RU2103234C1 - Concrete mix, method for manufacturing concrete articles from concrete mix and process line for manufacturing said articles - Google Patents

Abstract

FIELD: civil engineering. SUBSTANCE: concrete mix comprises Portland cement, sand with grain size not more 2 mm, filler in the form of crushed stone, dyeing agent and surfactant in the following ratio, wt.-%: Portland cement, 15-23; sand, 20-30; filler, 47-48; dyeing agent, 0.7-1.1; surfactant, 0.04-0.06; water, the balance. Crushed stone has particle size 3-10 mm. Method for manufacturing concrete articles includes placing concrete mix into plastic moulds, compacting mix by vibration, holding moulded articles in moulds until they acquire sufficient intrinsic strength and their removing. Method has the following novel features: concrete mix is placed into moulds treated by antistatic agent, mix is compacted by vibration in moulds as they are filled up with mix stage by stage, before removing moulds, the latter are heated up to temperature at which they are easily separated from articles. Line for manufacturing concrete articles comprises arranged in series and technologically connected concrete mixer, article moulding station, station for holding moulded articles and mould stripping unit. At outlet for spent moulds, mould stripping unit is connected to second inlet of article moulding station via station for making moulds ready for operation. Process line comprises additional unit interposed between station for holding moulded articles and mould stripping unit while station for making moulds ready includes units for antistatic treatment of moulds. The latter is made in the form of two baths adapted to contain, respectively, antistatic agent solution and washing water. EFFECT: higher efficiency. 27 cl, 3 dwg

Description

 The invention relates to construction, namely to concrete mixtures, methods for producing elements from concrete mix and production lines for their manufacture.

 Known concrete mixture containing the following ratio of components, in wt. %: Portland cement 21-50; siliceous component 17-52; neonol-based gas dispersion stabilizer; modified sodium lignosulfate in a ratio of 1: 1 - 0.35: 1.5; water the rest.

 A disadvantage of the known mixture is the high gas content, leading to porosity of the building elements and the limited use of the latter.

 Known concrete mixture suitable for the manufacture of an extended class of building elements containing Portland cement, sand with a particle size modulus of at least 2 mm, crushed stone with grain sizes of 10-20 mm and water in a ratio of 1-2-3-0.5, respectively, and plasticizing air-entraining additives in an amount of up to 0.2% by weight of cement and dye.

 The disadvantage of this mixture is its low ductility and, as a consequence, the difficulty of manufacturing building elements from it with a flat surface.

 A known method of manufacturing building products from concrete mix, including laying concrete mix in steel or wooden molds, vibration compaction of the mixture by exposing it to vertical vibrational vibrations with a frequency of 45-50 Hz and an amplitude of 0.35-0.40 mm, holding the compacted mixture in molds to a set of stripping strength and stripping of seasoned products.

 The disadvantage of this method is the difficulty of removing air bubbles from the mixture and the adhesion of the mixture to the molds, leading to insufficient strength and lower quality building elements due to irregularities formed on their surface.

 A known method of manufacturing building elements, including laying concrete mixture in metal molds, vibration compaction of the mixture in the molds by a combined effect on the mixture of horizontal and vertically directed vibrations with simultaneous pressing, holding molded products to a set of stripping strength and stripping the latter.

 The disadvantage of this method is the complexity of its implementation and the need for subsequent processing of the surface of the finished products due to defects caused by the adhesion of the mixture to the molds, as well as the need for mechanical cleaning of the molds after their use.

 A known production line for the manufacture of concrete products, including sequentially installed and technologically connected concrete mixer, molding post, holding station for molded products in steel or wooden molds, and a stripping plant connected to the outlet of the finished molds with the second input of the molding post through the post for mechanical cleaning of molds from concrete imperfections .

 A disadvantage of the known production line is the use of metal and wooden molds, the presence of a post for mechanical cleaning of molds from concrete residues, leading to the need for additional refinement of the surface of concrete products after their removal, the difficulty of their production technology and increased energy consumption for the production of concrete products.

