RU2358937C1 - Granulated filler based on perlite for concrete mix, composition of concrete mix for production of construction items, method for production of concrete construction items and concrete construction item - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: granulated filler for concrete construction items, made of silica-containing and lime-containing components is made in the form of granules with size of 0.5-10.0 mm, which contain core and shell, where core is produced by granulation of mixture of the following components that have been milled together down to specific surface of 150-250 m²/kg - silica-containing component - perlite and alkaline metal hydroxide at their mass ratio of 0.70-0.95 : 0.05-0.30 with binder - aqueous solution of sodium nitrate with density of 1.2-1.3 g/cm³ in amount of 0.1-7.0% from mixture, and shell is formed on core surface by means of its rolling in dry dusty mixture of jointly milled lime-containing component - quicklime and silicofluoric sodium in mass ratio of 0.85-0.95 : 0.05-0.15, with further hardening to density of at least 0.12 MPa. Concrete mix for production of construction items, which includes the following components, wt %: above mentioned filler 5-40, Portland cement 10-25, quartz sand 15-45, water - the rest. Method for production of concrete construction items from above mentioned concrete mix, including mixing of its components, moulding of construction items, maintenance in molds and further heat and moisture treatment of items at atmospheric pressure and temperature of 85-95°C. Concrete construction item produced by above mentioned method.

EFFECT: increased water resistance, reduced heat conductivity at increase and preservation of strength parametres of items that are exposed to heat and moisture treatment in process of their hardening.

4 cl, 1 ex, 2 tbl

Description

The invention relates to the production of building materials and can be used to obtain concrete building products subjected to heat and moisture treatment during hardening, for civil and industrial construction.

A known method of producing concrete building products subjected to heat and moisture treatment during hardening, the composition of the concrete mixture and aggregate in the form of granulate fractions of 5-20 mm, made from dispersed ash and slag waste from incinerators and concrete building product. A method for producing concrete building products includes mixing mechanically activated Portland cement (22-23 wt.%), Building sand (28-34 wt.%), Aggregate in the form of granulate (44-49 wt.%) And water, molding building products, holding in forms and their subsequent heat and humidity treatment in a steaming chamber at atmospheric pressure [RF Patent No. 2201410, cl. 7 C04B 28/02, 2000].

The disadvantages of this method, concrete mixture and aggregate is that the aggregate used does not increase the water resistance of concrete building products subjected to heat and moisture treatment during hardening, as well as high energy consumption when receiving mechanically activated Portland cement and granulate.

Granular aggregate for concrete mixtures in the form of granules consisting of a core made of fiberglass and a shell made of cement-ash mixture and a concrete building product is also known. Raw granules before being used as aggregate for concrete mix are preliminarily subjected to heat-moisture treatment in a steaming chamber at atmospheric pressure with isothermal exposure for 6 hours at a temperature of 80-90 ° C [USSR Author's Certificate No. 1219548, cl. 4 C04B 14/24, 1983].

The disadvantages of this aggregate are also the high energy and labor costs in obtaining fiberglass, forming granules from it by crushing and subsequent heat and moisture treatment of raw granules before using them as aggregate, which increases the cost of finished building products. The use of the specified aggregate does not contribute to an increase in water resistance and a significant decrease in the thermal conductivity of concrete building products subjected to heat and moisture treatment during hardening.

Closest to the proposed solution is a method of obtaining concrete building products subjected to heat and moisture treatment during hardening, the composition of the concrete mixture and the concrete building product. A method of obtaining concrete building products includes mixing Portland cement (10-25 wt.%), Sand (15-35 wt.%), Aggregate in the form of expanded clay gravel (5-40 wt.%) And water (the rest), molding building products, aging in molds and subsequent heat-moisture treatment in a steaming chamber at atmospheric pressure according to the 2 + 6 + 2 mode and the temperature of isothermal exposure 85-95 ° С [Gershberg O.A. Technology of concrete and reinforced concrete products. - M .: Stroyizdat, 1971, pp. 98-102, 305-313].

The disadvantage of this method of producing concrete building products and concrete mix is that the resulting concrete building products after heat and moisture treatment have low water resistance and heat-insulating ability.

