RU2376250C2 - Organo-mineral cement for special activities - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: organo-mineral cement includes, wt %: milled Portland-cement clinker 73.5-92.5, calcium sulfate dihydrate 4.0-5.0, floured siliceous component 1.0-10.0, keratin containing extract 2.50-12.5.

EFFECT: high-strength cement with low periods of setting, high resistance to corrosion, high freezing resistance and low water consumption, high aggregate resistance and extended period of storage not affecting activity.

4 tbl, 8 ex

Description

The proposal relates to the field of building materials and can be used for the preparation of heavy concrete with increased frost resistance and cellular concrete.

Known additive-free Portland cement according to GOST 10178-85 (patent No. 2288899), PC (300, 400, 500), D0, consisting of ground Portland cement clinker and gypsum CaSO ₄ * 2H ₂ O with a ratio of components in% by weight: clinker - 95- 96; gypsum 4-5.

Natural hardening cement at the age of 28 days has a compressive strength of 30, 40 or 50 MPa in accordance with the brand, frost resistance of 100-300 cycles of alternate freezing and thawing. Its water demand (normal density) is 23-27%, the start of setting is 2-3 hours, the end is 4-5 hours.

The disadvantage of this cement is that the guaranteed storage time of this cement is not more than 1 month, after which its activity decreases by at least 1 brand, the cement has low aggregate stability, therefore it easily crumbles, cakes, turning into stone.

Portland cement is also known according to GOST 10178-85 (patent No. 2002119043), including, in order to increase the resistance to leaching with fresh water and increase the resistance to salt corrosion, the addition of ground silica-containing component in an amount of 15-29% by weight, PC (300, 400, 500) D20. This kind of Portland cement has the same strength and water demand characteristics as above, and increased resistance to leaching and salt corrosion.

The disadvantages of this cement are low frost resistance, short storage time due to low aggregative stability, associated with it high caking, fast clumping during storage.

Closest to the proposed cement is Portland cement according to copyright certificate No. 259679, including ground Portland cement clinker, borogypsum sludge (consisting of 20-25% of finely ground siliceous component and 80-75% of gypsum gypsum - 5-6%, of the clinker containing 2 additional 5-4% by weight of dry sludge naphthenic or higher fatty acids (hydrophobic Portland cement).

Its characteristics of strength, frost resistance and corrosion resistance do not differ from the same properties of the above cements. The disadvantage of this cement is low aggregate stability (clumping) and delayed hardening.

In addition, none of the listed analogues of the proposed cement can be used to obtain cellular concrete without the use of special foaming or blowing agents.

The objective of this proposal is to develop a cement composition with high strength, corrosion resistance, high frost resistance and at the same time low water demand, high aggregate stability (lack of clumping and caking, long storage time without noticeable change in properties) and ability to mix with fine aggregate and water when mixed in a high-speed mixer to form a cellular foam-like structure.

The technical result of the proposal is to develop a cement composition with high strength, corrosion resistance, high frost resistance and at the same time low water demand and long storage time - more than 4 months - without reducing activity. At the same time, to obtain aerated concrete, the proposed cement does not require the introduction of foam or blowing agents. To obtain foam concrete on the proposed cement, it is only necessary to add fine aggregate and water to it and mix the mixture in a high-speed mixer.

The technical result is achieved in that in cement, including ground Portland cement clinker, gypsum, a finely ground silica component and an organic additive, keratin-containing extract is used as an organic additive in the following ratio of components, wt.%:

clinker Portland cement ground - 73.5-92.5.

gypsum two-water - 4.0-5.0.

fine silica component - 1.0-10.0.

keratin-containing extract - 2.50-12.5.

The implementation of the proposed composition of cement is illustrated by the following examples.

Example 1. Cement contains (wt.%):

Portland cement clinker, ground - 81.0;

keratin-containing extract - 12.5;

two-water gypsum - 5.0;

silica fume - 1.5;

Example 2

Portland cement clinker, ground - 80.9;

keratin-containing extract - 5.0;

two-water gypsum - 4.1;

granite dust - 10.0;

Example 3

clinker Portland cement ground - 78.0;

keratin-containing extract - 10.0;

gypsum gypsum - 4.0;

granulated ground slag - 8.0;

Example 4

clinker Portland cement ground - 83.5;

keratin-containing extract - 7.5;

gypsum gypsum - 5.0;

fine quartz - 4.0;

Example 5

Portland cement clinker, ground - 91.5;

keratin-containing extract - 2.5;

gypsum gypsum - 4.0;

silica fume - 2.0.

