Shrinkage characteristics of alkali-activated slag mortar with SAP

Abstract

The advantages of alkali activated slags (AAS) with adequate types and dosages of activators are high strength development, rapid setting, lower permeability, excellent durability, low hydration heat, high early-age strength and high resistance to chemical attack. The hydration products found in AAS are C-S-H with a low Ca/Si ratio related to GGBFS and the components of activators used. However, high autogenous and drying shrinkages of alkali-activated slag concrete are frequently reported. Therefore, researchers have continued their efforts to mitigate shrinkage strains and stresses. Two types of alkali activators and superabsorbent polymers were used to investigate autogenous shrinkage, and porosity characteristics of AAS. To mitigate shrinkage of AAS mortars, superabsorbent polymers (SAP) were applied to create an internal curing effect on the mixtures. As a result, autogenous shrinkage strains and AAS mortars that SAP were applied was significantly decreased, therefore, it is concluded that SAP played an important role on shrinkage mitigation of all mixtures.