RU2255918C1 - Composition for making wall article - Google Patents

Abstract

FIELD: building industry and materials.

SUBSTANCE: invention relates to compositions representing fine-grained concrete mixtures. The composition for making wall articles comprising white or gray Portland cement, ceramic sand, polymer-containing plasticizing agent, iron-containing pigment and water involves additionally hydrate lime, roasted ash from heat and electric power plant as an active mineral additive and limestone sand wherein limestone and ceramic sand are taken with fractions 0.315-2.5 mm, and super-plasticizing agent "C-3" or "C-4" is taken as a polymer-containing plasticizing agent in the following ratio of components, wt.-%: white or gray Portland cement, 18-25; hydrate lime, 3-5; ceramic sand with fractions 0.315-2.5 mm, 34-50; limestone sand with fractions 0.315-2.5 mm, 9.5-16; super-plasticizing agent "C-3" or "C-4", 0.1-0.15; iron-containing pigment, 1.9-3; roasted ash from heat and electric power plant, 5-7, and water, the balance. Invention can be used for manufacturing building wall articles - stones, bricks, among them face ones and for finishing the face layer of cinder blocks. Invention provides enhancing strength and crack-resistance in thermal-moisture treatment, retention of architecture expression due to conferring terra cotta color to articles.

EFFECT: improved properties of compositions.

1 cl, 2 tbl

Description

The invention relates to the field of construction, and in particular to compositions of compositions (fine-grained concrete mixtures), and can find application for the production of building wall products (stones, bricks, including facial ones), as well as for finishing the front layer of cinder blocks.

Known raw mix for the manufacture of lightweight concrete, given in ed. testimonial. USSR No. 392032, M. Cl ³ S 04 B 21/12, B.I. No. 32, 1973, including components, in the following ratio, wt.%:

- cement 20-25

- ceramic aggregate (expanded clay gravel) 25-40

- limestone sand from shell rock with specific

surface from 60 to 3000 cm ² / g 15-35

- water - the rest and

- over 100% of the mixture - 0.01-0.3 wt.% of the mass of cement - plasticizer "SSD".

Along with the great advantages of the concrete mix, namely: low average density of products 1000-1300 kg / m ³ ; sufficient strength for grades from M50 to M150, which meets the requirements of GOST 6133-84 “Concrete wall stones”; Limestone fine waste generated during the sawing of limestone stones in quarries (or blasting mines) is utilized; there are also disadvantages:

1. Low architectural appearance.

2. The formation of hollow stones is difficult due to the presence of large granules (from 5 to 20 mm) of ceramic aggregate (expanded clay).

3. Insufficient frost resistance.

Known and the second fine-grained concrete mixture, given in ed. testimonial. USSR No. 425869, MKL. From 04 to 15/00, 29/02, publ. 09/15/72, including, wt.%:

- cement 15-20

- quartz sand 55-70

- ash TPP with a specific surface of 1500-3000 cm ² / g 10-25

- gypsum 1-2

- sodium sulfate 0.2-7

Along with the advantages of the mixture (shrinkage is reduced, cement consumption is reduced), there are also disadvantages:

1. Low crack resistance during hardening and operation, due to the formation of the mineral ettringite, which can expand during crystallization, especially during heat-moisture treatment.

2. Low architectural appearance, as ash particles are coated with unburned carbon films, i.e. ash color is gray. Such ash, with admixtures of coal, negatively affects frost resistance. Ash TPP (see GOST 6233-84, appendix. No. 2, tab. No. 4) also refers to the number of gray pigments.

3. On the surface of the product formed efflorescence - light spots, due to the diffusion of sodium sulfate on the surface of the product, followed by carbonization with carbon dioxide contained in the atmosphere.

Known and the third composition given in ed. testimonial. USSR No. 624901, M.cl. From 04 to 25/02, 1976 and including components, in the following ratio, wt.%:

- Portland cement (gray) 15,8-16

- styrene butadiene latex 7.0-7.2

- quartz sand 65-67

- hydrated lime 2.0-2.5

- pigment (iron minium) 1.0-3.0

- water 6.5-7.0

The main disadvantages of this composition are: lack of strength, frost resistance and architectural expressiveness.

Closest to the proposed composition for high-quality and technical solution (prototype) is a polymer-cement composition given in ed. testimonial. USSR No. 1004304, M.Kl. ³ С 04 В 25/04, B.I. No. 10, 1983 and containing components, in the following ratio, wt.%:

- cement white 17-20

- quartz sand powder 10-12

- butadiene styrene (plasticizer) 5.5-6.0

- pyrite cinder (iron pigment) 1.7-2

- ground clay brick 54-61

- water the rest

Along with the great advantages of the composition, specifically:

1. Utilizes the marriage of ceramics (ground), performing at the same time three functions (filler, active aluminosilicate mineral additive of cement and additionally red pigment).

