Shrinkage of High-Strength Lightweight Aggregate Concrete Exposed to Dry Environment

This article presents the 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. The effects of the coarse aggregate density, steel fiber content, and silica fume were also studied and are discussed. The authors also discuss the risk of potential drying-shrinkage cracking of the concrete, the flexural tensile strength, and the modulus of elasticity. Normalweight sand was used for all of the concrete mixtures. Results showed 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 somewhat higher than that of the normalweight concrete with one exception. 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.