Use of an acrylic painting to increase the durability of reinforced concrete in a seawater environment

Abstract

One of the most aggressive environments for reinforced concrete is the contact with seawater. The chlorides present in seawater penetrate into the concrete and the possibility to armatures corrosion increases significantly. In this study an acrylic painting was used to protect the concrete and decrease the diffusion of chlorides. We used two concretes with different compositions. One composition respects the exigencies of European standardisation for this environment and the other one no. The acrylic painting was applied in one or two coats. The specimens were put in contact with seawater 18 days after casting. We maintained the immersion for 90 days. In order t accelerate the durability test, three immersion solutions were used. The first one was seawater, the second one was seawater more 35 g/dm3 of sodium chloride and the third one was seawater more 70 g/dm3 of sodium chloride. After the immersion period we determined the chloride content at three depths (5, 10 and 15 mm) to have the chloride profile. The diffusion coefficient was determined taking into account the chloride profile. The results obtained for the diffusion coefficients show that one coating is not enough to prevent the chloride penetration. Better results were achieved with two coatings. The normal concrete presents better behaviour than the ameliorated concrete related with chlorides diffusion. The chlorides diffusion increases with the concentration of sodium chloride in the solution in contact with the concrete.