Closest to the proposed solution is also a granular aggregate for concrete mix, consisting of a core and a protective shell. The core is made by granulation on a plate granulator of a mixture of dispersed silica-containing components - TPP ash (dispersion not less than 200 m ² / kg) and sludge from a biological wastewater treatment aeration station with a binder - ground lime (dispersion 500-600 m ² / kg) and gypsum ( with a brand name of at least 100 and a dispersion of at least 350 m ² / kg) in the ratio of the components of the mixture, respectively, 0.3: 0.5: 0.15: 0.05 by weight. After granulation, a 3-5 mm thick protective coating is applied to the core by wetting the core of the granule with liquid glass and dusting or pelletizing it on a disk or drum granulator with a dry, dusty mixture of lime, gypsum and mineral dispersed filler (ashes of a thermal power station, state district power station, loam, etc. ) in the ratio of the components of the mixture, respectively, 0.35: 0.10: 0.55 by weight. After the formation of the granules with the aim of curing, heat and humidity treatment is applied at a temperature of 90 ° C with isothermal exposure for one hour [RF Patent No. 2077517, cl. 6 C04B 20/10, 1993].

The disadvantage of granular aggregate according to the prototype is that in the manufacture of concrete products, increased heat energy is required for heat and moisture treatment - first, granular aggregate is subjected to heat and moisture treatment, then a molded building product including the aforementioned aggregate, as well as the resulting concrete building products subjected to heat and moisture treatment during hardening; they have low water resistance, strength and heat insulating ability.

The present invention solves the problem of increasing water resistance, reducing heat conductivity while increasing and maintaining the strength characteristics of concrete building products subjected to heat and moisture treatment during hardening and reducing energy consumption in the manufacture of concrete products by reducing energy consumption in the manufacture of aggregate.

The technical result is achieved using granular aggregate for a concrete mixture made of silica-containing and lime-containing components, according to the proposed solution, it is made in the form of granules with a size of 0.5-10.0 mm, consisting of a core and a shell, where the core is obtained by granulating a mixture of co-milled up to a specific surface area of 150-250 m ² / kg of silica-containing component - perlite and alkali metal hydroxide with their mass ratio of 0.70-0.95: 0.05-0.30 with a binder - an aqueous solution of sodium silicate with a density of 1.2-1 , 3 g / cm ³ in an amount of 0.1-7.0% of the mixture, and the shell is formed on the surface of the core by rolling it with a dry, dusty mixture of co-milled lime-containing component - quicklime and sodium silicofluoride with a mass ratio of 0.85-0.95 : 0.05-0.15, followed by hardening to a strength of at least 0.12 MPa.

The technical result is achieved in that the concrete mixture for the manufacture of building products includes the specified aggregate, Portland cement, quartz sand and water in the following ratio of components, wt.%: The specified aggregate - 5-40; Portland cement - 10-25; quartz sand - 15-45 and water - the rest.

The technical result is achieved by the fact that the method of obtaining concrete building products from the specified concrete mixture includes mixing its components, molding building products, holding in molds and subsequent heat and moisture treatment of products at atmospheric pressure and a temperature of 85-95 degrees. FROM.

The result is achieved using a concrete building product made in this way.

Component Feature:

1. As a binder used Portland cement ZAO Belgorodcement according to GOST 10178-85 of the following mineralogical composition, wt.%: C ₃ S - 65.4; C ₂ S - 18.1; C ₃ A - 4.1; C ₄ AF - 12.4. The fineness of grinding is 330 m ² / kg. The normal density of the cement paste according to GOST 310.4-81 is 27.12%, the beginning of setting 1 hour 40 minutes, the end - 3 hours 45 minutes. The activity during steaming is 38.4 MPa, the activity during normal storage at the age of 28 days is 43.7 MPa.

2. A volcanic water-containing glassy rock of the Mukhor-Talinsky perlite deposit (Republic of Buryatia) was used as a silica-containing component for the manufacture of the core of the filler — dust perlite formed during mechanical processing and not suitable for expansion. The chemical composition of perlite, wt.%: SiO ₂ -72.8; Al ₂ O ₃ - 12.1, Fe ₂ O ₃ - 1.1, TiO ₂ - 0.4, CaO - 0.6; MgO - 1.1; R ₂ O - 7.3; p.p.p. - 5.7.

3. As the alkali metal hydroxide used sodium hydroxide according to GOST 2263-79.

4. Sodium silicofluoride Na ₂ SiF ₆ according to TU 6-09-1461-91.

5. As a lime-containing component for the manufacture of a protective envelope for the aggregate, quicklime construction lime was used by JSC "Building Materials", Belgorod in accordance with GOST 9179-77.

