Integral Water Repellent Concrete Produced by Addition of Metal Soaps

Abstract

Laboratory testing and subsequent verification in practice has shown that surface impregnation of cement-based materials with silane prevents capillary uptake of water and aqueous salt solutions such as seawater or water containing deicing salts. Integral water repellent concrete can also be manufactured by adding silane-based compounds, such as silane emulsions to the fresh mix of concrete or mortar. Thus, service life of reinforced concrete structures in aggressive environments can be significantly extended by efficient water repellent treatment. This contribution presents the results of measurements carried out on integral water repellent concrete produced by addition of metal soaps. Four different types of metal soaps were added to the fresh concrete mix to achieve its integral water repellency. Chloride penetration into both reference and treated concrete was determined after exposure to seawater for 28 days. The distribution of the metal soaps in the treated concrete was also determined. It could be shown that chloride penetration into integral water repellent concrete prepared in the manner described was slowed down considerably. Although a complete chloride barrier could not be achieved by the addition of metal soaps, the service life of reinforced concrete structures can certainly be extended significantly by means of this technology.