Influence of corrosion inhibiting admixtures on strength and durability parameters of concrete: a comparative study

Abstract

Even though there are extensive studies conducted on the mineral admixtures to control chloride permeability, the very few studies were conducted in India on the usage of corrosion inhibitors in concrete in order to delay the corrosion process. The results of the laboratory studies conducted using two commercially available corrosion inhibitors to determine the effectiveness and their influence on strength and durability parameters of Portland cement concrete are presented in this paper. This study examined the workability, compressive strength, split tensile strength, flexural strengthdevelopment in concretes mixed with anodic inhibitor (calcium nitrite based) and bipolar corrosion inhibitor (amino alcohol based). The durability tests such as the Rapid Chloride Permeability Test (RCPT) and Water Permeability Tests (WPT) are also conducted to determine the effectiveness of inhibitors.Test results showed that addition of calcium nitrite based inhibitor has resulted in marginal increase of compressive strength of concrete at 28 days, whereas, the addition of bipolar inhibitor has resulted in marginal decrease of compressive strength of concrete at 28 days. Addition of both the inhibitors has improved the split tensile strength but reduced the flexural strength. The resistance to the penetration of chloride ions of concrete is marginally improved by adding both the inhibitors. Water permeability resistance was improved by adding both the inhibitors at 5% dosage.