Technical map for concrete work. TTK
CENTRAL INSTITUTE FOR REGULATORY RESEARCH AND SCIENTIFIC AND TECHNICAL INFORMATION "ORGTRANSSTROY"
MINISTRIES OF TRANSPORT CONSTRUCTION
PREPARATION OF CEMENT CONCRETE MIXTURE IN UNIT C-780
1 AREA OF USE
The technological map was developed on the basis of the application of methods of the scientific organization of labor and is intended for use in the development of a project for the production of work and the organization of labor on mixing plants for the preparation of cement concrete mixtures.
The automated cement concrete plant (CBP) with the C-780 unit is designed for the preparation of hard and plastic concrete mixtures with aggregate up to 40 mm.
The capacity of the plant is up to 30 m 3 / h; the capacities of the supply bins for cement, aggregates, and a water tank are designed for half an hour of operation at maximum productivity and the highest water-cement ratio \u003d 0.5.
The plant consists of a mixing and dosing section, an aggregates warehouse and a cement warehouse.
An open consumable warehouse of aggregates is located directly next to the S-780 concrete mixing plant. Screening and washing of the material is also organized here. Sand and crushed stone are delivered in railway cars, unloaded with a multi-bucket portal unloader S-492 directly over the funnels of vibrating trays of the gallery conveyor.
Automated cement warehouse C-753 is designed for short-term storage of cement. The silo tower with a capacity of 25 g is equipped with two cement level indicators of the UKM type. Cement from railway cars is unloaded directly to the cement warehouse using a pneumatic unloader C-577.
The batching unit of the plant consists of feed bunkers with continuous pendulum batchers S-633. The batchers are installed above a horizontal conveyor that feeds materials to the inclined conveyor. They are transported via an inclined conveyor into the loading chute of the mixing compartment.
The cement feed bin is a cylinder with a conical part at the bottom. Cement is fed directly to the C-781 dispenser with a drum feeder. Inside the bunker, there are two S-609A cement level indicators included in the warehouse control circuit. Turning on or off the mechanism that supplies cement from the warehouse is done using the same indicators.
The C-780 continuous forced mixing plant is the main equipment of the concrete plant. The working body of the mixer is two shafts of square section 80 × 80 mm with blades mounted on them. The blades end with blades measuring 100 × 100 mm. The agitator body ends with a collecting hopper with a jaw lock.
The S-780 concrete mixing plant is connected to the warehouses: cement aggregates and a dosing unit with a system of belt and bucket feeders.
In all cases of using a technological map, it is necessary to link it to local conditions, depending on the composition, grade and amount of the mixture produced.
Depending on the changing needs of the cement-concrete mixture, the plant can be adjusted to any capacity in the range from 15 to 30 m 3 / h by changing the capacity of its batchers: cement from 5 to 10 t / h, sand and crushed stone from 12.5 to 25 g / h and water up to 6 m 3.
So, for example, given the plant's laboratory consumption of materials per 1 m3 of concrete (cement-340 kg, sand-547 kg, crushed stone fraction 5-20 mm-560 kg, crushed stone fraction 20-40 mm-840 kg, water-170 kg ) the productivity of the plant will be:
|
Dispenser of the day |
Batching capacity, t / h at plant capacity m 3 / h |
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|
Crushed stone fraction 15-20 mm |
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|
Crushed stone fraction 20-40 mm |
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2. INSTRUCTIONS FOR PRODUCTION TECHNOLOGY
Prior to the commencement of the operation of the cement concrete plant with the C-780 installation, all equipment is inspected and, if necessary, the batchers of aggregates, cement and water are calibrated.
The dispensers are calibrated when the productivity of the plant, the grade and composition of the concrete mixture, the bulk density and granulometric composition of aggregates change.
When a certain plant productivity is established and, accordingly, the composition and brand of the mixture, it is also necessary to periodically calibrate the dispensers.
Calibration of aggregate batchers
Aggregate dispensers are calibrated by sampling. This requires:
a) fill the supply bins with sand, small and large gravel in an amount of at least 5 m 3 of each material;
b) set the dispensers on a level in a horizontal position (with material) by moving the weight lever or changing the weight in the ballast box (near the variator).
In this case, the movable dampers should be set at a height of 100 mm for crushed stone, and 80 mm for sand. Fixed dampers are installed 10 mm higher than movable ones. Checking the absence of jamming or jamming in the weighing system of the dispensers is carried out by lightly pressing on the edge of the weighing platform or by installing a weight of 0.5 kg. In this case, the platform should be lowered to the stop;
c) prepare commodity scales for calibration with a carrying capacity of at least 0.5 T, a box with a capacity of 200 m and a stopwatch.
For sampling, it is necessary to turn on the horizontal collecting conveyor to move in the opposite direction by switching the direction of the electric motor (reverse). When testing one dispenser, the others should be turned off.
The horizontal collection conveyor shall be switched on during the test period.
At the command of a laboratory assistant holding a stopwatch, the operator turns on the dispenser. Sand or crushed stone is poured onto a metal sheet for 4-5 seconds until a stable flow of crumbling material is obtained. After that, the stopwatch is turned on and the box is placed under the flow of the material being dispensed.
After the sampling time has elapsed, the collecting conveyor and dispenser are turned off at the signal of the laboratory assistant. The taken sample is weighed on a balance.
Three weighings are made for one position of the variator.
The hourly productivity of the batcher is determined by the arithmetic mean of the weight of three samples according to the formula:
where α - the arithmetic mean of the weight of three samples in kg without containers;
t - time of sampling in sec. If the sample weight does not exceed ± 2% of the calculated one, it is considered that at this position of the variator arrow the dispenser operates stably.
Calibration of the remaining aggregate dispensers is carried out in the same way.
To calibrate the cement dispenser, you must:
a) unscrew the fastening bolts of the cement bin pipe and turn the pipe 90 °;
b) make sure the cement feed hopper is completely filled with cement. Check the cement level in the feed hopper using the level indicators on the mixing unit control panel;
c) prepare for taring commodity scales with a carrying capacity of at least 0.5 T, two boxes with a capacity of 200 liters, a stopwatch, a shovel, a tin pipe with a diameter of 130-150 mm, a length of 3-3.5 m.
A sample is taken for each of all five positions of the variator arrow.
To do this, a box is installed under the branch pipe; at the command of the laboratory assistant, the driver turns on the cement dispenser. The cement from the dispenser enters the pipe, and from it into the box until a stable cement supply mode and the normal number of revolutions of the electric motor are established by eye. The time required to obtain a stable material flow is usually 50-60 seconds. After this time has elapsed, the stopwatch is simultaneously turned on and the branch pipe is transferred to the loading of the box. The box is loaded within 90 seconds for 1, 2, 3 positions of the variator arrow, and within 60 seconds for 4, 5 arrow positions. After the specified time has elapsed, the taken sample is weighed on the balance. Three samples are taken for each position of the variator arrow. Cement dosing accuracy ± 2% of the calculated weight.
