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dry mixing cement and soil, then wetting on the wall

 
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I'm building a new dome next year and for a variety of reasons I'll be using portland cement as a stabilizer. I tried to avoid it, but my local soil has near zero clay in it so lime doesn't function well enough and with no clay as a binder... there's no binding otherwise. I'm planning on a 9:1 or 10:1 add mix ratio (fines+small aggregate : portland cement), mixed in an electric 4 cubic yard mixer.

I read about this lady who used non stabilized (ie: just clay, no cement/lime) soil and has had good results with filling the bags with dry mix, then wetting once on the wall, them tamping.

I'm curious if I can do this with my soil cement version as well. It will be a very hot and arid environment so I'll be wetting the walls constantly anyway during cure time (overnight at the end of the work day, essentially).

Edit: I should add that a slower setting time, to the point where the interior of the bags potentially take months to cure from moisture in the walls, doesn't really bother me. I want the walls to be soil-cement hard in the long term, they'll be sufficiently fine in the short term to build with.
 
pollinator
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Clay is a critical component of any mix.
You cannot add portland cement to compensate for it.
Either look around your property for better soil or import it from somewhere.
Have a look at this; http://www.earthbagbuilding.com
 
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I don't know what the lower limit is, but for low clay soils, gypsum and lime (Alker) is supposed to work quite well.  I have not tried it, but I have certainly had good results with CSA cements which are "almost" the same thing.

Out here, drywall is not supposed to go into the landfill (it does...), so it costs to get rid of.  So you can likely find it for free.  That might get you half way, and reduce the cost of the clay?

 
Tony Hawkins
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John C Daley wrote:Clay is a critical component of any mix.
You cannot add portland cement to compensate for it.
Either look around your property for better soil or import it from somewhere.
Have a look at this; http://www.earthbagbuilding.com



I've talked to Owen previously and taken a few classes at cal earth. All of my understanding points to needing a binder, be it clay, lime, cement, or aspalt emulsion. Owen himself has that completely zero-stabilized zero-binding structure made entirely out of pumice. In Hunter and Kiffmeyer's book they make reference to zero-clay, zero-stabilized coral sand construction in some tropical island somewhere off.  

But for me I want a binder, and since I'm short of clay and even lime reacts better with clay, I'm stuck with Portland. I've checked around, I'm in a very mountainous area. The clay forms many miles away where water carried it.
 
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