Corrosion characteristics of rebar in Fly Ash-GGBFS synthesised alkali activated concrete

Abstract

Abstract Using accelerated corrosion technique, it is proposed to study the influence of anodic corrosion inhibitors like calcium nitrites (0%, 2%, 4%, 6%) and sodium nitrites (0%, 2%, 4%, 6%) on the Fe550 grade steel reinforcement corrosion of M20 grade Geopolymer concrete (70%FA+30%GGBFS) cylindrical specimens prepared using 3M and 5M alkali activators. Geopolymer concrete cylinders with rebar inserted are placed in the 5% NaCl solution and the corrosion time and corrosion current required for the corrosion of steel reinforcement bars was calculated by supplying a constant voltage of 12volts. Three cylindrical specimens of 200mm diameter and 100mm height are cast in each percentage of corrosion inhibitors and the corrosion characteristics like Corrosion rate, mass loss, Corrosion density, Corrosion current, Corrosion time of steel reinforcement were calculated. 200mm length and 10mm diameter steel reinforcement bar was used in the Geopolymer concrete cylindrical specimens. 4% of Calcium nitrite (Ca(No2)2) and 4% of Sodium nitrite (NaNo2) with 3M and 5M alkali activators were found to be optimum with less mass loss and rate of corrosion. The mass loss and rate of corrosion of 3M alkali activator Geopolymer concrete mix were less compared to that of 5M alkali activator geopolymer concrete.