RU2376266C1 - Method of dry construction mixture production for foam concrete and mixture produced by related method - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method of dry construction mixture production for foamed concrete manufacture provides for mixing dry mineral binder, dry fine mineral filler, metal sulphate and protein-containing additive. Fine mineral filler is used with fractions sizing from 0 to 0.315 mm and protein-containing additive is used as 30% colloidal solution of protein-containing concentrate in water at the following ratio of components, wt %: mineral binder 41-58, the said fine filler 26-48, the said protein-containing additive 9-15, metal sulphate 1-2. Dry construction mixture for foamed concrete manufacture is produced by the method as disclosed by this invention.

EFFECT: simplified technology, increased strength characteristics, extended shelf life.

2 cl, 6 ex, 2 tbl

Description

Numerous dry building mixtures are known, including a mineral binder, usually Portland cement or gypsum, fine aggregate and additives that give the composition special properties, for example, increased ductility, increased adhesion to the surface to be coated, etc. The main advantages of these mixtures are the guaranteed material composition, which ensures the stability of technical characteristics, convenience and cheaper transportation (since there is no water in such mixtures and they are packaged in bags). An important property of such mixtures is the possibility of long-term storage, up to 3 months. When using dry mixtures, the need for the use of dispensers and a number of other auxiliary mechanisms to ensure the accuracy of dosages for the separate use of components is eliminated. This, in turn, allows to reduce the energy intensity of the construction process.

Dry mortar is known (RF Patent 2233255, С04В 28/30, "Dry mortar"). The mixtures according to this invention are intended primarily for the manufacture of floor coverings, and can also be used for the manufacture of wall, ceiling, facade, roof, metal and wooden structures, piece construction products. The disadvantage of this mixture is the impossibility of foaming when mixed with water.

Known dry building mix (Patent No. 2182137, С04В 28/02, СВВ 111/20). The invention relates to the composition of mortars, concrete, artificial stones or similar materials containing inorganic binders or a reaction product of inorganic or organic binders, and in particular relates to a dry mortar and method for its preparation. EFFECT: increased durability, frost resistance and quality of a dry surface of concrete or mortar from a dry construction mixture containing cement, sand, a plasticizer additive, the latter is mechanically activated by grinding at acceleration from 10 to 20 g to reduce interfacial energy S-3 superplasticizer in the next the ratio of components, wt.%: cement 17-40; sand 60-83; the specified superplasticizer C-3 0.5-2 wt.% by weight of cement. The dry building mixture, in addition to the superplasticizer additive, may additionally contain an anti-frost additive in an amount of from 0.5 to 5 wt.% By weight of cement. In addition, in addition to the above additives, the dry mortar may also contain a sealing additive in an amount of from 0.5 to 2 wt.% By weight of cement. In addition, the dry mortar in addition to the above additives may also contain a dispersion-reinforcing additive in an amount of from 0.5 to 2 wt.% By weight of cement. In addition, the dry mortar may in addition to the above additives also contain a coloring additive in an amount of from 0.5 to 15 wt.% By weight of cement. In the method of obtaining a dry building mixture, which consists in mixing sand, cement, an additive - a plasticizer, a plasticizer, which is a C-3 superplasticizer, is subjected to mechanical activation by grinding it at an acceleration of 10 to 20 g to reduce interfacial energy, and then a cement concentrate is prepared by mixing a predetermined part of cement with mechanically activated superplasticizer C-3, and then the resulting cement concentrate is mixed with sand and the remaining part of cement. The method for producing a dry building mixture also provides that a cement concentrate is prepared by mixing a predetermined portion of cement with mechanically activated superplasticizer C-3 and with at least one of the following additives: antifreeze, sealing, dispersed reinforcing, coloring.

This mixture also does not have the ability to foam when mixed with water.

Also known is the mixture according to the patent of the Russian Federation No. 2259964, C04B 28/02.

This mixture contains components in the following ratio, wt.%: Portland cement 24.0-46.1, quartz sand 46.1-72.0, high-alumina bauxite slag 2.82-5.50, gypsum binder 0.72-1, 38, superplasticizer 0.23-0.46, sodium sulfate 0.23-0.46. As a superplasticizer, C-3 superplasticizer based on the sodium salt of naphthalenesulfonic acid with formaldehyde or AROS-F based on sulfonated aromatic wastes of the organic synthesis industry can be used.

EFFECT: obtaining expanding mounting fine-grained concrete based on dry cement-sand mixture with increased compressive strength characteristics at the daily and grade ages, adhesive strength while ensuring the necessary mobility and viability of the concrete mixture containing mineral binders, fine aggregate and organic air-entraining additive in the form of superplasticizer C-3.

