Compressed Earth Block
This is a collection of research. I am interested in CEB, stabilized with lime and covered in lime plaster. This combination looks to be cheap and provide great thermal and structural properties
Research
I would like to drastically extend the garden in a few years. That could be a good time to experiment with this. It would be a large project, probably a few weeks. There's also a mandatory delay period in the middle.
- Remove top soil - add to compost
- dig down to ~14" - set soil aside
- lay down plastic
- deep soil → rotary sieve → add concrete → brick press
- wait for bricks to cure
- build garden
I think I re-use plastic bottles as water reserves instead of the plastic tubes. I can also add cord wood to the base of the bed. The paths would be layer of sand (to protect the plastic) then a layer of gravel.
Vermeer BP714
An interesting press.
http://www.youtube.com/watch?v=c9cDy9XkXPw
Manual Press
Probably not the way to go, but possible a good way to experiment: https://tinyhousedesign.com/300-compressed-earth-block-hybrid-house/
http://www.rivendellvillage.org/CINVA_RAM_Compressed_Earthen_Block_Press.pdf
The Cinva press requires 80lbs of force. Instead of pushing, I could get an 80lb weight and use a pulley to lift it so the pressure is always even.
http://s82.photobucket.com/user/mscantrell/slideshow/Cinva%20Ram%20Block%20Press
Purchase: https://dwellearth.com/auram-3000-block-press/
This one looks like I could go pretty fast for a long time.
This is interesting, very simple manual process. I might be able to speed it up with some sort of reciprocating hammer. While the bricks will be harder to make, not needing any special equipment may make up for it. I also like the larger bricks he's making, good for thermal mass. I would add cylinders to the mold for conduit and cement. Looking more, some builders construct the whole wall this way.
I'd also like to try building this out of wood. It would be much larger, but I don't see any reason I can scale up the wood to handle the stress. This would also make the design far more accessible.
Detailed Article
http://unesdoc.unesco.org/images/0012/001282/128236e.pdf
The beginning talks about easy soil tests. It also addresses soil layers. On site, we should start by digging a small deep hole and testing soil every few inches.
On page 30 it talks about gypsum stabilization as an alternative to lime. However, lime may be better for clay soils which is what I am likely to encounter in Michigan.
Preparation
- Make soil uniform by mixing and passing through 5mm sieve
Pressure
From this it looks like you'd want 2000psi when pressing the brick. I want bricks that have 3 studs (like 1x3 lego), with each "chuck" being 4"x4", so a total of 48 sqin. for a grand total of 96,000 lbs of force. That would be 11,510 gallons of water, a cube 11ft per side. Not practical.
I'm interested in running everything off a mid-size gas engine fueled by a wood gassifier. That could power a hydraulic pump which could be hooked into the Librator.
Wall
The Lego brick shape provides an interlocking structure. The "studs" will have a hole in the center about 2" wide forming a series of hollow columns in the wall. Every third column will be filled with rebar and concrete to reinforce the wall. The two empty columns can be used for electrical or pipes.
One question is thermal mass. I could build a regular wall, put up a moisture barrier and pile dirt against it. That will need some buttressing to withstand the force. Another approach would be to make the blocks on the thinner side, but have the wall be 2 layers of bricks with some cross supports. The hollow spaces in the middle can be filled with dirt.
Soil Prep
For screening, make an octagonal structure that can be rotated with a motor. throw soil in the middle and it will tumble until strained.
Something like a cement mixer should be fine for mixing cement into the (pre-strained) soil. Setup a batch of soil and cement then add water until it's at the correct moisture.
It should be easy to get something setup to automatically measure out the correct amount of dirt for each brick.