CONCRETE MIXTURE FOR MANUFACTURING CONTSRUCTION AND STRUCTURAL HEAT-INSULATING ARTICLES Russian patent published in 1995 - IPC

FIELD: building materials production. SUBSTANCE: raw materials mixture contains (mass %): portland cement 15.5-17.0, dacite sand 31.0-37.0, dacite gravel 34.0-39.0, water the rest. Dacite gravel having density 450-500 kg/m³ and strength 2.6-2.8 MPa is used as origin material. Dacite and poor clay are crushed in jaw crusher, their mass ratio being 80-85:20-15. The process is followed by grinding in ball mill, granulation and by roasting. The former process is carried out till specific surface is 2500-3000 cm²/g. Said roasting takes place simultaneously with drying within 20-30 min at 1150-1200 C. The process is followed by cooling in thermostat. Mentioned above dacite sand is prepared by dacite gravel crushing. Dacite sand of 5 mm fraction is mixed with portland cement, dacite gravel of 10-20 mm fraction being added into thus prepared dry mass. Then water is gradually added into it. Duration of all mixing processes is 24 min. Blocks being mould of desired mixture are then affected by wet and heat treatment, the process is carried out at 85 C by isothermic heating. Strength thus prepared concrete is 16.8-18.1 MPa, its density being 1200-1250 kg/m³. EFFECT: improves quality of desired product. 1 tbl