Mitigating of drying shrinkage in alkali-activated slag composites

Abstract

Alkali activated slag composites are promising alternatives to be used as a replacement of Portland cement composites for different construction applications. However, despite the evolution of these composites over the years, its high drying shrinkage still poses a limitation on its application. The increasing interest in alkali-activated slag composites by the research community has resulted in the use of various methods and materials to mitigate the drying shrinkage. This current paper explores the different major types of mitigation techniques that can be used to reduce the drying shrinkage in alkali-activated composites. The mitigation techniques explored are in terms of the use of various materials and curing methods. Discussions presented in this paper showed that a significant reduction in the drying shrinkage can be achieved by partially replacing slag with mineral admixtures or incorporating chemical admixtures specifically made to reduce shrinkage. The use of appropriate internal or external curing method for alkali-activated slag was also found to reduce drying shrinkage effectively. However, it is recommended to carry out further research in order to fully understand the mechanism of drying shrinkage in alkali-activated slag composites in order to develop effective ways to mitigate it.