Effects of Presoaked Lightweight Aggregate Addition on Drying Shrinkage

Abstract

It is widely known that presoaked lightweight aggregate (LWA) is greatly beneficial for reducing autogenous shrinkage by providing additional water reservoirs for the mixture. However, in unsealed conditions, when concrete is subjected to drying, addition of LWA to the mixture might not be as effective in reducing drying shrinkage. This study examines the effects of LWA addition on drying shrinkage in different boundary conditions. By varying the number of sides exposed to the surrounding unsaturated environment, the severity of drying condition is altered, and its effect on drying shrinkage of mixes with LWA is studied. The performance of LWA in reducing drying shrinkage of mortar samples is shown to be highly dependent upon the exposure condition and the extent of external curing. The results of this work indicate that curing concrete internally may be an inadequate shrinkage-compensating strategy in a severe drying condition and when no external curing is implemented. Nonetheless, mixtures with LWA exhibited a denser microstructure which can be advantageous in terms of durability.