Effectiveness of Epoxy-Coated Reinforced Steel

Effectiveness of Epoxy-Coated Reinforced Steel
Author: Kenneth C. Clear
Publisher:
Total Pages: 94
Release: 1992-11-01
Genre: Epoxy coatings
ISBN: 9781895102901

The primary function of an eposy-coating is to act as a barrier to prevent corrosion-causing chloride ions and oxygen from reaching steel surfaces. For more than a decade, epoxy-coated reinforcing steel has generally been effective in reducing or preventing chloride-induced corrosion in bridges and other concrete structures. Recently, however, instances of corrosion problems or premature failures in Florida, Oregon and New York have focussed attention on the product and its quality. This report was initiated as a result of the questions raised by these failures.

Summary Report on the Performance of Epoxy-coated Reinforcing Steel in Virginia

Summary Report on the Performance of Epoxy-coated Reinforcing Steel in Virginia
Author: Richard E. Weyers
Publisher:
Total Pages: 32
Release: 2006
Genre: Concrete bridges
ISBN:

From 1992 to 2006, the Virginia Transportation Research Council and its contract researchers conducted a long-term systematic series of investigations to evaluate the corrosion protection effectiveness of epoxy-coated reinforcement (ECR) and to identify and recommend the best and most cost-effective corrosion protection system for Virginia bridge decks. This report summarizes this research and subsequent efforts to implement alternative reinforcement. The work was conducted, and is reported, in this general order: review of historical performance of ECR, ECR performance in solutions and concrete, and preliminary field investigations; investigation of field performance of bridge decks built with ECR; assessment of alternative corrosion protection methods; development of probabilistic service life models for bridge decks and laboratory assessment of ECR cores extracted from bridge decks to determine service life extension; efforts to implement alternative reinforcement. The series of studies demonstrated that the epoxy coating on ECR naturally degrades in the highly alkaline moist environment within concrete. The subsequent loss of bond, coupled with the inevitable flaws in the coating induced by construction, leads to an estimated service life benefit of ECR of as little as 3 to 5 years. Further, non-critical decks, beams, and substructure elements not exposed to marine environments, particularly on secondary and rural routes, can be cost-effectively constructed and maintained using low-permeability concrete and black reinforcing bar. However, because the Federal Highway Administration requires the use of corrosion-resistant reinforcement, and because ECR cannot provide adequate corrosion protection for structures designed for a 100-year+ service life as currently recommended by FHWA, the report recommends that the Virginia Department of Transportation amend its specifications regarding the use of ECR to require the use of corrosion-resistant metallic reinforcing bars such as MMFX2, stainless steel clad, and solid stainless steel.

Evaluation of Epoxy-coated Reinforcing Steel

Evaluation of Epoxy-coated Reinforcing Steel
Author: Wallace T. McKeel
Publisher:
Total Pages: 28
Release: 1993
Genre: Bridges
ISBN:

Virginia's first installation of epoxy-coated reinforcing steel, which was opened to traffic in 1977, was evaluated during construction and through 13 years of service. It was apparent at the time of construction that the integrity of the coating application did not meet the requirements of the specifications There were many flaws and holidays in the coatings on all of the bars, and patching with a liquid epoxy compound was not effective. Although the applicability of the findings, which are based on an application that does not represent the best practice, may be limited, useful information on the durability of the coated steel and its role in protecting the deck was developed. It was found that the coated reinforcement was exposed to relatively high chloride concentrations at transverse cracks in the decks early in the life of the structures, but the decks remained in good condition throughout the evaluation period. It was concluded that despite the poor coatings, the coated reinforcing steel contributed to the deck's durability by providing enhanced protection at critical cracked sections. Rebars taken from deck cores showed no signs of rusting, although the steel had a dull dark gray finish that may be underfilm corrosion. No debonding of the coating was evident.

Concrete Bridge Deck Performance

Concrete Bridge Deck Performance
Author: H. G. Russell
Publisher: Transportation Research Board
Total Pages: 188
Release: 2004
Genre: Bridges
ISBN: 0309070112

At head of title: National Cooperative Highway Research Program.