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TO ABTQPCNQMY CERTIFICATE1
Dependent on the author. certificate No. †"
Declared 21.111.1968 (No. 1231344 22-3) IPC E 21d 11/10 with application No.
Hvmitet le cases
UD K 622.26: 693.546.5. .002.5 (088.8
The applicant
All-Union Scientific Research Mining and Metallurgical Institute of Non-Ferrous Metals
CEMENT - A GUN OF CONTINUOUS ACTION
Cement guns of continuous action are known, consisting of a frame, an electric motor, a gearbox, a feed tank, a vertical auger, a blower, a blow chamber and a hose with co !! so! !.
However, such cement guns have a pulsating material feed, large overall dimensions and weight due to the complexity of the design, and poor performance.
In order to increase the efficiency of the cement gun, the driven stage of the reducer is made with two gears independent of each other by placing the shaft of the vertical screw on the hollow shaft of the supply tank.
On the drawing isoopa "
It consists of an electric motor 1, a gearbox 2, which is mounted in a frame 3 of a tubular section, on which a casing is fixed 4. Inside the casing there is a feed tank 5 with turners 6. The feed tank is fitted with HB shaft of a vertical auger 7 through the driven gear of the gearbox and mounted in »Her bearing.
In; 1 of the lower part of the pipe 8 of the screw, there is a pumping device in the form of a spiral blade 9.
The cement gun works as follows. The rotation of the vertical auger 7 and the feed tank is carried out from the electric motor through a three-stage cylindrical gearbox, which provides a single angle high speed.
Construction! tiv110e Vyso, 111cis rsdu whopa is such that psrhig two stepsllll psrsdachn have one gear ratio, and the third step is divided into two gears independent from each other: (with different rpm for
1ð output (driven) shafts, i.e. with different gear ratios !!
This is achieved by placing the shaft of the vertical auger inside the hollow shaft of the feed tank.
The dry concrete mix is loaded into a cement gun and continuously mixed with a tedder attached to the feed tank (.
Getting into the supply tank, the dry mixture is directed by a spiral-shaped bottom lidr NUT TO THE VERTICAL SH! ISK, WHICH feeds the ss into the blow chamber 10.
From the blowing chamber, the dry mixture is blown out with compressed air and transported through the hose 11 to the nozzle 12, where it is moistened and p5 is forcefully applied to the fixed surface.
The subject of the invention
Cement gun of continuous action, consisting of a frame, an electric motor, a reducer, a feed tank, a vertical auger, 300620
Compiled by M. Trusova
Editor 3.I. Gorbunova Tekhred L.V. Kuklina Proofreader 3.I. Tarasova
Zach. 2563 Ed. № 520 Circulation 473 Subscription
TsNIIPI of the Committee for Inventions and Discoveries under the Council of Ministers of the USSR
Moscow, K-35, Raushskaya pub., 4/5
For waterproofing such premises as swimming pools, reservoirs, damp basements, dense waterproof plaster is used - shotcrete - plaster.
Shotcrete - the plaster is applied using a cement gun. The method of applying plaster with a cement gun is called gunning. Shotcrete takes place under high pressure of compressed air, due to which a high speed is imparted to the solution stream. Shotcrete - plaster layer 15-25 mm applied to the surface is a fairly reliable waterproofing, since the applied solution is strongly compacted. After 28 days of hardening in natural conditions, shotcrete - plaster reaches a tensile strength of 15 kg/cm 3 .
Units for applying shotcrete - plaster. Shotcrete plaster is applied using a unit that includes a cement gun, an air cleaner, a water tank and a compressor. The main vehicle is a cement gun.
Cement guns are of various brands: СССМ-067, С-165А, С-165Б, С-320А and 0-54. Regardless of the design of the cement gun, the principle of operation is the same.
Cement gun СССМ-067 (Fig. 128, a) consists of an upper 11
and bottom 15
truncated cones-tanks, or chambers, fastened together.
The upper tank has a hopper through which it is filled with a dry mixture. A steel pipeline runs from the outside of the body; flexible hoses are connected to it from the compressor. Compressed air is fed through these hoses to the cement gun.
The S-165B cement gun (Fig. 128, b) has the same device as the SSSM-067. It can also be used as a sandblaster for cleaning surfaces of various structures from dirt, soot, and rust.
An air purifier is required to clean the compressed air that is pumped into the cement gun by the compressor.
The air cleaner is a welded cylinder. In the upper part of the bottom there is an inlet pipe to which a hose for supplying compressed air from the compressor is connected. The lid has an outlet pipe: an air hose is connected to it, supplying compressed air, purified from water and oil, to the cement gun. A porous porcelain filter is arranged inside the air cleaner, which cleans the air supplied by the compressor from dust, moisture and oil.
Before applying the sprayed plaster, water is supplied to the nozzle under a pressure of 0.5 atm higher than the air pressure in the cement gun. This can be achieved by connecting a water hose to the water supply. If there is no water supply or there is very little pressure in it, then a special reservoir is used for supplying water, to which a compressor is connected, with which you can increase the pressure.
Rubber hoses are used to connect the cement gun, air cleaner, water tank and compressor, as well as to supply the workstation from the cement gun to the nozzle of the dry mixture and from the water tank.
The hoses through which the dry cement-sand mixture is supplied are called material, through which air is supplied - air, and through which water - water. For durability, the hoses are reinforced with 3-5 layers of cord (special durable fabric). On the inside, the hoses are covered with soft wear-resistant rubber, and on the outside - with harder rubber, which prevents them from being pushed through.