6. As a fine aggregate of concrete mixtures used natural quartz Volsky sand according to GOST 6139-2003.

7. Tap water in accordance with GOST 23732-79.

8. When granulating the powder of co-ground perlite with sodium hydroxide on a plate granulator, an aqueous solution of sodium silicate (water glass) was used as a binder in accordance with TU 2385-001-54824507-2000 with a density of 1.2-1.3

g / cm ³ .

To obtain cores of granular aggregate in the implementation of the proposed method for producing concrete building products, perlite was dosed with sodium hydroxide by gravimetric method. The resulting mixture was loaded into a ball mill and mixed and milled until a specific surface of 150 ... 250 m ² / kg was reached. The ground material was fed to a standard plate granulator, where, when spraying an aqueous solution of liquid glass, core aggregates of a given size were obtained. The obtained core aggregates were directed to the formation of a protective shell by rolling into a drum mixer, into which a dry pulverulent mixture was also fed, i.e. similar to the method described in the patent of the Russian Federation No. 2077517. As a dry pulverized mixture, ground lime and sodium silicofluoride were used together with their mass ratio of 0.85-0.95: 0.05-0.15. The strength gain control of the granular aggregate during its hardening at ambient temperature by testing in a cylinder was carried out according to GOST 9758-86.

Example. Preparation of granular aggregate cores. Perlite (8 kg) and sodium hydroxide (2 kg), i.e. in a ratio of 0.80: 0.20 by weight (table., mixture 1), they were ground in a mill together to a specific surface of 200 m ² / kg. The obtained powder material was fed to a plate granulator. On the surface of the powder by spraying was applied an aqueous solution of sodium silicate with a density of 1.25 g / cm ³ in an amount of 4% relative to the mass of the core aggregate. The rotation speed and the angle of inclination of the granulator plate controlled the diameter of the resulting cores, which in this case was 4.4–4.5 mm.

Obtaining a protective shell on the nuclei. The resulting cores were sent for dusting with a powder of lime (9 kg), ground together with sodium silicofluoride (1 kg), i.e. in a ratio of 0.90: 0.10 to obtain granules with a size of 5.0 mm (table 1, mixture 1). Dusting was carried out in a drum mixer.

Part of the obtained granular material after storage for 7 hours at ambient temperature was tested for strength by compression in a cylinder according to GOST 9758, the strength was 0.26 MPa; the rest was used in the preparation of concrete mixtures for the manufacture of samples of building products.

Preparation of concrete mix. The dosage of the components was carried out by the gravimetric method: 2 kg of Portland cement (20 wt.%, Table 1, mixture 1), 2.5 kg of quartz sand (25 wt.%) And 3.5 kg (35 wt.%) Of granular aggregate were mixed in screw mixer until smooth and 2 kg (20 wt.%) of water was added.

Samples were formed in the traditional way by filling in standard forms 2FK-100 according to GOST 10181-2000. The exposure time in the forms is 6 hours.

Heat and moisture treatment of concrete samples was carried out in a steaming chamber at atmospheric pressure according to the 2 + 6 + 2 mode and isothermal exposure temperature of 90 ° С, thus, the concrete mixture was prepared, samples were molded and their heat and moisture treatment was performed according to the known method [Gershberg O.A. Technology of concrete and reinforced concrete products. - M .: Stroyizdat, 1971, pp. 98-102, 305-313].

The granular aggregate according to RF patent No. 2077517 consisted of a core and a protective shell. A filler with a diameter of 15 mm after steaming according to the 2 + 1 + 2 hours regime at an isothermal holding temperature of 90 ° C had a crushing strength of 0.21 MPa in the cylinder.

Product samples were tested for strength (according to GOST 10180), thermal conductivity (according to GOST 7076-99) and water resistance (according to GOST 12730.5-84) were determined. The test results are given in table. (mixture 1).

In the same way, wall products with other component compositions were obtained (Table 1), the test results are shown in Table 2, mixtures 1-5.

Analysis of the test results of the properties of samples of concrete building products shown in table 2, shows the following.

1. Introduction to the composition of the concrete mixture of the inventive granular aggregate with a size of 0.5-10 mm, consisting of a core in the form of together ground liquid perlite and alkali metal hydroxide, which is coated with a coating of ground lime and sodium silicofluoride in the claimed amounts, allows to obtain durable concrete building products with reduced thermal conductivity and water permeability, while due to the exclusion of steaming aggregate significantly reduces the energy consumption of the obtained wall products .

