The coating is cement concrete. Development of cement-concrete road construction in Russia Reinforcement and thermal insulation of concrete floors

Properties of concrete used in road construction

road concrete belongs to a special group building mixtures. It is characterized by high resistance to a number of aggressive factors:

• negative natural phenomena (temperature changes, the influence of water and air);
• dynamic influences (vibrations, regular pressure changes);
  chemicals (reagents for removing ice).

In addition, this composition is not prone to the formation of microcracks, which is especially important when working in adverse conditions. Therefore, the material is used for laying road surfaces and airfields, providing them with high wear resistance, strength, reliability and durability.

Types of mixtures
Concrete is used in road construction for a variety of purposes. Depending on them, it is divided into three categories, each of which has its own characteristics:

Mixtures designed to create outer layers of coatings. They must be of the highest quality, since it is on the surface that the greatest loads fall.
Compositions for laying the lower balls of two-layer coatings. Their quality is lower than the previous ones.
Materials that are used as bases in the creation of capital coatings. Their characteristics are quite average.
When constructing roadbeds, it is necessary to adhere to the requirements for the use of each type of concrete. This will depend operational properties coatings.

Road concrete - brand and price

Material	Unit rev.	Price with VAT, rub
М-100 B7,5 Zh4 F50	cube	2850
М-150 B12.5 Zh4 F50	cube	2950
M-200 B15 Zh4 F50	cube	3150

Road concrete: composition
Concrete for pavement, like the usual one, consists of cement, sand and filler. The optimal ratio of these components is 1:2:5. But road concrete (GOST 10268─80 contains a list of detailed recommendations for its preparation and use) requires a special approach. For example, to increase its wear resistance and create additional reinforcement, fiber should be used. In a solution intended for upper layers, should be fillers consisting of particles with a diameter of not more than 20 mm. And not even every type of cement is suitable for adding to road concrete (grades 300-400 and not lower).

Road concrete laying
The construction of a capital concrete route begins with the preparation of the foundation. They can serve as ordinary soil or a dismantled old highway. After cleaning and leveling the working area, a sand ball 3-5 cm thick and the same layer of gravel are laid on its surface. After that, the formwork is installed and poured with ready-made mortar. It is possible to use the coating only after the specified period of solidification of the mixture.

Road concrete production
Construction and repair of highways are large-scale activities. They demand a large number appropriate quality material. For its manufacture and testing of properties, special equipment is required, which our factory is equipped with.

8.2.2 In livestock buildings, concrete floor coverings are recommended for use in machines, boxes, etc. when animals are kept on bedding or when using mats or slats, as well as in driveways and aisles.

8.2.3 Concrete pavements can be designed in the form of an exploitable underlying layer, on a concrete base and on a reinforced concrete floor (Fig. 3 and 4).

8.2.4 The coating thickness should be assigned depending on the intensity of mechanical impacts (Section I, Table 2). When performing a coating that simultaneously performs the function of an underlying layer, the thickness should be increased by at least 100 mm.

8.2.5 Coatings with a thickness of 50 to 120 mm are recommended to be reinforced with one layer of a metal mesh made of wire with a diameter of 5 mm with cells of 100x100 or 150x150 mm, with a thickness of 120-180 mm - with two layers of a metal mesh, and with a thickness of more than 180 mm, a frame determined by calculation. The lower layer of the metal mesh is laid on spacers with a thickness of at least 20 mm, the upper one - with 6x6 m cards, and in special cases with 3x3 m cards on supports welded to the bottom layer of the mesh.

Rice. 3 Structural schemes floors with concrete coating over the underlying layer ( a) and over the overlap ( b)

1 - concrete pavement; 2 3 - waterproofing; 4 - base soil; 5 - heat and sound insulation; 6 - overlap; 7 - pipeline.

Rice. 4 Structural schemes of floors with steel-fiber concrete coating along the underlying layer ( a) and over the overlap ( b)

1 - steel fiber concrete coating; 2 - concrete underlay; 3 - waterproofing;

4 - base soil; 5 - heat and sound insulation; 6 - pipeline; 7 - overlap; 8 - concrete screed.

8.2.6 Steel fibers 50-80 mm long and 0.3-1 mm in diameter can also be used to reinforce concrete pavements. In this case, it is recommended to use fine-grained concrete of class B25 and B35 with a maximum size of coarse aggregate of 20 mm as a matrix composition (Table 8.2.1). Steel fiber reinforced concrete coatings are recommended to be made with a thickness of 40-100 mm.

Table 8.2.1

8.2.7 In floor coverings with a thickness of more than 50 mm, it is recommended to provide expansion joints in the longitudinal and transverse directions with a step of 3 to 6 m. boundaries of the top layer of reinforcement. The depth of the expansion joint should be at least 40 mm and at least 1/3 of the coating thickness, the width should be 3-5 mm.

8.2.8 When performing floor coverings on the base soil, in order to prevent floor deformation if the building is subject to settlement, cut-off of the floor covering from columns and walls through gaskets made of rolled waterproofing materials should be provided.

8.2.9 Portland cement (GOST 10178-85) of at least grade 400 should be used for concrete preparation. At the same time, sulfate-resistant expanding cement is recommended for waterproof and frost-resistant concrete.

8.2.10 For light-colored coatings, white (GOST 965-78) should be used, and for colored coatings - colored cement (GOST 15825-80) grade not lower than 400.

8.2.11 Crushed stone natural stone(GOST 8267-82), gravel (GOST 8268-82) and crushed stone from gravel (GOST 10260-82) for concrete classes B30, B22.5 and B15 must have a strength of 100, 80 and 60 MPa, respectively. The size of crushed stone or gravel should not exceed 15 mm and 0.6 of the total thickness of the coating.

8.2.12 Quartz or crushed sand (GOST 8736-85) from natural stone of crystalline rocks (granite, syenite, basalt and the like), coarse or medium-grained, used for concrete coatings, must contain no more than 3% clay or silt particles .

8.2.13 Consumption of coarse aggregate for concrete coatings (crushed stone, gravel, marble chips) must be at least 0.8 m 3 per 1 m 3 of concrete, and sand 10-30% of the volume of voids in coarse aggregate.