Its disadvantage is that it foams very weakly when mixed with water, involving only a small amount of air in the form of individual bubbles.

The closest to the problem to be solved and the technical effect achieved is the method of producing a foam concrete mixture according to the patent of the Russian Federation No. 2280628, С04В 38/10.

The method consists in the fact that dry cement, limestone flour, dry protein foaming agent and stabilizer metal sulfate are mixed without water. The dry mix can be stored for more than 1 year. When this dry mixture is mixed with water in a high-speed mixer, a foam concrete mixture is formed, which is then used to form the products. This invention is taken as a prototype.

The technical effect when using the discussed invention is that the dry building mixture acquires the ability to foam when mixed with water while maintaining high accuracy of the ratio of the components, maintaining the technical characteristics provided for by the selection of the material composition of the mixture, and increasing the shelf life to 1 year or more.

In accordance with the invention, in a method for producing a dry building mixture for the production of foam concrete, comprising mixing a dry mineral binder, dry fine mineral aggregate, metal sulfate and protein protein-containing additives, fine mineral aggregate fractions from 0 to 0.315 mm are used, and the protein-containing additive is in the form 30% colloidal solution of protein-containing concentrate in water, in the following ratio of components, wt.%:

- mineral binder - 41-58,

- specified fine aggregate - 26-48,

- the specified protein-containing additive is 9-15,

- metal sulfate - 1-2.

Dry building mix for the production of foam concrete obtained by the above method.

A colloidal protein-containing solution is obtained by cooking a bird feather in a NaOH solution, followed by neutralization of sulfuric or hydrochloric acid. In this case, the protein, which is a chain polypeptide, is split into short chains - oligopeptides, which form a colloidal solution. (Hereinafter, a 30 percent colloidal solution of oligopeptides is referred to as a “protein concentrate”).

A feature of the resulting mixture is a significant increase in its aggregate stability, as a result of which it does not crumple and does not change its technical characteristics for 12-16 months. The water included in the composition of the colloidal solution as a result of increasing the aggregative stability of the mixture does not separate into an independent phase, and the mixture remains dry with organoleptic determination (to the touch). The mixture is prepared by first mixing the cement with a liquid protein-containing concentrate and metal sulfate, and then a fine aggregate of a fraction of 0-0.315 mm is introduced.

The advantage and difference from the prototype of the proposed mixture and the method of its production is the exclusion of the drying operation of the protein foaming agent. At the same time, the strength of foam concrete obtained from such a mixture is higher than the strength of concrete of the same density according to the prototype (Table 1).

Table 1
Comparative characteristics of foam concrete The properties Characteristics of foam concrete Density grade, kg / m ³ 400 500 600 800 1000 Compressive strength, MPa prototype 0.8 1.4 1,6 3,5 - proposed 1,5 2,4 3.8 5.9 7.9

At the same time, all the advantages of dry building mixes listed above are fully preserved.

It should be noted that upon receipt of foam concrete mixtures using separate dosing of components, additional mechanisms and devices are used: foam generator, compressor, batchers of solid components of the mixture, warehouses of binders, aggregates and additives. On the whole, the unit for preparing the foam concrete mixture is not transportable, therefore, if it is necessary to transport the mixture for concreting objects removed to a distance of more than 10 meters, the foam concrete mixture, which is a complex three-phase liquid, is pumped through a hose using a pump and undergoes significant structural changes. As a result, the average density of the hardened foam concrete increases significantly, by 1.5 - 2.5 times, the shrinkage during hardening increases, and this leads to cracking of the foam concrete.

When using a dry foam concrete mixture at a concrete object, the need for the use of dispensers, a foam generator, a compressor, and warehouses of solid bulk components is eliminated. Only one mechanism is needed - a foam mixer, which, if necessary, can easily be moved both horizontally and vertically (with floor concreting of screeds on the floors of buildings) using traditional vehicles used in construction. Significantly simplifies the storage of bagged dry concrete mixture.

Obtained by mixing the proposed dry mix with water, the foam concrete mixture does not require transportation over considerable distances, since the foam mixer can be installed in the immediate vicinity of the concrete object. The properties of the hardened foam in this case exactly match the design.

Described can be illustrated by the following examples.

Example 1. The composition of the mixture (wt.%):

- Portland cement PTs400 D0

(CEM I 42.5B GOST 31108-2003) - 58,

- silica fume - 26.0

- protein protein-containing concentrate - 14.0

- iron sulfate - 2.

The components are mixed in a mixer and packaged in a plastic bag.

