The effect of red mud in the electrochemical behaviour of carbon steel embedded in mortar

The red mud (RM) is the main residue of the Bayer Process, in which alumina is extracted from bauxite. Due to huge amount produced worldwide (84.1x10(9) kg/year) and their high alkaline character, RM represents an important environmental problem in areas where the industry is implanted. RM particles in alkaline solutions are ionised with hydroxyl groups that can anchorage to a metallic surface. This feature suggests the possibility of using RM as an inhibitor for steel in alkaline medium. So a possible solution for these residues, as additive in reinforcing concrete, is presented in this study. The experimental results prove samples with RM do not present corrosion in spite of the high amount of chloride ions.