8.2.14 For non-sparking concrete coatings, crushed stone and sand from limestone, marble and other clean stone materials that do not form sparks when struck by steel or stone objects should be used.

8.2.15 For alkali-resistant concrete coatings, it is recommended to use crushed stone, gravel and sand from dense sedimentary (serpentinites, porphyrites, limestones, dolomites) or igneous (diabases, granites) rocks or basic blast-furnace slags. Use of pure quartz sand is allowed. Materials for such coatings must withstand at least 15 cycles of alternate saturation with a solution of sodium sulfate and drying without signs of destruction.

8.2.17 For concrete pavements produced by vibration treatment, it is recommended to use the concrete compositions given in Table 8.2.2

Table 8.2.2

8.2.18 Concrete mixes, which do not contain plasticizers, for coatings made by vibration treatment, should be characterized by a draft of a cone of 2-4 cm. 8% by weight of cement.

8.2.19 Works on laying concrete and steel-fiber-concrete mixtures should be carried out at an air temperature at floor level of at least +5 °C. This temperature should be maintained until the concrete acquires 50% design strength. When laying concrete in winter conditions at negative temperatures, sodium nitrate, potash, etc. should be added to the concrete mixture. In this case, it is possible to highlight white spots on the surface of the concrete coating.

8.2.20 Before laying concrete mixtures, the underlying layer must be cleaned of dirt and dust, and grease stains removed by washing with a 5% solution of soda ash, followed by washing with water.

8.2.21 Slots between prefabricated floor slabs, their junctions with walls, as well as mounting holes should be sealed with a cement-sand mortar with a strength of at least 15 MPa, flush with the surface of the slabs.

8.2.22 It is recommended to glue the lower parts of walls and columns to a height equal to the thickness of the coating with waterproofing roll material or, in the case of expansion joints in these places, with polyethylene foam sheet.

8.2.23 When laying coatings up to 50 mm thick, to improve interlayer adhesion, it is recommended to prime the surface of the underlying concrete layer with a composition based on PVA emulsion or latex.

8.2.24 When installing floor coverings on old oiled concrete bases, it is recommended to provide a separating layer of polyethylene film, kraft paper, etc., and make the floor covering at least 100 mm thick from concrete of a class not lower than B30.

8.2.25 The concrete mixture should be laid on the base in strips limited by beacon rails (rolled metal, non-removable aluminum or concrete rail forms) with a height corresponding to the thickness of the coating. In this case, the width of the strips is chosen taking into account specifications the equipment used, the distance between the columns in the building, as well as the planned location of expansion joints. Mounting joints must match expansion joints.

8.2.26 Beacon rails are recommended to be installed parallel to the long side of the wall on cement-sand mortar marks with orientation to the mark placed on the wall. In this case, the first row of rails should be placed at a distance of 0.5-0.6 m from the wall opposite the entrance to the room, and the next rows - parallel to the first at a distance of up to 3 m.

8.2.27 In places where the floor should have a slope towards ladders or channels, beacon rails should be installed in such a way that the top of the rail has a given slope.

8.2.28 Immediately prior to placing the concrete mixture, the underlying layer should be moistened with plenty of water so that at the time of laying it is wet, but there is no accumulation of water on it.

8.2.29 The concrete mixture should be laid between the beacon rails in strips through one. At the same time, the thickness of the leveled concrete layer, taking into account its subsequent settlement during vibration treatment, should be taken 3-5 mm above the lighthouse rails.

8.2.30 With a concrete floor covering thickness of up to 100 mm, it is recommended to compact the concrete mixture with a vibrating screed, and with a greater thickness, it is necessary to pre-treat the laid concrete mixture with a deep vibrator before compacting with a vibrating screed. The speed of movement of the vibrating screed should be 0.5-1 m/min with the number of passes 1-2.

8.2.31 Concreting is recommended to be carried out without technological interruptions. Otherwise, before resuming concreting, the hardened vertical edge of the previously placed concrete must be cleaned of dirt and dust and washed with water. In places of working joints, compaction and smoothing of concrete should be carried out until the joint becomes invisible.

8.2.32 The skipped lanes are concreted after the removal of the lighthouse rails, using the concreted lanes as formwork and guides.

8.2.33 Vacuuming of concrete is carried out using a set of equipment, including: a vacuum unit, suction mats, a vibrating screed, smoothing machines, guides for vibrating screeds, hoses and connecting devices, containers for washing suction mats.

8.2.34 When using the vacuum method, the recommended concrete mixes should have an increased sand content by 150-200 kg per 1 m 3 of the concrete mix compared to the compositions in Table 8.2.2.

8.2.35 Concrete mixtures used when using the vacuum method should have a draft of 8-12 cm. The increased water-cement ratio facilitates the laying and compaction of the mixture, and also allows you to get a more even floor covering.

8.2.36 The technological regulations for the manufacture of floor coverings by the vacuum method provide for laying mats with vacuum cavities on the vibro-compacted surface of the floor covering, connecting them with hoses to a vacuum pump and suction of excess water, thereby increasing the strength and uniformity of concrete.

8.2.37 Suction mats are laid on the freshly laid concrete mix with an overlap of 10-15 cm on each side, when laying on hardened concrete - at least 20 cm. lower panels, then they should be overlapped by at least 3 cm), and the upper one is rolled out, starting from the middle. This order of rolling improves sealing. The panels must be laid evenly, without wrinkles and folds. The upper panel, in addition, after laying, it is recommended to iron it with a roller, brush, etc.

8.2.38 The vacuum unit at idle must create a vacuum of the order of 0.09-0.095 MPa. The normal operating vacuum of a vacuum pump is 0.07-0.08 MPa.

The duration of the evacuation increases inversely with the drop in vacuum. At a rarefaction of less than 0.06 MPa, evacuation should not be performed. The evacuation time is calculated on the basis of 1-1.5 minutes per 1 cm of the concrete coating thickness. The end of the process is judged by the termination of the flow of the water-air mixture into the pipeline.

8.2.39 After the end of the vacuuming process, it is necessary to roll up the top panel so that the filter panel is open by 1-2 cm from both sides with the vacuum pump turned on for 10-15 seconds. Then the top panel is completely folded.

