A review on alkali-activated binders: Materials composition and fresh properties of concrete

Alkali-activated binders (AAB) have been extensively researched as a potential replacement of ordinary portland cement (OPC) concrete to minimize carbon emissions released during OPC production while reusing a significant amount of industrial waste by-products. This paper provides a comprehensive review on the materials composition and the fresh properties of AAB. The chemical, physical, and mineralogical properties of a suite of pozzolans used to make AAB are analysed including fly ash, slag, metakaolin, silica fume, rice husk ash, palm oil fuel ash, and others. Sodium and potassium based alkaline activator solutions are also highlighted. The influence of AAB properties on workability (namely consistency, flow, and slump), setting time, reaction kinetics (as measured by isothermal calorimetry), and temperature are synthesized from past literature. The findings show that fresh properties of AAB can be tailored for specific applications based on mix design and processing conditions. (C) 2020 Elsevier Ltd. All rights reserved.