The use of glass-ceramic bonding enamel to improve the bond between concrete and steel reinforcement

Typically concrete does not form a strong bond to reinforcing steel. The paste interface around the steel is a boundary where interpore water accumulates during the setting process. The water-rich paste and the deposition of crystals of portlandlite, produces a weak, permeable or interfacial zone. The weak interfacial zone makes it relatively easy to separate the steel reinforcement from the surrounding concrete. Coating the reinforcing steel with a glass-ceramic layer containing hydraulically reactive silicates such as calcium silicate and aluminoferrites reduces the water in the interfacial zone, creates a glass-ceramic coupling layer resulting in a concrete-to-steel bond that is over four times stronger than the typical bond. The glass enamel forms a protective cover that minimizes corrosion of the reinforcing steel when the chemistry of the surrounding paste changes due to carbonation and chloride infiltration and puts the steel at risk to oxidation. Enameling technology can be used on all forms of steel reinforcement including rebar, steel fiber, or steel decking.