RU2151752C1 - Portland cement - Google Patents

Abstract

FIELD: building materials industry, petroleum and mining industries. SUBSTANCE: portland cement comprises mixture of ground clinkers of different mineralogical composition, and gypsum, mixture including at least three ground clinkers having different mineralogical composition and grinding fineness. Instead of part of mixture of clinkers, cement may contain active or inert additives in amount of up to 60% based on weight of cement. EFFECT: improved early strength of portland cement. 2 cl, 3 ex

Description

 The invention relates to the composition of Portland cement and may find application in the building materials industry, in the oil and mining industries.

Known Portland cement, consisting of a mixture of Portland cement clinker, a special clinker, the main minerals of which are 2CaO • SiO ₂ and 3CaO • Al ₂ O ₃ , and gypsum. A special clinker in an amount of 5-50% is mixed with Portland cement clinker and a small amount of gypsum and crushed to a specific surface of 3000 cm ² / g (see Japanese Application No. 54-155221, published 07.12.1979, class C 04 B 13 / 02).

The closest analogue is Portland cement, obtained from a mixture of three Portland cement clinkers, one of which is necessarily clinker clinker, in addition, the mixture contains porous clinker obtained at temperatures up to 1250 ^o C (see DE N 2632691, C 04 B 7 / 00, 02/10/1977).

 The problem to be solved is obtaining Portland cement with increased early strength.

 The problem is solved due to the fact that Portland cement consists of a mixture of ground clinkers, differing in mineralogical composition, and gypsum. At the same time, the mixture includes at least three ground clinkers, differing in mineralogical composition and fineness of grinding. Cement instead of part of the clinker mixture may contain active or inert mineral additives in an amount up to 60% by weight of cement.

 Examples of carrying out the invention.

 Example 1

To prepare Portland cement, alite clinker (C ₃ S = 62%) is ground to a specific surface of 3000 cm ² / g, white cement clinker is up to 3500 cm ² / g and low-aluminate clinker (C ₃ S = 4%) to a specific surface of 3200 cm ² / g Ground clinkers are taken in a ratio of 1: 2: 1 and mixed with dispersed gypsum. The obtained Portland cement has a strength of 3 days at 31.7 MPa.

 Example 2

For preparation pre Portland cement ground to a specific surface of 2800 ^cm2 / g of quick-setting cement clinker, clinker Alitova to 3000 cm ² / kg clinker vysokoalyuminatny (C ₃ A 10%) to 4,000 cm ² / g. Ground clinkers are taken in a ratio of 2: 1: 1 and mixed with dispersed gypsum. The obtained Portland cement has a strength at 3 days of age of 32.4 MPa.

 Example 3

 For the manufacture of Portland cement, a mixture of clinkers according to example 1 in an amount of 45 wt.% And blast furnace granulated slag in an amount of 55 wt.% Are used. To these materials add gypsum in an amount of 4% of the total mass. The resulting cement has a strength at 3 days of age of 25.1 MPa.

Claims (2)

 1. Portland cement, consisting of a mixture of ground clinkers, differing in mineralogical composition, and gypsum, characterized in that the mixture includes at least three ground clinkers, differing in mineralogical composition and fineness of grinding.  2. Portland cement according to claim 1, characterized in that instead of part of the clinker mixture, it contains active or inert mineral additives in an amount up to 60% by weight of cement.