Building Code Requirements for Structural Concrete (ACI 318-95) prohibits embedding aluminum conduit in structural concrete unless it's effectively coated or covered to prevent aluminum-concrete reaction or electrolytic reaction between aluminum and steel. What coatings are effective and where can I obtain coated conduit?
A laboratory study conducted by the Portland Cement Association (PCA) in 1965 showed that some coatings made of lacquer or bitumen effectively protected aluminum conduit embedded in concrete and electrically coupled with embedded steel. However, the researchers cautioned that the coating performance under field conditions hadn't been evaluated. We couldn't find any recent studies of aluminum conduit coatings. We did find a company that coats aluminum conduit with a 45-mil thickness of polyvinyl chloride. You can obtain a product catalog from Perma-Cote Industries, 42 Feathers Ave., Uniontown, PA 15401(412-628-9700). Have any of our readers specified or used PVC-coated aluminum conduit in concrete? Reference G.E. Monfore and B. Ost, "Corrosion of Aluminum Conduit in Concrete," Journal of the PCA Research and Development Laboratories, January 1965, pp. 10-22.