 The objective of the invention is the creation of concrete mix, a method of obtaining building products from it and a technological line for their manufacture, which can improve the quality, durability of products and simplify the technology of their manufacture.

This is achieved by the fact that a concrete mixture containing Portland cement, sand with a fineness modulus of at least 2 mm, a crushed stone filler, a dye and a surface-active additive according to the invention, the concrete mixture contains the following ratio of components, wt.%:
Portland cement - 15-23
Sand - 20-30
Filler - 47-48
Dye - 0.7-1.1
Surfactant Additive - 0.04-0.06
Water - The rest,
while the grain size of crushed stone corresponds to 3-10 mm.

 It is advisable to use crushed stone from natural stone or gravel as a filler, and a hydrophobizing liquid based on organosilicon compounds as a surface-active additive.

 In addition, it is advisable to use redoxide, red iron or iron oxide pigment as a dye to obtain a red color. For yellow, it is desirable to use iron oxide pigment as a dye. For green, chromium oxide and phthalocinine pigment in a ratio of 16: 1 are used as a dye.

 The problem is also achieved by the fact that in the method for producing concrete products, including laying concrete mixture in molds, vibrocompressing the mixture, holding molded products in molds until the stripping strength is set and stripping them, according to the invention, the concrete mixture is laid in plastic molds treated with antistatic, vibration compaction of the mixture in the molds they are produced in the process of their gradual filling, and before the products are stripped off, the molds are heated to the temperature of separation of the latter from the products.

 The task is also achieved by the fact that in the production line for the manufacture of concrete products, containing sequentially installed and technologically connected concrete mixer, molding post, post exposure of molded products and stripping installation, connected at the exit of the finished molds to the second input of the molding post through the post of preparation of molds, according to The invention additionally introduces a mold heating unit installed between the holding station and the stripping unit, and the mold preparation unit contains an installation antistatic processing, while the installation for antistatic processing of forms is made in the form of two baths for a solution of antistatic and wash water, respectively.

 According to the invention, the rational selection of the component composition of the concrete mixture and the size of the filler provide an increase in the quality of the concrete mixture for an extended class of concrete products from building elements of road surfaces to cladding elements of building structures. At the same time, it is possible to increase the durability and quality of the front surface of concrete products with relatively simple technologies for their production.

 The manufacture of building products from concrete mix in plastic molds allows to improve the surface quality of concrete products by eliminating the adhesion of concrete to the molds.

 Vibro-sealing of the mixture in the molds as a result of the stage-by-stage filling of the molds with the mixture ensures the removal of air bubbles from the front layer and, as a result, provides an increase in the strength and durability of the products, the quality of their front surface (exclusion of shells).

 Heating the molds before stripping the products allows the molds to stick to the concrete products due to the difference in the thermal expansion coefficients of the plastic and concrete. This eliminates the defects in the front surface of concrete products associated with concrete sticking to molds using known technologies, facilitates the removal of products and eliminates the need for laborious mechanical cleaning of worked-out forms from adhering concrete, which is typical for known technologies for manufacturing concrete products.

 In general, these advantages can improve the quality and durability of concrete products and simplify the technology of their manufacture and, thereby, achieve the solution of the task.

 In FIG. 1 shows a functional diagram of a technological line for the manufacture of building products; in FIG. 2 is a functional diagram of a device for antistatic processing of plastic molds; in FIG. 3, a-c is a drawing explaining the design of the formwork installation and its elements.

In FIG. 1-3 - positions marked:
1 - concrete mixer;
2 - molding post;
3 - post exposure molded products;
4 - installation of heating molds;
5 - stripping installation;
5.1, 5.2, 5.3, 5.4, 5.5 - bed, movable frame, vibrator, receiving table, removable installation matrix 5, respectively;
6 - device for antistatic processing of forms;
6.1, 6.2 - bath for the antistatic solution and bath for flushing water of the device 6, respectively.

 The best embodiment of the invention.

