Fusion-bonded epoxy

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)... 

Hz for thick coatings such as reinforced coal tar enamel, being selected to minimise interference from commonly occurring frequencies while maximising the distance the signal will travel, some 5-10 km on a reasonably well-coated pipeline. For thin film, coatings, such as a fusion-bonded epoxy, a frequency of 200 Hz has been found more appropriate. 

Recent trends in protective coatings used on buried pipelines have been away from reinforced hot applied coal tar and asphalt enamels and butyl rubber laminate tapes, particularly where applied over-the-ditch . The more recently developed coatings based on fusion bonded epoxies, extruded poly-ethylenes, liquid-applied epoxies and polyurethanes, require factory application where superior levels of pipe preparation and quality control of the application process can be achieved. 

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... 

Fusion bonded epoxy AWWA/ANSI C213 BS 3900 Electrostatic spray in factory and for joints in field 0-3-0-65 Higher temperature iimitations and superior soii stress resistance compared with enamels. Requires careful handling in the field. Quality of pipe steel 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)... 

Fusidic acid, bacterial resistance mechanisms, 3 32t Fusinite, 6 707t, 719, 828 Fusion, PVC, 25 663-664. See also Cold fusion Deuterium fusion Fusion-bonded-epoxies (FBE), 10 440 Fusion carburization, 4 674-675 Fusion-cast refractories, 21 504 shapes of, 21 481-482 Fusion method, for tin content assays, 24 791, 792... 

Polyethylene tape, polyethylene extrusions, and fusion-bonded epoxy are the remaining viable choices. All have been applied successfully, and all have had problems. To obtain a satisfactory coating, careful attention must be given to the following ... 

Fusion-Bonded Epoxies. These are powder-based epoxies applied to hot substrates. The powder on contact with the hot substrate melts followed by a chemical reaction. On cooling, the solid film is formed. Fusion-bonded epoxies are widely used in pipelines and concrete rebar applications. 

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. 

The use of coatings in conjunction with CP is the most popular form of corrosion protection of pipelines. Some of the coatings used are fusion-bonded epoxy, extruded polyethylene, coal tar enamel, liquid epoxy, tape, polyurethane, mastic, and wax. Pipelines with each of these coatings remain in service at the present. The most widely used coating on pipelines is fusion-bonded epoxy. New multilayered coatings are now on the market. 

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. 

A specific example for epoxy is fusion bonded epoxy (FEE) coating [8]. It is widely used to protect steel pipes. In this case, the resin and hardener components of a dry powder stock of FEE do not react until the coating application temperature is reached. Then the powder contents melt and form a liquid which flows onto a steel surface where it becomes a solid coating by chemical crosslinking and the use of heat. This is known as fusion bonding and the chemical crosslinking reaction is not reversible. 

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

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