Material hoses are produced with a diameter of 25-38 mm... It is more advisable to use hoses with a diameter of 32 mm... Smaller hoses reduce the performance of the cement gun and lead to faster plugging. Water hoses are used with a diameter of 13 mm... The individual hose links are connected with screw-on couplings. Hose couplings are riveted or countersunk bolts. To keep air out of the hoses, the connections must be strong and tight.
... A nozzle is used to mix the dry mixture with water and apply the solution to the surface (Fig. 129). The nozzle consists of a body 1
and an annular chamber with inserted mixers 2
... The mixer is a ring with eight oblique radial holes. A metal conical barrel is attached to the mixer body from the front 3
with inner liner 4
made of rubber, which protects the barrel from rapid abrasion. On the rear side of the body, a material hose is reinforced with a half-nut 5
, through which the dry mixture is fed into the nozzle. A branch pipe is attached to the body at the top 6
with valve 7
, a water hose is connected to the valve 8
... The water supplied from the branch pipe enters the mixing chamber in streams and, meeting with the cement-sand mixture, mixes - a solution is formed. The solution is forcibly thrown by compressed air from the nozzle onto the surface, penetrates into all its irregularities and firmly connects to it.
The S-320A and O-54 cement guns are more advanced. They have water pumps that can supply water at the right pressure to the nozzle from any source. They can work without an air cleaner, which makes the unit more compact. In addition, they are mobile continuous machines.
Cement gun S-320A (Fig. 130) is designed to apply a waterproofing layer to various surfaces, to clean them with an air-sand jet. It consists of a bunker 4
, body, four wheels, sluice drum 8
, dispenser 10
with drive mechanism and water pump. Bunker 4
has a grid, which is necessary for the control sifting of the dry mixture.
An electric motor is installed on the cement gun; it drives a dispenser and a gear pump that supplies the nozzle with water.
Technical characteristics of the S-320A cement gun
Dry material consumption, m 3 /h .... 1,5
Average layer thickness applied at one time, mm ...... 20
Acceptable grain size, mm............... 8
Dry mix feeding distance, m:
horizontally ........................... 70
vertical ............................. 30
The greatest air pressure, kg/cm 2 ............ 3-3,5
Water pump (capacity), l/sec, with a head up to 40 m.... 0,23
Weight, Kg:
without hose ............................ 800
with hose ............................ 950
Cement Gun 0-54 is a smaller S-320 cement gun. The performance of the cement gun 0-54 is lower. Its main purpose is to clean facades using air-sand and water-emulsion mixtures, as well as to apply compacted plaster in one layer.
Technical characteristics of the cement gun 0-54
The area of the surface to be cleaned, m 3 /h:
using an air-sand mixture ........... up to 50
using water-emulsion mixtures .......... up to 15
Consumption of dry materials, m 3 /h............... to 1
Air consumption, m3 / min:
with air-sand mixture ............... up to 2.5
with water-emulsion mixtures .............. up to 1
Air pressure, kg/cm 3 ................. to 5
Feed range, m:
air-sand mixture ................. up to 30
water-emulsion mixtures ................ up to 40
Electric motor power, kW..........................2,8
Dimensions, mm:
length .......................... 1100
width .......................... 580
height ......................... 1100
Weight, Kg..............................250
Preparation of dry mix for shotcrete plaster. The dry mixture is prepared in stationary installations and delivered by car to the place of work. It is prepared both at the construction site in mixers and as an exception on the striker manually by prancing.
To protect the dry mix from moisture, it is necessary to have a chest with a tight-fitting lid at the work site.
The mixture brought from a stationary mortar unit or prepared at a construction site is recommended to be additionally sieved through a sieve with 8X8 cells before use. mm to mix better and become more homogeneous. This mixture is well transported through hoses.
For the preparation of shotcrete - plaster, cement grades 300 or 400 and river sand are used. The ratio between cement and sand ranges from 1: 1 to 1: 8.
The sand used must be sufficiently dry and clean; contamination of the sand reduces the strength of the shotcrete plaster. Allowable sand moisture 6-10%. If its moisture content is less than 4%, sand should not be used, since the prepared mixture will stratify during transportation through material hoses. Overdried sand does not mix well with water in a nozzle, and a cement slurry that is uneven in composition is obtained. The use of excessively fine sand reduces the strength of the sprayed plaster by a factor of two or more.
To accelerate the setting of the shotcrete plaster, additives of calcium chloride or water glass are introduced. Calcium chloride is injected no more than 5% of the mass of cement. Calcium chloride is used only at low temperatures (below + 5 ° C). Liquid glass is injected in the amount indicated by the laboratory.
To obtain greater water resistance, ceresite can be added to the sprayed plaster in a ratio of 1: 10 (1 part of ceresite and 10 parts of water) or sodium aluminate from 1: 6 to 1: 15, where 1 part is taken from 6 to 15 parts of water. These chemical additives are dissolved in water and poured into a dosing tank.
Shotcrete with a cement gun. Before starting work with a cement gun, first of all, a unit for gunning is installed (Fig. 131): near the cement gun 1
air purifier 4
, storage tank 3
for water and a little further the compressor. A hose with two branches is drawn from the compressor. One end is connected to the air cleaner, the other to the water tank. From the air cleaner, the hose is connected to the cement gun. Thus, compressed air will be supplied to the cement gun from the compressor. A material hose is connected to the nozzle from the cement gun, and a water hose from the reservoir.
