METHOD OF PREPARING COMPLEX ADDITIVE FOR CEMENT COMPOSITIONS Russian patent published in 1996 - IPC

FIELD: manufacture of building materials. SUBSTANCE: method is distinguished in that (i) as a plasticizer, a compound is used based on sodium salt of condensation product of naphthalene sulfonic acid and formaldehyde "S-3" or sodium salt of antracene-, phenantrene- or carbazol sulfonic acid with formaldehyde "N"; (ii) as an inorganic hardening accelerator, sodium nitrite-nitrate or intermediate in nitrite-nitrate salts' production - 40% sodium nitrite-nitrate aqueous solution (nitrodan) is used. Silica- containing component is mixed with a mixture of aqueous solutions of plasticizer and hardening accelerator at ratio (0.5-2.0):1, resultant mixture is dried at 105-150 C and then added to cement composition in amount 10-20% based on cement weight, concentrations of components in complex additive being the following (in wt %): plasticizer 1.5-14.3, accelerator 0.5-14.3, silica-containing component 71.4-98.0. Mobility of concrete mixture is as high as 18 cm, strength after 28 days of normal hardening up to 58.7 MP, and cold resistance 600 cycles. EFFECT: improved concrete performance. 2 tbl