Strength evaluation of clinker stabilized fly ash-mine overburden composites as an alternative haul road construction material

Opencast coal mining plays a major role in meeting the demand for fossil fuel. Large capacity haul trucks are being increasingly used to meet this demand. These trucks need well-designed haul roads. Opencast mining also imposes adverse conditions on the area due to substantial overburden lying unreclaimed. The current fly-ash production is about 180 MT that will rise to about 600 MT by 2030 in India. It adversely affects land, air and water resources. Strong effort is required to address this issue. An investigation has been taken up to evaluate the use of both fly ash as well as mine overburden material along with a selected additive to develop an alternative construction material to be used in the sub-base of haul road. This article reports the detailed laboratory investigations carried out on the development of Fly ash Composite Material (FCM) with mine overburden and clinker and determination of their suitability for haul road. Proctor compaction test, Unconfined Compressive Strength (UCS) test, Brazilian Tensile Strength (BTS) test and Scanning Electron Microscopy (SEM) were carried out. The composite with 62% fly ash, 30% overburden and 8% clinker exhibited adequate strength value for the haul road construction.