After installing the unit, it is necessary to check how it works and make sure that no air passes anywhere.
The cement-sand mixture is loaded into the upper chamber of the cement-gun, under the influence of its own weight, the mixture is poured into the lower chamber. The shutter closes and compressed air is admitted into the chamber. The mixture is fed by a distributor plate to the branch pipe. Compressed air passing through the nozzle picks up the mixture and blows it through the nozzle and material hose to the nozzle.
As soon as the loosened, suspended mixture, caught by a jet of compressed air, approaches the nozzle, it is wetted with water, mixed in the mixer, turns into a solution and is thrown out by a strong jet from the nozzle.
The amount of water supplied to the mixer is regulated by a valve. The dosage of water supplied to the mixture is checked by the color of the jet emitted from the nozzle, by the color of the sprayed plaster applied.
With an excessive dosage of water (Fig. 132, a), a liquid solution is obtained, slipping from the applied surface. With a lack of water (Fig. 132, b) in the mixture, the solution is not completely wetted and, when ejected from the nozzle, becomes very dusty.
Driver is obliged not only to monitor the operation of the cement gun and the air pressure, which must correspond to that specified in the passport of the machine, but also to monitor the presence of water in the tank; periodically 3-4 times per shift, he should blow the air filter.
Shotcrete of surfaces is performed by a unit consisting of two plasterers of the 4th grade, one plasterer of the 3rd grade and a machinist of the 4th grade.
The duties of the link include washing the gunned surfaces with water, preparing a dry mixture, loading it into a cement gun and gunning. For a change, the link must spray at least 100 m 2 surfaces.
In a properly assembled unit, productivity reaches 150 m 2 per shift with a layer thickness of 20 mm... With centralized mixing, productivity increases.
Engineer, in addition to controlling the cement gun, he is also obliged to take part in loading the cement gun with a mixture.
The 4th grade plasterer washes the surfaces, supervises the preparation of the mixture, applies a layer of mortar to the surface, tightens and removes the hoses, identifies the formed mortar plugs and eliminates them, monitors the operation of the machine, the quality of work and performs various auxiliary work.
The second plasterer of the 3rd grade helps the first one and, if necessary, replaces it; in addition, he is the liaison between the plasterer and the minder. With plaster of the 4th grade, he prepares a dry mixture and loads a cement gun.
If the dry mixture is prepared on site, then the 3rd grade plasterer delivers sifted sand and cement to the place of work, pours them onto the striker and shovels them together with the 4th grade plaster, loads the prepared mixture together with the minder into the cement gun.
If the surface of the shotcrete plaster needs to be wiped down, then a plaster of the 3rd or 2nd category is additionally attached to the link. When performing an improved plaster, a plasterer of the 3rd category works, and when performing a simple plaster - of the 2nd category.
For work, it is necessary to prepare such an area that could be shot during one work shift. The surface must be cleaned in advance, and only moisten with water before applying the gunning plaster.
It is recommended to plaster from top to bottom. Moreover, the thinner the applied plaster layers and the more of them, the stronger the shotcrete plaster and the more reliably it will provide water and gas tightness.
It is recommended to apply each new layer to the previous one after it has set, but not earlier than after 60 min... The first layer of shotcrete plaster is usually applied with a thickness of 15 mm, then it is leveled, cutting off individual irregularities with a spatula or trowel. The first layer is kept for 24 h, then it is moistened with water and a second layer is applied.
When gunning nozzle holds the nozzle perpendicular to the surface at a distance of 70-80 cm from her. Smaller sand grains of the solution are more quickly clogged into pores and cavities and first of all settle on the surface; larger grains of sand, hitting small ones, compact them, but at the same time partially rebound. With the growth of the layer of shotcrete plaster, large grains of sand also begin to sink into it. At first, the rebound of coarse sand reaches 20-25%, but gradually, as the layer is applied, it decreases. Basically, sand grains bounce off without a cement layer, so that the loss of binder is negligible. The joints of the shotcrete areas should be thoroughly cleaned of settled dust and moistened with water before starting work.
In order to avoid shrinkage cracks and increase the durability of the applied sprayed plaster, it must be properly maintained. Shotcrete areas should be protected from drafts, excessive solar heat and mechanical damage. It is best to cover the surfaces with two or three sheets of tarpaulin overlapping one another. The tarpaulin should be pre-moistened with water; for constant moistening of the tarpaulin over it it is necessary to arrange a perforated tube through which water is supplied. Where shotcrete plaster is used in the form of ordinary plaster, it is recommended to wet it for 5-7 days.
The cement gun, hoses and nozzles should be thoroughly cleaned every day after work; first blow with a jet of compressed air, and then, without disassembling the machine, clean all accessible places. Regularly, at least once a week, it is necessary to disassemble, clean and lubricate the machine, wash its individual parts with kerosene. Uninterrupted operation of the unit is possible only with proper and timely maintenance of it.
Safety precautions. Before starting work, the team servicing the cement gun must be instructed on the rules of labor protection.
Since an almost semi-dry mixture is thrown from the cement gun, plasterers need to wear goggles and a respirator. Work should be done in tight overalls and mittens. When working at heights, workers are required to wear safety belts and be firmly attached to the reliable structural elements of buildings.