To control the correctness of calibration, check the operation of the dispenser at the selected capacity and with continuous operation of the dispenser for 10 minutes by taking three samples into the box, especially paying attention to the operation of all mechanisms and the uninterrupted flow of material into the dispenser.
To calibrate the water dispenser, you must:
a) turn the drain pipe through which water enters the mixer by 180 ° on the flange and lengthen it with an additional pipe up to 4 m long;
b) turn off all equipment not related to water dosing.
The metering unit is calibrated by sampling, for which it is necessary to turn on the metering pump with the drain pipe closed. In this case, the water is returned to the tank from the tank through the dosing pump and the three-way valve. At the command of a laboratory assistant holding a stopwatch, the operator switches the three-way valve to the position of water supply to the mixer, and water is supplied to the barrel until a stable continuous flow of water is established. After that, the stopwatch is simultaneously turned on and the three-way tap is instantly switched to supply water to the water tank. The container is filled within 60 seconds for 1, 2 and 3 positions of the variator arrow, and within 30 seconds for 4 and 5 arrow positions. After the specified time has elapsed, at the command of the laboratory assistant, the three-way valve is switched to drain and the stopwatch is turned off. The operator switches the three-way valve to the position for supplying water in a loop. The sample taken is measured.
To maintain the main quality indicator of the concrete mixture (water-cement ratio), it is necessary to calibrate the water meter with an accuracy of ± 1%.
After calibrating all dispensers of the installation, a graph of the concrete plant's performance is plotted depending on the position of the arrow of the variator of each dispenser (Fig. 1).
Figure: 1. Graph of the dependence of the dispenser performance on the positions of the variator arrow:
1 - water; 2 - crushed stone of fraction 5-20 mm; 3 - crushed stone of fraction 20-40 mm; 4 - sand; 5 - cement
This schedule is valid when the plant is running on permanent materials that make up the concrete mix.
To change the performance of the dispensers, it is necessary to change the gear ratio by the variator. To do this, set the arrows of the variator (only on the move) at the appropriate division along the approximate curve and then calibrate the necessary correction to their position.
The correct operation of the dispensers is checked daily at the beginning of the shift by a representative of the laboratory of the CBR. The weighing device is installed in accordance with the composition of the concrete mixture approved by the chief engineer of the construction management and taking into account the moisture content of the aggregates. Access to weighing cabinets and dosing devices, as well as changes in the amount of materials, may only be made by laboratory personnel.
The components of the concrete mix immediately after entering the concrete plant are monitored by the laboratory of the CBP and the Central Laboratory of the Construction Administration. The quality of materials is checked by visual inspection and by sampling.
The plant operates according to the scheme shown in Fig. 2.
Figure: 2. Technological scheme of the cement concrete plant with the C-780 unit for the preparation of concrete mixture:
1 - vibrating feeders; 2 - conveyors; 3 - aggregates bins; 4-filler batchers; 5 - cement batcher; 6 - cement bin; 7 - belt conveyor; 8 - mixer; 9 - accumulator for concrete; 10 - water tank; 11 - dispenser for water; 12 - three-way valve; 13 - receiving hopper; 14 - silo can; 15 - filters
A bulldozer alternately pushes aggregates onto vibrating trays 1, from where conveyors 2 feed them into supply bins 3.
When the bins are fully loaded, the upper level indicator is triggered and the vibratory chute and conveyors are turned off after passing the material remaining on the belt, and the light signal of the end of loading is also turned on. When the material is depleted in the supply hopper to the lower level indicator, the conveyor, vibrating chute, light and sound signals of the start of loading are switched on.
Cement from the silo can 15 is fed into the supply hopper 6 by a pneumatic injection system. From the supply hopper, the cement enters the weighing pendulum batcher 5. Indicators of the upper and lower levels of cement have light and sound signals to the control panel of the cement warehouse.
Water is pumped into the tank 10 of the mixing compartment from a special container.
Crushed stone of fraction 5-20, 20-40 mm and sand are continuously dosed by belt pendulum dispensers 4, to which the material is supplied from feed bins.
First, crushed stone of fraction 20-40 mm is dosed onto the belt, then crushed stone of fraction 5-20 mm and sand, and on top of these materials - cement. This feeding order eliminates the adhesion of small particles of material to the belt.
The metered materials are fed through a hopper into the mixer. Water from the tank is metered by a metering pump and supplied through the pipeline directly to the running mixer.
Sulfite-alcohol stillage is prepared in a special installation and introduced into water in an amount of 0.2-0.3% of the weight of cement per 1 m 3 of concrete (0.68-1.0 kg / m 3).
In the mixer, the concrete components are intensively mixed and transported by paddle shafts to the outlet. From the mixer, the finished mixture enters the piggy bank, and through the jaw shutter is discharged into the dump truck.
The quality of the cement-concrete mixture obtained in the S-780 mixing plant primarily depends on the continuity of its operation, since at each stop, the calculated ratio of the components of the concrete mixture, in particular cement and water, changes.
Control over the quality of the cement-concrete mixture is carried out by the factory laboratory 2-3 times per shift.
With the same composition and correct dosage, the mobility, workability, volumetric weight and concrete yield must be constant.
The concrete yield is determined at least once a month with a change in the composition of the concrete.
The amount of concrete discharged from the plant and placed in the case should be checked daily.
When performing work, the following safety rules must be observed:
Persons familiar with the design of this equipment and safety rules are allowed to operate the equipment of concrete plants;
Before starting the equipment, check the reliability of the guards on all open, rotating and moving; parts;
It is necessary to ensure that not only the automation system is in good condition, but also the local starting mechanisms. In the event of a local start failure, the operation of the automated plant is not permitted;
It is allowed to turn on machines, tools and lighting lamps only with the help of starters or switches;
Repair of electrical equipment and wiring may only be carried out by an electric fitter;
Repair of pipelines of pneumatic systems under pressure is prohibited;
At the end of the mixing installation, it is necessary to turn off the general switch, and close the box in which it is located;
If there is no transport for more than 1.5 hours, it is necessary to clean the blades and trough from the concrete mixture and rinse the mixer with water, as well as clean the jaw gate of the storage hopper;
To prevent foreign objects from entering the hopper, a grate should be installed above the inlet. When preparing a mixture with chemical additives, the worker must use rubber gloves and safety goggles.
3. INSTRUCTIONS FOR LABOR ORGANIZATION
Work on the preparation of cement concrete mixture is carried out in two shifts.
The mixing plant is serviced by a team of 8 people, including cement-concrete mixers, machinists: 5 digits-1; 4 bit-1; dispenser for the components of the cement-concrete mixture 3 raz.-1; electrical fitter 5 bits-1; construction locksmith 4 size-1; bulldozer driver 5 pit-1; transport (auxiliary workers) 2 section-2.
