RU2837097C1 - Concrete mixture - Google Patents

Abstract

FIELD: construction materials.

SUBSTANCE: invention relates to the industry of construction materials and can be used in production of structural heat-insulating concrete for building envelopes. Concrete mixture containing binder, foamed glass crushed stone with particle size of 5-20 mm, pearlite sand as sand, water and additionally a plasticiser based on modified lignosulphonates – SikaSikament BV-3M, with the following ratio of components of the mixture, wt.%: portland cement “M500 ДО ЦЕМ” I 43.05-43.4; foam glass crushed stone 27.08-27.27; perlite sand 5.56-5.59; plasticizer additive 0.43; water is the rest.

EFFECT: disclosed is a concrete mixture.

1 cl, 1 tbl

Description

The invention relates to the building materials industry and can be used in the production of structural heat-insulating concrete for building enclosing structures.

The technical result consists in reducing the cost of raw materials for concrete mix by using waste from the glass industry and manufacturing products with high thermal insulation properties and, at the same time, structural strength, environmental safety, as well as a method for its manufacture using cement as a binder.

A raw mix for producing lightweight concrete is known, comprising cement, thermal power plant fly ash, a foaming agent solution, a chemical additive, a porous filler and water, containing granulated spherical foam glass of 5-40 mm fractions with a bulk density of 180-200 kg/ ^m3 as the porous filler, the foaming agent solution - "Belpor-1om", and liquid sodium glass as the chemical additive in the following ratio of components, % by weight (see IPC C04B38/00, description of the invention to patent RU 2255920 C1, published 10.07.2005).

Cement 46-48 Fly ash from thermal power plants 16-18 Granulated foam glass 18-20 Liquid sodium glass 1.38-1.44 Foaming agent "Belpor-1om" 0.78 Water The rest

The disadvantage of this concrete mixture is as follows:

- when using large porous filler of 5-40 mm fraction, the water absorption of cement composites increases due to the many small channels and capillary pores in the interpore walls of the granule;

- with a concrete mix density of 650 - 800 kg/ ^m3 , the strength of concrete is quite low;

- a large number of components in the mixture leads to an increase in the labor intensity of the manufacturing process of the final product. Another composition for lightweight concrete is also known, given in patent RU 2561121 C2, published 20.08.2015, containing, mass. %:

Cement M 500 8.0-10.0 Ferromagnetic slag 100 microns 25.0-29.0 Metakaolin 8.0-10.0 Magnesium sulfate 8.0-10.0 Lignosulfonate 0.05 Foaming agent PB-2000 0.25 Granulated foam glass 5-10 mm 17.00-21.00 Water The rest

Along with the advantages of achieving improved thermal, strength and operational characteristics of lightweight concrete, the work does not present the results of tests of the obtained concrete for compressive strength, as well as the two-stage method of preparing the concrete mixture with its movement from a forced-action mortar mixer for foaming into a through-type container with a rotating screw for uniform pressing of the porous filler into the concrete mixture, which leads to technological difficulties in obtaining a material with stable properties, complexity of quality control and, as a consequence, to an increase in the cost of the obtained material.

The closest composition in terms of qualitative content and technical solution to the proposed composition of the concrete mixture is given in the IPC patent C04B15/02, SU 990720 A1, published on 23.01.1983, consisting of components in the following ratio, mass%:

Cement 19.0-22.0 Granulated foam glass 20.0-29.0 Porous carbonate sand 31.0-39.0 Water The rest

The well-known product is characterized by fairly high strength, good thermal insulation properties, but high bulk density and low frost resistance.

The present invention is aimed at expanding the raw material base for the manufacture of building products characterized by the required, adjustable thermal insulation and structural properties using waste from the glass industry.

The set technical task is achieved by the fact that the proposed structural and heat-insulating concrete contains Portland cement, foam glass crushed stone of fraction 5-20 mm, perlite, water and plasticizer Sika Sikament BV-3M based on modified lignosulfonates (density 1.145 - 1.175 kg / dm ³ (at 20 ° C), pH value 4.5-7.0) (link to the manufacturer's website: https://rus.sika.com/ru/distribuciya/kompleksnye-resheniya/51381/sikament-bv -3m.html?ysclid=m4b1pplrlt869981126#productdetails).

