Concrete Reinforcing Steel Institute (CRSI) recently released a new eight-page Research Report, No. 12, Service Life Extension of Northern Bridge Decks
Concrete Reinforcing Steel Institute (CRSI) recently released a new eight-page Research Report, No. 12, Service Life Extension of Northern Bridge Decks Containing Epoxy-Coated Reinforcing Bars. A synopsis of a 62-page study prepared for CRSI by Wiss, Janney, Elstner Associates, Inc., this in-depth report completed by S.K. Lee, Ph.D., and Paul Krauss is based on a three-year research project.
The main objective of the research was to establish a statistical model for estimating the service extension offered by epoxy-coated reinforcing bars based on field data. Developed for industry use, especially targeting those interested in the service life of concrete bridge decks, the report presents current procedures and practices. It reviews the condition of 17 bridge decks, varying in age from nine to 27 years, located in seven northern states. Six of the decks used epoxy-coated reinforcement in both top and bottom mats; all the others used it only in the top mat. The report discusses procedures employed to assess bridge-deck condition, coring, 121 core samples, laboratory examination, laboratory test, and a summary conclusion.
In particular, the chloride concentration of the bridge decks was studied. From these findings as well as the decks’ damage level, a model was developed to predict bridge-deck service life. Three deck types were studied to estimate their corrosion rate: reinforced with uncoated reinforcing bars, reinforced with epoxy-coated reinforcing bars in the top mat only, and reinforced with epoxy-coated reinforcing bars in both mats. Specific examples of each were charted. Additionally, information is presented with a model validation from two previous studies completed by the West Virginia Department of Transportation and Iowa State University.
Conclusions end the report, providing modeling results that indicate bridge decks built with epoxy-coated reinforcing bar in the top mat only gain an average life extension of 40-plus years. For bridge decks built with epoxy-coated reinforcing bar in both the top and bottom mat, the average service life extension is 82 years or more.
Both forms of the report are available at the CRSI Web site, www.crsi.org/Epoxy Coating/Download Free Information. A printed copy of Research Report No. 12 can be obtained from CRSI’s John Prentice, 933 N. Plum Grove Road, Schaumburg, IL 60173-4758; 847/517-1200; [email protected]