The alkali-activated cements can be classified into five categories based on the composition of the cementing compo-nent(s): 1) Alkali-activated slag-based cements;2) Alkali-activated Portland blended cements;3) Alkali-activated pozzolan cements;4) Alkali-activated lime-pozzolan/slag cements;and 5) Alkali-activated calcium aluminate blended cement.Each category could include several cementing systems.The composition and characteristics of the five categories of alkali-activated cements are summarized.