The plasterer must carefully ensure that no one gets under the spray of the sprayed plaster.
All electrical wires leading to the unit must be carefully insulated and laid in boxes if they pass along the ground, or are suspended above a person's height, since the unit is powered by a 220V lighting network v.
Scaffolding decks must be solid and continuous. Before starting work, the plasterer is obliged to carefully check all the hose connections, during the work to ensure that the air pressure in the cement gun does not exceed the specified in the instructions.
When eliminating mortar plugs, workers who are not associated with this operation are prohibited from staying near the hoses; nozzle and open mortar hose must point in a direction that is safe for workers.
When disconnecting the hose, pressing the assembled unit and testing, there should be no unauthorized persons near the unit.
58 0
[TORKRET-PUSHKA] - installation for application by spraying under pressure of mortar or concrete mixture on the treated surfaces of structures
Values in other dictionaries
Cement gun
a device for applying construction mortar and concrete mixture to the surface of structures and structures (see Shotcrete). In the USSR, Ts.-p. with a sluice drum (for concrete mix with aggregate no larger than 10 mm, productivity 1.5 m3 / h) (see Fig.) and with a sluice chamber (for concrete mix with aggregate not larger than 25 mm, productivity 4 m3 / h). Horizontal feed distance ...
Cement gun
g) a pneumatic apparatus for applying smth. a layer of cement or lime mortar supplied with a jet of compressed air. ...
Cement gun
installation for spraying solution and concrete mixture (shotcrete) on the surface of structures and structures. It is used for construction and repair of hydraulic engineering, prom. and citizen structures, and also as a sandblaster. CPU performance up to 6 m3 / h, horizontal delivery distance up to 70 m. See fig. Cement gun ...
Alumina Cement (Aluminate)
cement, obtained by fine grinding of clinker, made by sintering rocks rich in alumina (bauxite) and limestone (or lime), with a predominance of low-basic calcium aluminates in the finished product. Differs in a rapid increase in strength. Varieties of alumina cement: lime-ash, lime-pozzolanic, lime-slag, clinker-free slag. ...
Cement-pushka
Pneumatic device for applying a layer of cement or lime mortar to the surface of something, supplied with a jet of compressed air.
- - an artillery gun for flat shooting at ground targets or for shooting at air targets. P. have a long barrel, high muzzle velocity, surpass all other types of artillery ...
Dictionary of military terms
- - cannon is a long-barreled artillery gun with a high initial velocity of the projectile and an elevation angle of the barrel not exceeding 45 ° ...
Encyclopedia of technology
- - ARTILLERY gun, consisting of a metal barrel, with the help of which projectiles are directed at the target and fire them thanks to the force of the explosion of gunpowder placed in the closed end of the barrel ...
Scientific and technical encyclopedic dictionary
- -: See also: - electron gun - blast ...
Encyclopedic Dictionary of Metallurgy
- - f english: blast-furnace gun deutsch: Stichlochstopfmaschine f français: machine f à boucher le trou de ...
Russian-English (-German, -French) Metallurgical Dictionary
- - art. a gun for flat shooting at ground, surface or for shooting at air targets. Distinguish P. small, medium and large caliber ...
Big Encyclopedic Polytechnic Dictionary
- - an artillery gun designed mainly for shooting at low elevation angles ...
Marine vocabulary
- - artillery gun with a flat trajectory; intended for shooting mainly at open vertical targets, as well as at targets located at long distances ...
- - a device for applying construction mortar and concrete mixture to the surface of structures and structures. In the USSR, Ts.-p. with sluice drum and sluice chamber ...
Great Soviet Encyclopedia
- - an artillery gun for flat shooting at ground targets or for shooting at air targets. The caliber of modern guns is 20-210 mm, the barrel length is 40-80 calibers, the firing range is up to 35 km and more ...
Big encyclopedic dictionary
- - R....
Spelling dictionary of the Russian language
- - ceme / nt-pu / shka, ceme / nt-pu / shki, genus. pl ....
Together. Apart. Hyphened. Reference dictionary
- - cement-gun Pneumatic device for applying a layer of cement or lime mortar to the surface of something, supplied with a jet of compressed air ...
Efremova's Explanatory Dictionary
- - ...
Spelling dictionary-reference
- - cement "ent-p" ...
Russian spelling dictionary
- - tector, shotcrete, ...
Synonym dictionary
"Cement Cannon" in the books
Cement
From the book Loggias and balconies the author Korshever Natalia GavrilovnaCement A cement floor can be made on a balcony or loggia, which can be the basis for other coatings (for example, linoleum, tiles, etc.). It can be left without covering materials, especially if it is decided not to glaze the space of the balcony or loggia. In warm weather
3.2. CEMENT
From the book Universal Foundation TISE Technology author Yakovlev R.N.3.2. CEMENT Cement is a fine gray, greenish or white powder. It is usually packed in kraft paper bags in 50 kg portions or dispensed from factories and trade warehouses in bulk. Cements are distinguished by name (ordinary Portland cement, pozzolanic
Alumina cement
From the book Handbook of building materials, as well as products and equipment for the construction and repair of an apartment the author Onishchenko VladimirAlumina cement Alumina cement is a fast-hardening (but normally setting) hydraulic binder obtained by fine grinding of a raw mixture of bauxite and lime that is burnt before melting (or sintering) with a predominance of
IIl.11. Cement
the authorIIl.11. Cement The basic material for construction is cement, without which no building can do. The quality of a building object largely depends on its brand. Various additives can accelerate or slow down its "maturation", make a cement mortar
III.11.2. White cement
From the book Country building. The most modern building and finishing materials the author Strashnov Viktor GrigorievichIII.11.2. White cement The whiteness of white cement (see insert, fig. 51) is about 90%, which is approximately equal to the whiteness of titanium dioxide. It is absolutely inert to pigments, does not "eat up" the color. White cement is the main component in many building materials, such
Fast hardening cement
From the book Great Soviet Encyclopedia (W) of the author TSBShotcrete and sprayed concrete
Shotcrete method consists in applying on vertical, inclined and horizontal surfaces of one or more protective layers of cement-sand mortar (shotcrete) using a cement gun or concrete mixture injected concrete syringe machine.
