Heat-resistant concrete of fine-grained structure attracts special attention of refractory applications manufacturers. The task of optimizing the grain size composition of heat-resistant concrete fillers on the basis of by-products and related products of silicon carbide (SiC) production and waste products of abrasive tools production on a ceramic bond of fine-grained structure is of research and practical interest. It is proposed to use grain size compositions of gapped grading for a fine-grained cement system of heat-resistant concrete. The analysis of methodological approaches in the calculation of the grain size composition of concrete fillers allowed us to determine the Fuller formula as an optimal one from a practical perspective. Due to the use of gapped grading of the grain component of the concrete composition, an optimal ratio between the size of the grains of quartz sand and the waste of abrasive production was achieved. Balanced distribution of the filler in concrete mix made it possible to obtain intimate contact between their grains, which resulted in dense, “well-packed” concrete structure, and will further enable 5-10% saving of the cement binder. The compressive strength of samples with gapped grading filler was 38.7 MPa, the thermal resistance (water, 800°C) amounted to 16 thermal cycles.

Heat-resistant properties of the cement stone are provided by both high-temperature filler and the modified matrix on the basis of the Portland cement. For production of heat-resistant compositions as high-temperature filler, it is offered to use the secondary and accompanying products of production of carbide of silicon (SiC) and production wastes of the abrasive tools on a ceramic base. Increase in heat-resistant properties of the Portland cement knitting substance is offered to be solved by introduction to the structure of a cement composition of single substituted orthophosphate of calcium. The choice as an additive to the Portland cement a single substituted orthophosphate of calcium (double superphosphate) is proved by questions of safety measures and ecology, when using ortho-phosphoric acid and its salts for giving to cement compositions heat-resistant properties. The multicomponent composition of fine-grained concrete makes it possible to operate effectively the processes of forming the structure of cement stone at all stages of the technology, and to obtain materials with the most diverse set of properties. An introduction to the structure of a composite of 5% of filler of cyclonic dust of carbide of silicon, and a replacement of quartz filler by waste of abrasive production gave the increase of the compressive strength at 12%, bending strength for 36%. The thermal firmness increased by 3 times. An introduction to the structure of heat-resistant composition of single substituted orthophosphate of calcium (double superphosphate) in a number of 0.2% of the mass of cement allowed to increase the thermal firmness of structures to 20 heat exchanges (water, 800 oС).