Effect of Internal Curing on Expansion and Shrinkage of Expansive Concrete

Abstract

This article presents an experimental study on early age length change of expansive concrete produced by adding expansive additive into concrete and partially replacing fine aggregate with bottom ash in order to investigate the effect of internal curing on the expansion behavior of expansive concrete. To evaluate the length change of the expansive concrete, three experiments were conducted. Free expansion and restraint expansion were tested to confirm the behavior of early age expansion of the expansive concrete. After that free shrinkage was tested to study subsequent shrinkage after the concrete was exposed to a drying environment. It was found, from the experimental results, that bottom ash can increase expansion of expansive concrete with and without fly ash in both free condition and restrained condition. However, the subsequent shrinkage of the expansive concrete is also increased. The experimental findings indicate that the internal curing can potentially be applied to increase the efficiency of expansive concrete however the balance between the enhanced expansion and the subsequent drying shrinkage must be carefully considered.

Keywords: expansive concrete; shrinkage compensating; expansive additive; restraint expansion; free expansion; internal curing; bottom ash; shrinkage; drying