The Inhibition of Chloride-Induced Corrosion in Reinforced Concrete by Calcium Nitrite

Abstract

Reinforcing steel in portland cement concrete is subject to accelerated corrosion in the presence of chloride ions. A corrosion-inhibiting admixture based on calcium nitrite has been shown to confer protection (that is, to inhibit corrosion) if the chloride to nitrite weight ratio (Cl−/NO2−) does not exceed 1.5. Visual observations made on rebars in limewater solutions containing chloride and nitrite ions, current and potential measurements on concrete cylinders with embedded reinforcing bars (rebars), and potential measurements on simulated concrete bridge decks were in substantial agreement.

Experiment and time‐varying characteristics of steel corrosion in magnesium oxychloride cement

“…The relation between the corrosion current density of steel in MOC and ages was fitted using Equations (13)- (15). The time-varying models of steel corrosion and their parameters are shown Table 5.…”

“…The Darex corrosion inhibitor mixed with cementitious materials can achieve the anticorrosive effect mainly by increasing the critical chloride ion concentration for the steel. 15,16 However, the chloride ion concentration in MOC is much higher than the critical chloride concentration of steel corrosion. Therefore, it is not advisable to adopt the Darex corrosion inhibitor to prevent steel corrosion in MOC.…”

“…There are many kinds of technical measures to prevent steel corrosion, which can be basically classified into three categories: corrosion inhibitor, coated steel, and special steel. The Darex corrosion inhibitor mixed with cementitious materials can achieve the anticorrosive effect mainly by increasing the critical chloride ion concentration for the steel 15,16 . However, the chloride ion concentration in MOC is much higher than the critical chloride concentration of steel corrosion.…”