Alkali-activated materials
While blastfurnace slag and metakaolin are known to produce a binder phase following alkali activation, the range of alkali-activated materials is wider than these two materials. This month Arthur Harrisson provides an overview of low-and high-calcium precursors that are subjected to alkali activation to produce binders.
Figure 1: fly ash, a low-calcium AAM precursor
Materials that arise as waste or a by-product from industrial processes other than Portland cement manufacture have proved beneficial to concrete producers for many years when used as supplements to clinker. The benefits have been in terms of financial savings, as being instrumental in improving the durability of concrete and also as a means of reducing the carbon footprint of cement and concrete production. Key materials among these have been fly ash and blastfurnace slag. Both of these materials are widely used in combination with Portland cement clinker to produce commercial products.