Before starting work, the cement mixers and the dispenser must check the completeness of the installation equipment, the absence of foreign objects near the rotating parts or on the conveyor belts.
Mixing plant operator 5 bits supervises the operation of the concrete mixing plant as a whole: monitors the approach, loading and dispatch of vehicles, gives a sound signal to drivers for loading, in the absence of vehicles, switches off the installation and makes sure that after switching off the installation, no concrete mixture remains in the mixer.
Mixing plant operator 4 bit checks the presence of water in the reservoir and dosing tank, cement in the feed hopper, inspects the mixer, checks the idle operation of the jaw valve and the mixer without materials, checks the operation of the variator, turns on the water pump that supplies water to the constant level water dosing tank, turns on the mixer, then the aggregate supply conveyor opens the water shut-off valve, turns on the cement batcher and controls the preparation of the cement-concrete mixture. Monitors the operation of the installation mechanisms, ensures the smooth operation of all units and makes current repairs.
Dispenser for cement concrete mix components 3 bits checks the presence of aggregates of materials in the feed bins of the batching compartment, the height of the fixed and movable flaps, the ease of swinging of the weighing conveyor and its horizontal position. Checks the idle operation of prefabricated and inclined conveyors and during their normal operation, in a certain sequence, includes prefabricated conveyors, vibration leaks and dispensers.
Construction locksmith 4 bits checks the presence of cement in the warehouse, the position of the slide gates and the presence of the required amount of cement in the pit or transition tray. At the direction of the driver of the central control panel, he checks the idle operation of the pneumatic pressure system.
Electrician 5 bits checks the grounding of electric motors, connects the installation to the power grid, together with the machinists, checks the operation of electric motors at idle speed, monitors the accurate operation of the automatic control system. During the operation of electric motors, he periodically monitors their operating mode, heating and the state of the contacts.
Bulldozer driver 5 bit feeds aggregates to the chutes of the underground gallery.
Transport (auxiliary) workers 2 bits. busy with preparatory and final work: they prepare sulfite-alcohol stillage, remove spilled material from conveyors and dosing units, remove foreign objects from conveyors.
4. SCHEDULE OF THE PRODUCTION PROCESS
|
Name of works |
unit of measurement |
Scope of work |
The composition of the link (brigade) |
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|
Preparatory work |
0,05 |
4 " - 1
Electrician Construction locksmith Bulldozer driver
|
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|
14,27 |
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|
Delivery of the shift |
0,03 |
|||||||||||||||||||
|
Final work |
0,05 |
|||||||||||||||||||
continuation
|
Name of works |
unit of measurement |
Scope of work |
Labor intensity for the entire volume of work, man-days |
The composition of the link (brigade) |
Production process time |
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|
Preparatory work |
0,05 |
Concrete mixers, drivers: 4 " - 1 Dispenser of cement concrete mixture components: Electrician Construction locksmith Bulldozer driver Transport (auxiliary workers) |
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|
Preparation of cement concrete mixture (supply of aggregates, cement, water, dosing them, mixing, preparation of additives) |
14,27 |
|||||||||||||||||||
|
Delivery of the shift |
0,03 |
|||||||||||||||||||
|
Final work |
0,05 |
|||||||||||||||||||
Notes.
1. The schedule does not include maintenance overnight.
2. During the start-up and adjustment of the plant, the composition of the team can be changed at the discretion of the chief engineer of the construction department.
5. CALCULATION OF LABOR COSTS FOR PREPARATION OF 210 m3 OF CEMENT CONCRETE MIXTURE BY THE S-780 MIXING PLANT
|
Code of norms and prices |
Link composition |
Description of work |
unit of measurement |
Scope of work |
Time rate, man-h |
Price, RUB-kopeck |
Standard time for the full scope of work |
The cost of labor costs for the full scope of work, rubles-kop. |
|
TNiR, § T-1-38, tab. 2a |
Concrete mixers: Component dispenser cement concrete mixture: Electrician Construction locksmith |
Preparation of a cement-concrete mixture (supply of cement to the supply hopper, dosage of aggregates in cement when feeding into the mixer), supply of water to the mixer and introduction (if necessary) of a solution of additives; mixing materials with the release of the mixture into the storage hopper; release of the finished mixture into dump trucks; paperwork for the mixture |
100 m 3 |
12-84 |
26-96 |
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|
By the time |
Bulldozer driver Transport (auxiliary) workers |
Supply of mineral materials (pushing materials to the conveyor gallery with a bulldozer; servicing the points of the feeders of the belt conveyor and the conveyor of the consumable warehouse and preparation of sulfite-alcohol stillage) |
1 shift |
13-50 |
13-50 |
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|
Total for 210 m 3 |
6. MAIN TECHNICAL AND ECONOMIC INDICATORS
|
The name of indicators |
unit of measurement |
By calculation |
On schedule |
How many indicators according to the schedule are more or less than according to the calculation,%. |
|
Labor intensity of work per 100 m 3 mixture |
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Average category of workers |
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Average daily wages per worker |
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|
Utilization factor of the C-780 installation |
7. MATERIAL AND TECHNICAL RESOURCES
a) Basic materials
The consumption of materials is determined according to the recipe for the cement-concrete mixture. This table shows the average material consumption.
|
Name |
Brand, GOST |
unit of measurement |
amount |
|
|
per unit of production (100 m 3 mixture) |
per shift (210 m 3 mixture) |
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|
Cement grade 500 |
GOST 10178-62 * |
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Medium-grained sand |
GOST 10268-62 |
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Crushed stone of fraction 5-20 mm |
GOST 8267-64 |
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|
Crushed stone of fraction 20-40 mm |
GOST 8267-64 |
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|
Sulfite-alcohol stillage |
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b) Machinery, equipment, tools, inventory
|
Name |
unit of measurement |
amount |
|
|
Mixing plant with automatic |
|||
|
Continuous dispensers |
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|
Automated cement cleaning |
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|
Bulldozer |
|||
|
Cement unloader |
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|
Belt conveyors |
T-144 and RTU-30 |
||
|
Installation for the preparation of additives SSB |
|||
|
Spanners |
set |
||
The technological map was developed by the department for the implementation of advanced experience and technical regulation in the construction of highways and airfields (executed by engineer T.P. Bagirova) based on the materials of the Rostov and Chelyabinsk regulatory research stations of the Orgtransstroy Institute
TYPICAL TECHNOLOGICAL CARD (TTK)
PREPARATION OF CONCRETE MIX AT THE CONSTRUCTION SITE
I. SCOPE
I. SCOPE
1.1. A typical technological map (hereinafter TTC) is a complex regulatory document that establishes, according to a specific technology, the organization of work processes for the construction of a structure using the most modern means of mechanization, progressive structures and methods of performing work. They are designed for some average working conditions. TTK is intended for use in the development of Projects for the production of work (PPR), other organizational and technological documentation, as well as for the purpose of acquainting (training) workers and engineering and technical workers with the rules for the production of work on the preparation of concrete mixture on a mixing plant for the preparation of cement concrete mixtures in conditions construction site.
