how to pour concrete into formwork correctly

Proper pouring of concrete into formwork is the key to beauty, quality and the best performance characteristics of the future structure. Most often, these works are carried out at the initial stage of building construction, becoming the basis of the structure. And how reliable the foundation or floors will be and meet the required parameters depends precisely on the pouring of cement into the monolithic structure.

Basic conditions for high quality work: pouring technology must be followed, the best and appropriate materials must be used. The choice of the correct formwork design depending on the task at hand (type of structure, method of supplying mortar, volume of concreting), and the use of tools and devices are important.

Formwork is a panel structure that is made from different materials and is used to pour concrete inside, which in the future will act as a load-bearing element of the building. Metal frames are usually installed inside the formwork to strengthen the concrete and give it the desired characteristics. It is quite possible to do all the work yourself, having first studied the technology and selected everything you need.

Pouring concrete into formwork

Correct pouring of concrete into formwork is the basis for the quality and beauty of the future structure.
Any business at the beginning requires a solid foundation - this is a guarantee that its result will be strong and durable. In construction, the foundation is the foundation of the building, and the fate of the building will depend on how correctly the concrete is poured into the foundation formwork. There are several conditions, adhering to which, you can achieve the best quality when pouring formwork:

compliance with technology when performing work;
use of quality materials;
the use of formwork design that most closely matches the design of the building under construction.

Working methods

It is very convenient to feed concrete into the formwork directly from the mixer tray. This method is the simplest. To do this, you must ensure that the mixer reaches the formwork at a distance of the length of the tray.

Diagram of the construction of an armored belt made of permanent formwork.

The next method requires some additional work. You will have to make a wooden chute from any suitable boards to extend the mixer tray. In this case, additional workers are needed to push the concrete along the gutter.

A more expensive way is to hire a concrete pump. In this case, when ordering, you must specify that the concrete must contain an additive that will increase its flow property without loss of quality.

You can also use the “bell”, but even here you will need to hire special equipment, so this method cannot be called cheap. The bell is filled with concrete, then it rises, at the unloading site the drain hole opens - and the concrete is in place. After this, you only need to level the solution.

Formwork for concrete - types, materials, installation technology

Formwork for concrete

Formwork is a hollow form, the internal volume of which is filled with concrete during the construction of monolithic structures: foundations, walls, ceilings, columns.

To this day, one of the oldest technologies is used for pouring mortar into a dug earthen trench, which is also formwork.

Removable and permanent formworks are used in construction. One of the main advantages of removable formwork is the possibility of reusing it. Removable formworks for pouring concrete are made from a variety of materials - wood, laminated plywood, metal, plastic and differ in design:

frame system consisting of panels, supporting posts and fastening elements;
beam system, which includes formwork slabs, beams, crossbars, supporting elements, and fastening parts.

Mandatory requirements for concrete formwork:

the strength of the material from which it is made - to protect the structure from deformation;
smoothness of the inner surface of the formwork - for easy removal after pouring and drying concrete, as well as to reduce the cost of subsequent wall finishing;
absence of gaps in the structure - to avoid concrete leakage when pouring mortar into the formwork.

To accurately install concrete formwork in a vertical position, plumb lines, magnetic or water levels are used. The formwork, carefully installed in accordance with the drawing, must be strengthened with special clamps, spacers, and support posts. Its internal volume is filled with reinforcement to enhance the strength of the future structure. To determine the height of pouring concrete into the formwork, a cord is attached to the top of the reinforcement.

What is formwork and its types

Formwork is a panel structure made of various materials, inside which metal structures are installed to increase the strength of the structure.

Then a concrete solution is poured into the formwork. To improve the result of the work, do-it-yourself pouring must be carried out in strict accordance with all requirements and rules:

Before pouring concrete formwork, it must be checked for various defects: holes, cracks. If any are found, they need to be closed.
It is important to check the rigidity of the formwork. The load exerted when pouring the structure should not lead to deformation.
Before installing the structure, its dimensions and configuration are calculated.
The inner surface of the boards must be flat and smooth. This will greatly simplify further work.