This method is used to strengthen the surfaces of thin-walled structures in one-sided formwork (domes, vaults, shells, tanks), to apply a "dense and waterproof protective layer of underground structures, as well as to grout seams, correct defects in concrete, during repair and restoration work. and to strengthen reinforced concrete structures.
High-quality cements are used for gunning. Under normal conditions, Portland cement of the 500 grade is used, and for grouting, creating waterproof linings and repairs, fast-setting cement. The sand should be as clean and dry as possible and not contain grains exceeding 8 mm. To accelerate the setting of the mixture, additives are dissolved in the mixing water. The set of equipment for shotcrete consists of cement gun, compressor, water tank, air and material hoses and nozzles
A dry cement-sand mixture of the appropriate composition, prepared in a mixer, is loaded into a cement gun. Under a compressed air pressure of 2-3.5 kg / cm2, the mixture is fed through a material hose to the nozzle. At the same time, water from the tank enters the nozzle, the pressure of which should be 1-1.5 kgf / cm2 higher than in the cement gun. The moistened mixture, flying out of the nozzle at a speed of up to 100 m / s, hits the shotcrete surface and sticks to it. The result is a dense and durable layer shotcrete... Some part of the cement-sand mixture bounces off the surface and falls at the place of shotcrete. These losses are called rebounds.
Ceilings are shotcrete in several layers, floors - at once to the full thickness.
With multi-layer shotcrete, the time between the application of individual layers is determined by the construction laboratory. This time should be such that the previous shotcrete layer does not collapse under the action of the mixture jet. On the other hand, to ensure that the fresh layer is embedded in the previously applied layer and for better adhesion, the maximum break should not exceed the setting time of the cement.
To reduce the rebound, surfactants (sodium abietate, soap) are added to the mixing water, which increase the adhesive ability of the mixture.
Before gunning thin-walled structures, install and fix the one-sided formwork, leaving one side open for gunning, and mount the reinforcement. The surfaces are thoroughly cleaned and rinsed before applying protective linings, repairing and grouting. To ensure better adhesion of the shotcrete layer to concrete, a notch is made on smooth surfaces. Before gunning, check the serviceability of all mechanisms, the cleanliness and connections of the hoses, and also apply a test of the gunning to a portable wooden board.
To obtain dense shotcrete and reduce the rebound, the nozzle during application should be kept at a distance of 0.7-1.0 m from the shotcrete surface, and the mixture stream is directed perpendicular to it. To obtain a layer of shotcrete of uniform thickness, the nozzle is moved in a circular motion during the application process.
On vertical, inclined and curved surfaces, shotcrete is applied from the bottom up. To prevent freshly applied shotcrete from slipping off them, regulate the flow of water into the mixture and the thickness of the layers, which is controlled by the beacons. The optimum thickness of the shotcrete layer applied in one pass is 25-30 mm.
To obtain smooth surfaces concreted by gunning methods, immediately after applying the last layer, it is smoothed and rubbed with steel trowels or half-trowels. Then the surface is ironed. After such processing, structures with smooth surfaces are obtained, which are distinguished by density, water resistance and frost resistance.
Sprayed concrete method used for the construction of thin-walled structures, lining tunnels, grouting joints, as well as for correcting defects in concrete and repair work. Unlike shotcrete the mixture applied by spraying contains, in addition to cement and sand, also crushed stone or gravel with a particle size of up to 25 mm.
Concrete is sprayed onto vertical, inclined and horizontal surfaces. Before starting work, one-sided formwork and fittings are installed, the surfaces are cleaned and washed.
A set of equipment for applying sprayed concrete is mounted on a two-axle trailer (12-2). It includes a forced action concrete mixer with a skip hoist, a multi-bucket elevator, a storage hopper, a C-630A spray machine, two water tanks, hoses, a nozzle and a compressor.
The dry mixture prepared in the mixer is fed by the elevator into the hopper, and the spraying machine is loaded from it. Under an air pressure of 4-5 kgf / cm2, the mixture is fed through a hose to a nozzle, into the mixing chamber of which water enters. The moistened mixture is ejected from the nozzle at a speed of 120 m / s. The optimum distance between the surface to be concreted and the nozzle is 1-1.2 m. The rotational movements of the nozzle ensure a uniform layer thickness, which should be 50-70 mm.
Concreting by the method of sprayed concrete provides high quality surfaces of structures. Sprayed concrete has a dense structure, high strength, waterproof and frost-resistant. The shift capacity of the installation shown on 12-2, served by three workers, reaches 18-21 m3, which provides a very high output per person - 6-7 m3 per shift.
