SPECIAL PORTLAND CEMENT Russian patent published in 1998 - IPC

FIELD: building materials industry, more particularly manufacture of concrete and reinforced concrete products and structures operating in sulfate aggressive media, and cementation of oil and gas wells. SUBSTANCE: special portland cement comprises, wt.%: portland cement clinker containing not higher than 3% three calcium aluminate, 15-75; portland cement containing not more than 3% three calcium aluminate, 15-75; and gypsum, the balance. Special portland cement comprises active mineral additives, hydrophobilizing additives hardening accelerator, and polymers. EFFECT: special portland cement having improved strength and reduced water separation. 7 cl, 2 tbl