The plasticity of clay-based green bodies including bottom ash(BA) from power plants were investigated. The plasticity indices of clay-base green bodies using Atterberg limits were measured. The usefulness of plasticity indices was confirmed by mapping the applicable forming region and through the actual extrusion process. Possible forming compositions were examined using various contents of water, bottom ash, stone dust, and sewage sludge. The relationship between the properties of aggregates and plasticity of green bodies was also investigated. Suitable compositions for forming aggregates by the extrusion method can be found by measuring the plasticity indices of green bodies and a map of the plasticity indices was matched with the results of actual extrusion process. The properties of aggregates were greatly influenced not only by the raw materials but also by the plasticity of green bodies.

Keywords: Bottom ash; Atterberg limits; Plasticity index; Plastic limit; Liquid limit; Aggregates