Sulfate Portland cement is produced by co-fine grinding of Portland cement clinker, gypsum. Sulfate release Portland without additives and mineral supplements - Granulation domain and electrothermophosphoric slag (10 - 20%), supplements of sedimentary rocks, except gliezhey (5 - 10%). Make cement without additives - 400 with additives - 400, 500. It is used for hydraulic structures in sulfate aggression.
Sulfate is a kind of ordinary Portland cement and Portland cement differs from the latter mainly to the fact that detects increased resistance to sulphate in a systematic aggression of alternate freezing and thawing or wetting and drying. Prepared by sharing this cement clinker grinding normalized composition and gypsum.
Chemical and mineralogical composition of the clinker used in the production of Portland cement sulphate, must meet the following requirements:
calculated tricalcium silicate content - not more than 50%;
Estimated content of tricalcium aluminate - no more than 5%;
alumina modulus value - not less than 0.7.
Calculated amounts of clinker C3A + C4AF, shall not exceed 22%. The need to obtain clinker normalized chemical and mineralogical composition determines the requirements for raw materials.
Highly advisable to use tripoli or diatomaceous earth or flask in the clay component. In Portland sulfate is not administered active mineral dooavok, and only under favorable conditions of service in some cases (by agreement between the supplier and the consumer) allowed the introduction of grinding a small amount of additives. The latter shall comply with the requirements of GOST 6269-54 for active mineral additives astringent substances' or in the case of an additive granulated blast-furnace slag - the requirements of GOST 3476-60 for granulated blast-furnace slag for cement production. Resistance sulphate Portland sulphate aggression action increases when introduced into its composition of surfactant. Therefore, according to GOST 970-61 allowed the introduction of its composition and sulfite-alcohol stillage or oil soap. In these cases, it is assigned a name or plasticized hydrophobic sulfate-portland cement.
By this cement strength parameters are divided into three marks 400, 500 and 600. Due to the moderate amount of clinker tricalcium silicate and tricalcium aluminate low-sulphate Portland is different from the usual portladtsementa less heat. The inherent properties of sulfate-resistant Portland cement and determine its practical use. The most advisable to use this cement for concrete and reinforced concrete structures, including pre-stressed, hydraulic structures exposed to sulfate aggression at varying levels of the water table, as well as for the manufacture of piles, construction of bridge piers, breakwaters, designed for service in the saline waters.
Allowed the use of sulfate-resistant Portland cement for underwater parts of the sea and ocean structures, however, for these purposes is a more economical use of sulfate-resistant Portland cement pozzolan Because sulfate-resisting portland cement active fuel minerals (C3S and C3A) are contained in a smaller amount, in some cases, it can be used instead of Portland cement with moderate exotherm in the outer zones of massive hydraulic structures.