Manufacturing artificial lightweight aggregates using coal bottom ash and clay

The artificial lightweight aggregate (ALA) was manufactured using coal bottom ashes produced from a thermoelectric power plant with clay and, the sintering temperature and batch composition dependence upon physical properties of ALA were studied. The bottom ash (BA) had 13 wt% coarse particle (>4.75 mm) and showed very irregular shape so should be crushed to fine particles to be formed with clay by extrusion process. Also the bottom ash contained a many unburned carbon which generates the gas by oxidation and lighten a aggregate during a sintering process. Plastic index of green bodies decreased with increasing bottom ash content but the extrusion forming process was possible for the green body containing BA up to 40 wt% whose plastic index and plastic limit were around 10 and 22 respectively. The ALA containing 30 similar to 40 wt% BA sintered at 1100 similar to 1200 degrees C showed a volume specific density of 1.3 similar to 1.5 and water absorption of 13 similar to 15 % and could be appled for high-rise building and super-long bridge.