Characterization and utilization of fly ash

Abstract

Nearly 73% of the country’s total installed power generation capacity is thermal of which coal-based generation is 90%. Some 85 thermal power stations, besides several captive power plants use bituminous and sub-bituminous coal and produce large quantities of fly ash. High ash content (30% - 50%) coal contributes to these large volumes of fly ash. The country’s dependence on coal for power generation has unchanged. Thus fly ash management is a cause of concern for the future. The purpose of this project is to find a suitable utilization for a particular fly ash sample depending upon its geotechnical properties and thus reduce the need for vast areas for disposal of fly ash which in turn causes considerable damage to the environment. In this project various geotechnical experiments are performed on fly ash samples. Some of them are Standard Procter Compaction test, Liquid limit test, Permeability study, Unconfined compressive strength study etc. Based on the results obtained from these experiments, a suitable end use for the fly ash based on the characteristics of the sample is ascertained. The results from the geotechnical experiments help in determining the potential of the fly ash for use, in highway embankments, in construction of bricks, as an aggregate material in Portland cement, filling of low lying areas etc. From the results obtained it was found that the fly ash can be compacted over a large moisture content range thus it has a potential to be used in fills and embankments. Also since fly ash is having low permeability thus it further benefits the use in fills and embankments by reducing the chances of damage to the ground water resources. The low specific gravity of fly and the pozzolanic activity of fly ash aids for its use along-with cements for construction purposes and also in manufacturing of bricks.