Chemically reactive enamel coating of steel rebar for enhanced durability of reinforced concrete structures

Abstract

In this paper, the corrosion performances of three types of enamel coating (pure, mixed and double enamel) applied on smooth and deformed steel rebar are compared based on the electrochemical impedance spectroscope (EIS) tests in 3.5 wt.% NaCl solution. The effects of mortar cover, rebar deformation, enamel coating and coating thickness variation on the corrosion resistances of steel rebar are investigated. Mortar cover increases the corrosion resistance of tested specimens. The coated deformed rebar has lower corrosion resistances than the coated smooth rebar due to the variation in coating thickness around rebar ribs. Due to the isolated nature of air bubbles trapped during high temperature firing, pure and double enamel coatings are more corrosion resistant and more sensitive to the coating thickness than the mixed enamel coating with interconnected pores. Therefore, pure and double enamel coatings are recommended for the design of reinforced concrete structures in corrosive environments.