2. Architectural expressiveness is achieved (red-brown color), which is ensured by ground brick and oxide-iron pigment — pyrite cinders giving a lilac color (see “pigments” - Appendix No. 2, Table 4 GOST 6133-84 “Concrete wall stones”) .

The main disadvantages of the prototype are:

1. Requires a large number of metal molds for molding, because the mixture is formed by vibration and subsequent hardening in metal forms, which is explained by the high content of styrene butadiene latex.

2. Insufficient strength of 21.5 MPa, which limits the ability to receive hollow bricks and hollow stones, including face with a brand of at least M100.

3. The composition is not subject to accelerated hardening (thermal moisture treatment), because styrene butadiene latex does not harden at high temperatures. During heat-moisture treatment, products are covered with cracks.

4. Paraffin and white Porland cement are expensive materials.

5. The products do not acquire a terracotta color imitating the color of wall ceramics made on the basis of red or light red burning clay.

The objective of the invention is to increase the strength and crack resistance during heat-moisture treatment, while maintaining architectural expressiveness, by giving the products a terracotta color.

To achieve this, the composition for the manufacture of wall products, including white Portland cement, ceramic sand, a polymer-containing plasticizer, iron pigment and water, additionally contains hydrated lime, an active mineral additive - calcined TPP ash, limestone sand, and Portland cement can also be taken gray. limestone and ceramic sand were taken with fractions of 0.315-2.5 mm, and “S-3” or “S-4” superplasticizer was taken as a polymer-containing plasticizer, with the following ratio ii all components, wt.%:

- Portland cement white or gray 18-25

- hydrated lime 3-5

- ceramic sand with fractions of 0.315-2.5 mm 34-50

- limestone sand with fractions of 0.315-2.5 mm 9.5-16

- superplasticizer “S-3” or “S-4” 0.1-0.15

- iron pigment (red) 1.9-3

- calcined ash TPP 5-7

- water the rest

Characterization of components for the implementation of the composition

1. Astringents

1.1. Staroskolsky PTs500, normal density of 27.5-29.5%. Mineralogical composition. Freedom CaO - 0.2%; C ₃ S - 60 ± 2%; C ₂ S - 13%; C ₃ F 7 ± 1%; C ₄ AF - 13 ± 1%. Conforms to GOST 10178-95. Bulk density -1130-1190 kg / m ³ .

1.2. Hydrated lime. Meets the requirements of GOST 9179-77. Grade - I.

2. Fillers (sands)

2.1. Ceramic ground sand. For grinding, it is recommended to take any unglazed ceramics (marriage of bricks, crevice stones, tiles or burnt clay in the form of fireclay), which has a red, light red or dark red color. Fraction 0.315-2.5 mm. It is not recommended, in the proposed composition, a fraction of less than 0.315 mm (ground aluminosilicate mineral additive - cement, because the latter plays the role of calcined ash - TPP, i.e. a more durable filler).

2.2. Limestone sand. It is recommended and adopted for the implementation of the composition of the composition - waste from the extraction of dense limestone in the form of fine and coarse sand formed during blasting, as well as in the form of seedlings from crushed stone produced in factories for melting ore in blast furnaces, raw materials for Portland cement and aggregate of heavy concrete. Sands and seedlings from the Barsukovsky quarry and crushed stone production plant (Tula region) were accepted. Wastes (sand) have a bulk density of 1490-1500 kg / m ³ and contain 97-99% CaO. The rest is clay and quartz impurities with traces of iron oxides. A fraction of 0.315-2.5 mm is recommended because a fraction of less than 0.315 mm contains a less dense rock - clay impurities that reduce the strength of the composition, and particles of a fraction of more than 2.5 mm make it difficult to produce slit (hole) stones by vibrocompression, followed by pushing the products onto a pallet. The color of the sand is almost white with a grayish tint .;

3. Calcined ash TPP until complete removal of coal particles

The specific surface of the calcined ash TPP 2800-3000 cm ² / year Bulk density 900-950 kg / m ³ . The color of the ash after calcination is orange or light orange. The initial ash - TPP near Moscow basin meets the requirements of GOST 4810-78. The chemical composition of the ash TPP after calcination, wt.%: SiO ₂ - 65.06; Al ₂ O ₃ - 22.72-30.15; TiO - 1.03-1.34; FeO - 1.92-3.80; Fe ₂ O ₃ - 7.32-9.49; MgO - 0.68-0.98; CaO - 1.05-1.09; K ₂ O - 0.76-0.91; Na ₂ O - 0.42-0.44. P.P.P.-0%.

