Influence of metakaolin and red mud blended cement on reinforcement corrosion in presence of chloride and sulfate ions

Abstract

This paper investigates the impact of partial replacement of Ordinary Portland Cement (OPC) with Metakaolin (MK) and Red Mud (RM) on reinforcement corrosion in presence of both chloride and sulfate ions. To achieve this objective, 36 slab specimens of size 300 × 300 × 52 mm were cast. First set of slabs had been cast with water to binder ratio 0.48, with the replacement of OPC by 5% of RM and 10% of MK one after the other. Similarly, the second set of slabs cast with water to binder ratio 0.51. Each set was admixed with 5% NaCl, 2% MgSO4, 5% NaCl + 2% MgSO4 by using weight of water. The corrosion behavior of reinforcing bars was monitored through half-cell potentials based on ASTM C876. To make sure the compressive strength of slabs, concrete cubes were tested. The numerous results, which indicate the effects of MK, RM, w/b ratios and concomitant presence of chloride and sulfate ions on reinforcement corrosion have been provided and compared the same. At higher w/b ratios (0.51), it was observed that the specimens with RM had lowest corrosion potentials as compared to OPC specimens and MK in the presence of chloride ions. Further in the presence of combined chloride and sulfate ions, corrosion potentials of MK and RM are less in comparison to the OPC concrete at higher water to binder ratios.