8.2.40 In order to improve the evenness and smoothness of the surface of concrete floor coverings after compacting the concrete mixture and setting it to a state where light traces remain on the surface during walking, it is necessary to carry out the primary treatment of the coating - grouting with concrete finishing machines with leveling discs. The secondary processing of the coating - with concrete finishing machines with blades - is carried out no later than after 6 hours.

8.2.41 When using the vacuuming method, the primary smoothing of the concrete surface is carried out immediately after the end of the vacuuming, and the secondary processing - after 3-5 hours.

8.2.42 To increase the resistance of concrete floor coverings to mechanical stress, reduce dust separation and reduce water permeability, it is recommended to harden the surface of the coatings with dry mixes or impregnate the coatings polymeric materials. A combination of these techniques is also possible. The use of colored reinforcing mixtures makes it possible to obtain colored concrete floor surfaces.

8.2.43 Concrete pavement with a hardened top layer is recommended to be made at least 70 mm thick.

8.2.44 The device of a hardened top layer can be provided for a coating made as traditional way, and with the use of vacuum.

8.2.45 For hardened concrete floor coverings, concrete of the following compositions is recommended, wt. hours:

8.2.46 Dry mixtures used for hardening concrete pavements must contain Portland cement grade not lower than M400 and wear-resistant filler, which can be used as metal powders, corundum, quartz, etc., as well as modifying additives. As such a mixture, it is recommended to use a hardening mixture of the Mastertop brand according to TU 5745-003-40129229-01.

8.2.47 The application of hardening mixtures is carried out on the wet concrete surface of the concrete pavement, that is, before the stages of grouting and smoothing. When hardening concrete coatings made with the use of vacuum, the application of the hardening mixture is carried out immediately after vacuuming.

8.2.48 Before applying the hardening mixture, the concrete must be smoothed to soften the crust formed on the surface. After the appearance of moisture on the smoothed surface of the concrete, a dry mix should be applied to the concrete manually or using a mechanical distributor. The consumption of the hardening mixture is 5 kg per 1 m 2 of the coating surface.

8.2.49 It is recommended to apply the hardening mixture in 2-3 steps. At the beginning, 2/3 of the total amount of the mixture is applied. The mixture must be completely evenly saturated with moisture sucked from the concrete, as judged by the uniform darkening of the mixture. The addition of water to the hardening mixture is not allowed.

8.2.50 The smoothing of the surface is carried out by a concrete finishing machine with a disk, which excludes the formation of bubbles and shells. Areas that cannot be troweled by machine must be troweled by hand. After applying the remaining mixture, smoothing is repeated.

8.2.51 Finishing the hardened surface should be done with a machine with blades.

8.2.52 Not later than 2 days after the coating is applied, expansion joints should be cut using joint cutters with a diamond disc. When using non-removable rail molds, the grooves in the upper part of the rail molds are used as expansion joints and the cutting of the joints is carried out only in the transverse direction.

8.2.53 Concrete coating after its installation must be kept in humid conditions (covering with polyethylene film, etc.) for at least 7 days, then natural drying is carried out. It is also possible to use compositions applied to a wet concrete surface and forming a film in order to prevent premature removal of moisture from the concrete. As a rule, one-component compositions based on acrylic dispersions are used as such compositions, in particular Master-Cur 113 sealant-hardener (MVT concern, Belgium). It is also recommended to use Rizopox 5601W water-dispersion epoxy paint (TU 2257-011-43548961-2002) and Rizopox 1301W water-dispersion epoxy primers (TU 2257-027-43548961-2003) and Koropox brands (Korodur, Germany). ).

8.2.54 The application of such compositions is carried out by roller immediately after the smoothing stage, with at least two layers of the composition being applied.

8.2.55 The use of the compositions specified in clause 8.2.54 to prevent premature drying of concrete on coatings on which polymer impregnation is planned is not recommended.

8.2.56 After the concrete has reached an air-dry state (moisture content not higher than 5%), expansion joints should be sealed by laying an elastic polyurethane cord into the formed groove and pouring it flush with a curable elastic urethane composition, which is recommended as a sealant "Gerteks" (TU 5770- 006-04002274-00). When performing expansion joints near columns and along walls, polyethylene foam gaskets should be removed and the resulting groove should be filled with a polyurethane composition.

8.2.57 When the concrete reaches an air-dry state, in order to reduce dust separation from floor coverings and their water and oil permeability, it is also possible to apply impregnating compositions, the compositions of which and application technologies are given in Chapter 9.

8.2.58 The operation of the floors is allowed after the concrete has acquired the design compressive strength, pedestrian traffic on these floors can be allowed if the concrete compressive strength is at least 5 MPa.

Asphalt is the main material used for road construction. After a few years, such a coating needs to be repaired, then its operational properties are restored annually. Concrete pavement is much better than asphalt pavement, but it is used to a limited extent. There are reasons for this, related to insufficient funding, low productivity, climatic conditions, insufficient amount of cement of the required grades, and relief areas. This technology is not particularly popular in Russia yet, since asphalt roads are much cheaper. However, we note that gradually the cost of these types of linen is slowly equalized. The construction of concrete roads, bridges, runways at airfields begins.

Advantages of concrete roads

Such coatings have certain advantages:

• concrete road has good strength, repair work does not need. The coating can be used for at least four decades, and for asphalt this period is limited to a decade with annual repairs;
• automotive technology consumes less fuel. This is due to the fact that during the movement of a heavy vehicle, road concrete is not subjected to deformation, from which vehicle it is necessary to move a fifth of the fuel less;
• The coating is resistant to sudden changes in climatic conditions. He is not affected heavy rains or sudden changes in temperature;
• there is a preservation of air purity, because cars need less fuel, the exhaust gases of which pollute the environment;
• natural resources are used sparingly. Limestone is used to make concrete, and oil is used to make asphalt.

Construction technology

The device of concrete roads includes certain stages:

1. The ground base is being prepared. It is rolled to achieve the desired density, if necessary, moistened or dried.
2. Water drainage is organized to extend the operational period of the canvas and give the ride safety.
3. The underlayment is being installed. It is a sandy layer, the thickness of which is up to two to four tens of centimeters.
4. The formwork structure is being assembled. Its elements are made of lumber, while taking into account the height of the fill.

