Coal-based thermal power plants all over the world face serious problems of handling and disposal of the ash produced. The high ash content (30–50%) of the coal in India makes this problem complex. At present, about 145 thermal power stations in India produce nearly 184 million(quantity) tonnes of coal ash per annum (CEA,2015). Safe disposal of the ash without adversely affecting the environment and the large storage area required are major concerns. Hence, utilization of fly ash in different areas of engineering such as embankment construction, cement industry, concrete, as adsorbent in waste water treatment plant, bricks, building materials, as a backfill material etc. are being made to utilize this waste rather than dump it. Despite this usage, the full fledged utilization of fly ash is still a distant dream. So, to further utilize the fly ash in road construction, attempts are being made to utilize this waste in base and sub-base layer of the pavement. In order to utilize the fly ash, it is desirable to improve its engineering properties such as compressive strength and stabilize with cement and meets the desired design strength (unconfined compressive strength UCS) in base and sub-base layer. In a related research, the optimization of fly usage in base and sub-base layer has been done as per its UCS value. After meeting the desired engineering properties, a pavement of 0.5 MSA was designed as per Indian Road Congress (IRC) specification for further performance evaluation. This paper demonstrates the design, optimization for construction of test section with Fly Ash in base and sub-base layer.
Contributors: Khan S, Nagabhushana M N, Vittal UK.