Effect of Larger Sized Coarse Aggregates and of Microsilica on Environmental Properties of Portland Cement Concrete Pavements and Structures. Volume 2 of 2

摘要

This project examines whether the addition of microsilica, or the use of aggregates with maximum size above 1.5 in., in concrete mixes prepared by the Ohio Department of Transportation (ODOT) for bridge decks and highway pavements can have adverse effects on the durability properties of such structures. The behavior of several series of concrete specimens has been monitored over a period exceeding a year, and numerous measurements have been recorded. Such data are evaluated to determine if altering the standard ODOT concrete mix design on either end of the gradation spectrum can indeed lower the cement content and increase its cost effectiveness and efficiency. It was found that different coarse aggregate gradations did not impact significantly the environmental properties of concrete examined. Differences observed were confounded by variability issues related to the testing protocols themselves, and by mineralogical distinctions among the various aggregate blends.