Effectiveness of surface coatings to protect reinforced concrete in marineenvironments

Coatings can contribute to extending service life of concrete structures ex posed to marine environments by reducing the rate of chloride penetration. In the present paper, the effect of coatings on the rate of chloride uptake was studied by measuring their concentration profiles at different times, extending up to 24 months. Using a solution of the so-called Fick's second law of diffusion, least-square fitting leads to the value of chloride conce ntration under the coating (C-0) which allowed us to compare the effectiven ess of different coatings. Depending on the formulation, some of the studie d acrylic coatings could reduce the value of C-0 by more than 80% in compar ison to the unpainted concrete. Water permeability coefficients were measur ed for the same coating;, according to EN 1062-3. The ranking of effectiven ess to stop chlorides is the same as the water imperviousness, but the mini mum requirement proposed by prEN 1504-2 (0.1 kg.m(-2).h(-0.5)) did not prov e to be enough for an efficient protection against chloride permeation.