Epoxy Coated Rebars in concrete structures

Reinforced concrete is inherently a durable and near maintenance-free construction material under normal conditions. Harsh environmental conditions, such as exposure to deicing salts or seawater, however, can cause premature deterioration of the material. The expected service life of a reinforced concrete structure can be significantly reduced when chloride penetrates the concrete to the level of the steel reinforcement. When corrosion of the reinforcing steel is initiated, the products of corrosion expand and occupy a greater volume than the original steel and eventually cause cracking of the concrete. once corrosion of the reinforcing steel has cracked the concrete, more chloride enters to attack the steel, and deterioration of the reinforced concrete component or structure proceeds at a faster pace. Premature deterioration of reinforced concrete structures due to corrosion of the reinforcing steel is of concern world-wide.

Epoxy-coated reinforcing bars have emerged as a viable and cost-effective corrosion-system for reinforced concrete structures. According to the original research, the epoxy coating is a physical barrier system that prevents moisture and chlorides from coming in contact with the bar. Epoxy coating is also being regarded now as an electrochemical corrosion barrier which electrically isolates the bar by reducing the flow of corrosion current.

In the USA, epoxy-coated reinforcing bars were used for the first time in highway bridge construction in 1973. During the intervening years, epoxy-coated bars have attained the status of being the preferred corrosion-protection system for bridge decks in a deicing salt environment.
Epoxy-coated bars are also used in other components of reinforced concrete bridges, and in continuously reinforced concrete pavements. Other applications include parking garages, tunnels, wastewater treatment plants, and marine structures.

The Advantages of Epoxy Coated Steel Bars

 Epoxy-coated bars are often used to help support concrete structures, and they have a variety of advantages. Most importantly, they don't corrode as easily as regular steel bars, which makes the structure last longer and also makes it safer. Indeed, all of the advantages of epoxy-coated steel bars link back to stability and general safety.

1,Barrier

   Epoxy on steel bars acts as a physical barrier for salts. This keeps corrosion to a minimum as the salts strike the epoxy and bounce off rather than take hold in the steel and corrode it. It also acts as an electrochemical barrier, making a slight current over the steel bar, which repels salts before they even touch the epoxy.

2,Maintenance

   Epoxy-coated steel reinforcing bars are low-maintenance. The epoxy only needs to be put on once, and from that point forward the bars have reduced corrosion. This is much easier and less expensive than it would be to constantly monitor, adjust and replace reinforcing bars, which allows a project management team to devote its maintenance resources to other, more pressing issues.

3,ROI (Return On the Investment )

  Coating steel bars with epoxy offers a tremendous return on the investment (ROI). This is because the cost and time of coating bars with epoxy is substantially smaller than the cost of replacing a concrete structure like a highway overpass. This means that using epoxy-coated steel bars are an example of making a great impact in the future with a small change in the present.

Epoxy Coating Industry Practices

Steps in the basic procedure to epoxy coat reinforcing bars are abrasive blast cleaning of the bars to near-white metal; preheating of the cleaned bars to a temperature recommended by the manufacturer of the epoxy powder; application of the epoxy powder by the electrostatic spray method to the clean bars; and curing of the coating.

Fabrication consists of cutting the coated bars to the lengths, or cutting and bending the coated bars to the configurations, required for the construction project. The cut ends, resulting from fabrication, should be coated with the patching material that is used for repairing damaged coating. Damaged coating on the bars, resulting from handling and fabrication, will be properly repaired prior to shipment of the coated bars to the jobsite.