Use of Vitreous Enamel Coated Bars in Structural Concrete Subjected to Corrosive Environment

Abstract

Steel-reinforced structural concrete is a common building material that has proven itself to be versatile, economical and affordable. Under a spectrum of operating conditions and circumstances, steel-reinforced concrete can be categorized as being both strong and durable thereby enabling in maintenance-free service during its life span. However, corrosion, or environment-induced degradation, of the steel reinforcement embedded in concrete is of concern particularly in aggressive environments, to include both aqueous and gaseous. A gradual degradation of the steel within concrete causes several problems ranging from cracking to spelling of the concrete coupled with reduced bond strength between the steel bars and the surrounding concrete. A reduction in bond strength contributes to a gradual loss in strength coupled with increased deformation, ease of initiation of flaws spanning both microscopic and macroscopic, and concurrent growth of the flaws through the microstructure. An evaluation of steel reinforcing bars coated with a new and emerging coating material is presented in this paper. Two potential applications for this type of coated bars include (a) the role of enamel-coated dowel bars for use in concrete pavements, and (b) enamel coated bars as viable reinforcement for structural concrete. The results of the study are aimed at evaluating and understanding the influence of environment on corrosion resistance of enamel coated steel reinforcing bars with concomitant influence on mechanical performance of reinforced concrete structure is presented, and comparisons are made with the performance of structural concrete reinforced with conventional steel reinforcing bars. Structural tests on beam specimens reinforced with enamel-coated steel reinforcing bars demonstrated the role of vitreous enamel coating on steel reinforcing bars and proved that the performance of reinforced concrete beams with such bars is marginally better in terms of improved flexural strength and shear strength.