Shrinkage of high-strength lightweight aggregate concrete exposed to dry environment

Abstract

This paper presents results of an experimental study on the shrinkage for up to approximately 2 years of high-strength lightweight concrete exposed to a dry environment compared with that of the normalweight concrete. Normalweight sand was used for all of the concrete mixtures. The results indicated that the shrinkage of the normalweight concrete with granite aggregate was higher than that of the corresponding lightweight concretes with equivalent mixture proportioning in the first 6 months. The shrinkage decreased with a decrease in the aggregate density that corresponded to an increase in the aggregate porosity and water absorption. After 1 year, the shrinkage of the lightweight concretes was some-what higher than that of the normalweight concrete with one exception. The same trend was observed for the lightweight concrete with expanded clay aggregate (particle density = 1.24) and the normalweight concrete with a similar 28-day compressive strength. The shrinkage value was reduced with an increase in the fiber content from 0 to 1.5% by volume of the lightweight concrete. The incorporation of 5% silica fume reduced the shrinkage of the concrete significantly, and its effect on the lightweight concrete was more substantial than that on the normalweight concrete. Copyright © 2005, American Concrete Institute. All rights reserved.