OpenUCT :: Browsing by Author "MacKechnie, James"

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Concrete mixes for durable marine structures
(2003) Alexander, Mark; MacKechnie, James
The marine environment provides a severe test of the durability of reinforced concrete structures. Predictions of durability need to consider the complex interactions between environment, materials and structure that affect long-term performance of marine structures. An empirical chloride prediction model has been developed for chloride ingress into marine concretes. The prediction model was formulated from the relationship between early-age chloride conductivity test results and medium- and long-term observations of the performance of concrete in different marine environments. This paper presents some of the practical results of this approach in terms of design limits and mix design recommendations. Design guidance is given such that a matrix of factors may be optimised, including water/binder ratio, binder type, cover depth, environment, and construction practice, in order to produce durable marine concrete structures. Preferred concrete mixes for marine applications are also given, showing the advantage of concrete containing supplementary cementitious materials. However, good material selection and design are not sufficient to ensure durability, and recommendations are made for a system of performance specifications to ensure durable marine structures.