Strength characteristic study of fly ash composite material

Abstract

Nearly about 67% of the total energy consumption in the country is fulfilled by coal as it is one of the primary sources of energy. India has one of the largest reserves of coal in the world. Indian coal has high ash content and low calorific value. The reserves are likely to last over another 100 years as the rate of coal extraction is increasing. The energy derived from coal in India is about twice that of energy derived from oil, as against the world, where energy derived from coal is about 30% lower than energy derived from oil. Most of the country’s total installed power generation capacity is thermal. Coal-based generation is 90%. Thermal power stations, besides several captive power plants use 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 is increasing and so the production of fly ash will be more. Fly ash causes air, water and soil pollution when it is exposed to environment. This project report is an attempt to find a suitable utilization for a particular fly ash sample depending upon its geotechnical properties. The area required for disposing fly ash will be minimised and so damage to the environment will be minimum. In this project various geotechnical experiments were carried out on fly ash samples. Some of them are Tensile strength study, Unconfined compressive strength study etc. Based on the results obtained from these experiments, a suitable use for the fly ash is ascertained. Fly ash composite material (FCMs) was developed from captive power plant of NALCO, Angul, Odisha, India. The main constituents of the composite are:
1. Fly ash 2. Lime
Compressive and tensile strength were determined from the FCMs after 7, 14, 21 days of curing time. Different samples were taken with different percentages of lime (i.e. 5, 10, and 15 %) with fly ash and their properties were studied. The results from these above experiments helped in determining the potential of the fly ash for use, in manufacture of bricks, in highway embankments, as an aggregate material in Portland cement, filling of low lying and mine void areas etc. Composite material made of fly ash is subject to a variety of different loading conditions, and so different types of stresses develop. Based on the different strength of composites it can be used in various geotechnical applications like construction of roads, Embankment, dams and reservoirs and mine filling.