Compaction behaviour of Indian coal ashes

Abstract

Fly ash is a waste product obtained by burning pulverised coal in thermal power stations. In India, it is estimated that about 90 million t of ash is produced every year. The problem of ash disposal in the vicinity of power plants is difficult because of the limited space available. Its bulk utilisation is feasible only through geotechnical applications such as embankments, backfill material and the like. For this purpose, an understanding of its physical engineering and chemical properties is necessary. The compaction behaviour is an important engineering property that needs to be thoroughly understood. Hence the present study investigates in depth the compaction behaviour of coal ashes. A new method of representing the compaction data is suggested to account for the wide range of specific gravities for coal ashes. The studies show that the compaction behaviour of coal ashes resembles that of cohesionless sands or sandy gravels. However, the curves are flatter compared to those in soils which are sensitive to variation in water content.