Cement Composition and Concrete Durability in Sea Water

摘要

The effects of cement composition on durability of concrete in sea water were investigated. The separate and combined effects of alkali-silica reaction and sulfate attack were evaluated both in the laboratory and using concrete specimens from 16 mixtures exposed in warm sea water at St. Augustine, Florida. Three mixtures were made that were susceptible to both alkali-silica reaction and sulfate attack, three that should not manifest either reaction, three susceptible to alkali-silica reaction only, and seven susceptible tp sulfate attack only. Performance of specimens in the field plus some laboratory tests indicated these intents were generally successful. A major finding from this work was the combined effects of both reactions caused quicker and more complete destruction of concrete and mortar than either reaction alone. While one would intuitively guess this would be the case, this work provided proof of this for the first time, so far as is known. Another result was to confirm that the mitigating effects of a pozzilan are optimized when the proper amount of pozzilan is used. This work also showed more alkali-silica reaction due to high potassium levels than to high sodium levels.