The substances used in the examples have the following compositions:

Clinker Portland cement of the Gornozavodsky cement plant composition (wt.%):

Alite 3CaO * SiO ₂ - 59.56;

Belite - 2CaO * SiO ₂ - 21.12;

Tricalcium aluminate - 3CaO * Al ₂ O ₃ - 4.6;

Four-calcium aluminoferrite - 4 CaO * Al ₂ O ₃ * Fe ₂ O ₃ - 14.72.

Plaster two-water Ergachinsky quarry contains (wt.%):

CaSO ₄ * 2H ₂ O - 89.8

SiO ₂ - 4.9;

Al ₂ O ₃ - 1.7;

Fe ₂ O ₃ - 0.9;

MgO - 2.7.

Keratin is a water-insoluble vertebrate protein that forms their hair, coat, and horn integument. They differ from the closest analogues of scleroproteins in their chemical composition, in particular, in the content of significant amounts of cystine (di-β-thio-2-aminopropionic acid), and, as a result, the ratio of acids, alkalis and enzymes, different from other peptides.

Keratin is slowly hydrolyzed by concentrated acids and quickly hydrolyzed in the cold by strong alkalis.

Thus, the alkaline hydrolysis of keratins is quite simple and leads to the formation at the first stage of hydrolysis of amide bonds, as well as the destruction of polysulfide bonds of cystine. As a result, carboxyl groups take the form of sodium (potassium) salts and up to 18% nitrogen is released in the form of ammonia, and polysulfide bonds are converted to sodium (potassium) mercaptides.

Alkaline hydrolyzate is a brown solution of water-soluble oligomers with surfactant properties. When adding stabilizers FeSO ₄ , ZnSO ₄ , etc. Apparently, complexation by sulfide and amino groups occurs, which structures the oligomers, and exposure to atmospheric oxygen creates a three-dimensional spatial structure of surfactants.

Upon contact with Portland cement, sodium (potassium) salts are exchanged for calcium, i.e., additional chemical bonds are formed, and the released Glauber salt binds water in the form of crystallization with the formation of mirabilite.

The blast furnace granulated slag of the Chusovsk Metallurgical Plant has the chemical composition of typical “neutral” slag. It mainly consists of slag glass, light brown, sometimes pale green due to iron oxides.

Chemical composition (wt.%):

SiO ₂ 26.2-29.21; Al ₂ O ₃ 13.6-15.8; FeO - 2.0 - 2.4; Fe ₂ O ₃ - 0-1.3; CaO - 29.7-30.9; MgO - 9.8-10.3; TiO ₂ - 10.8-11; Cr ₂ O ₃ - 0.15-0.4; V ₂ O ₅ - 0.3-2.36; P - 0-0.04; S-0-0.3; MnO - 0.5-0.6.

Phase composition (wt.%):

- glass with a refractive index of 1.594-1.623 - up to 75.0;

- crystalline phases - up to 25.0.

Mineral slag:

- okermanite - 2CaOMgO2SiO ₂ - prevails in the form of tabular crystals with a size of 0.01-1.0 mm There are skeletal envelope-shaped forms, dendrotoid germination - up to 50% of crystalline phases;

- melilite - 4CaOAl ₂ O ₃ MgO2SiO ₂ - in the form of small crystals of round shape - up to 25%;

- monticellite - CaOMgOSiO ₂ - needle crystals of 0.1 mm in size - up to 25%.

As accessory minerals are found:

- Rankite SCaOSiO ₂ ,

- pseudovolastonite α - CaOSiO ₂

- spinel Fe ₂ O ₃ Al ₂ O ₃ .

The indicators of basicity and activity of the slag are as follows:

m _o = 0.85-1.04, m _a = 0.47-0.6.

Silica fume, a waste of the ferroalloy production of Lipetsky Metallurgical Plant, contains SiO ₂ - 89.6% by weight; its specific surface is 15000-16000 cm ² / g.

Ground quartz contains 100% SiO ₂ , and its specific surface is 4000-4500 cm ² / g.

Granite dust has a chemical composition (wt.%): SiO ₂ - 70.18; Al ₂ O ₃ - 14.47; FeO - 1.67; Fe ₂ O ₃ - 1.78; CaO - 1.99; MgO - 088; TiO ₂ 0.39; Na ₂ O - 3.48; K ₂ O - 4.11; P ₂ O ₅ - 0.19; MnO - 0.12.

