What is Geopolymer cement?
I have been confused by the term “Geopolymer cement (concrete)” for long time. Some researchers told me Geopolymer cement is essentially alkali activated cement/material (AAMs), such as alkali activated slag and fly ash. Since alkali activated slag is indeed a kind of geopolymer cement, it looks logical to consider Geopolymer cement as alkali activated cement.
Is it correct? Recently, I read the State of the Art report on alkali activated cement (Alkali Activated Materials State-of-the-Art Report, RILEM TC 224-AAM), finding the description:
Low-calcium alkali-activated systems, predominantly dealing with alkali aluminosilicates and including those materials which are now widely known as ‘geopolymers’.
It is clear that not all alkali activated cements are geopolymers. Just those with low calcium materials activated by alkali in cement industry are regarded as geopolymer cement, in other words, geopolymers are shown here as a subset of AAMs, with the highest Al and lowest Ca concentrations.
BTW, Davidovits is the first researcher applied the name ‘geopolymer’ to these low calcium materials activated by alkali. He was working in France, patented numerous aluminosilicate-based formulations for niche applications from the early 1980s onwards.