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

Abstract

The effect of different percentages of cement components (tricalcium aluminate C 3A) on the corrosion of embedded reinforcing steel bars was studied in presence of 5% NaCl or 5% MgSO 4 solutions. Different electrochemical techniques namely; half-cell potential measurement, impressed voltage method and impressed current method were used. The C 3A 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 C 3A increased in cement from 2% to 10% the steel corrosion decreased proportionally. The rate of corrosion in 5% MgSO 4 solution was decreased as the percent of C 3A 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.