Epoxies reinforcing bars

Virmani, Y.P., Clear, K.C. and Pasko, T.J. (1983). Time to Corrosion of Reinforced Steel in Concrete Slabs, Vol. 5, Calcium Nitrite Admixtures or Epoxy Coated Reinforced Bars as Corrosion Protective Systems, FHWA-RD-83-012, FHWA, US Department of Transportation, 71. 

Corrosion Evaluation of Epoxy-coated Metallic-clad and Solid Metallic Reinforcing Bars in Concrete, US Department of Transportation, Federal Highway Administration, Publication FHWA-RD-98-153, December 1998. 

The cost of various techniques can only be given very roughly, and any estimate will be incomplete, since the actual cost will vary from one application to another. Furthermore, different types of prevention mechanisms are not directly comparable. Beyond this, it can be said that with respect to normal carbon-steel reinforcement, use of galvanized and epoxy-coated bars costs about twice as much, and the cost of stainless-steel reinforcement is about 5 to 10 times higher. The use of nitrite inhibitors in higher doses costs approximately 30 /m of concrete (volume). Coatings may vary from 7 to 50 /m of concrete surface, hydrophobic treatment costs about 10 /m. Cathodic prevention varies from 50 to 100 /m. ... 

Epoxy coating of reinforcing bars is a protective technique developed in the 1970s in North America. Laboratory results confirmed the effectiveness of the epoxy-coated bars, in many cases, in preventing corrosion of reinforcement in carbonated or chloride-contaminated concrete [46]. Recently, however, doubts have arisen about their long-term durability in very aggressive environments, doubts borne out above all by negative experience reported on structures in tropical environments [47-49]. 

Requirements for epoxy-coated reinforcing bars are reported in different international standards and recommendations the first dates back to 1981 (ASTM A775-81) and more recent national standards in European countries are based on it, even though their requirements are much more rigorous. 

It is, furthermore, important to pay attention to those cases in which, for economical reasons, coated steel is used only in the most critical areas of the stracture. In these cases it is important to ensure that epoxy-coated bars are electrically insulated from the uncoated reinforcement, in order to avoid macrocells. 

If concrete removal is not required or supplementary reinforcing bars cannot be used, external reinforcement can be applied. For instance, steel bars may be encased in a shotcrete layer or steel plates may be bonded onto the concrete surface. Recently, the use of steel plates has been substituted by fibre-reinforced plastics (F. R.P.), that are composite materials with glass, aramide or carbon fibres embedded in a polymeric matrix (usually an epoxy system). F. R.P. are available in the form of laminates or sheets that are bonded to the concrete surface using an epoxy adhesive [11]. They are typically used to improve the flexural and shear strength or to provide confinement to concrete subjected to compression. The... 

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... 

Covering of reinforcing bars with resin, apphed as an anti-corrosion protection, can lower their adhesion to cement paste. Worsening of adhesion occurs in the case of vinyl polychloride, but it does not occirr if the epoxy resins are used. However, some epoxy resins reveal the creep effect [56]. 

ASTM A775-81. Standard Specification for Epoxy-coated Steel Reinforcing Bars, American Society for Testing Materials. 

Concrete should not be relied upon as an electrical insulator. Reinforcing bars should be coated with, for example, epoxy resin. They should not be connected to building steel and should not be allowed to form a continuous path along the length or the width of the building. The joints between sections of precast reinforced concrete should be insulated. 

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... 

Rebars are polymer fibre reinforced-concrete composites, and they are used as primary structures. It is estimated that replacement of steel reinforcing bars by non-corrosive polymer fibres, i.e., by Kevlar or carbon fibres (which gives rise to Kevlar or C-composite bars) for concrete structures produces structures with one-quarter the weight and twice the tensile strength of the steel bar. It is known that, corrosion of steel reinforcement from carbonation or chloride attack can lead to loss of the structural integrity of concrete structures, and such a danger is non-existent for rebars. Thermal expansion coefficient (TEC) values of these fibres are closer to concrete than that of steel, which provides an another advantage and they have the same surface deformation patterns as the steel bars. In addition, they can provide more economy than epoxy-coated steel bars. 

Epoxy coated carbon steel reinforcing bars... 

Fusion-Bonded Epoxy Coating of Steel Reinforcing Bars... 

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