The raw material mixture for the preparation of building products from concrete contains the following components, wt.%:
Portland cement - 15-23
Sand with a fineness modulus of at least 2 mm - 20-30
Crushed stone with a grain size of 3-10 mm - 47-48
Dye - 0.7-1.1
Surfactant Additive - 0.04-0.06
Water - Else
As a dye, the concrete mixture contains mineral and organic pigments in accordance with the data in table. 1.

 As a plasticizing additive, the concrete mixture contains a hydrophobizing liquid (product 134-342) according to GOST 24211, GOST 26633.

 Examples of the composition of the concrete mixture for various options for building products are shown in table 2.

The method of obtaining building products from concrete mix includes the phased (in terms of filling) placement of the concrete mix in plastic molds treated with an antistatic agent, vibration compaction of the mix in the molds by the action of vertical vibrational oscillations with a frequency of 40-60 Hz and an amplitude of 0.3-0.5 mm after each another additive in the form of concrete mixture until cement milk appears on its surface, holding the compacted mixture in completely filled forms at 28-30 ^o C until the formwork strength is set (at least 2 days), heating the plastic molds m on products up to the temperature of their detachment from the plastic molds, holding them at a temperature for 1.5-2 minutes and stripping the products, which consists in removing the plastic molds from the products by vertical vibrations with an amplitude of 1-4 mm and a frequency of 40-60 Hz

 The production line for the manufacture of the proposed mixture and building elements according to the proposed method contains sequentially installed and technologically connected concrete mixer 1, molding post 2 made in the form of a vibrating table, holding post 3, a heating unit 4, a stripping unit 5, the outlet of which is connected to the used molds through the installation of antistatic treatment 6 with the second input of the molding post 2. In the simplest embodiment, the installation 4 is made in the form of a bath for heating plastic molds. In other embodiments, the heating unit of forms 4 can be made in the form of infrared lamps with reflectors or in the form of a steam generator.

 Installation of antistatic treatment 6 is made in the form of two baths (Fig. 2), for antistatic processing of forms 6.1 and their washing 6.2, respectively.

 The stripping unit 5 is made on the basis of a vibrating table and contains a frame 5.1, on which a frame 5.2 is mounted with the possibility of vertical movement, a receiving table 5.4 with lever suspension and a vibrator 5.3, the output of which is kinematically connected to the frame 5.2. Frame 5.2 is equipped with a removable matrix 5.5, in which there are receiving windows (Fig. 3f) with dimensions and shape corresponding to the size and shape of the longitudinal section of the products.

 An example of the operation of the production line according to the proposed method is considered on the example of the production of paving slabs (option 1, table. 2).

 For the selected version of the building product, the required component composition and the quantitative composition of the raw mix for concrete mixer 1 are determined. At the same time, at post 2, the corresponding plastic molds are installed on its vibration table, which have undergone antistatic processing at installation 6, and the corresponding matrix 55 is installed on the stripping unit 5.

 In accordance with the selected component composition of the mixture in a concrete mixer 1 with a volume of at least 16 l, the concrete mixture is prepared in the following order. Initially, 2/3 of the mixing water and the entire volume of the hydrophobizing liquid are poured into the concrete mixer 1. After mixing them into the concrete mixer, cement, sand, crushed stone are loaded in the appropriate ratio and mixed. At the same time, the corresponding pigment is introduced into the residue (1/3 /) of mixing water, mixed and poured into concrete mixer 1. Mixing of the composition of the concrete mixture in concrete mixer 1 is carried out until a homogeneous, plastic concrete is obtained. The resulting concrete mixture is laid in layers in plastic curved forms on a vibrating table of post 1, for example, at first the first table is 10-20 mm thick. Include a vibrating table. Under the influence of vibration, the concrete mixture in the molds on the vibration table is freed from the air in it. When the mixture is completely freed from large air bubbles that cause the appearance of shells on the surface and inside the product, cement milk appears on the surface of the concrete mixture in the form.

