Liquid limit determination of Class F coal ash

Large production of coal ash, a waste material, demands its bulk utilizatio n. Bulk utilization of these ashes is possible only through geotechnical ap plications such as embankment construction, as a back-fill material, a subb ase material, and the like. Hence their physical and engineering properties need to be determined for effective utilization. Liquid limit is one of th e important physical properties. The existing popular methods of liquid lim it determination of soils, namely Casagrande's percussion method and the fa lling cone method, have limitations for their use in nonplastic materials l ike coal ash. In this paper, a new method has been proposed to determine th e liquid limit of coal ash. The proposed method is based on the premise tha t at its liquid limit water content, soil/coal ash does not imbibe or give out any water under a particular vertical stress under the K-o condition. T his vertical stress is found to be 0.9 kPa. Experimental results are presen ted to substantiate the proposed method.