There are two types of formwork: fixed and removable. Permanent formwork is a polystyrene structure with partitions. They are necessary to give rigidity. Such structures are more often used for the construction of thermal houses. Thermohouse systems are polystyrene boxes without a bottom or lid. Each element is equipped with protrusions and holes that increase assembly accuracy. No special knowledge is required to work with such structures. They are assembled very quickly according to the principle of a designer.

The traditional formwork option is trenches dug in the ground, the walls of which are reinforced with plank boards. This design is most convenient for the construction of buildings on a simple strip foundation; it is used mainly in private construction.

Removable wooden formwork can be used for concreting several times.
They are used in the work of organizations that have been constantly engaged in construction work for a long time. Such structures are made of laminated plywood or metal. Before pouring, they need to be treated with special emulsions or lubricants, which subsequently facilitate separation from the concrete. The most convenient to use are metal shields made in industrial conditions, as they have standardized fasteners and a reinforced working surface. A prefabricated metal structure allows for accelerated installation and is most convenient for the construction of buildings with a concrete frame base.

Requirements for concrete for pouring into formwork

Mortar for pouring formwork can be ordered from suppliers. The finished concrete solution must be at least grade M 200, M 300.

When making a solution at home, you need to adhere to the correct technology:

if there is no need for special strength of concrete, prepare a solution from 1 part of cement grade M 400 and 3 ÷ 8 parts of gravel-sand mixture;
high-strength concrete is a mixture of 1 part M 400 cement, 2.5 ÷ 5 parts crushed stone and 1.5 ÷ 2 parts sand.

All parts of the future solution for pouring the formwork are thoroughly mixed by hand with shovels or in a concrete mixer, and after adding water they are mixed again. As a result, the resulting concrete should not spread over the shovel, but settle on it.

Concrete mortar must be used within 4-6 hours after production.

Drying

How long the formwork should stand after the foundation is poured is an individual question. In each case, the requirement of the design specification must be observed, which determines at what concrete strength it is recommended to remove the formwork when concreting.

In order for the final results of the work to be at the proper level, it is necessary to organize proper drying of the concrete.

This process will require water and plastic film. The structure is covered with polyethylene to protect it from the negative effects of ultraviolet light. The surface of the concrete structure is periodically moistened with water to prevent its premature drying.

They begin to wet the concrete five hours after pouring it, and continue this procedure for ten days, using water taking into account the outside temperature. If you don’t know how many days it takes to remove the formwork from the foundation, count one and a half weeks and carefully begin dismantling the panels. In summer, it is not recommended to remove the formwork from the foundation after such a period until the surface of the concrete turns white.

If the concreting process is carried out in the cold season, anti-frost additives are added to the concrete mixture and electric heating and heat guns are used during drying.

Violations of drying conditions provoke the appearance of cracks and further destruction of the structure. To avoid this, it is recommended to use permanent formwork to fill the foundation.

Pouring concrete into formwork - the whole process from A to Z

Pouring concrete into formwork

How to pour concrete into formwork? If there are large volumes (when the solution is delivered from the factory on a mixer), concrete is poured immediately along the entire perimeter to a predetermined height. At home, it is usually not possible to prepare a large amount of solution. There are two methods for correctly pouring concrete into formwork using hand-prepared portions of mortar:

pouring the entire perimeter of the formwork with concrete to a thickness of up to 0.5 meters, while the presence of too thin layers is not allowed;
Filling a separate area with mortar to the entire height of the formwork. The side edge of the poured concrete should be beveled for more reliable adhesion between the individual parts of the structure.

How to pour concrete into formwork? Concrete supply is carried out:

manually, carrying buckets of solution;
direct pouring from a concrete mixer;
imported concrete is poured directly from the mixer tray; if necessary, the tray can be extended with wooden or metal gutters.

When the entire volume of the pouring solution has been moved into the formwork, air bubbles formed during mixing and pouring of concrete are removed from it. To do this, it is compacted with a deep vibrator or shovel. You can pierce the concrete layer with reinforcement every 0.4–0.5 meters and gently tap the formwork walls with a sledgehammer.

The concrete surface is leveled with a shovel or building rule. If for any reason the work on filling the formwork with mortar is stopped for more than 24 hours, it can be resumed only after the concrete has completely dried. Before starting new concreting, the concrete working seam is wiped with a brush and washed with water.

Construction of houses

0 votes

Vote for!

—

Vote against!

