Performance evaluation of organic coatings against corrosion in reinforced cement mortars

Abstract

Protection against corrosion in reinforced concrete structures is commonly accomplished by the usage of organic coatings which are applied on the surface of the mortars. Nine coatings from five major categories produced in Greek industry were studied in order to evaluate their performance when applied on cement mortars and exposed to highly corrosive environment under the presence of chloride ions or carbon dioxide. An appropriate series of tests was conducted in order to examine and verify the protection of the coatings against corrosion. The implemented evaluation methods included: (a) half-cell potential measurements and linear polarization technique to determine the protection provided by coatings against chloride ions corrosion, (b) carbonation depth measurements, (c) estimation of the mass loss that steel rebars exhibit after the end of the experiment and (d) determination of liquid water and water vapour transmission rate for the coatings tested. The results suggest that acrylic coatings can offer a satisfying protection level against carbonation and elastomeric coatings can protect rebars from chloride ions corrosion.