Fusion-bonded epoxy coating

Galvanised steel provides increased corrosion resistance in carbonated concrete. In concrete with more than 0.4% chloride ion with respect to the cement content, there is an increased risk of corrosion and at high chloride contents the rate of corrosion approaches that of plain carbon steel. In test conditions the rate of corrosion is greater in the presence of sodium chloride than calcium chloride. Fusion-bonded epoxy-coated steel performs well in chloride-contaminated concrete up to about 3.9% chloride ion in content. 

Treadaway, K. W. J., Davies, H. and Brown B. L., Performance of fusion bonded epoxy coated steel reinforcement. Proceedings of the Institute of Structural Engineers (in press)... 

After their initial development in the USA, fusion bonded epoxy coatings (FBE) are now factory-applied worldwide. Their specification as the first choice alternative to enamel coatings is still contested, although important... 

Hoiberg, A. J., (ed.). Asphalts, Tars and Pitches, Interscience Publishers (John Wiley) (1965) ANSI/AWWA C213-79, Standard for Fusion Bonded Epoxy Coatings for the Interior and Exterior of Steel Water Pipelines... 

Omori, K., Watanabe, U. and Takeda, T., Improvement of Fusion Bonded Epoxy Coating, 5lh International Conference on the Internal and External Protection of Pipes, Innsbruck Austria, pp. 67-79, BHRA, London (1983)... 

At present, epoxy-coated rebar is the most common corrosion protection system and is used in 48 states. At present, there are nearly 20,000 bridge decks using fusion-bonded epoxy-coated rebar as the preferred protection system. This amounts to nearly 95% of new deck construction since the early 1980s. 

Epoxy coatings cost approximately 4.7-5.3/l while antifoulants are more expensive at 11.8-21.1/1. Environmental regulations have led to decreased amount of chemicals released from industrial installations along waterways, especially corrosives such as chlorine. The materials of construction for some water structures have also changed. Piers and docks are no longer constructed with wood, but instead are constructed with steel-reinforced concrete. To improve the lifespan of the structure and prevent corrosion of reinforcing steel, fusion-bonded epoxy-coated reinforcement or corrosion-inhibiting admixtures are sometimes utilized in the concrete mix. 

Lempton, R. D. Jr., and Schemberger, D. 1996. Improving the Performance of Fusion-Bonded Epoxy Coated Steel Reinforcing Bars, CORROSION 96, Paper No. 323, NACE International, Conferences... 

A.S. Khanna. Dual fusion bond epoxy coatings—versatile solution for underground pipelines. Chemical World, 2010, 52-54. 

Since the maximum voltage that can be generated with zinc anodes is extremely unlikely to generate hydrogen embritdement, galvanic systems have been used to protect prestressed concrete members. They are also used on fusion bonded epoxy coated steel reinforced piles as the effects of electrical discontinuity between bars is unlikely to lead to significant stray current induced corrosion as the currents and potentials are low. 

The protection system of choice on highway bridges in North America for a ressive chloride conditions continues to be fusion bonded epoxy coated reinforcement (FBECR). It was first installed in a bridge deck in Philadelphia in 1973 (Manning, 1996). It was estimated by the EHWA that 100 million sqnare feet (10 million m ) of bridge deck on the US federal-aid highway system contains epoxy coated rebar up to 1889 (Virmani and Clemena, 1998). 

Advantages and limitations of fusion bonded epoxy coated rebars... 

The issue of coated and corrosion resistant reinforcement presently seems to be moving in the direction of stainless steel and stainless steel clad reinforcement. The high price of metals on the international markets has held back wider use of stainless steel at the time when its use was starting to be more widely considered. The move to develop new organic coatings for reinforcement seems to have diminished as no clear improvement to fusion bonded epoxy coating has yet emerged. 

Fusion-bonded epoxy-coated steel performs well in chloride-contaminated concrete up to about 3.9<7o chloride ion in content. 

Walkways are fabricated with FRP grating. All concrete surfaces in the cell room are constructed with fusion-bonded epoxy coated steel reinforcing bars, and Type V... 

The problems of pitting and under-coating corrosion are more difficult and are well known in pipeline corrosion where fusion bonded epoxy coatings are frequently applied to the outside of pipelines and then cathodic protection applied to protect the pinholes that inevitably occur. However, these cathodic protection systems are applied from new so no corrosion is established. The FBECR structures are already corroding when cathodic protection is applied. It is therefore possible for corrosion to be established under the coating where the cathodic protection current cannot reach, The small driving voltage of a sacrificial anode system means even less protection or penetration of current than for an impressed current system. 

Case No. 3 requires additional systematic testing, exhumation, and critical examination of existing structures involving dozens of bridge structures from different regions throughout the U.S. The structures, constructed with fusion bonded epoxy coated bar, must have been in service in high chloride environments for between 20 and 30 years. Part of the structure selection process has to include determination that chlorides have permeated to the rebar mat level at sufficient concentration levels to activate substantial corrosion if the structure were constructed from hare rebar. 

Internal Coating of Line Pipe for Non-Corrosive Gas Transmission Service Unprimed Internal Fusion Bonded Epoxy Coating of Line Pipe... 

C116/A21.16 ANSI Standard for Protective Fusion-Bonded Epoxy Coating for the Interior and Exterior Sinfeces of... 

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