ABSTRACT
Mary Emerson is a Senior Scientific Officer at the Scottish Branch of the Transport and Road Research Laboratory, Craigshill West, Livingston, West Lothian, UK.
INTRODUCTION
One of the topics at present dominating the literature, thinking and finances associated with the maintenance of concrete bridges is the corrosion of reinforcement caused by the ingress of chloride contaminated water. In an uncontaminated state, the highly alkaline Portland cement used in concrete encourages the formation of an oxide film on the surface of steel reinforcing bars. In theory, this film protects the reinforcement from corrosion. In practice, water contaminated with chlorides from de-icing salts used in winter maintenance, or from a marine environment, sometimes penetrates the concrete cover to the reinforcement. The protective oxide film is then destroyed, and the reinforcement corrodes.