1.2. This map contains instructions on the preparation of a concrete mixture by rational means of mechanization, data on quality control and acceptance of work, industrial safety and labor protection requirements in the production of work.
1.3. The regulatory framework for the development of technological maps are: SNiP, SN, SP, GESN-2001 ENiR, production rates of material consumption, local progressive rates and prices, labor costs, rates of consumption of material and technical resources.
1.4. The purpose of creating the TC is to describe solutions for the organization and technology of preparing concrete mixture in order to ensure its high quality, as well as:
- reducing the cost of work;
- reduction of construction time;
- ensuring the safety of the work performed;
- organization of rhythmic work;
- unification of technological solutions.
1.5. On the basis of the TTK, as part of the PPR (as mandatory components of the Project for the production of works), Working Flow Charts (RTK) are developed for the performance of certain types of work on the preparation of concrete mixture. Working flow charts are developed on the basis of standard charts for the specific conditions of a given construction organization, taking into account its design materials, natural conditions, the available fleet of machines and building materials tied to local conditions. Working flow charts regulate the means of technological support and rules for the implementation of technological processes in the production of work. Technological features, depending on the brand of the prepared mixture, are solved in each specific case by the Working Project. The composition and level of detail of the materials developed in the RTK are established by the relevant contractor construction organization, based on the specifics and volume of work performed. In all cases of using the TTK, it is necessary to link it to local conditions, depending on the composition, grade and amount of the concrete mixture produced.
Working flow charts are considered and approved as part of the PM by the head of the General Contractor for the construction organization, in agreement with the Customer's organization, the Customer's Technical Supervision.
1.6. The technological map is intended for work manufacturers, foremen and foremen performing work on the preparation of concrete, as well as for technical supervision of the Customer and is designed for specific conditions of work in the III temperature zone.
II. GENERAL PROVISIONS
2.1. The technological map is developed for a complex of works on the preparation of concrete mixture.
2.2. Work on the preparation of concrete mix is \u200b\u200bcarried out in one shift, the duration of the working time during the shift is:
Where 0.828 is the utilization rate of mechanisms in time during the shift (the time associated with preparing for work and carrying out the ETO - 15 minutes, breaks associated with the organization and technology of the production process and the driver's rest - 10 minutes every hour of work).
2.3. The technological map provides for the implementation of work by an integrated link with mobile concrete mixing plant BSU-30TZ, overall dimensions of the installation 42500x5850x8400 m, with a capacity of 30 m / h equipped concrete mixer SB-138, bunkers of inert materials m, the capacity of the consumable cement silo - 60 tons, the total power consumption of electricity 75 kW (see Fig. 1).
Fig. 1. Concrete mixing plant BSU-30TZ
2.4. The concrete mixing plant is equipped with an automated control system based on an industrial computer, which provides:
- automated control of all technological production processes;
- multi-recipe mixing technology (up to 50 recipes);
- accounting of material consumption and concrete output by brands;
- accounting of the execution of applications with saving information about the Customer, the time of entry and execution of the application, the recipe number and the volume of the mixture;
- output of accounting information to the display and printer.
2.5. Work should be carried out in accordance with the requirements of the following regulatory documents:
- SP 48.13330.2011. Organization of construction;
- SNiP 3.03.01-87. Supporting and enclosing structures;
- GOST 27006-86. Concrete. Squad selection rules;
- GOST 30515-97. Cements. General technical conditions;
- GOST 8736-93. Sand for construction work;
- GOST 8267-93. Crushed stone and gravel from dense rocks for construction work;
- SNiP 12-03-2001. Labor safety in construction. Part 1. General requirements;
- SNiP 12-04-2002. Labor safety in construction. Part 2. Construction production.
III. ORGANIZATION AND TECHNOLOGY OF WORK PERFORMANCE
3.1. The automated concrete mixing plant (BSU) with the SB-138 unit is designed for the preparation of hard and plastic concrete mixtures with aggregate up to 40 mm. Plant productivity up to 30 m3 / h; the capacity of the supply bins for cement, aggregates, and the water tank are designed for half an hour of operation at maximum productivity and the highest water-cement ratio of 0.5. The mobile concrete mixing plant consists of mixing and batching rooms, aggregates storage and cement storage (see fig. 2). The installation is controlled from the driver's cab, and the electrical equipment is located in a special room. The driver's cab is equipped with devices that record the progress of the technological process.
Fig. 2. Concrete mixing plant diagram
1 - filler feed bins; 2 - batching conveyor; 3 - reloading conveyor; 4 - concrete mixer; 5 - concrete mixer frame; 6 - cement batcher; 7 - dispenser for chemical additives; 8 - water dispenser; 9 - unit of chemical additives (at the request of the customer); 10 - consumable cement silo with filter; 11 - screw conveyor
3.2. Consumable storage of sand and fractional crushed stone of an open type with dividing walls is located directly near the concrete mixing plant. Sand and fractional crushed stone are delivered to the consumable warehouse in railway cars. In the case of delivery of non-fractional or contaminated crushed stone, sorting of the material into fractions (screening) and washing of the material is also organized here. Sand and crushed stone are fed into the feeders of the metering compartment and unloaded front loader TO-49 directly over the funnels of the gallery conveyor vibrating trays. The dosing unit of the SBU consists of filling bunkers with pendulum batchers of continuous action С-633... The batchers are installed above a horizontal conveyor that feeds materials to the inclined conveyor. They are transported along an inclined conveyor into the loading chute of the mixing compartment.
3.3. Consumable automated cement warehouse С-753 with a capacity of 300 tons is intended for short-term storage of cement. Cement from railway wagons is unloaded directly to the cement warehouse using pneumatic unloader С-577 or auto cement trucks.
The silo tower with a capacity of 60 tons is equipped with two cement level indicators of the UKM type. The cement feed bin is a cylinder with a conical part at the bottom. Cement is fed directly to dispenser S-781 with drum feeder... Inside the bunker there are two cement level indicator С-609Аincluded in the warehouse management scheme. Turning on or off the mechanism that supplies cement from the warehouse is done using the same indicators.
3.4.
Concrete mixing plant SB-138 continuous forced mixing is the main equipment of the concrete batching plant. The working body of the mixer is two shafts of square section 80x80 mm with blades mounted on them. The blades end with blades measuring 100x100 mm. The agitator body ends with a collecting hopper with a jaw lock.
Concrete mixing plant SB-138 connected with aggregates cement warehouses and a dosing unit by a system of belt and bucket feeders.