Welcome to ZAO "Service for the Protection of Structures" - a team of professionals working in the field of protection and restoration of structures. Buildings and structures for civil, military, industrial and transport purposes are the basis of the economy of any country in the world. According to experts, a significant number of these objects, due to natural aging and corrosion, are in a pre-emergency and emergency state, which poses a threat of man-made accidents and disasters. Constant monitoring of the condition of structures and timely measures for repair and restoration is the only way to resolve the issue of long-term and safe operation of fixed assets. One of the modern technological methods of protection and restoration of structures, widespread in the world and used by ZAO "Service for the Protection of Structures", is concrete shotcrete on the surface of the structure to be repaired or the protected object. Shotcrete allows not only to restore operational characteristics, but also to adapt structures to changing natural and man-made conditions. Our experience and experience of foreign companies in gunning testifies to unlimited possibilities shotcrete in the field of general construction and repair and restoration works.
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ISO 9001-2000 |
The section "Normative documents" contains normative and technical documentation for the application concrete shotcrete at the facilities of sea, rail and road transport, including those developed jointly with NIIZhB and JSC TsNIIPromzdaniy - Technical specifications TU 5745-001-16216892-06 "Shotcrete" and "Guidelines for the use of shotcrete in the construction, repair and restoration of building structures of buildings and structures." These documents have been developed taking into account the requirements of the European Specifications for shotcrete(European Specification for Sprayed Concrete). In the section "Publications" - articles from the American magazine "Shotcrete" about the experience of using shotcrete at various structures in various parts of the world.
On the Russian market of professional construction work shotcreting takes a leading position, having established itself as a unique and irreplaceable technology for the repair and restoration of structures.
Shotcrete
Shotcrete is a method of applying one or several layers of cement-sand mortar or concrete mixture under the pressure of compressed air on vertical, inclined and horizontal surfaces.
Shotcrete is used to strengthen the surfaces of thin-walled structures in one-sided formwork (domes, vaults, shells, tanks), to apply a dense and waterproof protective layer of underground structures, as well as to grout seams, correct defects in concrete, during repair and restoration work and to strengthen reinforced concrete designs.
Shotcrete is carried out with special equipment - a shotcrete installation. With the help of compressed air, the mixture is accelerated, flies out of the nozzle and, hitting the shotcrete surface, sticks to it.
Varieties
There are two types of application on surfaces under pressure of working compounds: dry and wet.
In the dry method of gunning, the initial dry mixture in suspension is fed into a nozzle, where the mixture is mixed with mixing water. In the nozzle, the mixture is mixed with its subsequent supply under the pressure of compressed air to the surfaces to be concreted.
In the wet method of gunning, a ready-made concrete mixture or mortar is supplied to the nozzle under the pressure of compressed air. In the nozzle, the mixture becomes suspended and under pressure is applied to the surfaces to be concreted.
Properties
The properties of the resulting shotcrete are different from those of conventional concrete or mortar. Shotcrete has a high density (approximately 2400 kg / m2), mechanical strength (40-70 MPa), water resistance (not less than W8) and frost resistance (not less than Mrz 300).
By adjusting the composition of the mixture, special properties can be imparted. The high adhesion of the shotcrete allows the concrete to be placed using one-sided formwork. The transporting of the shotcrete mixture through a flexible hose allows you to work in confined spaces.
concrete spraying The moisture content of the applied shotcrete based on VBC cement should be: 12-13% in unreinforced shotcrete, 13-15% in reinforced shotcrete in the layer under the mesh and 11-13% in the remaining layers, and in the shotcrete based on Portland cement: 9- 11% in unreinforced shotcrete, 11% in reinforced shotcrete in the layer under the mesh and 9% in the surface layers. On the surface of a properly applied layer of shotcrete, there should be no dry spots resulting from a lack of water, and shedding of the layer with an excess of water. The supply of the dry mix should be regulated by changing the rotation speed of the feed plate of the cement gun. A normally nutritional dish is about; 100 rpm When applying shotcrete to poorly prepared surfaces with ledges: other irregularities, the number of revolutions per minute of the nutrient plate should be increased to 120, and when laying the last leveling layer of shotcrete reduced to 75. The thickness of the shotcrete and the number of layers in it are set in the project; the total thickness of the shotcrete should be at least 3 cm. The thickness of the individual layers of shotcrete is checked during the application process by dipping a thin steel needle, awl or wire into them in different places. The puncture sites must be sealed immediately. Each subsequent layer of shotcrete should be applied when using VBC, after 30 minutes. after laying the previous layer, and when using Portland cements after the end of setting. The layer of shotcrete applied before a break in work should be with a gradual decrease in thickness to the border of the site on a strip of 1 -1.5 m. Before resuming work, the surface of this strip of shotcrete should be cleaned with a steel brush or a jet of compressed air and moistened with water. After that, the thickness of the previously laid layer must be brought to the required value. When removing water from the surface of the lining with drainage pipes, the latter must be sealed after the first layer of shotcrete has hardened. The protruding part of the tube should be cut flush with the first layer, and the remaining part should be stamped with expanding cement (VRC, gypsum-alumina, etc.). The thickness of the last layer of shotcrete should be such that it covers the ends of the anchor rods, fittings and drain pipes by at least 15 mm. The rebound of sand and sand from the sand nests under the reinforcement during work should be removed by blowing out with compressed air. For grouting a shotcrete surface, if necessary, a layer of shotcrete should be applied on fine sand no earlier than 2 hours when using shotcrete on VBC cement and no earlier than 12 hours, but no later than 24 hours. when using shotcrete on Portland cements. The surface of such a freshly applied layer must be trowelled immediately. During the period of setting and hardening, shotcrete must be protected from freezing, drying, shock, mechanical damage and chemical influences for: 6 hours. - when using VBC cement and 7 days - when using Portland cements, counting from the moment of its application.
