Geotechnical and Morphological Properties of Lime-stabilized Fly Ash Mine Overburden Mixtures for Subbase of Haul Road

Handling and the disposal of fly ash is a severe problem in the coal-based thermal power plants. Fly ash is a substantial by-product of the thermal power plants that adversely affect land, water, and air. It's a gainful usage is being explored continuously in many areas. The use of fly ash in the haul road construction for the opencast coal mines is one of the alternatives. This paper reports, detailed laboratory investigations executed with the lime stabilized fly ash-mine overburden mixes to assess their suitability for subbase of a mine haul road. The composite materials were prepared from fly ash, mine overburden, and lime at different proportions. Proctor compaction test, California bearing ratio (CBR) test were carried out at the various curing periods. The combination of the mix with 25% fly ash and 66% overburden, stabilized with9% lime, produced the highest possible compressive strength, and bearing ratio value as compared to that of the other mixes with curing, suitable for mine haul road construction. A laboratory test has been executed with different percentages of lime (3%, 6%, to 9%). Scanning electron microscopy (SEM), along with dispersive energy X-ray (XRD) analyses has been conducted at 7, 28 & 56 days cured samples. The experimental results showed that strength values of fly ash mine overburden and mixes up increased because of the lime treatment method.