 When cement milk appears on the surface of the first layer of concrete mixture, the vibrating table at station 1 is turned off and the next layer of concrete mixture is laid in molds. Re-enable the vibrating table and produce vibration compaction of the total layer of the mixture in the molds. Moreover, the more stages of formation and the smaller the thickness of the products (thinner molding layer), the higher the quality of products from concrete mix. In the limit, it is possible (on this line) the process of continuous formation of products by slow continuous pouring of forms with a solution (until they are completely filled) with a vibrating table constantly on. The continuous process of formation, although it provides an increased quality of products, however, complicates the process of formation due to the need to observe a strict dosage regimen and the speed of pouring the solution into the mold.

 For the manufacture of building products with a standard thickness of 40-60 mm, it is sufficient to use a simplified molding process (two-stage), in which at the first stage molds are filled to half their depth, followed by vibration compaction for 10-15 seconds, and at the second stage, molds are filled to their full filling with subsequent vibration compaction for 15-20 seconds.

 Molded on a vibration table, the products are laid out on a wooden pallet in height of 8-10 rows. Each row is laid with a PVC film and a sheet of fiberboard or plastic.

 The completed pallet with products from the molding post 2 is transferred using a tong grab or a manual hydraulic trolley to the holding post 3.

At the post 3, the pallets are installed in a row, the distance between the rows is 0.5 m. The stacks are covered with a sheet of tarpaulin and heat is supplied. The products are kept at post 3 at 28-30 ^o C for a period of not less than two days (46-60 h) until the formwork strength is obtained.

After the manifestation of the formwork strength, the pallet with the products in the molds is fed to the installation 4. At the installation 4, the molds are heated for 1.5-2 minutes. at a temperature of 50-60 ^o C, for example, by immersing the products in the molds in a bath with warm soda to a depth at which water does not reach the upper edge of the mold by 2-3 mm. In this case, due to the difference in the coefficients of thermal expansion during the specified time, complete detachment of concrete products from plastic forms occurs. Next, the products in the molds are fed to the stripping unit 5. On the installation 5, the molds are installed upside down on the matrix 5.5. Turn on the vibrator 5.3. The vibrations of the vibrator 5.3 are transmitted to the frame 5.2 with the products in the molds installed on its matrix 5.5. In this case, the plastic molds are affected through vertical vibrational vibrations with a frequency of 40-60 Hz and an amplitude of 0.6-0.8 mm, leading to the release of products from the molds. Freed from the forms of the product under the influence of its own weight, they fall into the receiving windows of the matrix 5.5 and are fed to the receiving table 5.4. If all products from the dies 5.5 get onto the table 5.3, the total weight of the products will exceed the tension of the springs of the lever suspension of the table 5.4, the latter is lowered and pushed out from under the frame 5.2 along with the products that are free from molds. Products from table 5.4 are stacked in rows on a pallet at a height of 8-10 rows and transferred for storage. The molds remaining on the matrix 5.5 of the stripping unit 5 are transferred to the antistatic treatment unit 6 (Fig. 2), where the molds undergo antistatic treatment by lowering them into the bath 6.1 with an antistatic solution, for example, phosphoric acid solution, and subsequent washing in the bath 6.2, pre-filled with flushing liquid, for example, water.

 The forms washed from the antistatic agent are fed to molding post 2 and the manufacturing process of building products is repeated.

 The proposed invention has undergone a pilot test at AOZT "Reinforced Concrete Products-2" and is undergoing industrial development.