The specified ingredients are taken in the following proportions, mass%:

Portland cement M500 DO CEM I 43.05-43.4 foam glass crushed stone 27.08-27.27 perlite sand 5.56-5.59 plasticizer additive Sika Sikament BV-3M 0.43 water the rest

Compared to polystyrene foam, expanded clay, perlite, vermiculite and other porous fillers, foam glass crushed stone has high physical, mechanical and thermal characteristics.

The internal structure of the filler plays a major role in the formation of the physical, mechanical and thermal properties of concrete based on it. Foam glass crushed stone has a highly developed porous internal structure, which consists of many rounded cells. The sizes of the internal pores are much larger than the sizes of the pores located near the walls. The internal and external areas of the granule have a similar chemical composition. The cells of the structure are predominantly rounded, separated from each other by a thin partition, including smaller closed pores. The crushed stone has a vitrified surface with a uniform distribution of rounded pores. The high content of glass phase and the uniform distribution of small pores of regular shape predetermine the increased strength and reduced thermal conductivity of the filler, compared to traditional fired fillers, such as expanded clay.

When foam glass aggregate comes into contact with liquid, water is retained by capillary forces in the inter-piece space, as well as in roughness and open external voids, but the closed external pores do not allow it to penetrate into the internal space of the filler. Based on the above data, the prospects for using foam glass aggregate as a porous filler for lightweight concrete are noted.

When perlite sand is added, the density and thermal conductivity of concrete decreases. Expanded perlite grains are 70-90% air, which is why concrete based on it has the highest thermal insulation values compared to competitors.

The introduction of a plasticizer based on modified lignosulfonates into the raw mix for structural and heat-insulating concrete allows achieving the maximum water-reducing effect, which leads to an increase in the mobility and strength of concrete.

The production of structural and heat-insulating foam glass concrete for enclosing structures is traditionally carried out in a forced-action concrete mixer in the following order:

1. The foam glass aggregate is crushed and sifted (screened) to the required fraction of 5-20 mm.

2. Measure out the dry components of the mixture and mix thoroughly.

3. Water and plasticizer additive are dosed.

4. The additive is mixed with the remaining mixing water.

5. Prepare the concrete mixture by mixing the measured components in a stationary forced-action concrete mixer in the following sequence: foam glass crushed stone, cement, perlite sand, mixing water with additive until the required mobility is achieved. Mixing duration is 5 minutes.

6. Concrete hardening takes place over 28 days at a temperature of 20±5°C and a relative humidity of 90-100%; on the 3rd day, the product is stripped of its formwork.

Strength indicators were determined according to GOST 10180 - 2012, average density - according to GOST 12730.1-2020, water resistance - according to GOST 12730.5-2018, frost resistance - according to GOST 10060-2012, thermal conductivity - according to GOST 7076-99.

The physical and mechanical characteristics of the structural and heat-insulating concrete from the proposed composition on foam glass crushed stone, presented in Table 1, show that the proposed composition of the concrete mix ensures the production of structural and heat-insulating concrete for enclosing structures of class B 3.5 with characteristics that meet the requirements of the main regulatory documents for lightweight concrete. The use of foam glass crushed stone and perlite as fillers, as well as traditional methods for the production of the proposed mixtures, can reduce the cost of manufacturing this material and solve the problem of recycling waste from the glass industry.

The above mentioned features indicate that the set objective has been achieved.

Claims (2)

A concrete mixture comprising Portland cement, sand, foam glass filler and water, characterized in that it contains Portland cement M500 DO CEM I, foam glass crushed stone of 5-20 mm fraction as foam glass filler and perlite sand as sand and additionally a plasticizer based on modified lignosulfonates - SikaSikament BV-3M, with the following ratio of components (mass%): Portland cement M500 DO CEM I 43.05-43.4 foam glass crushed stone 27.08-27.27 perlite sand 5.56-5.59 specified plasticizer 0.43 water the rest