COMPRESSED EARTH BLOCKS
Compressed earth blocks are natural building materials made up mostly of damp clay soil that is compressed at high pressure to form bricks.
COMPRESSED EARTH BLOCKS – BASIC RECIPE
- 15-40% non-expansive clay
- 25-40% silt powder
- 40-70% sharp sand to small gravel content
The more modern machines do not require aggregate (rock) to make a strong soil block for most applications. Soil moisture content ranges from 4-12% by weight. Clay with a plasticity index (PI) of up to 25 or 30 would be acceptable for most applications. The PI of the mixed soil (clay, silt and sand/gravel combined) should not exceed 12 to 15; that is the difference between the Upper and Lower Atterberg limits, as determined by laboratory testing.