Specifications of Concrete for Marine Environments: A Fresh Approach

Abstract

There is significant debate around the world regarding the most appropriate test methods for assessing the performance of concretes in marine environments. Much research work has been conducted on chloride ion penetration into concrete and its relationships to embedded steel passivity and rate of corrosion. This paper summarizes work from a series of studies. The focus of this work was on the long-term performance of reinforced concrete under high-chloride conditions. Work included the monitoring of concrete performance using half-cell potential measurements, concrete resistivity, and the determination of gravimetric weight loss of steel through corrosion. Corrosion rates of steel in concrete were also measured using anodic polarization techniques. Concretes considered were made with a range of commercially available portland cement and supplementary cementitious materials. Concretes were classified on the basis of observed long-term performance based on resistivity and the time taken for embedded steel to reach a probable active corrosion state. The development of a method for designing and assessing concretes for critical marine structures based on the information is reported. Use of this method will lead to improved specifications for concrete when compared with existing design specifications.