Protection Against Chloride-Induced Corrosion

Abstract

Where deicing salts are used, or in marine environments, protection against chloride-induced corrosion is now a requirement. Although research has shown that quality concrete is the first line of defense against chloride-induced corrosion, it is no protection against deicing salts or marine environments. This article describes microsilica and calcium nitrite corrosion inhibitor, which are two proven corrosion protection products that delay onset of corrosion. Microsilica reduces the permeability of the concrete, which slows the ingress of chloride ions to the reinforcement, while calcium nitrite controls the rate of corrosion once the chlorides reach the reinforcement. Both products have been used separately or in combination to protect cast-in-place parking structures. Microsilica is gaining popularity for bridge decks and overlays, as well as where a combination of high strength and corrosion protection are required.