Admixtures

Abstract

To commence the discussion of admixtures in alkali-activated binders, it is necessary to first give a brief discussion on the definition of the word ‘admixture’. Many of the components which are essential to the formulation of alkali-activated binders are sometimes described as admixtures (mineral or chemical) in Portland cement systems. In the context of alkali activation chemistry, neither the alkaline activator nor the solid (alumino)silicates should be considered to be an admixture; these are binder components. Similarly, the addition of clinker compounds, or related materials such as cement kiln dust, is beyond the scope of this review. The discussion to follow will predominantly address organic admixtures, although a brief discussion of inorganic components used as accelerators or retarders will also be presented.