Example 2. The composition of the mixture (wt.%):

- Portland cement PTs500 D20

(CEM II / H-42.5N GOST 31108-2003) - 55.0

- river sand fractions less than 0.16 mm - 28.5,

- protein protein concentrate - 15.0

- zinc sulfate - 1.5.

The components are mixed in a mixer and packaged in a plastic bag.

Example 3. The composition of the mixture (wt.%):

- Portland cement PTs400 D0

(CEM I 32.5B GOST 31108-2003) - 48.0,

- quartz sand fractions less than 0.16 mm - 39.0

- protein protein-containing concentrate - 12.0

- iron sulfate - 1.0

The components are mixed in a mixer and packaged in a plastic bag.

Example 4. The composition of the mixture (wt.%):

- slag Portland cement PC-400 D0

(CEM III / A 32.5H GOST 31108-2003) - 52.0

- expanded vermiculite fraction 0.16-0.315 mm - 36.0,

- protein protein concentrate - 10.0

- copper sulfate - 2.

The components are mixed in a mixer and packaged in a plastic bag.

Example 5. The composition of the mixture (wt.%):

- pozzolanic cement PTs-400 D0

(CEM IV / A (P-Z-MK) 32.5N GOST 31108-2003) - 57.0

- expanded clay sand fraction 0.16-0.315 mm - 33.0

- protein protein concentrate - 9.0

- iron sulfate - 1.0.

The components are mixed in a mixer and packaged in a plastic bag.

Example 6. The composition of the mixture (wt.%):

- alumina cement HZ 500-41,

- fireclay sand fraction 0.16-0.315 mm - 48,

- protein protein concentrate - 10,

- iron sulfate - 1.

The components are mixed in a mixer and packaged in a plastic bag.

The mixture was stored in an unheated room. To obtain a foam concrete mixture, the required amount of dry mixture was placed in a high-speed mixer, the calculated amount of water was added and mixed for 2-3 minutes. After mixing, the volume of the foam concrete mixture was determined and the mixture was poured into molds. Samples were tested for foam concrete:

on Portland cement - after 28 days,

on alumina cement - after 3 days.

The first tests were carried out one day after the preparation of the dry mixture, the repeated tests were performed after 6 and 8 months.

The estimated amount of mixing water and the test results are shown in the table.

Table
Test results of foam concrete obtained from dry foam concrete mixtures Example No. The composition of the foam concrete mixture, kg Hardened Foam Concrete Properties Time after preparation of the dry mixture Dry mix Water 1 day 16 months Density, kg / m ³ Compressive strength, MPa Density, kg / m ³ Compressive strength, MPa one 350 280 390 1.7 410 1,5 2 490 343 580 3.8 625 3.4 3 660 598 795 5.9 820 5.3 four 320 256 355 1.4 390 1,2 5 390 312 415 1,6 430 1,2 6 870 505 975 7.9 1050 7.3

The characteristics of the placeholders used in the examples are as follows.

Silica fume MK-85 is a waste of the ferroalloy production of the Lipetsk Metallurgical Plant. It consists of particles of amorphous silica SiO ₂ , the content of which is 99.9 wt.% In it. The specific surface is 850 m ² / m ³ . Bulk density 500-600 kg / m ³ . Externally, it is a powder of light gray color. Humidity does not exceed 0.3%.

Expanded vermiculite fraction 0-0.315 mm according to GOST 12865-67 (1988).

River sand fraction 0-0.16 mm contains, wt.%: Quartz - 91.5; hydromica particles - 8.5.

Fireclay sand fraction 0.16-0.315 mm - crushed fireclay bricks, the private residue on sieve 016 after sifting through a standard set of sieves for sand.

Quartz sand fraction less than 0.16 mm - powdered silica quartz in accordance with GOST 9077-82 has the following characteristics:

- mass fraction of metallic iron,%, not more than 0.25

- mass fraction of silicon oxide,% not more than 98.0

- mass fraction of iron oxide,% not more than 0.15

- mass fraction of alumina,%, not more than 1.0

- mass fraction of calcium oxide,%, not more than 0.15

- loss on ignition,% 0.1-0.2

- sieve residue: 016 not more than 1.0

Claims (2)

1. A method of obtaining a dry building mixture for the production of foam concrete, comprising mixing a dry mineral binder, dry fine mineral aggregate, metal sulfate and protein protein-containing additives, characterized in that the fine mineral aggregate uses fractions from 0 to 0.315 mm, and a protein-containing additive in the form of 30 % colloidal solution of protein-containing concentrate in water in the following ratio of components, wt.%: mineral binder 41-58, the specified fine aggregate 26-48, the specified protein-containing general additive 9-15, metal sulfate 1-2. 2. Dry mortar for the production of foam, obtained by the method according to claim 1.