The disintegration of concrete structures made of ordinary Portland cement (OPC) is a worrying topic of increasing significance. The
development of new binders with longer durability is therefore needed. Alkali-activated binders have emerged as an alternative to OPC
binders, which seems to have superior durability and environmental impact. This paper reviews current knowledge about alkali-activated
binders. The subjects of Part 1 in this paper are historical background, terminology and hydration products. The proper terminology to
designate these new binders will be discussed. The influence of the prime materials and the type of alkaline activator on the reaction
mechanisms and on the nature of the reaction products will be described