I hope to use this thread to share and discuss my results on a series of experiments. I think that post and beam structures with geopolymer infill could be made in a highly efficient fashion. They would be beautiful buildings. I would want a rock-like filler on the outside of each gap and a foam-like filler on the inside of each gap.

I am starting out with trying to figure out a good geopolymer formula using our red Georgia clay. This clay contains silica, alumina, and some iron compounds. From what I have read online, a mixture of 10 parts clay, 1 part sodium hydroxide, and enough water to be fully mixed and hydrated, but not soupy, should produce a decent stone.

I have already conducted one experiment, just to get a sense of what I would be dealing with. My experiment was just based on eyeballing the amounts and was not intended to produce any kind of usable artificial stone.

Experiment 1 conclusions:
- Sometimes I an an idiot, and I am going to get myself killed one day.
- The fumes that come from mixing sodium hydroxide (lye) with water are awful.
- It partially melted the plastic cup. I need a metal mixing container.
- A respirator, good ventilation, gloves, long sleeves, and a mask are a great idea.
- I don't think I used enough clay, and I did not properly mix it. The result was a goop that did not harden - at least, it did not harden yet. It has only been a few minutes. Geopolymers typically harden very quickly.

All constructive feedback is welcome.

Peace,

J

I was interested in geopolymer cement a few years ago. IIRC it was made in NC or somewhere in the south east US from kaolin clay. My interest was in a porous cement filtration system. The pH7 geopolymer allows use of 3 bacterial strains that separate contaminants from water. It was patented a few years ago and caught my interest. I would have considered paying the high price for a small bag if I could have just found the bacterial strains. I found only 2 of the 3.

pH7 seems to contridict using lye to make your own. Not only is your safety a concern, what about the long term issues with something you fabricate? At least a manufactured product can provide some technical data that will help you control the safety issues. I think the geopolymer cements take more than 1000 degrees F to formulate from kaolin clay, not sodium hydroxide. Gloves and a respirator are common for just mixing Portland dry. I say forget the metal cup and the lye.

I am sure I could work out the safety protocols...

But I am having doubts about geopolymers. They just seem like one of those things that is great in the lab, but hard to implement in the field. They all call for materials that have been heat-activated, like metakaolin. Most of them are more expensive than OPC.

After reading several reports that seemed to point to a very inexpensive form of cement, I was feeling pretty hopeful about the idea. However, upon researching it further, it seems that the only inexpensive form of geopolymer uses fly ash. Fly ash typically contains a high amount of toxic metals. I don't know that I would trust the claims that the toxic chemicals are fully contained and do not leach.

I am starting to sense more hype than fact with geopolymers. It is a shame.

Thanks for your feedback,

J

I think fly ash is great. I have used both C and F types. The F type is without toxic metals. The toxic metals in C are minimal. The cost is the same as Portland, but it lessens the amount of Portland used. Since it is a recycled product, it is takes less energy to make. Using it with Portland at about 2to1 instead of just 3 Portland makes a stronger concrete which is easier to work with than conventional concrete mixes.

With an acrylic additive (not the big box variety), the mix using fly ash becomes water proof when cured. I dont see how that could be more toxic?

I like post and beam structures. SIPs would definitely be easy to use on one. I don't see how filling in the gaps as you described above would benefit from geopolymer cements. Why any cement except for the foundation beams?

Consider MgO SIPs.
Gary