If water seeps into the ground, the pavement is gradually destroyed.

The construction technology is complex, and each stage will be considered in detail.

Concrete road structure

The canvas includes certain layers:

• underlying - for its device, gravel is used, which drains groundwater, and sand, with which the resulting loads are compensated;
• reinforcing - represented by low-grade concrete that binds the bulk layer;
• the roadbed is a concrete surface.

The construction of a concrete road for heavy vehicles is made of stressed and non-stressed reinforced concrete, the reinforcing frame base in which does not allow the stone to crack from the weight of trucks.

In private construction works or when arranging a concrete pavement of roads on soils oversaturated with moisture, it is laid out on a sand cushion waterproofing material preventing severe wetting roadbed followed by corrosion of stones and reinforcement. As a waterproofing material, ordinary roofing material is used.

Execution of works

Let's take a closer look at what constitutes a particular construction stage of concreting roads.

Training

Earthworks are difficult, and they are quite expensive. Their beginning is preceded by the preparation of a detailed design solution, the conclusions of which are based on geological studies of the area. If there is such an opportunity, then the concreting of roads is carried out horizontally, removing small hills or laying compacted rock in the recesses.

If a large highway is being built, then a layer of fertile land is removed in in full, and for the construction of a concrete road in the yard, it will be enough to remove from fifteen to twenty centimeters of soil.

The prepared base is compacted by rollers and vibration mechanisms, which are characterized by a large weight.

This stage is considered a crucial moment, since the stiffness index and the integrity of the road surface depend on the strength of the base, even when dynamic loads are quite intense.

At runtime earthworks the device is being thought out drainage system to be able to remove ground and rain moisture. For this purpose, the base is brought out in a plane, the inclined angle of which is from two to four degrees. Concrete gutters are installed on the sides of the road or slopes of a natural type are arranged, along the slopes of which water will enter the receiving wells or go into the ground.

Litter layer

A sand cushion is arranged, the thickness of which is twenty to forty centimeters. This element can be omitted, but it perfectly protects against moisture coming from the ground, improves the drainage process. The bedding layer is necessary to prevent erosion and heaving during frosts, which leads to the formation of depressions and cracks in the cast-in-place concrete.

Most problems appear on clay, peat and other areas of the terrain that can hold water. In most cases, such layers are partially removed, the bottom is covered with large stones and gravel. The rolled layer reaches a height of thirty centimeters. The costs and time required for construction will depend on such preparation.

The minimum thickness of the base depends on the type of soil and climatic conditions. Determine it according to a special table. If the layer is laid out from various materials, then a geotextile is spread between them.

Align the layers in accordance with the designed slopes. Stone backfills are strengthened with binders - cement, granulated slag from metallurgical production, to which quicklime is added, ash from thermal power plants, ground slag.

formwork

For the manufacture of this structure, boards are used, the height of which corresponds to the level of pouring concrete for the road. As a rule, it is equal to ten to fifteen centimeters. When determining its dimensions, it must be taken into account that ribs are arranged along the edges of the concrete to improve strength. The thickness of the boards should not be less than 5 cm. Each structural element should be covered special composition, which will facilitate detachment from the cured concrete.

Requirements are imposed on wooden formwork panels in terms of strength from expansion by their fresh concrete mass and the forces that arise as a result of tamping.

If heavy equipment is used for the construction of roads made of concrete, with which the concrete is compacted, then a formwork made of steel material should be installed. It will last much longer. At the heart of each element is a sole that improves stability.

Formwork sections are set in one line, firmly fixed. This is especially important if the vibrating of the concrete mass is carried out by heavy machinery. In places where the level of the base is reduced, lean concrete is poured under the formwork to improve stability.

Reinforcement

If the technological process of constructing a concrete road involves this type of work, then the reinforcement should be a metal mesh, the cell area of ​​which reaches 150 mm. sq. This choice of material will make it possible to avoid expansion and cracking in the concrete thickness.

Laying of the reinforcing mesh is carried out in the process of pouring the concrete mixture at a height of three to four centimeters from the lower level. Before this, the poured concrete is leveled, the frame mesh is covered, and, if necessary, fixed. Now you can continue to work.

fill

The litter layer is covered with a material that is resistant to getting wet, waterproofing, or simply moistened. Road concrete, corresponding to GOST, is laid out in thickness in one go. When reinforcement is applied, the process is carried out in stages.

Concrete for the road, the brand of which meets all the requirements, is applied quickly, since it does not have a long pot life. It is not recommended to add water to the mass, because the mechanical properties of the coating will deteriorate. Since construction volumes are large, factory-prepared road cement is delivered to the place of work. The mixture is unloaded in one cubic meter and leveled to give the entire layer the same density.

The best option for laying a concrete canvas is two or three layers.

The concrete mixture is compacted by special mechanisms, represented by wooden or metal beams, which are acted upon by pneumatic hammers mounted on them. Such a device descends into the mixture, begins to move in it. Having processed one section, the beam is moved further.

If reinforcement is used, then the vibration device should be located five to seven centimeters above the upper edge of the frame.

In a special machine, in addition to the vibration device, there is also a leveling device located in front.

The concrete composition must be flexible and sufficiently mobile, but not too liquid, so that it cannot float, flowing through the formwork panels. All this will negatively affect the strength of the coating.

Seam cutting

A prerequisite is the device of expansion joints. This type of work is possible when concrete reaches a certain level of strength, which is 50 - 60 percent. In this form, the canvas is able to withstand the weight of not only the worker, but also a special tool for cutting seams.

In this way, the thermal expansion to which concrete is subjected to varying degrees is compensated. Road segments do not form cracks during seasonal changes.

Sawing is performed by jointing - a special tool. The distances between the seams are determined by design calculations. As a rule, for this, the thickness of the monolithic coating is multiplied by thirty.

To prevent moisture from getting into such seams, they are filled with mastic.

Materials for constructing a concrete web

M400 - universal concrete composition. Its strength allows it to withstand loads from various wheeled vehicles. The basis is Portland cement, which is resistant to moisture. Plasticizers are also added to the solution to improve hydrophobicity and strength.

