Novel molecular approach using triazine inhibitor to control corrosion and limit chloride ion penetration in steel reinforced concrete

Abstract

The presence of chloride ions exceeding its critical concentration in its surrounding is one of the major causes for reinforcing steel corrosion, and subsequently, reduction in the strength of the structure occurs. A common method of preventing such deterioration is to prevent chlorides from penetrating the structure to the level of the reinforcing steel bar by organic corrosion inhibitors. The electrochemical behaviour of mild steel in seawater with or without 4[{(4,6-diamino-1,3,5-triazine-2-yl)imino}methyl]-2,5-cyclohexadiene-1-one, a new triazine inhibitor, is identified and synthesised by Insilco techniques in parts I and II of our previous study. Part III presents the evaluation of the new inhibitor in reinforced steel concrete specimens by current induced accelerated corrosion method and also its performance to prevent chloride penetration in concrete structures. Tests were conducted to Indian standards, ASTM standards and Council of Scientific and Industrial Research guidelines to control rebar corrosion. Results showed that the inhibitor efficiency is up to 85%, and also the rate of chloride penetration into the concrete specimens was decreased when the new inhibitor is used as admixture. In addition, the relationship between the molecular structure of these compounds and their inhibition efficiency has been investigated by ab initio quantum chemical calculations using Cerius 2 software program.