- Author
- Mathey, R. G. | Clifton, J. R.
- Title
- Bond of Coated Reinforcing Bars in Concrete.
- Coporate
- National Bureau of Standards, Washington, DC
- Journal
- Journal of the Structural Division, Vol. 102, No. ST1, 215-229, January 1976
- Report
- Paper 11855
- Keywords
- concretes | coatings | reinforced concretes | steels | structural engineering
- Abstract
- The premature deterioration of concrete bridge decks in 5 yr-10 yr has become a major problem during the past decade . Often, this early deterioration has been attributed to accelerated corrosion of steel reinforcing bars (rebars) caused by chloride ions from deicing materials. The use of the two more commonly applied deicing materials, sodium chloride and calcium chloride, has increased substantially during the past decade. Corrosion of reinforcing bars results in spalling and cracking of concrete, necessitating in many cases extensive and expensive repairs. The possibility of protecting steel reinforcing bars from corrosion with organic-type coatings was investigated. Evaluations of the physical and chemical durabilities of 47 different coatings including epoxy and polyvinyl chloride materials were reported in the earlier phase of the investigation. Assessments of the coatings protective qualities were made to determine their properties with regard to chemical resistance, film integrity, adhesion, chloride permeability, impact resistance, abrasion resistance, hardness, extensibility as determined from bar bend tests, and film thickness. It was concluded that among the organic materials, epoxy coatings had the most promise as a protective coating for reinforcing bars. The epoxies that had the best protective qualities and physico-chemical durabilities were selected for testing in a comprehensive evaluation program. The program included determining the structural characteristics, bond and creep strengths, of coated reinforcing bars embedded in concrete prisms. The bond strengths were measured in tests using pullout specimens and the results are reported herein. Creep studies of coated reinforcing bars are curently being performed and these results will be reported in the future. Little attention has been previously devoted to epoxy materials as protective coatings for reinforcing bars because of the supposition that the coated bars will have unacceptable bond strengths.