RU2259969C1 - Method of concrete mix preparation - Google Patents

Abstract

FIELD: building materials, particularly used for producing concrete structures and articles.

SUBSTANCE: method involves metering quartz sand and components of ash-and-slag-and-alkaline binging material including carbon containing liquid glass and grinded dump ash-and-slag mixture; mixing above materials and forming articles. Liquid glass is produced from large-tonnage crystalline silicon production waste obtained at aluminum smelter, namely of microsilica, and including highly-dispersed carbon mixtures, namely graphite and carborundum with silica modulus n=1, in amount of up to 6-7% by weight. Grinded dump ash-and-slag mixture is obtained by brown coal burning. Ash-and-slag mixture contains 25% of slag component and 75% of ash component and is grinded so that not more that 1% of material is retained on sieve with 0.08 mm openings. The ash component is obtained from combustion of brown coal at heat generating plant. Concrete mix components are taken in the following amounts (% by weight): liquid glass - 13.5-28.2, ash-and-slag mixture - 24.3-55.1, quartz sand - 31.4-54.5. The mix may be hardened under temperature of up to -18°C.

EFFECT: increased frost-resistance and extended range of concrete mix hardening temperatures, simplified process of concrete mix preparation and reduced cost of ready product.

1 ex, 2 tbl

Description

The invention relates to the construction materials industry and can be used in the manufacture of structures and concrete products.

A hydraulically hardening composition is known that hardens at low temperatures and contains 50-80 parts of BTsM, 13-35 parts of fly ash, 0-10 parts of metakaolin, 0-6 parts of slag, 0-4 parts of timing control additives setting the binder, and 1-5 hours of potassium carbonate [US Patent No. 4842649, 1989].

The disadvantage of this composition is its multicomponent.

The closest analogue to the described invention is a method of preparing a concrete mixture, including dosing quartz sand and binder components, mixing and molding products. As a binder in this method, an ash-and-alkali binder is used, consisting of 3.5% of the ash and slag mixture obtained by burning brown Kansk-Achinsk coal at TPP-7 in the city of Bratsk, Irkutsk region and carbon-containing liquid glass made up to a sieve residue No. 008 from large-tonnage waste from the production of crystalline silicon of the Bratsk Aluminum Plant - silica fume and containing up to 6-7 wt.% highly dispersed carbon impurities - graphite C and carborundum SiC, with a silicate module n = 1 and density ρ = 1.4 3-1.5 g / cm ³ [RF patent on the application No. 2001103552, publ. 02/20/03, class C 04 B 28/26].

The disadvantages of the described method for the preparation of concrete mix are the relatively low frost resistance (150-200 cycles) of concrete, the limitation of the hardening temperature to -10 ° C, the relatively narrow range of density values of liquid glass.

The problem solved by the invention is to improve the quality of concrete.

The technical result is an increase in frost resistance of concrete and an increase in the temperature range of hardening (up to -18 ° C), expanding the range of density values of liquid glass.

The specified technical result in the implementation of the invention is achieved by the fact that the preparation of concrete mixture includes dosing of quartz sand and components of an ash-and-alkali binder consisting of carbon-containing liquid glass made from large-tonnage waste from the production of crystalline silicon from the Bratsk aluminum plant - silica fume and containing up to 6-7 wt.% Fine carbonaceous impurities - graphite, silicon carbide SiC and C, with the silicate modulus n = 1 and a density of 1.35-1.55 g / cm ^3, and ash and slag moldboard Mesi obtained from the burning of brown Kansk-Achinsk coal at TPP-6 in the city of Bratsk, Irkutsk Region and ground to a residue on sieve No. 008 to 1%, 25% consisting of a slag component and 75% of an ash component, their mixing and molding products in the following ratio of components, wt.%:

specified liquid glass 13.5-28.2 specified ash and slag mixture 24.3-55.1 quartz sand 31.4-54.5

The chemical composition of the ash and slag mixture is presented in table 1

Table 1
The average chemical composition of the ash and slag mixture of the TPP - 6 (Bratsk) Content, wt.%; SiO ₂ Fe ₂ O ₃ Al ₂ About ₃ CaO MgO SO ₃ R ₂ O 57.3 13.5 12.0 13.7 2.2 0.7 0.5

Example. Concrete mixture was prepared as follows. In a laboratory ball mill, the grinding ash and slag mixture, consisting of 25% of slag and 75% of the ash component, was ground to a residue on sieve No. 008 to 1%. The ground ash and slag mixture in the amount of 32.8 wt.% Was mixed with quartz sand. taken in an amount of 51.6 wt.%, and shuttered 15.6 wt.% of carbon-containing liquid glass of silica fume with silicate module n = 1 and density ρ = 1.46 g / cm ³ . The mixture was mixed in a forced-action concrete mixer for 2-3 minutes. The samples were formed on a laboratory vibratory platform. Samples in the molds solidified at a temperature of 16-20 ° C in air-dry conditions for 24 hours, after which they were redressed and placed in a freezer at a temperature of -18 ° C for further testing. The test results are shown in table.2.

table 2
Properties of concrete based on ash and slag binder, hardening at low temperature Hardening temperature Compressive strength, MPa aged Frost resistance cycles -18 ° C 1 day 3 days 7 days 14 days 28 days 250 6.8 11,4 12.5 17.7 25.8

Analysis of the obtained data shows that the proposed concrete mixture is able to gain strength not only at temperatures up to -10 C, but also at lower temperatures (-18 ° C). The frost resistance of concrete obtained from the proposed concrete mixture also differs more favorably from the frost resistance of known concrete (250 instead of 150-200 cycles). In addition, in the proposed concrete mixture, the indicated technical results can be achieved in a wider range of liquid glass density values (1.35 ... 1.55 g / cm instead of 1.43 ... 1.5 g / cm ³ ), which allows to significantly simplify the process of obtaining the proposed concrete mixture and to expand the possibility of using liquid glass.

Claims (1)

A method of preparing a concrete mixture, including dosing of quartz sand and components of an ash-and-alkali binder, consisting of carbon-containing liquid glass made from large-tonnage waste from the production of crystalline silicon of the Bratsk Aluminum Plant - silica fume and containing up to 6-7 wt. % of finely dispersed carbon impurities - graphite C and carborundum SiC with a silicate module n = 1 and ground ash and slag mixture obtained from burning brown Kansk-Achinsk coal, mixing and forming products, characterized in that they use the specified liquid glass with a density of 1.35- 1.55 g / cm ³ , as the ash and slag mixture - the specified ash and slag mixture, ground to a residue on sieve No. 008 to 1%, 25% consisting of the slag component and 75% of the ash component obtained from the combustion of the specified coal at the TPP -6 Bratsk, Irkutsk area in the following ratio of components, wt.%: Specified Liquid Glass 13.5-28.2 The specified ash and slag mixture 24.3-55.1 Quartz sand 31.4-54.5