Nonmetallic Coatings for Concrete Reinforcing Bars.

摘要

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, 47different coating materials were evaluated to some extent,consisting of: 21liquid and 15powder epoxies; 5polyvinyl chlorides; 3polyurethanes; 1polypropylene; 1phenolic 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.