Influence of various additives on the early age compressive strength of sodium carbonate activated slag composites: An overview

Abstract

Abstract The use of sodium carbonate as an alkali activator for slag to produce alkali-activated slag is promising due to its sustainable, economic and user-friendly properties. However, the lower early age performance of composites made with such binder has limited its use especially in applications where higher early age is required. Hence, in order to propel the application of this sustainable binder, it is imperative to find ways in which the early age performance can be enhanced without having a detrimental effect on later age performance. One of the effective and sustainable ways to enhance the early age strength of sodium carbonate activated slag is by incorporation of various additives as partial replacement of sodium carbonate on/and slag. In order to propel more application of sodium carbonate slag for various applications, this current study was undertaken. In this paper, an overview of the types of various additives that can be used to enhance the early age compressive strength of sodium carbonate activated slag composites was discussed. The mechanism and dosage of each of the additives were briefly discussed alongside the limitation and advantages of the additives. Findings from this overview showed that the early age compressive strength of sodium carbonate activated slag can be enhanced with the use of additives such as calcium oxide, calcium hydroxide, Portland cement, sodium hydroxide and sodium silicate.