The quality of finished concrete or reinforced concrete structures depends primarily on their manufacturing technology. One of the important production processes is pouring concrete into formwork. We’ll talk about the features and subtleties of the rules for pouring concrete formwork further.

Content:

Pouring concrete into formwork: types of formwork
Technology of pouring concrete into formwork
Pouring concrete for permanent formwork: methods and recommendations
Collapse of floor formwork when pouring concrete

Pouring concrete into formwork: types of formwork

Formwork is a panel structure, for the manufacture of which materials of various compositions are used. The only requirements for which are their high strength and ability to withstand high operating loads. Reinforcement bars are installed inside the formwork, providing additional strength to the concrete elements.

Formwork is a special form into which reinforcement is placed, which is then filled with concrete mortar. High-quality formwork must be manufactured in accordance with certain standards described below:

the shape, height and length of the formwork must be pre-designed in the drawings;
before pouring formwork using concrete mortar, check it for strength and rigidity, since concrete mortar exerts high pressure on the formwork walls, reducing their strength;
during the process of filling the formwork with concrete, its panels should not be subject to deformation;
The inside of the formwork should be smooth and have a flat surface.

Formwork manufacturing systems are either removable or permanent. Most often, when constructing private houses, soil trench walls or wooden panels are used as supporting formwork walls.

Removable formwork for concrete has multiple uses. For the manufacture of formwork, various materials are used in the form of wood, metal or plastic. Metal types of collapsible formwork have excellent performance characteristics. These designs are distinguished by the possibility of accelerated installation, excellent fastening systems and the presence of reinforcement on the working surfaces. These types of formwork are used in the manufacturing process of houses with a frame base made of reinforced concrete. Permanent formwork is relevant for use in the construction of thermal buildings. Such formworks have structures based on polystyrene foam, which have internal ribs that provide it with additional rigidity.

Each of the formwork elements has a specific system with protrusions and holes, which ensure high quality connections after the formwork is assembled. After installing the formwork, a concrete solution is placed inside it.

Technology of pouring concrete into formwork

Before starting concreting, it is necessary to take into account climatic factors such as outside air temperature, humidity, soil quality and its moisture level. In relation to these indicators, an individual selection of concrete is made in relation to its brand and quality.

The characteristics of the soil on the site also determine the type of formwork and materials for its manufacture. In order to increase the quality of concrete structures, reinforcement is placed inside the formwork, the amount of which is determined by the load on the concrete base.

It is possible to purchase ready-made concrete or make it yourself using a concrete mixer. Please note that saving on the quality of the solution is impractical. Since in the future the entire structure will suffer. Buy only high quality concrete. To make your own concrete mortar, use a concrete mixer.

In the process of constructing a concrete solution with your own hands, listen to these tips:

combine all components in strict adherence to the proportions specified in the recipe for a solution of a particular brand;
use only clean tools with which to prepare the concrete solution;
ensure careful connection of all components to each other.

The minimum grade of purchased concrete mortar is 300, of course 400 is better. Buy products only from trusted suppliers with good reviews.

Concrete is poured into the formwork using:

shovels;
measuring instruments;
hammer;
sledgehammer;
devices for mixing concrete;
vibration machine.

At the initial stage of work, the formwork is installed. The design is installed in relation to its purpose, and as mentioned earlier, it can be of a removable or non-removable type. To adjust the position of the shields, you must use supports. Reinforcement is installed in the inner part of the formwork. In order to fill the formwork evenly with the composition, fix the cord on its upper part, according to which the filling is carried out. Check that the cord is evenly positioned with a level.

After making the formwork and checking it for evenness, it is necessary to fill it with concrete mortar. When using a ready-made composition, it is enough to fill it one time around the perimeter of the formwork.

If the composition is manufactured on site, the process continues gradually. The freshly prepared concrete solution is poured into the formwork in parts, compacting it using a vibrator.

If the interval between pouring layers is more than one day, then work is carried out only after the previous layer has completely dried.

Pouring concrete for permanent formwork: methods and recommendations

The simplest and most popular method of pouring concrete into formwork is pouring from a mixing tray. However, this method is not always possible. Since the machine with the concrete solution must drive directly to the pouring site, which is not always possible. In some cases, the length of the mixing tray is increased by using wooden or steel gutters.