2. Reducing the amount of granular aggregate in the concrete mix to 5 wt.%, As well as the ratio in the core of the sodium hydroxide aggregate to 0.05 relative to the mass of perlite, the specific surface of the powder material of the core to 150 m ² / kg, the ratio of sodium silicofluoride in the granule shell up to 0.05 with respect to the weight of lime and the diameter of the aggregate granules to 0.5 mm reduces the strength of the granular aggregate, reduces its reactivity, which leads to an increase in thermal conductivity, a decrease in water permeability and strength of the resulting samples of concrete building products (mixture of 2, Table 2), the composition taken as a boundary.

A further decrease in these ratios and parameters leads to a significant decrease in the physico-mechanical properties of concrete building products, therefore, the composition of the mixture 4 goes beyond the scope of the claimed compositions of concrete building products.

3. The use of granular aggregate in the composition of the concrete mixture in an amount of 40 wt.%, As well as the ratio in the core of the filler of sodium hydroxide in an amount of 0.30% relative to the mass of perlite, the specific surface of the powder material of the core up to 250 m ² / kg, the ratio of silicofluoride sodium in the protective shell of the granules to 0.15 relative to the mass of lime and the diameter of the granules of the aggregate to 10 mm also reduces the strength of the granular aggregate. Excessively high activity of a granular aggregate of size 10 mm during the heat and moisture treatment of concrete products leads to the formation of large pores in their massif with many structural defects, which also leads to an increase in thermal conductivity, a decrease in water resistance and strength of the obtained samples of concrete building products (mixture 3, Table 2) , this composition is accepted as boundary.

A further increase in these ratios and parameters leads to a significant decrease in the physico-mechanical properties of concrete building products, so the composition of mixture 5 goes beyond the scope of the claimed compositions of concrete building products.

With an optimal ratio of components (mixture 1, Table 1), the resulting concrete building products have the following advantages compared to the known ones:

1) strength indicators increase by 12-16%, the brand for water resistance at the same time increases from B2 to B6, thermal conductivity decreases by 1.6-1.8 times;

2) the inventive granular composite aggregate does not require autoclaving before entering it into the concrete mix, thereby reducing energy consumption when receiving building products.

When using raw concrete mixtures with boundary component ratios (mixtures 2 and 3, Table 1), the resulting concrete building products practically retain the brand for water resistance and strength characteristics in comparison with the similar properties of the prototype.

In the process of applying a protective shell of ground lime and sodium silicofluoride to the core of the aggregate, the interaction of the components of the shell with liquid glass leads to a rapid increase in the strength of the granules of the composite aggregate at ambient temperature, which allows it to be used in the preparation of concrete mixtures without additional energy-intensive heat and moisture curing. In the process of moisture and moisture treatment of the claimed concrete building products, in the cores of the granular aggregate, water-soluble sodium silicates are synthesized, which, penetrating the protective shell, provide extremely strong adhesion of the claimed granules with the concrete matrix of the product.

Granular aggregate according to the prototype when introduced into the composition of concrete building products in the process of heat and moisture treatment do not show any activity and do not interact with the concrete matrix in volume. When an external load is applied (compression and bending strength test), the destruction of these building products occurs along the boundaries of the contacts between these granules and concrete, i.e. their strong adhesion to concrete is not observed.

Obtained by the present method, concrete building products have improved adhesive properties with respect to plaster mortars.

Claims (4)

1. Granular aggregate for concrete building products made of silica-containing and lime-containing components, characterized in that it is made in the form of granules with a size of 0.5-10.0 mm, consisting of a core and a shell, where the core is obtained by granulating a mixture of co-milled to specific the surface of 150-250 m ² / kg of silica-containing component - perlite and alkali metal hydroxide with a mass ratio of 0.70-0.95: 0.05-0.30 with a binder - an aqueous solution of sodium silicate with a density of 1.2-1.3 g / cm ³ in an amount of 0.1-7.0% of the mixture, and about the cell is formed on the surface of the core by rolling it with a dry, dusty mixture of co-milled lime-containing component - quicklime and sodium silicofluoride in a weight ratio of 0.85-0.95: 0.05-0.15, followed by hardening to a strength of at least 0.12 MPa . 2. Concrete mixture for the manufacture of building products, including aggregate according to claim 1, Portland cement, quartz sand and water in the following ratio of components, wt.%:
Specified Placeholder 5-40 Portland cement 10-25 Quartz sand 15-45 Water Rest 3. The method of producing concrete building products from concrete mix according to claim 2, including mixing its components, molding building products, holding in molds and subsequent heat and moisture treatment of products at atmospheric pressure and a temperature of 85-95 ° C. 4. Concrete construction product made by the method according to claim 3.