The concrete mixture consists of:

• cement - 1 part;
• gravel - 5 parts;
• sand - 2 parts.

The composition of concrete and its characteristics are specified in the construction project.

Slab covering device

Concrete slabs for the road are made as follows:

1. Forms of the required size are being prepared, or formwork panels are being set up.
2. If necessary, a reinforcing cage is prepared to improve the strength of the plates.
3. Pouring is carried out with a ready-made concrete mixture, it is advisable to immediately tamper to remove air bubbles.
4. After some time, when the concrete hardens, you can remove the formwork and give the slabs time to gain the desired strength.

With the help of such material, you can make a concrete road with your own hands. Under all conditions, it will serve you well for a long time.

Conclusion

The concrete pavement of the road is durable, but needs some care. The resulting cracks must be immediately repaired so that they do not increase in size. To do this, use special putty compositions or concrete mortar. If a fracture has formed, the entire section of the concrete sheet should be removed.

→ Building quality control

Polyvinyl acetate-cement-concrete coatings

Polyvinyl acetate-cement-concrete coatings are made from a mixture of crushed stone, sand, cement, polyvinyl acetate emulsion and water, and, if indicated in the project, also dye pigments. This type of floor consists of several films of polyvinyl acetate mastic, each 1-1.5 mm thick, applied to a well-prepared base. Polyvinyl acetate coatings are high-strength, wear-resistant, slow-burning, have good adhesion to any kind of bases and are of the type of warm and elastic floors. The device of polyvinyl acetate floors is not allowed in rooms with abundant or. prolonged hydration, as they are slightly water resistant. To increase water resistance, floors can be coated once or twice with high-strength varnishes No. 170, 52 or 4-c. The bases for polyvinyl acetate coatings must be rigid, so they are made of concrete, cement mortar or xylolite. Humidity. concrete base or cement screed before application. mastic should not exceed 6%, xylolite-15%; the strength of concrete and xylolite must be at least 50 kg / cm2, lightweight concrete panels - 150, gypsum concrete - 75 kg / cm2. Before applying polyvinyl acetate mastic, it is necessary to accept the bases prepared for the bulk coating. Polyvinyl acetate mastics are prepared from a mixture of polyvinyl acetate emulsion, powdered filler, pigments and water. The use of a porridge-like emulsion with resinous grains exfoliated from water for the production of coatings is prohibited. The emulsion can be stored in hermetically sealed containers at temperatures from 0 to +40 ° C for no more than one year. This must be taken into account when accepting it for construction. The emulsion stored at negative temperatures, regardless of the shelf life, is rejected. As pulverized fillers, marshalite or finely ground light-colored stone materials are used with a compressive strength of at least 400 kg / cm2 (quartz sand, light granite, marble, etc.) and a grain size of not more than 0.15 mm. The pulverized filler must be uniform in color for the given scope of work, air-dry, with a moisture content of not more than 3%. without lumps, clay, organic and other impurities. Dusty materials must be stored in a dry place. Pigments used for mastic must be finely ground, acid-resistant and light-resistant (ochre, red lead, mummy). Before use, they must be ground with the addition of a small amount of water, which ensures their uniform distribution in the mastic and completely guarantees against the formation of dry lumps. The color of the coating is selected according to the standards visually, evaluated in daylight according to hardened dry samples (cement-sand tiles-standards 20X30 cm in size). Coloring must be agreed with the customer and architectural supervision. All sinking irregularities, cracks and potholes of the base are puttied with polyvinyl acetate mastic with a composition of 1: 3 (polyvinyl acetate emulsion, dust-like filler) without the addition of dye and water, and the tubercles are ground down with carborundum or an electric grinder. When preparing the mastic, its weight composition, the amount of added water, viscosity (90-100 s, measured with a 133-4 viscometer) and the duration of movement (at least 5 minutes) are controlled. The prepared mastic is filtered through a sieve with a mesh size of 0.5 mm. Then, after settling for 15-20 minutes, the floating foam is removed from the surface of the mastic, and the mastic is loaded into the tank of the spray apparatus. The tank has a conical bottom, and the mastic withdrawal tube must reach the cone so that foam does not enter the nozzle. Spraying is carried out with a nozzle-nozzle or gun. Spray units have spare nozzles to replace clogged ones. The prepared mastic should be used in 5-6 hours at air temperature: a 10-15 °C and in 2-3 hours at 20-25 °C. Dilution of thickened mastic with water or polyvinyl acetate emulsion is prohibited. It is necessary to control that the tanks of the spraying units are washed with water before loading a new, freshly prepared mastic. The hardening time of coatings made of polyvinyl acetate mastic is 4-5 hours for putty consistency and 3-4 hours for the top layer. It is recommended to apply the second layer one day after the first one and carefully dedust its surface before that. Layers should be applied in strips 1-1.25 m wide towards the exit door. Walking on unhardened mastic or laying running boards and other devices on it is not allowed. During a break in work, the floor area is fenced with slats or strips of plywood. When resuming work, the edge of the previously laid layer is covered with slats to protect against fresh spray and continue to apply mastic to the adjacent floor area. It is necessary to control that the hardening of the applied layer occurs without moisture and dust getting on the floor; the room should be ventilated without creating drafts. In living rooms, mastic floors are usually rubbed with colorless wax parquet mastics. Washing polyvinyl acetate floors with water is not allowed. When accepting polyvinyl acetate floors for operation, they are subject to the same requirements as for parquet.

Concrete is most commonly used for floor coverings. The material provides high structural strength, resistance to aggressive operating conditions. Floor construction technologies are well studied, do not cause excessive costs and are characterized by a wide range of applications.

Concrete underlying layers are arranged where, during operation, the action of oils, solutions, solvents, and various aggressive liquids is possible. In all other cases, you can get by with the installation of non-rigid sand-gravel, slag, asphalt concrete, clay concrete pads.

The thickness of the preparation depends on the design loads. The characteristics of the soils and the materials used are always taken into account. However, current regulations determine the minimum thickness of the underlying layers. If they are laid in residential and public premises - this is 80 mm, if in production - 100 mm.