The fineness of grinding on the specific surface for all solid components of cement, except silica fume, should be 3500-4500 cm ² / g

The compositions described in examples 1-5 were tested according to GOST 310-87. For this, the normal density of the test, the setting time and the strength of the beam samples with dimensions of 4 × 4 × 16 cm from a solution with standard sand in a ratio of 1: 3 were determined.

The test results of the compositions in examples 1-5 according to GOST 310.1-87 are given in table 1.

Table 1 No. of examples The normal density of the test,% Setting time, hour: min The strength of the samples, MPa Start end when bending under compression one 25.0 1:25 4:00 12.30 38,20 2 22.5 0:20 1:30 12.54 35.40 3 21.25 0:15 1:05 12.30 39.20 four 18.75 0:15 1:10 12.54 39.80 5 16.25 0:10 0:50 12.30 37.60 6 24.3 0:45 6:30 a.m. 12.60 39.10 Note: line 6 shows the test results of Portland cement of the Gornozavodsky cement plant ПЦ400 D20 without organic additives.

The same compositions stored in paper bags in a heated room for 4 months were tested under conditions similar to the previous five examples. At the same time, all five cement samples, when opening the bags, turned out to be loose, without signs of caking, suitable for use. At the same time, cement was tested in row 6 of table 1, which was stored under the same conditions.

Tests according to GOST 310-87 showed the following results (table 2).

table 2 No. of examples The normal density of the test,% Setting time, hour: min The strength of the samples, MPa Start end when bending under compression one 29.5 1:40 6 a.m. 12.30 38.64 2 24.2 0:40 4:00 12.30 34.68 3 22.5 0:15 4:20 12.30 39.80 four 18.8 0:20 0:50 12.79 39.60 5 15.1 0:15 0:40 12.79 37.80 6 28.9 1:25 8:10 a.m. 6.85 22.45 Note: line 6 shows the test results of Portland cement of the Gornozavodsky cement plant ГЦ400 D20 without organic additives

The tests were repeated after 6 months of storage under the same conditions.

The test results are shown in table.3.

Table 3 No. of examples The normal density of the test,% Setting time, hour: min. The strength of the samples, MPa Start end when bending under compression one 15.0 1:40 8:05 - 23.64 2 30.5 1:35 6:35 a.m. - 14.32 3 20,0 1:00 7:40 a.m. - 17.39 four 15.0 1:40 8:05 - 2.60 5 27.5 2 a.m. 7:25 a.m. - 11.30 6 31.6 2 a.m. 8:30 a.m. - 11.70 Note: line 6 shows the test results of Portland cement of the Gornozavodsky cement plant ПЦ400 D20 without organic additives

Example 6

Cement composition 1 was mixed with sand fraction 0.16-0.315 mm in a ratio of 1: 3. Water was added to the mixture, the water-cement ratio being 0.8. Mixing of the components was carried out using a turbine mixer and a drive providing a stirrer speed of 800 per minute. The resulting foamy mass was poured into the form of cubes 10 × 10 × 10 cm in size. Cubes were redistributed a day later and left to harden for 27 days, after which the density and compressive strength were determined.

Example 7

Cement of composition 2 was mixed with sand fractions of 0.16-0.315 mm in a ratio of 1: 3. Water was added to the mixture, the water / cement ratio being 0.9. Then they acted as in example 6.

Example 8

Cement of composition 3 was mixed with sand fractions of 0.16-0.315 mm in a ratio of 1: 3. Water was added to the mixture, the water / cement ratio being 0.9. Then they acted as in example 6.

The test results of the resulting foam concrete are given in table.4.

Table 4 No. of compounds Density, kg / m ³ Compressive strength, MPa 6 600 3.0 7 600 2.0 8 550 2.5

An analysis of the above results indicates that the above distinguishing features are individually and collectively aimed at solving the problem and are significant. The use of the proposed combination of significant distinguishing features in the data known from the patent and scientific and technical literature has not been established, therefore, the proposed technical solution has novelty.

The combination of known essential features with new, previously unknown, provides a solution to the problem. However, such a combination is not obvious and experimentally established by the authors.

Claims (1)

Organomineral cement, including ground Portland cement clinker, gypsum, a finely ground silica component and an organic additive, contains a keratin-containing extract as an organic additive in the following ratio, wt.%:
Portland cement clinker 73.5-92.5 gypsum gypsum 4.0-5.0 fine silica component 1.0-10.0 keratin extract 2,50-12,5