4. Superplasticizer “S-3” or “S-4”

Conforms to TU 6-14-29-258-79.

5. Pigment

It is recommended that the iron-oxide-containing pigment gives a red color, such as iron minium, which meets the requirements of GOST 8135-74, or any other oxide-iron-containing pigment that gives red or yellow-red.

Pyrite cinder is not recommended as a pigment, as in accordance with GOST 8135-74 they report a lilac color, not red.

Composition Implementation Experience

Pre-crushed marriage of ceramic bricks and tiles, having a red color. The grinding product was sieved through two sieves: the top with a mesh diameter of 2.5 mm and the bottom with a mesh diameter of 0.315 mm. The remainder on the lower sieve was taken for experiments on the implementation of the composition. Lignite ash - thermal power plants (Aleksinsky, Tula region), were calcined on the floor of a ring furnace together with fired ceramic bricks at a maximum firing temperature of 900 ° C. The resulting ash was introduced into the composition together with mixing water, i.e. in the form of sludge, so that microparticles of free burnt lime contained in the ash are pre-quenched, which prevents the likelihood of cracks during hydrothermal processing of products.

Limestone fine waste from the explosive development of dense limestone of the Barsukovsky quarry (Tula region) and seeding from limestone crushed stone was sifted through two sieves with a mesh diameter of the upper 2.5 mm and lower 0.315 mm. The residue on a sieve with a particle diameter of 0.315 mm is accepted for sale.

Pre-prepared components: ceramic and limestone sand fr. 0.315-2.5 mm, calcined and hydrated ash (orange), in the form of slag, as well as the other components shown in table 1 and in the indicated ratio, were dosed by dry weight, mixed until smooth, and then molded as cylinder samples in metal form with a diameter and height of 70 mm, vibration compaction method with a specific pressure of 0.04 MPa and for 20 seconds, followed by pushing from the mold onto a perforated wooden pallet. After the end of setting (1.5-2 hours), the products together with the pan were placed in a steaming chamber for 2 + 8 + 2 hours, at a maximum temperature of 70-80 ° C. After steaming, part of the samples were tested for strength and other properties, and the second part was left for further hardening under normal conditions, for concrete and, after 28 days, they were tested for strength and other properties.

The test results were compared with the requirements of GOST 6133-84 “Concrete wall stones”, as well as color and other property indicators with the requirements of GOST 530-95 “Brick and ceramic stones” (except heat resistance). At the same time compared with the indicators of the properties of products made from the composition of the prototype, the test results are shown in table 2.

Table 1 The composition of the molding composition No. Materials The proposed composition Prototype, wt.% p / p 1 2 3 4 5 1. Portland cement 1.1 - white 17 18.0 22 25 26 17 twenty eighteen 1.2 - gray plain 17 18.0 22 25 26 - - - 2. Hydrated Lime 6 5 4 3 2 - - - 3. Placeholders: 3.1 Ground quartz sand - - - - - 10 12 10.65 3.2 Ceramic crushed sand fr. 0.315-2.5 mm 51 fifty 41 34 33 - - - 3.3 Clay brick, ground, including active aluminate mineral additive (cement) - - - - - 61 54 57.5 3.4 Limestone crushed sand fr. 0.315-2.5 mm. nine 9.5 thirteen 16 16.5 - - - 4. Iron Pigment Oxide: 4.1 Iron red lead (color red), 1.81 1.9 2.0 3.0 3.2 - - - 4.2 Pyrite cinder (lilac color). - - - - - 1.7 2 1.85 5. Polymer-containing plasticizer: 5.1 Styrene butadiene latex, - - - - - 5.5 6 6 5.2 Formaldehyde-containing superplasticizer “S-3”, “S-4” 0.09 0.1 0.12 0.15 0.16 - - - 6. Calcined ash TPP 4 5 6.5 7 7.5 - - - 7. Water 11.1 10.5 11.88 11.85 11.64 4.8 6.0 6.0

table 2 Properties of products (samples) made on the basis of the composition No. Properties Proposed composition Prototype 1* 2 3 4 5* 6 7 8 1. Strength at: 1.1 - compression, MPa

15,5 21.5 17.4 1.2 - bending, MPa

4.2 5.2 6.6 2. The presence of cracks after thermal moisture treatment not not not not not there is there is there is 3. Color of finished products Terracotta Red with a gray tint. Red with a brown tint Note: * Compositions No. 1 and No. 5 are transcendent because No. 1 does not meet the goal in terms of strength, and No. 5 - in terms of architectural expressiveness. * The denominator is the strength after heat-moisture treatment.