3.5. Depending on the changing needs of the cement-concrete mixture, the plant can be adjusted to any capacity in the range from 15 to 30 m / h by changing the capacity of its batchers: cement from 5 to 10 t / h, sand and crushed stone from 12.5 to 25 t / h and water up to 6 m.
So, for example, given the plant's laboratory consumption of materials per 1 m3 of concrete (cement - 340 kg, sand - 547 kg, crushed stone of 5-20 mm fraction - 560 kg, crushed stone of 20-40 mm fraction - 840 kg, water - 170 kg) plant productivity will be.
I. SCOPE
The technological map is developed on the basis of the methods of the scientific organization of labor and is intendedfor use in the development of a project for the production of work and the organization of labor on mixing plants for the preparation of cement concrete mixtures.
The following basic conditions are accepted in the card.
An automated plant with a SB-78 mixing unit operates in a common complex of machines and mechanisms.on the arrangement of cement-concrete pavements of highways.
The open-type storage of sand and fractionated crushed stone with dividing walls is located next to the mixing plants. Ha stock of materials must be created in the warehouse, sufficient for the operation of the units for 10 days. Sand and fractionated crushed stone are delivered to the consumable warehouse in railway cars or by road. In the case of delivery of unfractionated or contaminated crushed stone, washing and sorting of material into fractions should be organized. Sand and crushed stone are fed to the feeders of the dispensing department with bucket loaders of TO-18 or Case type.
The mixing plant is supplied with cement from a 300-ton consumable warehouse.
Cement is delivered to the consumable warehouse by auto cement trucks.
The site of the plant has a hard surface, a drainage system is provided. The territory of the plant is fenced with a temporary fence. To the plant underwater and electricity supplied.
The mixing plant has a paved access road. The movement of cars is organized in a ring pattern without oncoming traffic.
For the export of cementa column of dump trucks with the estimated number of cars is fixed to the concrete mix.
The number of vehicles is adjusted depending on the range of transport of the mixture and road conditions.
Technological this card provides installation capacity 320 m 3 per shift.
When changing the conditions adopted in the technological map, it is necessary whenknitting it to new conditions.
... PRODUCTION TECHNOLOGY INSTRUCTIONS
Automated Cementobeton plant (CBZ) with the SB-78 unit is designed for the preparation of hard and plastic concrete mixtures with aggregate fractions up to 40 mm .
Technical specifications
Prod vigor, m 3 / h .............................................. ........60
Fra number cts of placeholders:
sand................................................. .......................... 1
chippings ny ................................................. ........................ 3
The greatest nd filler size, mm................................... 70
The capacity of the supply bins, m 3
fill carriers ................................................. ............ 36
cement and................................................. ...................... 12
Mouth new power, kW ..............................................57,8
Dimensions sizes, mm:
dl ina ................................................. .......................... 36800
width................................................. ....................... 2600
height................................................. ........................ 12520
Weight, t....................................................................................... 3
Installation a consists of the following main blocks (see figure):
a continuous-action concrete mixer, the working body of which is square shafts, with cast blades of 35 GL steel mounted on them. Work surfaces lothe jaws are located at an angle of 45 ° relative to the shaft axis;
the cement supply hopper, which is a cylindricala conical container and a dispenser intended for receiving cement and feeding cement. The bunker is equipped with a filter for cleaning the exhaust air before it is removed to the atmosphere and automatic indicators of the lower and upper levels;
dosing unit, consisting of four consumable buanchors for crushed stone and sand with dispensers. A V-21 vibrator is attached to the inclined wall of the sand bin. The batchers are installed above a horizontal collecting conveyor, through which materials are fed to the inclined conveyor, and then to the concrete mixer.
Process flow diagram of the pulp and paper mill with the SB-78 mixer:
Notes. 1 ... The numbers above the line are the duration of operations in minutes.
Description of work
The composition of the link (brigade)
unit of measurement
Scope of work
Time rate
Price, RUB-kop.
Standard time for the entire scope of work,people-h
Cost of labor costs for the entire scope of work, rubles-copy.
Local regulation SU-921 of the Dondorstroy trust
Checking SB-78 assemblies before starting work. Dispenser settingcoping and checking the operation of all dispensers. Checking the operation of nodes idle. Checking the quality of the concrete produced and adjusting the water and cement supply. Preparation and release of ready-mixed concrete in automatic mode. Tidying up work stations and mixing plant at the end of the shift. Maintenance of the installation, monitoring the technical condition of power equipment
Mixing plant operator 6 bit - 1
Driver's assistant (construction locksmith) 4 digits - 1
The operator of the wheel loader "Case" 6 digits. - 1
Locksmith for supplying cement 4 bits - 1
Road worker servicing inert material dispensers 3. - 1
Electrician 5 bits - 1
100 m 3
15,6
10-62
99,84
67-97
Total: 640 m 3
99,84
67-97
for 100 m 3
15,6
10-62
... TECHNICAL AND ECONOMIC INDICATORS
|
unit of measurement |
According to the calculation A |
Schedule B |
By how many% is the indicator according to the graph more (+) or less (-) than according to the calculation |
Laborious bone works per 100 m 3 mixes |
people-h |
15,6 |
Average category of workers |
Average slave wages of one worker |
rub-cop |
TYPICAL TECHNOLOGICAL CARD (TTK) APPLICATION OF CONCRETE WITH ANTI-FREEZE ADDITIVES 1 area of \u200b\u200buse 1.1. The technological map was developed for concreting structures in winter conditions using antifreeze additives. 1.2. Winter conditions are defined as conditions under which the average daily outside temperature is below 5 ° C and the minimum daily temperature is below 0 ° C. 1.3. The essence of the method of introducing antifreeze additives into the concrete mixture is the introduction into the concrete mixture during its manufacture of additives that lower the freezing point of water, ensuring the reaction of cement hydration and its delayed hardening at negative temperatures. 1.4. Antifreeze additives are used in the case of the device during the construction in winter conditions of monolithic concrete and reinforced concrete structures, monolithic parts of precast-monolithic structures, monolithic joints of prefabricated structures. 1.5. The scope of work considered by the technological map includes: Laying of concrete mix with anti-freeze additives; 1.6. Concreting in winter conditions using antifreeze additives is carried out in accordance with the requirements of federal and departmental regulations, including: SNiP 3.03.01-87. Supporting and enclosing structures; SNiP 12-03-2001. Labor safety in construction. Part 1. General requirements; SNiP 12-04-2002. Labor safety in construction. Part 2. Construction production. - "Guidelines for the production of concrete work in winter conditions, regions of the Far East, Siberia and the Far North". Moscow, Stroyizdat, 1982; - "Concrete Works Guide". Moscow, Stroyizdat, 1975; - “Guidelines for quality control of construction and installation works”, St. Petersburg, 1998. 2. Organization and technology of work 2.1. Before starting the device, the robot for the application of concrete mixtures with antifreeze additives in winter conditions must: Execute and accept the underlying structures; Prepare tools, accessories, inventory; Deliver materials and products to the workplace, Instruct workers on labor protection; To acquaint performers with the technology and organization of work. 2.2. The use of concrete mixtures with antifreeze additives includes: Choice of antifreeze additives; Preparation of concrete mix with anti-freeze additives; Transportation of concrete mix with anti-freeze additives; Laying concrete mix with anti-freeze additives; Curing of concrete with anti-freeze additives; Quality control and acceptance of works. 