When pouring concrete manually, it is brought to the work site using buckets or other containers. To perform the work better and faster, concrete should be delivered to the site by several people.

Pouring concrete into formwork using a concrete mixer is quick and quite simple. The unit is installed near the pouring site. To perform the pouring, equipment is used from which the concrete solution falls directly into the formwork. In order to evenly distribute the solution inside the formwork, use a shovel or a rule.

In order to obtain a high-quality structure, compact the concrete solution with a vibrator. Using a deep concrete vibrator ensures high-quality adhesion of concrete to reinforcement. The device is capable of immersion to a depth of up to 100 cm, while ensuring high compaction of the concrete composition.

When performing layer-by-layer filling, compaction of each layer is carried out separately from the previous one. If there is no deep vibrator at the construction site, then use reinforcing bars to compact the concrete composition. They are installed 30-50 cm inside the solution, removing excess air from the solution.

In addition, by tapping the formwork with a hammer, it is also possible to compact the concrete composition without using a vibrator. Carry out the work with extreme caution to avoid damage to the formwork.

The time for removing formwork after pouring concrete is determined individually. The final stage of formwork installation is drying the concrete structures. The final result of the work directly depends on the technology of its implementation.

During the drying process of a concrete structure, the presence of water and a polyethylene film will be required. The film protects the structure from direct exposure to ultraviolet radiation. Water prevents the concrete from drying out quickly.

Wetting of concrete begins after five hours from the moment it is laid in the formwork. If the work is carried out in late autumn or winter, then a special version of concrete with frost-resistant additives is used for the work. In addition, you should use heat guns and electric heating.

Collapse of floor formwork when pouring concrete

Floor formwork requires special care during its installation. Floors are installed using reinforced concrete slabs with voids. During the installation of floor formwork, it is necessary to adhere to certain safety rules:

If there is a multi-tiered structure, each of the subsequent tiers is installed only after the previous one has been installed. Installing several tiers of formwork at one time is strictly prohibited.
If the height of the installed structures is more than 500 cm, it is possible to install the formwork using portable ladder structures. For larger building heights, the formwork is mounted from a portable scaffold or scaffold.
Before pouring the formwork, carefully check it for strength and absence of mechanical damage. During the process of pouring the formwork, people are not allowed to be in the area under the formwork.

The height of pouring concrete into the formwork is determined individually and is limited by a cord. The main function of slab formwork is to provide concrete on the surface before it hardens.

The answer to the question of when to remove the formwork after pouring concrete is clear: after the concrete composition has completely hardened. Installing formwork requires a lot of physical and time effort, but without it it is impossible to achieve a monolithic, high-quality reinforced concrete structure.

Before installing the formwork yourself, carefully consider its location, design the size and shape. To make formwork for the ceiling you will need:

wooden beam;
edged board;
plywood with moisture-resistant characteristics;
boards for forming braces;
fasteners;
a device for determining the evenness of formwork;
reinforcing bars.

Please note that there will be enough high-quality lumber to install the formwork. The bars that serve as racks must have a cross-section of 13x13 or 15x15 cm. The minimum thickness of the plywood used is 2 mm.

After preparing all the necessary materials, decide on the number of racks that will reduce the load on the base. To perform calculations, use a special program or the recommendations below:

with a floor thickness of up to twenty centimeters, the interval between the racks will be 200 cm;
as this indicator increases, the interval between the racks increases.

Initially, the first longitudinal row of formwork is installed. Install the beam so that the load from the concrete falls on the supports. Install a longitudinal beam on the wall. Make sure the base is rigid; to do this, install boards under the base. The formation of the second row of formwork is carried out in the same way as the previous one.

After this, the timber is installed, the installation step of which is 60 cm. Using a plumb line, the racks are aligned. After installing the formwork, the horizontal installation of the timber is checked. If necessary, the support type racks are aligned.

Next, braces are installed, with their help the racks are connected to each other. Thus, the supporting frame of the formwork has already been formed. Next, you should check the formwork for the strength and rigidity of the ceiling. An inspection of the bottom, racks, and connections of all parts to each other is also carried out.

If there are cracks on the formwork through which the concrete solution can flow out, it is necessary to get rid of them. To seal them, use slats or boards. In order to protect the floor from frost, install bricks with foam plastic around its perimeter. Next, a reinforcement frame is installed inside the formwork. After this, filling is done.