Shotcrete concrete mix
A versatile and economical method of restoring and strengthening structures is shotcreting... The company "GidroPromStroy" is ready to perform gunning works of any volume and complexity at affordable prices.
Shotcrete surface: definition and types
Shotcrete work is the application of a layer of concrete mortar to building structures under compressed air pressure. As a result, the cement particles come into close interaction with the treated surface, and the filling of cracks, cavities and tiny pores is also achieved. The use of such technologies makes it possible to achieve higher strength, frost resistance and other positive qualities for buildings and structures.
Shotcrete works are carried out using two methods: dry and wet. In the first case, shotcrete - the installation is filled with cement and the necessary additives in the right ratio, without adding water. The flow of the dry mixture in the nozzle is moistened, as a result of which the material can be continuously supplied to the surface to be treated. If this method is implemented, it is not necessary to maintain a certain fluidity and viscosity of the concrete mixture during transportation and during operation. The low moisture content allows this sprayed concrete to be applied without thickness limitation, including on vertical and overhead surfaces.
When concrete is wet sprayed, a mixture of cement, fillers, additives and water is prepared in advance, after which it is pumped into the transport hose using a pump. Here, shotcrete plants also often have special nozzles. They can supply moisture or compressed air to the mixture. The wet method of gunning allows the application of concrete layers no more than 150 mm thick. To obtain greater thickness, the work is carried out in several stages.
Stages of work when spraying the surface
The procedure for carrying out shotcrete works is as follows:
depending on the characteristics of the object and the requirements for the surface, the optimal set of equipment is selected;
a mixture of cement and necessary additives is being prepared;
the surface is prepared for the wall gunning procedure, including its cleaning, removal of destroyed elements, destructive layers, roughening, blowing, washing, moistening, in some cases - reinforcement;
the mixture is loaded into the installation and sprinkled;
final surface treatment is carried out.
Specifications
Shotcrete due to the high speed of solution delivery (120-180 m / s) to the surface allows obtaining a durable concrete layer with unique properties. Compared to conventional shotcrete, shotcrete has a significantly longer service life, it is distinguished by increased mechanical strength, water resistance and frost resistance. When repairing concrete using shotcrete technologies, surfaces with different structures can be obtained.
The specialists of GidroPromStroy LLC are ready to inspect your facility, select the appropriate equipment, concrete mix and carry out shotcrete work at a low price.
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Shotcrete and Shotcrete Technology shotcrete, concrete repair, lining |
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Shotcrete [from lat. (tec) tor (ium) - plaster and (con) cret (us) - compacted], a method of concrete work, in which the concrete mixture is applied in layers to the surface to be concreted under compressed air pressure. Shotcrete is carried out using a shotcrete machine. (TSB. T. 26. M., "Sov. Encyclopedia", 1977.) The material obtained as a result of shotcrete is called shotcrete. Shotcrete is used: when erecting thin-walled reinforced concrete structures (shells, arches, tanks, etc.); when arranging lining in tunnels; strengthening of slopes, slopes, coastlines; • when waterproofing and sealing joints of prefabricated structural elements; when repairing and strengthening concrete and reinforced concrete structures and products, etc. There are two methods of gunning - "dry" and "wet" method. The “wet” method, in turn, is subdivided into “wet” with a continuous flow and “wet” with a discharged flow. Each of these methods has its own advantages and disadvantages. "Dry" shotcrete The method of "dry" shotcrete was first used at the beginning of the 20th century. With this method, a dry mixture is preliminarily prepared from cement, aggregates (sand, crushed stone) and additives (if necessary). The mixture is fed into the "dry" shotcrete plant. Compressed air is supplied through a hose to the nozzle, wetted in it with water supplied through another hose, and at a high speed (130-170 m / sec) is thrown onto the shotcrete surface.
The process of building up a layer of shotcrete is as follows: • in the first period (measured in milliseconds), practically the entire mixture bounces off the surface; only cement laitance remains on the surface, which forms an adhesive layer; • In the next instant, the smallest aggregate remains on the surface, everything else bounces off; • Subsequently, increasingly coarse aggregate remains on the surface until the rebound is stabilized. The resulting shotcrete layer has the following positive properties due to the application method: • high adhesion due to the fact that the boundary layer is formed by cement laitance with the finest filler; • high density and cohesion due to the high speed of flight of the particles of the mixture - the particles are literally driven into the already applied layer of shotcrete; • optimal water-cement ratio - an experienced nozzle operator delivers the amount of water not exceeding that required for the hydration reaction; • the possibility of applying a layer of up to 10-15 cm in one pass - high consistency of the applied composition, everything that is poorly fixed - bounces off. However, up to 25% of the mixture goes into the rebound. "Wet" continuous flow shotcrete "Wet" shotcrete appeared half a century later. This was primarily due to the development of construction chemistry. With this method, the ready-mixed concrete is fed into a "wet" shotcrete plant (concrete pump) and hydraulically (in a continuous flow) is fed through a hose to the nozzle. Compressed air is supplied to the nozzle through another hose, with the help of which the continuous flow of the mixture is broken and delivered to the shotcrete surface. The spraying speed is significantly lower. As a result, the amount of rebound is reduced to 10%.