2.3. As antifreeze additives, it is possible to use chemical substances, the characteristics of which are given in table. 2.1. Complex additives containing compatible plasticizing and antifreeze (simultaneously accelerating hardening) components are recommended. 2.4. The field of application of concretes with antifreeze additives and hardening accelerators are given in table. 2.2. 2.5. The antifreeze additives listed above have a different mechanism of influence on the process of concrete structure formation. Some of them only reduce the freezing point of water and do not affect the rate of setting and hardening of concrete (for example, НН, М). Other additives, along with effective antifreeze properties, are simultaneously accelerators of setting (P) and hardening (NK, NNK). The approximate strength of concrete with anti-freeze additives is given in Table 2.3. 2.6. The optimal amount of antifreeze additive depends on the minimum temperature of the concrete mix. When curing concrete with antifreeze additives, it is necessary to create such conditions that during the period of transportation and laying the concrete mixture does not cool below 0 ° C. In this case, the optimal amount of antifreeze additives should correspond to the data in table. 2.4. 2.7. Concrete mixtures with additives NK, NNKi, especially P, are characterized by accelerated setting times, which makes it difficult to lay the concrete mixture and degrades the structure of the cement stone. Therefore, simultaneously with the specified antifreeze components, it is recommended to introduce plasticizing substances into the composition of the concrete mixture. As a plasticizing component of a complex additive, which increases the mobility and reduces the water demand of the concrete mixture, it is recommended to use the additives given in table. 2.5. Concrete with the addition of potash should have a negative temperature during setting and initial hardening. 2.6. The most effective complex additives are formulations that include surfactants and electrolytes. With properly selected dosages of electrolyte and surfactant additives, it is possible to use the plasticizing properties of the latter and at the same time to obtain a high hardening rate. The list of the most effective complex antifreeze additives and their reduced amount is given in table. 2.5. 2.7. The recommended amount of chemical additives for complex concrete curing is given in Table .. 2.6. The use of concretes with antifreeze additives should be preceded by laboratory tests of the effect of the additives on the strength and speed of concrete hardening. 2.8. The final choice of the type of chemical additives is made taking into account the prices of manufacturers and suppliers of chemical additives. 2.9. The preparation of the concrete mixture is organized at the concrete plant. The selection of the concrete composition for winter laying is carried out in accordance with GOST 27006-86. The selection of the composition is carried out by calculation and experimental method, which includes the solution of the following issues: Determination of all requirements for the quality of concrete mix and concrete; Quality assessment and selection of materials for the preparation of concrete mix; Calculation of the nominal composition of concrete; Experimental verification of the calculated composition; Correction of the composition and calculation of the production composition of concrete. 2.10. When preparing a concrete mixture, it is possible to heat the mixing water, heat or heat the components, as well as heat the concrete mixing unit, metering and bunker compartments. 2.11. To obtain the maximum temperature of the concrete mix at the outlet of the concrete mixer, the water is heated to the maximum possible temperature of + 80 ° C. 2.12. The mixing time of the concrete mixture in the concrete mixer should be 25% longer compared to summer conditions, and not less than the values \u200b\u200bgiven in table 2.7. 2.13. The amount of chemical additives established in accordance with the recommendations is introduced during the preparation of concrete mixtures in the form of aqueous solutions of working concentration. Salt solutions are prepared in water heated to 40 ° C in mixers. The main indicators of aqueous solutions of antifreeze and plasticizing additives are given in table. 2.8, Table 2.9. 2.15. Transportation of the prepared concrete mix is \u200b\u200bcarried out by concrete mixer trucks. To minimize heat loss, the open parts of the drum of a concrete mixer are covered with moisture-proof materials and insulated. The neck of the drum of the concrete mixer is insulated and closed with a heat-insulating cover or the neck is heated with exhaust gases from the engine. When using only potash, it is recommended to add it on site by introducing an aqueous solution of potash with mixing all components in the drum of a concrete mixer. The place of transfer of the concrete mixture from the drum of the concrete mixer should be to the rotary bin protected from wind and precipitation. The bunker for supplying concrete mix must also be insulated. 2.16. When using concrete pumping units for the delivery of concrete mix, all units and parts in contact with the concrete mix are insulated. At the same time, especially carefully insulate pipelines and the main components of the concrete pump in order to maintain the initial temperature of the concrete. At extreme temperatures up to -40 ° C, in addition to the insulation of the main units of the concrete pump, additional heating of the insulated concrete pipeline with flexible heating elements is required. There should also be provision for the availability of hot water in insulated tanks for washing concrete pipes after concreting. 2.17. Holding monolithic concrete and reinforced concrete structures erected from concrete with antifreeze additives is performed in compliance with the following guidelines: Concrete surfaces not protected by formwork, in order to avoid moisture loss or increased moisture due to precipitation, should be immediately covered with a layer of waterproofing material at the end of concreting (plastic film, rubberized fabric, roofing material, etc.); Concrete surfaces that are not subsequently intended for monolithic connection with concrete or mortar can be coated with film-forming compounds or protective films (bitumen-ethinoleic, ethinol varnish, etc.); In case of an unforeseen decrease in the temperature of concrete below the design structure, it is necessary to insulate or heat up until the concrete reaches critical strength. 2.18. Stripping of load-bearing concrete and reinforced concrete structures should be carried out after the concrete has reached the strength given in Table. 2.9. 2.31. If it is impossible to provide the required concrete strength by the time the structure is loaded with a standard load, it is allowed, with an appropriate feasibility study, to use a concrete class increased by one step. 2.32. It is allowed to remove the formwork that absorbs the mass of concrete of structures reinforced with load-bearing welded frames, as well as side elements that do not bear the load from the mass of the structures, after the concrete reaches its critical strength. 2.33. The strength of the concrete before stripping must be confirmed by tests. 2.34. Removal of thermal protection and formwork from structures, when using concrete with antifreeze additives - upon reaching the strength specified in section 3. 3. Requirements for quality and acceptance of works 3.1. When curing concrete with antifreeze additives in winter conditions, production quality control is carried out, which includes: Incoming control of materials for the preparation of concrete mix, reinforcement and embedded parts, heat-insulating materials; Operational control of the implementation of reinforced concrete works; Acceptance control of the work performed. At all stages of work, inspection control is carried out by representatives of the customer's technical supervision. 