REINFORCED CONCRETE BLOCK OF PRECAST LINING FOR HIGHWAY TUNNELS Russian patent published in 2006 - IPC C04B28/00 E04B1/04 E21D11/08 

FIELD: reinforced concrete blocks for precast lining of highway tunnels; erection of transport structures.

SUBSTANCE: proposed reinforced concrete block is made from concrete mix containing cement, crushed stone of 5-10-mm and 10-20 mm fractions, sand, plasticizing agent, filler and water; use is made of granite crushed stone at ratio of fractions 5-10 mm and 10-20 mm equal to 1:2.17-2.35; quartz sand contains fractions from 0.16 to 5 mm at the following total screening residues, mass-%: 2.5 mm -3.2-6.0; 1.2 mm - 12.8-16.2; 0.6 mm - 35.8-54.1; 0.3 mm - 70.4-89.3; 0.16 mm - 100; mix contains also granite sand from screenings up to 5 mm in size; used as plasticizing agent is super-plasticizing agent C-3; used as filler is ground quartz sand at specific surface of 2200-3500 cm²/g and additive at the following consumption of components per cubic meter of concrete mix, kg: cement, 300-370; crushed stone, 1100-1210; quartz sand, 650-750; granite sand, 60-75; ground quartz sand, 20-100; water, 125-143.3; super-plasticizing agent C3, 0.8-1.0 of mass-% of cement; additive, 0.1-0.3 of mass-% of cement.

EFFECT: enhanced strength, freeze resistance, water resistance and crack resistance of blocks.

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