RU2259968C1 - 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 fly-ash and carbon containing liquid glass; mixing above materials and forming articles. Fly-ash is obtained from combustion of brown coal at heat generating plant. Liquid glass is produced from large-tonnage crystalline silicon production waste obtained at aluminum smelter, namely from 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. The fly-ash is taken from the first zone. Liquid glass has density of 1.42-1.5 g/cm³. Hardening intensifier, namely Portland cement including 60% of 3CaOхSiO₂, is also included. All above mix components are taken in the following amounts (% by weight): liquid glass - 15.2-31.4, fly-ash taken from the first zone - 23.8-54.5, quartz sand - 29.2-52.3, Portland cement - 1.1-2.9. 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.

Known hydraulically hardening composition, hardening at low temperatures and containing 50-80 h of BCM, 13-35 h of fly ash, 0-10 h of metakaolin, 0-6 h of slag, 0-4 h of an additive that regulates the setting time of the binder, and 1 5 hours 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, comprising dosing quartz sand and binder components, mixing and molding products, and as a binder use a gold-alkali binder consisting of fly ash obtained from burning brown Kansk-Achinsk coal at a thermal power station -7, Bratsk, Irkutsk region, and carbon-containing liquid glass made from large-tonnage waste from the production of crystalline silicon of the Bratsk aluminum microsilica plant ma and containing 6-7 wt. % of finely dispersed carbon impurities — graphite C and carborundum SiC with a silicate modulus of n = 1 and density ρ = 1.45-1.49 g / cm ³ [RF Patent No. 2130904 C1, 1999].

The disadvantage of the described method of preparing concrete mix is the ability of the concrete mix to harden only when steaming, which significantly limits the possibility of its use.

The problems solved by the invention are to improve the quality of concrete and expand its fields of application.

The technical result is the ability to harden at a negative temperature, which allows the use of such a mixture not only in the factory, but also in the conditions of the construction site.

The specified technical result in the implementation of the invention is achieved by the fact that the preparation of the concrete mixture includes dosing of quartz sand, components of the ash and alkali binder, consisting of fly ash of the first field obtained from burning brown Kansk-Achinsk coal at TPP-7 in Bratsk, Irkutsk region, and 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.% highly dispersed carbon impurities d - C graphite and silicon carbide SiC, a silicate module n = 1 and the density ρ = 1,42-1,50 g / cm ^3, and additives - intensifier hardening - Portland cement 400 Angarsky plant with a content 3SaO × SiO ₂ 60%, their mixing and molding of products, in the following ratio of components, wt. %:

Carbon Liquid Glass

silica fume 15.2-31.4 Fly ash I field 23.8-54.5 Quartz sand 29.2-52.3 Portland cement 1.1-2.9

The chemical composition of fly ash is presented in table. 1.

Table 1
The average chemical composition of fly ash of the first field of the TPP is 7 (Bratsk) The content of the compounds. % by weight SiO ₂ Fe ₂ About ₃ + FeO Al ₂ About ₃ CaO MgO SO ₃ R ₂ O P.P.P. 51.9 7.9 10.8 20.1 5.1 2.2 0.6 3.2

Example. Concrete mixture was prepared as follows. 23.8% of fly ash of the first field was mixed with 52.3% of quartz sand and 1.2% of Portland cement. After that, the dry mixture was closed 22.7% 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 T = 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 ZSCh, hardening at a negative temperature Hardening temperature Compressive strength, MPa aged Frost resistance cycles -18 ° C 1 day 3 days 7 days 14 days 28 days more than 200 6.8 10.9 12,2 16,2 25.9

Analysis of the data shows that the proposed concrete mixture is able to gain strength not only at high positive (TBO), but also at negative temperatures (-18 ° C). This allows you to significantly expand the possibilities of using such a mixture: factory conditions, construction site conditions. Moreover, in the latter case, the construction period also increases significantly, i.e. it becomes possible to carry out construction work not only in the summer period, but in the spring-autumn season (at T up to -18 ° С).

Claims (1)

A method of preparing a concrete mixture, including dosing of quartz sand and components of an alkaline binder, consisting of fly ash obtained from burning brown Kansko-Achinsk coal at TPP-7 in the city of Bratsk, Irkutsk region, and carbon-containing liquid glass made from large-tonnage crystalline silicon production waste Bratsk aluminum plant - silica fume and containing up to 6-7 wt. % finely dispersed carbon impurities - graphite C and carborundum SiC, with a silicate module n = 1, mixing and forming products, characterized in that they use the specified fly ash I field, the specified liquid glass density ρ = 1.42-1.50 g / cm ³ and additionally an additive - hardening intensifier - Portland cement of grade 400 of the Angarsk plant with a content of 3CaO x SiO _{2 of} 60% in the following ratio of components, wt.%: Specified Liquid Glass 15.2-31.4 Indicated fly ash 1 field 23.8-54.5 Quartz sand 29.2-52.3 Specified Portland cement 1.1-2.9