The concrete solution is poured into the floor formwork in one layer, followed by compaction with a vibrator. After the concrete floor has dried, the formwork is dismantled. All work is carried out gradually. First you need to remove that part of the formwork that is in contact with the wall. Since the finished structure rests on the walls. Next, the rest of the formwork is dismantled.

The formwork should be removed only after the concrete has completely formed. If, when removing the formwork, the concrete begins to shrink or changes shape, then this process stops until the floor dries completely. The procedure for disassembling the formwork is the same as its assembly. Initially, all fasteners in the form of nails, nuts, and self-tapping screws are removed. Next, all wooden parts of the formwork are separated from the concrete composition. It is possible to reuse the formwork when constructing the floor. All formwork parts are thoroughly cleaned of excess concrete. Next, the structure is well dried.

The price for pouring formwork with concrete is determined by the volume and complexity of the work and is calculated individually.

Features of performing concrete pouring work in winter

In winter, concrete work is carried out only in cases of special need. To prevent freezing of the concrete mixture (minimum temperature of the mixture is + 3°C), use:

heat guns;
electric heating of the solution;
protection of poured concrete with insulation or polyvinyl chloride film;
special frost-resistant additives - antifreeze.

Formwork filled with concrete must be insulated until the concrete reaches 50% strength.

To perform a job efficiently, a builder needs to know all the intricacies when working with a material such as concrete. You need to know the hardening time.

A foundation without formwork facilitates construction work. The filling procedure is simple, but requires certain knowledge. Building a house without formwork can lead to...

The blind area around the house is a strip located around the entire perimeter of the room. Its main role is to drain surface water from the foundation.

There are many types of foundations. However, they all perform one important task - they serve as the basis for the entire structure. For this reason .

Curing

In summer, concrete should be covered with plastic wrap and watered every 4 hours for the first 3 days with water by spraying. Then they water it every day for another week (more often if it’s hot), after 10 days the formwork can be dismantled, after 28 days the concrete will have fully gained its strength.

It is better not to carry out work in winter, but if it is really necessary, the concrete must be protected from freezing and provided with a temperature of at least +3C - you can use heat guns, electric heating, insulation, and special frost-resistant additives. The formwork must be insulated until the concrete reaches at least 50% strength.

Depending on the requirements for the concrete base, one or another type of formwork is chosen. Thus, when building a bathhouse or sauna, for swimming pools and greenhouses, residential and industrial buildings, completely different types of structures will be needed to allow pouring to be carried out in accordance with established standards and requirements for the future monolith.

If preliminary calculations are carried out correctly, all necessary equipment and tools are used, quality materials are selected, pouring concrete into the formwork with your own hands will provide the desired result.

Types of formwork

The most common type of formwork is a wooden structure assembled from boards and fastened with timber equipment. The planed side of the boards faces the inside of the fence to obtain a smooth surface of the monolith. Dismantled boards are reused or for other household needs.

One of the most common types of formwork is wooden

Construction plywood has laminated side surfaces. Plywood is assembled into panels. On the outside, the shields are reinforced with stiffening ribs made of bent metal profiles. The equipment is made of metal profiles. Installation and dismantling is carried out using a truck crane.

Metal panels are enlarged into mounting panels. The formwork is installed in the design position using a lifting mechanism. The fencing parts are assembled and fixed by welding and bolted connections.

In order to avoid concrete sticking, the inner surface of the formwork is lubricated with an emulsion.

Mobile formwork is used for multi-level construction of building walls. As the concrete hardens, the metal panels are dismantled and moved higher to another level. Mobile fencing is widely used in industrial and residential construction.

How to remove formwork from a structure

Stripping diagram

When to remove formwork from concrete, each developer decides independently. The main thing is that by this moment the monolith has managed to gain a sufficient level of strength. In order to remove the formwork of the structure, you will have to remember all the stages of installation and perform all the same work, only in reverse order.

Despite its apparent simplicity, this process has its pitfalls, because the work must be done in such a way as not to damage parts of the created product.

The instructions for stripping include the following recommendations:

Even during the construction process, options for removing each element should be considered;
Removal should be carried out only when the developer is confident in the strength of the structure.