On floors with a slope, organized runoff, the seams coincide with the watershed, in other cases - with the expansion joints of the building

The concrete must provide the load-bearing capacity of the preparation. As the main material, a mixture of class B22.5 is used. Less durable concrete (but not lower than B7.5) can be taken at low operational loads, in particular, at low tension in the underlying layer.

If the operating conditions are such that the floor will accept sudden temperature changes, expansion joints are always cut. They are placed with a step of 8-12 m in mutually perpendicular directions.

Soil preparation

Before pouring concrete preparation, it is required to prepare a soil base.

The principle of work is as follows:

• if necessary, excavation of vegetable soil is carried out;
• if a high occurrence of the aquifer is revealed, measures are taken to lower the level ground water;
• dusty, clay and loamy soils must be dried. The operation lasts until the bearing capacity is restored;
• if the floor is arranged in unheated rooms + protection against deformation is implemented on heaving bases;
• porous soils are removed and replaced with soil with a small draft, or they are fixed;
• if the base has a broken structure, or it is bulk, it should be cleaned of debris, impurities and compacted. Mechanical or manual rammers are used for work. Manual labor justified only if the equipment can provoke the displacement of adjacent structures and foundations. According to the technology, soils are poured in layers (10 cm each), ramming each layer.

The surface of the subgrade must comply with all planned design elevations. Based on the lower level of the surface, the soil is leveled, poured, compacted. If mixtures of soils are used for the construction of foundations, they are laid in layers of 50-75 mm with layer-by-layer compaction.

Backfilling of underlying layers

When working on the ground concrete preparation laying the underlying layers.

The works are carried out as follows:

• a layer of building sand is poured onto the base (prepared and leveled). It is spread over the entire area of ​​\u200b\u200bwork in a continuous even layer. The thickness of one layer should be 5-10 mm. Compaction is carried out, for which the sand is pre-moistened;
• then a crushed stone layer is laid out. It is selected by size, composition, stacked and moisturized. As a result, a uniform continuous layer should be formed, 80-200 mm thick. Crushed stone is leveled and rammed mechanically or hand tool. If gravel is used, it is laid in a similar manner;
• on dry grounds, it is permissible to work with adobe mixtures. The material is laid in a layer up to 100 mm, compacted until moisture reaches the surface.

If multi-layer preparation is implemented, each subsequent layer is laid after careful processing of the previous one.

To improve adhesion in the underlying layers, moisturizing is applied between them.

Pouring concrete preparation

The material can be transported to the place of work by concrete pumps, carts, dump trucks. If the structure does not require reinforcement, concrete is laid directly from carts or dump trucks to the center of the pour area. If a reinforcing layer is provided, the concrete is unloaded by tipping to the side.. If required, the placement of the reinforcement mesh is adjustable, but the reinforcement must not be moved when pouring. For large volumes of work, it is advisable to use a concrete pump that ensures uniform distribution of the solution.

The working principle is as follows:

• beacons with strict horizontal control are placed on the base. Boards can be used as the main material, the width of which corresponds to the thickness of the concrete preparation, 4-6 cm thick. On the base, the beacons are fixed with wooden pegs hammered to a depth of 30 cm, in increments of 1.5 m. Instead of boards, it is permissible to take a metal channel;
• if a slope is to be organized on the floor surface, it is provided at the preparation stage by cutting off the upper edge of the beacons at the required level;
• with a large amount of work for the device of concrete preparation, the construction of a collapsible formwork is required, with reliable fixation of all elements;
• concrete is brought to the surface. Concreting is carried out in strips through one;
• first of all, the strips remote from the entrance are poured, successively approaching it;
• when the concrete has set, proceed to the processing of adjacent unfilled strips. The side faces of the finished slabs are pre-treated with hot bitumen. Application layer - 1.5-2 mm. These faces will form expansion joints;
• proceed to the formation of shrinkage seams. To do this, a metal profile is deepened into a freshly poured preparation, 4-5 mm thick, 80-100 mm wide. The profile should be deepened by 1/3 third of the thickness of the preparation. The material is left for 20-40 minutes and removed. When the concrete has matured, shrinkage joints are poured with cement mortar or hot bituminous mastic.

After completion of work, the surface is treated with trowels.

Waterproofing

The waterproofing layer is arranged for concrete preparation with medium and high intensity of exposure to water and other liquids on the floor (+ alkalis, solutions, acids). These can be floors of unheated premises, structures built on subsiding soils, floors on floor slabs, areas with a risk of capillary suction of groundwater. Besides, protection is necessary if the concrete preparation is placed below the level of the blind area.

The choice of material is subject to the following principles:

• if it is required to provide protection against the action of water, chemically aggressive liquids, materials such as polyethylene film, polyvinyl chloride film, hydroisol can be used;
• against the background of medium intensity of action Wastewater waterproofing works successfully. It is permissible to work with bituminous materials, applying them in 2 layers. ;
• against the background of the high intensity of the action of liquids on the floor, it is possible to arrange pasting waterproofing, but with a doubling of the number of layers;
• under concrete preparation, it is permissible to arrange waterproofing based on crushed stone and other bulk materials, followed by impregnation with hot bitumen.

Polymer gluing waterproofing is placed in 1 layer

In the latter case, protection is arranged after filling the crushed stone cushion. The layer is impregnated with an asphalt distributor or manually. Hot bitumen is evenly applied to the base, with a layer 5-6 mm thick. If the bituminous impregnation is arranged in several layers, sand (fractions up to 5 mm) or stone chips are allowed along the first one. Compaction is carried out with a roller, after which a second layer up to 0.25 mm thick is implemented, using sand powder.

Regardless of the materials used, the waterproofing layer must be continuous, sealed, protruding above the floor to a height of at least 300 mm from the level of the coating.

Principles of coating waterproofing device:

• the base must be flat, dust-free. A primer based on bituminous mastics or polymer-based solutions is applied. The composition can be distributed manually with brushes or by means of sprayers;
• as a result, an even thickness, the same primer layer should be formed, in which there are no gaps. The optimal thickness is 0.5-2 mm;
• the next layers should be applied only after the previous ones have completely dried, which can be determined by the cessation of tack;
• when working with joints, they are covered with mastic and strips of rolled material 10-20 cm wide are glued, after which another mastic layer is applied.

