Use of the burnt rock of coal deposits slag heaps in the concrete products manufacturing

The paper presents the results of the comprehensive study of the composition, properties and structure of the burnt rock found at the mining dumps of Cheremkhovo coal deposit (Irkutsk region, Russia). In the course of laboratory research, which included optical crystallography, there have been established the reasons accounting for the extent of burnt rock activity when in contact with cement during the cement stone formation. The benefit of the burnt rock as an active mineral additive, compared to the fly ash used by the cement plants, was confirmed as well. The optimal ratio of cement and burnt rock in concrete mixtures was determined experimentally. Likewise, the most effective method of using burnt rock as an active mineral additive was developed as the result of semi-industrial tests when the sample was subjected to the pressing and steam treatment. Finally, the impact such an additive can have on the production cost have been calculated.