Chemically Reactive Enamel: A Steel Rebar Coating for Enhanced Durability of Concrete Structures


Since 2007, the research group at Missouri University of Science and Technology has initiated and sustained a series of systematic studies on steel rebar and plates coated with vitreous enamels for enhanced corrosion resistance and for rebar bond strength in concrete. This paper presents a summary review on the corrosion performance and performance consistence of various enamel-coated steel rebar and plates in two corrosion environments. Specifically, three types of enamel coating (pure, mixed, and double enamel) were investigated with four types of specimens (steel plates, smooth steel rebar, deformed steel rebar, and smooth steel rebar embedded in mortar cylinder) in 3.5wt.% NaCl solution and saturated Ca(OH)2 solution. Their corrosion resistances and mechanisms are compared with fusion-bonded epoxy coating. Electrochemical impedance spectroscope and linear polarization resistance tests were respectively performed for short-term and long-term corrosion performances of coated rebar over a period of 173 days. An emphasis is placed on the effects of coating thickness, thickness variation, potential damage, mortar protection, and corrosion environment on the corrosion behavior of uncoated and coated steel. Due to the isolated nature of air bubbles trapped inside them during high temperature firing, the pure and double enamel coatings are more corrosion resistant and more sensitive to the coating thickness and potential damage than the mixed enamel coating. This general conclusion is independent of the test solution. Mortar cover further increases the corrosion resistance of tested specimens. For deformed steel rebar, coating damage and thickness variation due to the presence of rebar ribs are the two main causes for low corrosion resistance. The double enamel coating provides the most consistent corrosion performances for various specimen applications and is thus recommended for the design of reinforced concrete structures in corrosive environments.

Meeting Name

3rd International Conference on the Durability of Concrete Structures (2012: Sep. 17-19, Belfast, United Kingdom)


Civil, Architectural and Environmental Engineering

Second Department

Materials Science and Engineering

Keywords and Phrases

Concrete buildings; Concrete construction; Corrosion resistance; Epoxy resins; Mortar; Reinforced concrete; Thickness measurement; Corrosion environments; Durability of concrete structure; Electrochemical impedance; Fusion-bonded epoxies; High-temperature firing; Linear polarization resistance; Science and Technology; Enamels

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2012 Hokkaido University Press, All rights reserved.

Publication Date

01 Sep 2012

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