Principles of work with asphalt waterproofing:

• the material can be laid on hot mastics applied in a continuous uniform layer. The applied layer requires leveling, compaction with trowels or rollers;
• the next one is applied after the bottom is ready, that is, the mastic has completely cooled down;
• joints are arranged apart, an overlap of 200 mm is observed;
• the top layer of protection must be even, with the observed thickness and slope;
• if they work with cold mastics, the principle of work remains the same.

Principles of work with rolled waterproofing:

• the material can be glued on cold or hot bituminous mastics. Substrate preparation requirements remain typical;
• when using hot mastics, adjustment of the panels is required;
• the roll is rolled out over the base so that an overlap of 100 mm is provided;
• the laid material is left for 24 hours to eliminate irregularities and waves. The temperature in the room should not be lower than +15 degrees;
• when the panels have rested, they are rolled back, leaving only the first longitudinal row and a guide line for gluing is outlined;
• about 0.5 m is bent from the roll to be glued and mastic is applied. The base under the roll is processed with the material;
• the area with mastic is glued, pressing tightly to the base, rolling with a roller from the middle to the edges;
• then turn off the rest and act in a similar way;
• the edges of the glued material are rolled with a roller;
• the next roll is glued with an overlap of 10 cm, observing the lubrication of the edges and processing with a roller. Then they act in a similar way, filling the entire area of ​​\u200b\u200bwork;
• when the first layer is ready, proceed to the device of the second, observing a longitudinal overlap of 20 mm. Control the placement of seams apart.

If the base does not have slopes, roll materials are rolled out over the surface. If there is one, they work from low areas to high ones.

thermal insulation

Effectively apply thermal insulation materials with high density. These can be mats or fiberglass-based plates, mineral wool or more modern polystyrene foam. The optimal layer thickness during work is 100 mm.

Thermal insulation is laid closely on the base, ensuring a snug fit of the joints. As an alternative, it is permissible to use bulk thermal insulation based on expanded clay. It is applied to the base in layers, followed by leveling and compaction.

In the areas where the structure adjoins walls and other vertical surfaces, a gap should be left, which is closed with a tape of soundproofing material.

Concrete pavement technology

Floors with concrete coatings are general-purpose structures that are successfully used both in public construction and in production. A well-made floor is able to withstand high mechanical loads, the action of solutions, oils, salts, and water. On practice the finished system is able to withstand heating up to 100 degrees.

Concrete coating can be arranged on the ground, on the underlying concrete preparation, on cement-sand screeds M150 and higher, on reinforced concrete floor slabs. At the place of work, optimal temperature regime- not lower than +5 degrees, up to a solution of half of the design strength.

Materials for the preparation of concrete:

• Portland cement is not lower than M400 in terms of brand strength;
• gravel or rubble. The fineness should not be more than 15 mm, or 0.6 of the coating thickness. You should count on an average consumption in the region of 0.8 cubic meters per cubic meter of concrete;
• medium or coarse sand;
• water.

If a non-sparking concrete pavement is required, sand and crushed stone based on marble or limestone should be used, which do not spark when struck by metal objects.

The brand of concrete cannot be lower than M200. The mobility of the solution is controlled - 2-4 cm. It is permissible to introduce C-3 plasticizers or other modifying additives into the formulation, which will reduce labor costs during laying.

Concrete laying sequence:

• when starting work, the base is cleaned of dust and dirt;
• if oil stains have formed on the underlying layer, they should be removed with special ready-made solutions or a solution of soda ash (5%). After treatment, the area is washed with water;
• if laying is carried out on prefabricated floor slabs, cracks. . Filling is carried out flush with the surface of the plates.

Recesses, mounting holes are subject to sealing, for which they prepare cement-sand mortarМ150, not lower

Proceed to install beacons using either steel pipes, or wooden beam or metal profile. The diameter and height of the material must correspond to the design thickness of the coating.

The first row of lighthouses is laid out with an indent from the wall equal to 0.5-0.6 m. The subsequent ones are parallel to it with a step of up to 3 m. It is permissible to lay out the layout immediately throughout the entire work area or as separate cards, with docking along the axis and offset by the width of the rail.

Take for fixing cement mortar. The guides are aligned according to the level, in accordance with the previously applied markings. To correct the position, light blows of a hammer or hand pressure are used. Horizontalness is checked with a rail or special devices.

The subsequent installation process is as follows:

• before pouring concrete, the base is abundantly moistened. By the time the mortar is laid, the surface should be damp, but without excess water;
• then determine the scope of work, calculating the speed of concrete preparation, laying, the period of initial setting;
• the solution is delivered to the site from the concrete mixing unit by truck mixers. If pouring is carried out along the first floors, the solution is unloaded directly onto the concreting strip. If work is carried out on the second and upper floors, the solution is transferred to transfer bins and portionwise fed to the work site by lifts, cranes;
• the solution is placed between the beacons, through one lane;
• the layer is leveled with shovels or special scrapers so that it exceeds the beacons by 3-5 mm;
• unfilled strips are poured after dismantling the beacons, using ready-made strips as guides and formwork.

Compaction is implemented with the participation of vibrating screeds, moving them along the lighthouses. If the thickness of the structure is small, the vibration time is minimized, - act until moisture forms on the surface. Excessive vibration exposure can cause settling of coarse aggregate and stratification of concrete.

The optimal speed of movement of the vibrating screed is set within 0.5-1 meter per minute. When moving the tool, a roller 2-5 cm high should be assembled at its lower edge. In the wall zones, in areas near the columns, compaction is carried out with manual rammers, weighing at least 10 kg.

If breaks were made during pouring, before resuming laying, the vertical edges of the coatings that have had time to harden are dedusted, cleaned and washed with water. Where the working seams are placed, sealing and smoothing is carried out until the seam becomes invisible.

Vacuum technique for concrete floors

When laying concrete pavements on concrete preparation, it makes sense to turn to the vacuum technique. In this case, the coating is carried out simultaneously with the underlying layer. As a result, the strength of the surface layer is increased by a third compared to the original values. A high-quality floor with excellent physical and mechanical characteristics is formed.

According to the technology, a liquid concrete solution is laid on the base, compaction is carried out. With the help of special equipment, excess water is removed from the concrete thickness, which works on the strength and rigidity of the layer.

