Abstract
Sewage sludge is a biomass resource produced in human societies. The mechanical properties of an experimental sewage sludge charcoal were evaluated from the viewpoint of geotechnical engineering by one-dimensional compression tests and triaxial compression tests. It was found that the charcoal could be used as a light weight soil because of the porous structure and low dry density. A little particle crushing occurred on the application of vertical compression stress from 200kN/m2 to 300kN/m2, which corresponds to the yield stresses obtained from the compression curves of charcoal. The principle of effective stress was applicable to sewage sludge charcoal, and the shear behavior was found to be similar to that of sand. The failure line of the consolidated drained shear tests coincided with that of the consolidated undrained shear tests. Furthermore, the angle of internal friction of the sand mixture decreased, whereas that of the silt mixture increased. Lightening was expected as the dry density of a mixture of both soils was reduced with increases in charcoal content.