3.2. Incoming quality control of materials, semi-finished products, products and parts consists in checking by external examination their compliance with GOST, TU, project requirements, passports, certificates confirming the quality of their manufacture, completeness and compliance with their working drawings. At the entrance control, they also check compliance with the rules for unloading and storage. Incoming control is carried out by line personnel when materials, structures, products arrive at the construction site. 3.3. Operational control should be carried out during the performance of reinforced concrete work and ensure the timely detection of defects and the adoption of measures to eliminate and prevent them. During operational control, they check the compliance of the work performed with the working design and regulatory requirements. The main tasks of operational control: Compliance with the technology for performing reinforced concrete works; Ensuring compliance of the work performed with the project and the requirements of regulatory documents; Timely identification of defects, the reasons for their occurrence and taking measures to eliminate them; Performing subsequent operations after eliminating all defects made in previous processes; Increasing the responsibility of direct executors for the quality of their work. 3.4. When laying concrete mix, it is necessary to control: The quality of the concrete mix; Rules for unloading and distribution of concrete mix; Concrete mix temperature; Concrete compaction mode; Concreting procedure and ensuring the solidity of the structure; Timeliness and correctness of sampling for the production of control concrete samples. 3.4. When laying and compacting a concrete mixture with antifreeze additives, laid in winter conditions, the requirements given in table must be followed. 3.1. 3.5. When holding concrete with antifreeze additives, control: Maintenance of temperature and humidity conditions; Protection of hardening concrete from mechanical damage; Concrete holding time. 3.6. Technical requirements for holding concrete with antifreeze additives are given in table. 3.2. 3.6. Concrete quality control provides for checking the conformity of the actual concrete compressive strength in the structure with the design and specified in the time of intermediate control. The compressive strength of concrete should be checked by testing control cube samples with dimensions of 100x100x100 mm in accordance with GOST 10180-90. Test pieces are made from samples of the concrete mixture used. Samples are taken at the place of preparation of the concrete mixture and directly at the place of concreting. At the place of concreting, at least two samples must be taken. From each sample, one series of control samples is made (in a series of at least three samples). Control samples are concreted in steel detachable forms corresponding to GOST 22685-89. Before concreting, the inner surfaces of the molds are lubricated. The concrete mix is \u200b\u200bplaced in molds immediately after sampling with a bayonet or vibration compaction. Control samples are stored under conditions of concrete hardening of the structure. De-lay the samples after curing the structure. The timing of testing control samples is assigned by the construction laboratory, taking into account the achievement of the design strength by the time of testing. Samples stored in frost before testing should be kept for 2 ... 4 hours at a temperature of 15 ... 20 degrees C. Intermediate control is carried out after the temperature has dropped to the calculated final temperature. 3.7. When accepting a sustained structure, check: Conformity of the design to the working drawings; Concrete quality compliance with the project; The quality of materials used in construction, semi-finished products and products. 3.8. The requirements for the finished design are given in table. 3.3. ...22. Technology of preparation of concrete mixThe technological process of concreting structures includes preparing a concrete mixture and transporting it to a facility under construction, supplying, distributing, laying and compacting it in a structure, taking care of concrete during hardening. The concrete mix cannot be prepared in advance and transported over long distances. After preparation, it must be delivered and placed in the building blocks before setting (usually 1 ... 3 hours). Therefore, the concrete mixture must be prepared near the places of its laying so that the time spent on the way in the summer does not exceed 1 hour. The concrete mixture is prepared at a mechanized or automated concrete plant in finished form, delivered to construction or prepared at on-site inventory (mobile) concrete mixing plants. Preparation of concrete mix consists of the following operations: reception and storage of constituent materials (cement, aggregates), weighing (dosing) and mixing them with water and delivery of ready-made concrete mixture to vehicles. In winter conditions, this technological process includes additional operations. The concrete mix is \u200b\u200bprepared using a complete or dismembered technology. With a completed technology, a ready-made concrete mixture is obtained as a product, with a dismembered one - dosed components or dry concrete mixture. The main technical means for the release of concrete mix are supply bins with distribution devices, batchers, concrete mixers, systems of internal vehicles and communications, a distribution bunker. Stationary technological equipment for the preparation of concrete mixture can be solved according to one-stage and two-stage schemes. A single-stage (vertical) scheme (Fig. 6.1, a) is characterized by the fact that the constituent materials of the concrete mixture (binders, aggregates, water) rise to the top point of the technological process once and then move downward under the influence of their own gravity during the technological process. Advantages: compact, economical, and disadvantages - the complexity of installation (due to the considerable height, up to 35 m). With a two-stage (parterre) scheme (Fig. 6.1, b), the lifting of the constituent materials of the concrete mixture occurs twice, i.e. the constituents of the concrete mixture are first raised into the supply hoppers, then they are lowered by gravity, passing through their own batchers, fall into the common receiving funnel and rise up again to be loaded into the concrete mixer. The advantage of this scheme is the lower cost of installation, and the disadvantage is the large building area. When the need for a concrete mix is \u200b\u200bnot more than 20 m 3 / h, mobile concrete mixers with gravity-type mixers are usually used. Figure: 6.1. Layout schemes for concrete mixing plants and installations: a - single-stage; b - two-stage; 1 - conveyor of aggregate warehouse in the supply bins; 3, 9, 10 - rotary guide and distribution; 4 - supply bins; 5 - cement supply pipeline; 6 - cement batcher; 7 - filler dispenser; 8 - water dispenser; 11 - concrete mixers; 12 - dispensing hopper; 13 - concrete truck; 14 - cement truck; 15 - skip lift. The design of concrete mixing plants allows you to transfer from the working position to the transport position during one work shift and transport them on a trailer to the next object. The use of such installations is advisable at large dispersed objects located from stationary concrete plants at distances that exceed technologically permissible. Concrete plants usually produce two types of products - dosed components and ready-mixed concrete. As equipment for the preparation of conventional concrete mix, mixers of cyclic and continuous action are used. Batch-type concrete mixers differ in the volume of the finished mixture dispensed in one batch. Cyclic concrete mixer performance P \u003d q n k w / 1000, m 3 / h where q is the volume of ready-mix concrete for one batch, l; n is the number of batches per hour; k in - the coefficient of use of the concrete mixer in time (0.85 ... 0.93). The batching concrete mixer is loaded in the following sequence: first, 20 ... 