rate of corrosion in 5% MgSO4 solution was decreased as the percent of C3A increased from 2% to 6%. From 6% to 10% the steel corrosion rate was rapidly accelerated. In general the presence of chloride and sulphate solutions in surrounding media reduced the destructive effect of sulphate ions on embedded steel bars.