The concrete formulation is selected based on the quality of Portland cement and available aggregates. But,

To ensure the maximum sealing effect, first, an increased content of the mortar part is added to the concrete composition.

The essence of the vacuum method is as follows:

• the concrete mortar is mixed with an excess amount of water so that the draft of the cone reaches 9-11 cm;
• the mixture is unloaded at the place of laying and evenly leveled over the entire area;
• after pouring, the solution is compacted with a vibrating screed if the layer thickness does not exceed 10 cm. On thicker screeds and in the presence of reinforcement, deep vibrators are additionally attracted;
• suction mats are placed on the leveled and compacted layer and connected through the sleeve to the vacuum equipment;
• the filtered bottom panel of mats is placed directly on fresh concrete;
• the top panel is rolled out, smoothing with brushes or rollers. Work starts from the middle of the web, which will have a good effect on sealing in the system during vacuum processing.

If two or more panels are laid on the surface, they should be placed with an overlap of at least 3 cm. The upper edge should overlap the lower one by 10-15 cm. Then vacuuming begins. The duration of the technology is calculated as follows: 1-1.5 minutes per 1 cm layer of concrete.

When no water movement is observed, the treatment is stopped. Concrete must gain density, at which only a slight trace remains on it. The suction mats are removed.

After vacuum processing, you can immediately start smoothing. For the first time they work with trowels with discs, the second time - with blades.

Primary treatment of concrete floors

When the filled layer is sufficiently compacted and managed to grab, you can proceed to the primary processing. The readiness of the coating can be determined as follows - when walking on it, light traces should remain.

The main working equipment - trowels, trowels, with installed trowel discs. The operation helps to correct minor defects that could have been made during pouring and compaction; after processing, a finishing horizon is formed.

Secondary grouting is possible after 1-6 hours. Instead of discs, the blades act as the working body. In hard-to-reach areas, they work manually or with a trowel for processing cement screeds. Such areas are subject to priority grouting due to quick setting.

Care

Concrete is a material that must mature in wet conditions. To provide such an environment, the surface is covered with wet burlap, wet sawdust, maintaining the material in this state for 7-10 days.

The frequency of wetting is selected based on temperature and humidity conditions, however, the material should not dry out even partially

Grinding and milling of concrete floors

This type of processing requires the release of the base from debris, mechanisms and devices. In the milling process, ordinary diamond wheels or cutters with a diameter of 250-500 mm should be used.

Milling is carried out in parallel strips, overlapping the edge of the strip in the next approach by 2-3 cm. In one pass, you can work to a depth of 2-7 mm, focusing on the mechanical and physical characteristics of concrete. The purpose of such treatment is the complete exposure of the aggregate grains, that is, the surface must reach such a strength that its chipping is impossible.

Work is usually carried out in two stages. At the first stage, the milling machine removes a layer of 3-5 mm in one pass. Next, polishing is carried out in 1-2 passes using grinders. When processing, it is necessary to organize a thorough cleaning of the surface in time.

Finishing

Finishing allows you to improve the performance of concrete floors. When choosing materials, they are guided by the conditions under which the structure will work.

You can act as follows:

• surface impregnation with fluates. The coating is applied no earlier than 10 days after pouring the solution. The temperature regime is observed in the room - not lower than +10 degrees. Before work, the base must be dried and thoroughly cleaned. construction vacuum cleaners. The material is applied until the concrete stops absorbing it. Practice shows that three approaches with an interval of 24 hours are enough for this;
• sealant impregnation. For these purposes, liquid glass is used, aqueous solutions calcium chloride. Processing is performed in three approaches with a daily interval. When the treatment is completed, the concrete must be rinsed with water;
• adding toppings. For hardening, special dry mixtures (corundum, quartz, metal) are used. The type of material is selected based on the design loads. Toppings are applied to fresh concrete after initial setting in two passes using concrete finishing machines;
• polyurethane, epoxy varnish can be used as a protective layer. The material is applied to concrete during the initial hardening period, immediately after the completion of the grinding operation. Clean the floor before work industrial vacuum cleaner, treated with a moistened rag and primed with the same varnish, but with a diluted solvent. The compositions are spread by brushes, rollers or spraying. Layer-by-layer drying is observed, during which the surface is protected from moisture.

In addition to polyurethane varnishes for the device of the top layer, you can use polymer coatings(epoxy, acrylic). Paint layers are applied in a thin layer, no more than 0.3 mm thick.. If you want a decorative effect, good choice there will be self-leveling floors forming a seamless matte surface. In conditions of high loads, you can turn to the device of highly filled coatings.

Choice in residential premises finish coat practically unlimited - it can be tiles, laminate, carpet, cork, linoleum ...

Safety

When constructing concrete floors, safety regulations in construction are always observed. All workers must be familiar with the conditions of work, briefing, training in handling equipment and tools.

The device of floors is carried out using technological equipment. Personal and collective protective equipment, hand construction tools are used. Workplace in hard-to-reach places should be well lit.

When laying waterproofing on hot bituminous mastics, special care is required. Ventilation is provided in enclosed spaces. Prolonged contact of cement mixtures with the skin is unacceptable.

cost of concrete flooring

The concrete flooring technology is available and does not require too high costs. On average, the financial costs of laying 1 sq.m. "turnkey" start from 850-1100 rubles. To this cost, you can safely add the cost of purchasing and shipping materials.

Equipment, tool

Concrete work is carried out with the participation of a standard set of machines and tools.

The following set should be assembled at the construction site:

• in the case of self-preparation of solutions, concrete mixers are required;
• preliminary compaction of soils, underlying layers is carried out by mechanical rammers;
• filling is compacted by vibrating rails, deep vibrators;
• finishing processing is carried out with the participation of trowels, grinders;
• industrial vacuum cleaners are used for cleaning and dedusting;
• level, level - a tool for measuring, controlling the horizontal, evenness of the structure;
• shovel, clean container, spatulas.

conclusions

The installation of concrete floor coverings must be implemented in strict accordance with technological process. A qualitative result is achieved with professional work, with a phased quality control of the work.

The device of industrial concrete floors is shown in detail in the video: