The epoxy coating is a factory-applied layer of protection to steel before it is shipped out, ensuring that it is resistant to corrosion. Epoxy-coated reinforcing bars (rebar) can be used in any concrete structure that is exposed to corrosive conditions, such as de-icing salts or marine waters. When handled and installed correctly, epoxy-coated rebar can be beneficial for a variety of concrete projects. The corrosion resistance of epoxy-coated steel makes it especially useful for structures located in marine environments or those that are regularly exposed to de-icing salts.
The most commonly used ASTM standards for epoxy-coated rebar are ASTM A775, “Standard Specification for Epoxy Coated Steel Reinforcing Bars” and ASTM A934, “Standard Specification for Prefabricated Epoxy Coated Steel Reinforcing Bars.” Proponents of galvanized bar point out that the zinc coating must be completely eroded before the steel is exposed. Epoxy coating is considered a barrier-type coating, while galvanizing is both a barrier and a sacrificial coating. To prevent the epoxy coating from being marred or damaged by cables or chains, nylon strapping and multiple lifting points should be used along the length of the bar. Additionally, epoxy-coated steel should not be handled at temperatures below 50 degrees Fahrenheit, as this may cause the epoxy coating to crack.
According to the Concrete Reinforcing Steel Institute, welding epoxy-coated rebar is possible, but first you need to determine what kind of steel is under the epoxy coating and take appropriate precautions. If the steel used for clad bars complies with ASTM A706, the bars are designed to be welded without preheating and should therefore be specified for applications that require an appreciable amount of welding. Fusion-bonded epoxy rebar coating was chosen as the best option for reducing corrosion in many countries due to its proven protective coating properties. To increase the strength of concrete, contractors often reinforce the slab with steel reinforcing bars, or rebar for short.
In addition to the manufacturing process, there are several test methods to confirm the quality of the epoxy coated TMT bar. When assembling reinforcing cages with epoxy-coated reinforcing bars, technicians must take care in assembly so as not to damage the epoxy coating. The heat from the solder will discolor or cause the epoxy in the vicinity of the solder to peel off the reinforcing bar. A good quality epoxy coated TMT bar must have a uniform, chemically stable coating and adhere to a high pH environment.