Unburnt colliery spoil, or minestone, is the waste product from coal mining and this study has been directed towards examining its use in highway construction. An initial review is presented which deals with its bulk utilization in embankment construction and incorporation in the pavement structure. In view of its inherent low quality, some form of stabilization is necessary to produce a material capable of carrying the stresses associated with pavement structures. The work reported in this paper has been concerned with the use of cement.
The results reported have been obtained both from extensive laboratory studies and from associated field trials. The suitability of the stabilized spoils has been assessed using laboratory characteristics such as strength, frost resistance and resistance to immersion. It is clearly shown that certain colliery spoils can be stabilized with cement to produce material suitable for inclusion in pavements both as sub-base or road-base material. Field data is also included which indicate the compaction levels and strength that can be achieved on site. The results again demonstrate that cement-stabilized colliery spoil can be considered for incorporation in the pavement layers.