Advice. Premature removal of frame elements can lead to cracking of the monolith under the influence of load and the entire construction process will have to start over again, and the cost of this process is very high.

Basic rules for stripping

The demoulding process is carried out in compliance with the following rules:

Removal of the tower, tour and support posts is left until the end of the work because these elements support the structure;
The first step is to remove the tie wire by unscrewing the bolts holding it together . This action will make it possible to separate the racks and shields;
Dismantling should be carried out starting from the upper parts, smoothly moving to the lower parts;
First, elements should be removed from the corners and edges of the structure;
Removal of grasping ribs;
Separate the shields from the monolith;
Now remove the supporting elements of the structure.

Note! The process of removing product elements can sometimes take weeks.

The final monolith

The removed parts can be reused for pouring foundations, for which they should be stored in appropriate conditions.

Preparation for pouring formwork

Before loading the formwork with the mixture, a series of preparatory measures are carried out: they check whether the geometry of the enclosing structures is correctly maintained, control the verticality of the formwork walls, and the absence of gaps in the joining seams.

If any gaps wider than 4 mm are found in the formwork, they should be sealed immediately. Possible leakage of liquid from the concrete mixture significantly reduces the load-bearing capacity of concrete.

The diagonals between opposite corners of the formwork should not differ by more than 20-30 mm.

The internal space of the formwork is cleaned of debris, dirt and foreign objects. The reinforcement frame must be equipped with clamps that prevent the reinforcement from coming into contact with the surface of the enclosing structure. During organized construction, the developer accepts fencing for pouring concrete into the formwork according to the work acceptance certificate.

Do-it-yourself formwork for strip foundations

The most voluminous is the formwork for strip foundations. It follows the contours of the house and all load-bearing walls on both sides of the tape. When constructing a more or less large building with a large number of partitions, the cost of materials for foundation formwork will be very significant. Especially when laying a deep foundation.

Construction of shields and their connection

When assembling the formwork with your own hands, it is important to make the panels strong: they will need to hold the mass of concrete until hardening occurs.

The dimensions of the formwork panels vary and depend on the geometry of the foundation. The height is slightly higher than the height of the foundation; you determine the length of each panel yourself, but usually it is from 1.2 to 3 m. It is inconvenient to work with very long structures, so the optimal length is about 2 m. The total length of the entire formwork should be such that they were placed exactly according to the markings of the foundation (do not forget to take into account the thickness of the shield).

How can formwork for a strip foundation be installed: in a trench dug according to the dimensions of the strip and in a pit with braces

When making formwork from boards, cut several pieces of the same length and fasten them together using bars and nails or self-tapping screws. When using nails, hammer them in from the inside of the shield and bend them onto the block. It is easier to work with self-tapping screws: they do not need to be bent, since due to the thread they ensure a tight fit of the elements. They are screwed from the inside of the shield (the one that will face the foundation wall).

The first and last bars are attached from the edge at a distance of 15-20 cm. Between them, at a distance of 80-100 cm, additional ones are placed. To make it convenient to install the formwork panels, two or three bars (at the edges and in the middle) are made 20-30 cm longer. They are sharpened and driven into the ground during installation.

Approximate dimensions of formwork panels made from edged boards

Panels made of plywood or OSB are assembled on a frame made of bars. When assembling, it is important to strengthen the corners well. In this design they are the weakest point. They can be strengthened using metal corners.

Do-it-yourself formwork installation

If the shields are made with several elongated bars, they need to be aligned along the cords of stretched markings. The difficulty is that you need to set it in the vertical plane at the same time. For fixation, you can use bars hammered to the mark and aligned vertically. When installing, align the plane of the shields close to these bars. They will be both support and guides.

Panels with extended cross bars are easier to install

Since the bottom of the trench or pit must be flat (it is compacted and leveled), it should be easy to position the panels horizontally. Try not to hammer them too much: it will be easier to level them later. Lower one of the corners to the level of the bedding. There should be no gaps, the solution should not leak out. Having achieved a tight fit, take a building level, place it along the shield and hammer in the second edge until the top edge is installed horizontally. You already set the next shield relative to the installed one: they should be on the same level and in the same plane.