Claims (27)

 1. Concrete mixture containing Portland cement, sand with a fineness modulus of at least 2, aggregate in the form of crushed stone, dye and surface-active additive, characterized in that the concrete mixture contains the following ratio of components, wt. Portland cement 15 23
Specified sand 20 30
Placeholder 47 48
Dye 0.7 1.1
Surfactant Additive 0.04 0.6
Water Else
while the grain size of crushed stone corresponds to 3 10 mm  2. The mixture according to claim 1, characterized in that the aggregate in the form of crushed stone is obtained from natural stone or gravel.  3. The mixture according to claim 1, characterized in that as a surface-active additive it contains a hydrophobizing liquid based on organosilicon compounds.  4. The mixture according to p. 1, characterized in that as a dye it contains redoxide, red iron oxide.  5. The mixture according to claim 1, characterized in that it contains iron oxide pigment as a dye.  6. The mixture according to p. 1, characterized in that as a dye it contains chromium oxide and phthalocyanine pigment in a ratio of 16 1.  7. The mixture according to claim 1, characterized in that it contains manganese ore as a dye.  8. A method of producing concrete products from a concrete mixture, including laying concrete mixture in molds, vibration compaction of the mixture in molds, holding molded products in molds before gaining formwork strength and stripping them, characterized in that the concrete mix is laid in plastic molds treated with antistatic, vibration compaction of the mixture in the molds is carried out in the process of their gradual filling, and before stripping the products, the molds on the products are heated to the temperature of their detachment from the molds and held at this rate temperature until the product is completely detached from the inner surface of the molds.  9. The method according to p. 8, characterized in that the vibration compaction of the mixture is carried out in two stages, while in the first stage after filling the mixture with molds to half their depth, in the second stage after they are completely filled.  10. The method according to p. 8, characterized in that the vibration compaction of the mixture in the molds at each stage is carried out until the cement milk appears on the surface of the mixture.  11. The method according to p. 10, characterized in that the vibration time at the first and second stages is selected in the range of 10 15 and 15 20 s, respectively.  12. The method according to PP. 8 10, characterized in that the vibration compaction of the concrete mixture is carried out by vertical vibrational vibrations with a frequency of 40 to 60 Hz and an amplitude of 0.3 to 0.5 mm.  13. The method according to p. 8, characterized in that the heating of the forms on the products is carried out with superheated steam. 14. The method according to p. 8, characterized in that the aging of molded products is carried out for at least two days at a temperature of 28 30 ^o C.  15. The method according to p. 8, characterized in that the heating of the molds is carried out by infrared radiation.  16. The method according to p. 8, characterized in that the heating of the molds is carried out by immersing the products with the mold in a bath of warm water to a depth at which the water does not reach the top of the mold by 3-4 mm. 17. The method according to PP. 15 and 16, characterized in that the heating of the molds is carried out at a temperature of 50 to 60 ^o C on the surface of the molds for 1.5 to 2 minutes  18. A technological line for the manufacture of concrete products, containing a sequentially installed and technologically connected concrete mixer, a molding post, a holding station for molded products and a stripping unit connected to the outlet of the finished molds with the second entrance of the molding post through a mold preparation station, characterized in that the installation is additionally introduced heating the molds installed between the holding station and the stripping unit, and the mold preparation station contains an anti-static processing unit.  19. The production line according to claim 18, characterized in that the mold heating installation is made in the form of a bath with a water heating device.  20. The production line according to claim 18, characterized in that the mold heating installation is made in the form of a steam generator.  21. The production line according to claim 18, characterized in that the mold heating installation is made in the form of infrared lamps with reflectors.  22. The production line according to claim 18, characterized in that the antistatic mold processing unit comprises sequentially installed and technologically connected bath for the antistatic solution and a bath for rinsing water.  23. The production line according to p. 18, characterized in that the stripping installation is made in the form of a vibrating table with removable matrices containing stripping windows.  24. The production line according to claim 23, characterized in that the shape and dimensions of the stripping windows are made corresponding to the sizes and shape of the longitudinal sections of the concrete products to be stripped.  25. The production line according to p. 23, characterized in that the stripping installation is equipped with a receiving table on a lever suspension mounted under the stripping windows of the matrices.  26. The production line according to p. 23, characterized in that the vibrating table is made with the possibility of vertical vibration in the range of 0.6 to 0.8 mm  27. The production line according to p. 18, characterized in that the molding post contains a vibrating table made with the possibility of vertical vibration in the range of 0.3 to 0.5 mm

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