A comparative analysis of the properties with similar properties of the prototype shown in table 2 shows:

1. Samples of products of normal hardening have a higher strength (higher by 6.2-25%).

2. On the surface of the samples of accelerated hardening, after heat-moisture treatment, there are no cracks, and on the surface of the samples from the composition of the known mixture cracks are formed up to failure.

3. Samples acquire a terracotta color, ie no architectural expressiveness is lost.

4. Wall products from the proposed composition simultaneously meet the requirements of two GOSTs, in addition to heat resistance, ie GOST 6133-84 “Concrete wall stones” and GOST 530-84 “Brick and ceramic stones”.

Achieving the goal can be explained by the following factors and physicochemical processes:

1) The combination of colors: white from Portland cement and hydrated lime, red from ceramic bricks and pigment - iron minium, light gray (almost white) from limestone sand and orange from calcined brown coal ash of thermal power plants, white from S-3 superplasticizer or “S-4” - allows you to get a terracotta color.

2) A tight packing is achieved by selection of granular composition, because less durable particles of ceramic sand and limestone (fr. less than 0.315 mm) are replaced by stronger and finer particles of calcined ash TPP, which positively affects the increase in strength.

3) Limestone sand and glass coating of ash TPP particles belong to the group of lyophobic (water-repellent) materials, and finely ground quartz, adopted in the prototype - to the number of lyophilic, i.e. chemisorptively attracts water molecules, forming shells from silicic acid gel. This is proven by science.

Therefore, when molding the proposed mixture by vibropressing, part of the excess water is easily separated from the part of the mixture and exits through the perforated bottom of the mold, which positively affects the strength. In the prototype, the excess water (remaining from the hydration reactions of the minerals of clinker cement) is not removed, but evaporates during hardening, leaving pores in the products, which. adversely affects strength.

4) Three factors contribute to crack resistance during moisture treatment:

- higher capillary-conducting ability of evaporating moisture, due to the larger fraction of crushed sand;

- the correct selection of more heat-resistant and capable of polymerizing during thermo-wet processing of superplasticizer;

- preliminary extinguishing of particles of burnt lime in the ash - TPP.

The proposed composition has the following techno-economic advantages:

1. There is no need to acquire metal molds.

2. No expensive paraffin required.

3. For finished products does not require the development of special specifications or GOST and technological regulations, because they are manufactured according to the generally accepted technology for the production of concrete slag blocks with heat-moisture treatment and vibrocompression followed by pushing, and they meet the requirements (except heat resistance) of two GOSTs No. 6133-84 “Concrete wall stones” and No. 530-95 “Brick and ceramic stones” with a predominance of frost resistance and bending strength with imitation of the color of wall ceramics (terracotta). Therefore, we recommend calling such products “ceramic concrete” composites.

4. Limestone waste from quarries of the extraction of dense limestones and lignite ash of thermal power plants, which are calcined (calcined) together with ceramic bricks, are utilized.

5. Provided that the products are manufactured in brick factories, no steaming chambers are required, as heat treatment is carried out with drying of ceramic bricks of plastic molding, for 72-100 hours with soft and wet conditions in the first day.

On the basis of paragraphs.1-5, the cost of products is reduced by 28-30% relative to the products of the prototype and ordinary ceramic bricks.

Claims (1)

Composition for the manufacture of wall products, including white Portland cement, ceramic sand, polymer-containing plasticizer, iron pigment and water, characterized in that hydrated lime, an active mineral additive — calcined TPP ash, limestone sand, is added to it, and Portland cement can also be taken gray , limestone and ceramic sands were taken with fractions of 0.315 - 2.5 mm, and “S-3” or “S-4” superplasticizer was taken as a polymer-containing plasticizer in the following ratio of all to mponentov, wt.%: Portland cement white or gray 18-25 Hydrated lime 3-5 Ceramic sand with fractions of 0.315-2.5 mm 34-50 Limestone sand with fractions of 0.315-2.5 mm 9.5-16 Superplasticizer “S-3” or “S-4 0.1-0.15 Iron Pigment 1.9-3 Calcined ash TPP 5-7 Water Else