EXPOSURE OF CONCRETE IN DIFFERENT MARINE ENVIRONMENTS

The severity of marine environments varies depending on location and h as a major bearing on the durability performance of marine structures. A series of concrete specimens was cast, was exposed to four marine e nvironments for two years, and the effect of marine exposure was estim ated from chloride ingress levels. Two marine sites in South Africa we re chosen, being either sheltered or exposed to severe wave action. At each site, concrete was placed in the tidal and spray zones. Results from this work indicated that concrete in the tidal zone exposed to he avy wave action had significantly higher chloride levels than concrete sheltered from wave action. When predicting the potential durability of marine concrete, allowance must be made for the severity of exposur e together with material properties since both factors determine long- term durability performance. The results also have implications for la boratory simulations of marine exposure under relatively stagnant cond itions.