High quality shotcrete is achieved by adding additives: • adhesion to the surface - by forced application of an adhesive layer; • application of a thick layer - by introducing setting accelerators, the solution of which is supplied to the nozzle with a separate hose; optimal water-cement ratio - using plasticizers. "Wet" shotcrete is more in line with the industrial construction method. The concrete mix can be prepared at a specialized enterprise (concrete plant), delivered by a concrete mixer truck, and when applied, the nozzle operator's qualifications play a lesser role. However, the need to introduce additives significantly increases the cost of the applied mixture. In addition, the transportation of the mixed concrete through the hose excludes the possibility of even short interruptions in gunning without the laborious operation of flushing the hose (the concrete mix is seized in the hose). "Wet" shotcrete in a discharged stream With this method, the ready-made concrete mixture is placed into a pneumatic concrete pump and, with the help of compressed air, is delivered to the nozzle from where it is thrown onto the surface at high speed. This method occupies an intermediate position between the above methods. There is a possibility of preparing a ready-made (mixed) mixture at a concrete plant and there is no need to introduce plasticizers. The disadvantages of this method include a high rebound of up to 25%, the need to apply an adhesive layer and the use of setting accelerators, the obligatory flushing of the material hose during breaks in work. |
Dear colleagues, most likely this article will be relevant for construction companies wishing to carry out repair work on their own, as well as for operators who have quite large production and housing areas on the balance sheet, which are, to put it mildly, in an inadequate condition.
I will not resist the "temptation" to tell you about my first practical "acquaintance with this amazing technology. It was 25 years ago, in Azerbaijan not far from Baku. Do not be surprised, because it was then that there was a kind of center for the development of offshore oil fields, and this technology was also used in this industry.
And more specifically, in this way, the weighting of large-diameter oil and gas pipes was carried out to lay them along the bottom of the seas, so that they did not float up and did not move during waves. In short, in a huge workshop, a tube with a diameter of about 1 meter and a length of 20 meters was attached to the stand, a reinforcing cage was welded on, the tube was slowly rotating. Shotcrete machines with manipulators moved along the rails, next to the pipe, and shotcrete was sprayed in layers in automatic mode. The equipment was all German.
Well, in principle, I think everything is clear to you. I was invited just to look, or rather I asked for it myself. To tell. that I was delighted, this is nothing to say, as a concrete worker I was simply "shocked" by what I saw, of course in a good sense of the word. Of course, I previously knew in general terms about this technology, but what I saw amazed me with its technological splendor, clear organization of the process and, of course, excellent "German quality". Well, of course, I did not fail to "stick in" and give some useful advice to the Germans, of course "on trifles", which they were certainly unspeakably surprised at, but after consulting with me they agreed, and so we, too, "are not bastard."
And since then I am simply "in love" with this technology. Sorry, if anything, for the digression is not on the merits. Well, okay, let's go further.
To begin with, there are very few general provisions. Shotcrete (Latin tor - "plaster" + cret - "compacted") - application to the surface of concrete, reinforced concrete. or other structures of a layer of concrete or other mortars (plaster, concrete mixture, clay and other repair compounds).Shotcrete concrete
or a shotcrete mixture is applied under the pressure of compressed air, as a result of which the cement particles interact tightly with the surface of the structure, filling cracks, cavities, tiny pores or just the surface of products.
The result of gunning is an increase in strength, density, water resistance, frost resistance of the surface layer of products.
Most often, a cement-sand mortar is used as a shotcrete in a ratio of 1: 2 - 1: 6. Aggregate size no more than 8 mm. Cement grade not lower than 400.
The main gunning tool is a cement gun, which delivers mortar at a speed of 80-100 m / s. The air pressure is 1.5-5.0 atm.
But now, before moving on to specifics, I would advise you to watch a few short video clips on this topic, much in our conversation with you will become more understandable, solook
Watch the video... This is the simplest installation, I wanted you to see the process itself, with this simple installation you can carry out minor repairs and plastering work. Then I will talk about this installation, by the way, this is wet shotcrete, the shotcrete mixture is supplied through a "thick" hose, ready-to-use mortar mixture, and through a thin hose compressed air, which with force "sprays" this mixture onto the surface, Ideal for beginners for the first time master this technology.
Watch the video... This is dry shotcrete - Appliedshotcrete concrete layers of shotcrete installation - The process of overlaying concrete layers by the TORKRET machine is shown, obviously the process of repairing a hydraulic structure is underway. Note that the large hose supplies the dry mixture with air, and the smaller hose supplies water with additives.
Watch the video... Wet gunning of a pre-reinforced basement section of a building, which is obviously located on a fairly largedilapidated foundation , it is sprayed concrete that is applied, the composition of which is a coarse aggregate, with a fraction of no more than 8 mm. The capabilities of this technology are very clearly shown, it is almost impossible to perform this work in another way.
Watch the video. This film may not be directly related to today's topic, but I really wanted you to watch it. It is a repair mortar for waterproofing basements and foundations with the addition of Penetron. The principle of operation is shown very popularly. Very simply, at an accessible but completely scientific level, an explanation is given and the principle of capillaries in concrete and the influence of water-repelling compositions of a penetrating action - this greatly increases the water resistance of concrete structures.
