Concrete @ your Fingertips

Alkali activated cements (including geopolymer cements)

Alkali-activated cements gain their strength, and other properties, via chemical reaction between a source of alkali (soluble base activator) and aluminate-rich materials.


The aluminate-containing material - the pozzolan/latent hydraulic binder component of the cement - can be coal fly ash, municipal solid waste incinerator ash (MSWIA), metakaolin, blastfurnace slag, steel slag or other slags, or other alumina-rich materials.


The alkali used as the activator tends to be an alkali silicate solution such as sodium silicate (waterglass) but can also be sodium hydroxide solution, or a combination of the two, or other source of alkali (such as lime).


Geopolymeric cements are particular examples of ´alkali-activated pozzolanic cements´ or ´alkali-activated latent hydraulic cements´.


All alkali-activated cements tend to have lower embodied energy/carbon footprints than Portland cements (up to 80-90% but this is pozzolan dependent).


Manufacture on a commercial basis is underway in Australia, USA and possibly, China.


Covered by PAS 8820:2016 Construction materials. Alkali activated cementitious material and concrete. Specification


For more information, see:


Acknowledgement: The Concrete Society