30% of the required amount of water is fed into the mixer, then cement and aggregates are simultaneously loaded, without interrupting the water supply to the required amount. Cement is fed into the mixer between batches of aggregate, thereby eliminating overspray. The duration of mixing the concrete mixture depends on the capacity of the mixer drum and the required flexibility of the concrete mixture and ranges from 45 to 240 s. Continuous concrete mixers are produced with a capacity of 5, 15, 30 and 60 m 3 / h, and gravity-type machines with a drum mixer - with a capacity of 120 m 3 / h. The duration of mixing in these concrete mixers is indicated in the passports of the machines. When preparing a concrete mixture using a separate technology, the following procedure must be observed: water, a part of sand, finely ground mineral filler (if used) and cement are dosed into the mixer. All these components are thoroughly mixed, the resulting mixture is fed into a concrete mixer, pre-loaded with the remaining part of sand and water, a large aggregate, and once again the whole mixture is mixed. The composition of the concrete mixture must provide the properties specified for it, as well as the properties of the hardened concrete. There are certain requirements for concrete mix: 1) it must maintain uniformity (during transportation, reloading and laying in the formwork), which is ensured by connectivity (non-segregation) and water-holding capacity. All this is achieved by the correct selection of the composition of the mixture, the accuracy of dosage of the components and thorough mixing of all components; 2) be workable. Workability is the ability of a concrete mixture to flow and fill a mold under the influence of vibration. It depends on the grain size composition of the mixture, the amount of water, the degree of reinforcement, methods of transportation and compaction of the mixture. Dry building mix (CCC) is increasingly used - a mixture of binder, aggregates, additives, pigments, dosed and mixed at the factory, and mixed with water before use. Accurate dosing of components allows to obtain higher technical characteristics of the finished product in comparison with mixtures obtained at the construction site. An important advantage of dry mixes is the ability to add chemical additives and microfillers to them, both improving their structure and prepared for use in the cold season. Concrete mix transportation technology Concrete transport includes delivering it from the place of preparation to the construction site, supplying the mixture directly to the place of laying, or reloading it onto other vehicles or devices, with which the mixture is delivered to the concreting unit. A concreting block is a structure prepared for laying a concrete mixture or a part of it with installed formwork and mounted reinforcement. In practice, the process of delivering concrete mixture to concreting blocks is carried out according to two schemes: From the place of preparation to direct unloading into the concreting unit; From the place of preparation to the place of unloading at the object to be concreted, with the subsequent supply of concrete to the concreting block. This scheme provides for intermediate unloading of the concrete mix. The transportation and laying of the concrete mixture must be carried out by specialized means that ensure the preservation of the specified properties of the concrete mixture. The transportation of the concrete mixture from the place of preparation to the place of unloading or directly to the concreting block is carried out mainly by road, and transportation from the place of unloading to the concreting block is carried out in buckets by cranes, hoists, conveyors, concrete pavers, vibratory feeders, motor-carts, concrete pumps and pneumatic blowers. The method of transporting the concrete mixture to the place of its laying is chosen depending on the nature of the structure, the total volume of the concrete mixture being laid, the daily requirement, the transportation distance and the lifting height. With any method of transportation, the mixture must be protected from atmospheric precipitation, freezing, drying, as well as from the flow of cement milk. The permissible duration of transportation depends on the temperature of the mixture at the exit from the mixer: it should not exceed 1 hour at a temperature of 20-30 ° C; 1.5 h - 19-10 ° C; 2 h - 9-5 ° C. Long-term transportation on bad roads leads to delamination. Therefore, in vehicles without stimulating the mixture on the way, it is not recommended to transport more than 10 km on good roads and more than 3 km on bad ones. Choice of vehicles carried out based on the conditions of the object under construction: the amount of concrete work; the term of their production; travel distances; the size of the structure in plan and in height; TEP (productivity, travel speed, unit cost of transportation). In addition, it is also necessary to take into account the requirements to preserve the properties of the concrete mixture - to prevent decomposition, changes in homogeneity and consistency. For transporting the mixture to the facility, road transport is widely used - general-purpose dump trucks, concrete trucks and concrete mixers (mixers). Transporting the mixture by dump trucks. Disadvantages: difficulties arise in protecting the mixture from freezing, drying, cement laitance leakage through cracks in the bodies, the need for manual cleaning of the body. Transportation of concrete mix by concrete trucks equipped with hermetic trough-shaped tipping bodies. Advantages: the mixture can be transported over a distance of 25-30 km, and without splashing it and flowing out of cement milk. Transportation of the mixture by truck mixers (mixers). This is the most efficient means of transportation. Concrete mixer trucks are loaded at the factory with dry components and are prepared with concrete on the way or on the construction site. The capacity of concrete mixer trucks for the finished batch is from 3 to 10 m 3. Mixing of components with water usually begins 30-40 minutes before arrival at the site. In concrete mixers (mixers), it is also advantageous to transport ready-made concrete mixtures due to the existing possibility of stimulating them along the way due to the rotation of the drum. Advantages: The range of transportation of dry components of the mixture in concrete mixer trucks is technologically unlimited. The concrete mixture delivered to the object can be unloaded directly into the structure (when concreting structures located at ground level or shallowly buried) or reloaded into intermediate containers for subsequent delivery to the concreting site. The mixture is fed to the structures to be concreted by cranes in fixed or swivel buckets or by belt conveyors (conveyors), concrete pumps and pneumatic blowers (through pipes), link trunks and vibrating trunks, belt pavers. Swivel buckets with a capacity of 0.5 - 8 m 3 are loaded directly from dump trucks or concrete trucks. Belt mobile conveyors used when it is difficult or impossible to deliver the mixture to the place of laying by means of delivery or in buckets. Conveyors up to 15 m long serve the mixture to a height of 5.5 m. To reduce the height of the free fall of the mixture during unloading, guide flaps or funnels are used. Disadvantage: conveyors must be rearranged frequently during concreting. Therefore, self-propelled belt conveyors are more effective in this respect. concrete paversmounted on the basis of a tractor, equipped with a skip hoist and a belt conveyor up to 20 m long.To supply the mixture to structures located in cramped conditions and in places not accessible to other means of transport, use concrete pumps... They supply the mixture through a steel detachable pipeline (concrete pipeline) at a distance of up to 300 m horizontally and up to 50 m vertically.Also, they use pneumatic blowers... The maximum range of transportation by them is 200 m horizontally or up to 35 m vertically when feeding up to 20 m 3 / h. For supply and distribution of the mixture directly on the place of laying at a height of 2 - 10 m, use trunks, representing a pipeline of conical metal links and an upper funnel; vibrobots, representing a link trunk with a vibrator. On the loading funnel with a capacity of 1.6 m 3 and sections of the vibrobot with a diameter of 350 mm, vibrators-stimulators and dampers are installed every 4-8 m. The supply and distribution of concrete mixture in the structure at a distance of up to 20 m with a slope to the horizon of 5-20 ° is ensured vibrating grooves in conjunction with vibrating feeder with a capacity of 1.6 m 3. They can lay mixtures up to 5 m 3 / h at an angle of inclination of 5 °, and at an angle of 15 ° - up to 43 m 3 / h. Recommended related articles
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D.V. Sichinava, 2011 View (a term of Church Slavonic and Russian grammatical tradition; in other languages \u200b\u200b- French, English a spect, German Aspekt ...
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