I love geopolymers
I have to say, I agree 100% with you there! I've been reading up on them a bit and it's fascinating. That, and I have an idea as to how an enterprising permie might make one in their very own backyard, assuming they had some knowledge of chemistry.
Sodium silicate (aka waterglass), when combined with fly ash and water, seems to create a relatively strong geopolymer. A quick search of "fly ash and sodium silicate geopolymer" brings up a great number of papers measuring compressive strength and plenty of other important factors meant for people much smarter than me.
The great thing here is that fly ash is a waste product of coal (and some electric-fired) powerplants, and is a pretty big component of most land fills. A cheap waste product that would end up in a landfill or dump if I didn't use it? How could it get any better?? Reminds me of people using shabby old tires for rammed earth thermal mass.
Another big plus is that just about anybody could make sodium silicate in their backyard, if they were careful and (again) had some knowledge of chemistry. Just take lye, aka sodium hydroxide, (easy enough to buy or make by filtering water through wood ash) and dissolve it in water. Then add silicates, and you've got waterglass! On a small scale people suggest using those little "do not eat" packets of silica gel, but you can actually use a different source of silicates...sand! It is, of course, more complicated and a little more dangerous than that if you're trying to use just clean sand rather than lab-grade silicate, and I wouldn't suggest anyone try it unless they know more about it than I do. That said, I think it's a pretty cool little bit of information.