Strength behaviour of surface coal mine overburden–fly ash mixes stabilised with quick lime

Abstract

Surface coal mine overburden, typically treated as waste material, consists of a mixture of coarse-grained particles, rock fragments and fine-grained particles. It often causes geotechnical and environmental problems at the disposal site. Fly ash, a coal combustion by-product, has the potential to change the behaviour of other similar products when mixed at optimum conditions. Both fly ash and overburden are still being treated as waste products. An investigation has been carried out to evaluate the utilisation prospects of both combined. This article describes the results of an investigation on the compressive strength and bearing ratio behaviour of surface coal mine overburden material and fly ash mixes stabilised with quick lime at varying percentages. The same has also been compared with results obtained from fly ash-mine spoil and mine parting mixes and fly ash-soil.

Keywords:

• compressive strength
• bearing ratio
• coal mine overburden
• fly ash
• lime

Acknowledgements

The authors would like to acknowledge the fund provided by Fly Ash Unit, Department of Science and echnology, Govt. of India under R&D Scheme vide approval No: FAU/DST/600(17)/2008–09 dated 9 September 2008.