Abstract
The application of clean-water sludge, generated in the water-treatment processes of water service, as a geomaterial was examined. A design California bearing ratio test was conducted to assess the use of the sludge as a subgrade construction material for subgrade and back filling applications. The improvement effect of mixing a decomposed granite soil into clean-water sludge is larger in terms of decreasing the water content than in increasing the strength. The application of sludge as a subgrade material or base course material was examined by a modified CBR test. If clean-water sludge is appropriately dried and a decomposed granite soil is added to it, the sludge can meet quality requirements for other than the base course by simply reducing its water content to less than 100%. Adding a decomposed granite soil further increases the improvement effect.
