So, the soil in my area is almost entirely expansive clay, and I haven't found any local suppliers here of soil suitable for Compressed Earth Bricks. However, we are a concrete jungle full of crumbling streets always being repaired. One of the biggest expenses for the construction is getting rid of the used concrete. My question is:
A) can concrete powder be pressed into blocks with CEB presses?
B) will it expand in heat or rain like the cured concrete does
C) will it take more pressure than is feasible to do so?
Dave, no expert here, but I may have a few thoughts that may help. Let start with a question, what and how are you building? First, with the clay you have, if you added sand and straw and preesed into bricks, would that work like a form of adobe? Also, if you crush concrete down to powder, it can be made back into concrete again, just balance out mix with more cement. The issue is the machines and energy to do so. It is expensive, labor intensive and lots of carbon foot print. May I suggest using the concrete sections like brick. Urbanite goes into landfills and is buried. Suchba waste of a raw material. I plan on a permeable drive with urbanite and gravel. It is great as a retaining wall, garden border, pathway, etc. Just darn heavy if too big and rebar in it may need to be cut.
As far as the pressure, again it depends on recipe for blocks. If you added a small amount as powder or aggregate, it may work. This may be an experiment in a recipe and process to test. Once you work it out, please post and share for all to learn. Hope that helped a little.
Steve Lansing wrote:Let start with a question, what and how are you building? First, with the clay you have, if you added sand and straw and preesed into bricks, would that work like a form of adobe? Also, if you crush concrete down to powder, it can be made back into concrete again, just balance out mix with more cement.
R Ranson wrote:I don't know much about concrete - but I wonder...
It sounds like you have the perfect resources to make a cob house. Could the concrete be used to create a foundation the build the cob walls on top using some of that lovely clay you have?
The problem with our soil is it absorbs water like a sponge, killing the concrete foundations. As to making cob out of it, I don't know if it would work for cob. It tends to expand to several times it's size when wet. In a wet year the ground can rise over a foot. Never worked with cob, though I've done some research on it. I'm planning on several projects that CEB would be perfect for. First for building a graduated raised garden bed (beds that are on different levels like stairs). Also planning on making a rocket stove grill, wood outdoor fire pit,and a kiln. Obviously I'm gonna need a fireproof building material for it. I'm going to build bio-char briquettes anyway, so a press could be used for that too.