So what proportion of this binder should I use to either soil, more of the same type of clay or builders sand (with or without bigger pieces of stone)?
For non castable mixtures like for bricks and plates the lye content of the total dry mass can vary from 1%-5%.
Zeolite as aggregate requires about 7% NaOH or 10% KOH.
The chemical reactions depend on the lye concentration, thus a higher water content requires a higher lye content as well.
For most castables a lye content of about 5% is sufficient.
The lye per total mass and the mineral/lye ratio of the binder determines the amount of aggregates.
Quartz sand causes problems with thermal cycling due to the many crystal phases, each occupying a slightly different amount of space.
Quarz has a much higher thermal conductivity than alumino silicates.
Larger pieces of virtually any kind increase thermal conductivity as well.
High insulation requires small particle boundaries.
Crossing a particle boundarie requires a small additional amount of energy,
thus the more particle boundaries the better.
Even pores can be calculated as particle boundaries.
Geopolymers usually require some dissolved minerals to get hard and strong.
Lye in the final concentration can usually not dissolve a sufficient amount.
Therefore waterglass is used or a LTGS binder prepared in advance.
Only grogs and powderized hard stones can be cured with lye alone.
If one mixes zeolite with lye without preparing a binder first it will get hard but extremely brittle.
Clay will not even get hard
Expansive clays are not very suitable for casting.
The high amounts of water required lower the lye concentration to much.
Also castables usually require some caustic lime or cement as accelerator, which makes the result more brittle.
Geopolymers can be reinforced with fibers and be applied like adobe, which is a very powerful building technique.
Double shoe box rockets can be easily build from plates.
Plastic clay mixtures can be rolled to plates, which can be cut with knifes.
Potters call that a slab.
Potter slabs are usually rather thin, but can be made much thicker.
www.youtube.com/watch?v=PDdX5FfYhhwwww.youtube.com/watch?v=WOCoivzq_pgBased on my experiments 4cm should be more than sufficient.
I have two professional degrees, each equivalent to a bachelor degree.
I had to learn a lot about building materials and insulation against heat, moisture and noise.
But about 40 years ago Davidovitz had just started his research and virtually nobody did knew anything about geopolymers.
By far the most of my knowledge in quite a lot different areas I have learned as an autodidact and by experiments .
Self made knowledge is by far the best knowledge.
Davidovitz has never recognized the true potential of LTGS and quite abviously nobody else but me.
The paper anout LTGS bricks is virtually the only available literature aside of my posts.