Frequently Asked Questions
When was Epoxy-Coated Steel Reinforcing Bar first used?
Epoxy-Coated Steel Reinforcing Bar was first used in 1973 on the Schuykill Bridge near Philadelphia, Pennsylvania.
Why should I use Epoxy-Coated Steel Reinforcing Bar?
- Structures built with Epoxy-Coated Steel Reinforcing Bar have longer lives than structures built with black steel.
- Epoxy-Coated Steel Reinforcing Bar protects even in cracked concrete.
- Life-cycle analysis shows that Epoxy-Coated Steel Reinforcing Bar provides the lowest cost.
- Unlike corrosion protection systems used within the concrete mixture, Epoxy-Coated Steel Reinforcing Bar is readily identified at the job site.
Where can Epoxy-Coated Steel Reinforcing Bar be used?
- Bridge Decks
- Continuous reinforced concrete pavement
- Parking garages
- Piers and pier caps, docks
- Cooling Water towers
- Columns and Parapet Wall
What specifications cover Epoxy-Coated Steel Reinforcing Bar?
Epoxy-Coated Steel Reinforcing Bar is covered in IS-13620 and ASTM A775.
What precautions should I take when using Epoxy-Coated Steel Reinforcing Bar?
- Minimize damage during transport, handling, and placement.
- Repair damage using two-part epoxy coating, approved by bar supplier.
- Use plastic headed concrete vibrators during concrete placement.
What design issues should be considered if I specify Epoxy-Coated Steel Reinforcing Bars rather than black reinforcement?
The development length for Epoxy-Coated Steel Reinforcing Bar is longer. Maintain concrete cover.
Is Epoxy-Coated Steel Reinforcing Bar environmentally friendly?
Yes. Epoxy-Coated Steel Reinforcing Bar is manufactured using reinforcing bars that are made using almost 100% recycled steel.
- Epoxy-Coated Steel Reinforcing Bar can also be recycled after use.
- Epoxy-Coated Steel Reinforcing Bar produces No VOCs during manufacture or use.
- Structures that use Epoxy-Coated Steel Reinforcing Bar are more durable than those that do NOT.
Epoxy-Coated Steel Reinforcing Bar cost?
Generally, Epoxy-Coated Steel Reinforcing Bar will cost 25 percent to 35 percent more than uncoated bars. However, that increase represents a minute incremental addition to the bridges total cost.
How does Epoxy-Coated Steel Reinforcing Bar compare with stainless steel reinforcing bar?
- Stainless-steel bars cost up to Five times as much as black bars and may increase the total structural cost by 10 percent or more.
- Additional funding often is not available for these products.
- Stainless-steel bars use materials from hard-rock mining operations, while Epoxy-Coated Steel Reinforcing Baruses scrap steel.
- Not all stainless steels have demonstrated good corrosion performance in concrete as it depends on the grade of stainless.
- Care must be taken to ensure that stainless-steel bars are not contaminated with the black bar.
What’s the best way to specify Epoxy-Coated Steel Reinforcing Bar for construction projects?
- The following ASTM specifications are to be used when specifying Epoxy-Coated Steel Reinforcing Bar.
- IS 13620 and ASTM A775/A775M. (Coating Application and Powder Qualification).
- Make sure that proper specifications are included for all stages of the project: coating application, fabrication, field handling, and material pre-qualification.
How long will structures with epoxy-coated bars last?
Answering this question requires an understanding of the concrete, the coating, and the localized environment; however, epoxy-coated bars are routinely specified for structures with a desired 75-year design life and often for structures with a 100-year design life, given an appropriate concrete.
In environments subjected to marine or deicing salts, corrosion initiates when sufficient chloride ions reach the reinforcing steel. The time for these salts to reach the bars is dependent on the concrete permeability and the amount of cracking in the concrete as well as the exposure conditions.
The permeability of concrete depends on the water-cement ratio as well as the presence of pozzolans including fly ash and silica fume or various concrete additives that impart water resistance. When uncoated reinforcing is placed in cracked concrete, corrosion initiates almost immediately the concrete is placed in contact with the salt solution; thus, the presence of cracks will significantly reduce the repair -free life of a structure. Epoxy-coated bars have been found to perform well in cracked concrete compared with the use of concrete modifications alone.
To optimize the design life of structures that use epoxy-coated bars it is recommended that high-quality concrete is used with an appropriate cover over the reinforcing and that cracks in the concrete are repaired.
How does the initial and life-cycle cost of epoxy-coated reinforcing bars compare with other materials?
A study was recently conducted by the University of Kansas for the FHWA and Kansas DOT that compared the life-cycle costs of epoxy-coated reinforcing steel, uncoated and stainless steel reinforcing bars in bridge decks. This study found that the initial costs of stainless steel in bridge decks was $319/yd2, compared with $189 and $196/yd2 for decks containing uncoated and epoxy-coated reinforcing steel, respectively. Thus, use of stainless steel was $130/yd2 greater than that of the deck containing the epoxy-coated bar. Life cycle costs for the epoxy-coated reinforcing steel was the lowest at $237/yd2 compared with $319 and $444 /yd2 for decks containing uncoated and stainless steel reinforcing bars. Thus, the epoxy-coated bars were $82/yd2 less than that of the stainless steel reinforcing over a 75-year design life
Epoxy-coated Reinforcing Steel in Repair of Concrete.
When repairing concrete that has deteriorated due to corrosion, it is important to ensure that the repair does not establish conditions that increase the rates of corrosion in surrounding concrete. This condition, frequently called the “ring anode” effect is described below.
When sufficient chloride reaches the level of the reinforcing steel in concrete, corrosion of the steel occurs. The location that has the highest corrosion rate is generally the location with optimum levels of chloride and moisture. At this anode location, the steel releases electrons that are then consumed at the cathode, which may be in areas of the structure that can be substantially further away from the damage.
During a typical concrete repair, it is common only to remove the damaged concrete, where the steel corrosion has resulted in an expansion that sufficiently damages the concrete. Unless precautions are taken as part of the repair process, corrosion damage in immediately surrounding areas may rapidly occur. This “ring anode” effect occurs as the area after the repair becomes the new anode, and the repaired area may become a strong cathode. At the cathode, electrons react with water and oxygen.
Due to the dielectric (non-conducting) coating on epoxy-coated bars, it is difficult for these bars to become cathodes. Thus, replacing exposed bars in the repair area with epoxy-coated bars substantially reduces the cathode and thus dramatically reduces the ring anode effect, leading to significantly enhanced repair life. Where bars are too short to be replaced or where areas of exposed uncoated reinforcing bars are present, it is recommended that they be coated with a repair material specifically designed to reduce the cathodic effect.