- Author
- Clifton, J. R. | Beeghly, H. F. | Mathley, R. G.
- Title
- Nonmetallic Coatings for Concrete Reinforcing Bars.
- Coporate
- National Bureau of Standards, Washington, DC
- Sponsor
- Federal Highway Administration, Washington, DC
- Report
- NBS BSS 065, August 1975, 44 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- concretes | coatings | bridge decks | chloride ions | corrosion | deicing salts | epoxy coatings | organic coatings | polyvinyl chloride coatings | steel reinforcing bars
- Abstract
- This work was undertaken to ascertain the feasibility of using organic coatings, especially epoxies, to protect the steel reinforcing bars embedded in concrete of bridge decks from rapid corrosion. This corrosion is caused by the chloride ions from the most commonly applied deicing salts, sodium chloride and calcium chloride. Altogether, 47 different coating materials were evaluated to some extent, consisting of 21 liquid and 15 powder epoxies; 5 polyvinyl chlorides; 3 polyurethanes; 1 polypropylene; 1 phenolic nitrile; and one zinc rich coating. The chemical and physical durabilities, chloride permeabilities, and protective qualities of coatings were assessed. The bonds between coated and uncoated bars and concrete were measured by both pullout and creep tests. The results indicate that both epoxy and polyvinyl chloride coatings, if properly applied, should adequately protect steel reinforcing bars from corrosion. However, only the epoxy coated bars had acceptable bond and creep characteristics when embedded in concrete. The powder epoxy coatings overall performed better than the liquid epoxies, and four powder eopxy coatings have been identified as promising materials to be used on reinforcing bars embedded in concrete decks of experimental bridges.