Prevention of reinforcement corrosion by hydrophobic treatment of concrete

Corrosion of reinforcement in concrete bridge decks may occur due to penetration of de-icing salts, even in the presence of an asphalt overlay. This paper reports a laboratory study into additional protection of concrete by hydrophobic treatment. It was found that hydrophobic treatment strongly reduces chloride ingress, both during semi-permanent contact and under wetting/drying exposure. The water repellent effect remains effective for at least five years under full exposure to outside conditions. After five years, carbonation of concrete was found to be similar for non-treated and hydrophobised concrete. Under wet conditions, hydrophobic treatment does not stop ongoing corrosion that has been initiated by chlorides before the treatment. Methods and criteria for testing hydrophobic products are available. Hydrophobic treatment is an effective, low cost preventative measure against corrosion of reinforcement in chloride contaminated environment. In The Netherlands, it has become standard for all new concrete bridge deck