If the shields are made without long bars, at the bottom of the pit, along the line marking the tape, a block is fixed that will serve as a stop. The shields are placed close to it, then fixed with the help of bevels and spacers.

Strengthening - braces and stops

In order to prevent the formwork from falling apart under the mass of concrete, it must be secured from the outside and from the inside.

Braces are installed outside. Supports should be placed at least every meter. Particular attention should be paid to the corners: here stops are placed on both sides. If the height of the shield is more than 2 meters, then one stop belt is not enough. In this case, at least two tiers of spacers are made: upper and lower.

Stops and braces are placed on the outside of the formwork. At high altitudes they are made in several tiers. Pay attention to the thickness of the support beam

It is also necessary to stabilize the distance between two opposing shields. To do this, use reinforcement studs with a diameter of 8-12 mm, metal gaskets and nuts of the appropriate diameter. The studs are installed in two tiers: at the top and bottom, at a distance of 15-20 cm from the edge.

The length of the pins is about 10-15 cm longer than the width of the tape. There are two options:

Threads are cut at both ends of the reinforcement. Then each stud will require two metal sealing plates and nuts.
On one side, the pin is bent and flattened, and a thread is cut with the arc. In this case, one nut is needed (there are still two plates).

The internal distance between the panels, equal to the design width of the tape, is fixed using sections of plastic pipes. Their internal clearance should be slightly larger than the thickness of the studs.

How to make spacer pins in formwork

The assembly proceeds as follows:

Holes are drilled in both shields with a long drill.
A piece of pipe is installed between them.
The pin is threaded through.
Metal plates are installed (they will prevent the pin from tearing the shield material).
The nuts are tightened and tightened.

You need to work together, or better yet, three. One person installs tubes inside between the shields, and one person each to install the studs and tighten the nuts.

When removing the formwork, first unscrew the nuts and remove the studs, then dismantle the slopes and stops. The released shields are removed. They can be used further.

Preparation and pouring of liquid concrete

Based on construction conditions, concrete for formwork is prepared in various ways:

Mortar unit

During the construction of large projects where mortar is constantly needed, a mobile workshop for its preparation is set up. The mixture is prepared using an automated method.

Dispensers load cement, sand, solid filler (usually crushed stone of a certain fraction) and water into the mixing container in proportions corresponding to the required grade of concrete. Ready concrete for formwork is delivered from the bunker to the body of the vehicle.

The work manager submits a request for what time, what brand of mixture is needed and its quantity. At the appointed time, the concrete mixture is delivered to the construction site by motor transport.

Automixer

An automixer or concrete mixer truck is a vehicle equipped with a rotating drum. The drum is loaded with all the ingredients of the mixture. During transportation from the mortar unit to the construction site, the mixture in the rotating mixer reaches full readiness without losing its fluidity.

At the construction site, an automixer, using a pump and a hose, pours the liquid mixture into the formwork. If accessibility to the formwork is limited, the automixer unloads the mixture into special bunkers. Then the bunker is transported by crane to the unloading site.

Concrete mixer

The concrete mixer is used in the construction of small projects. The rotating bulb of a conventional mixer holds about 150 liters of solution.

Using shovels, cement, sand, solid filler and water are loaded into the pear in proportions corresponding to the brand of concrete. The stirrer significantly reduces manual labor costs. You should not load the concrete mixer bulb by eye.

It is necessary to calculate how many full shovels of cement, sand and crushed stone, and buckets of water will be required for one batch. This is necessary in order to obtain concrete of the same grade with each subsequent batch.

Manual method

When the volume of pouring is very small, for example, when laying a foundation for a barn or greenhouse, then the solution is prepared manually. Mix the mixture with a shovel in any suitable container.

Compacting concrete

When the mixture is poured into the formwork, each layer (no more than 200 mm thick) must be compacted. The most common tool for compacting concrete mortar is a hand-held vibrator.

At the end of the supply cable there is a metal cylinder, inside of which the core vibrates under the influence of an alternating magnetic field. The oscillations of the core cause strong vibration of the cylinder.

The formwork is poured with concrete continuously. The break should not exceed two hours to prevent delamination of the monolith mass.

Compaction and drying process of concrete

During the process of pouring concrete into the formwork, each layer with a maximum thickness of 20 centimeters must be compacted. For this, manual submersible vibrators are usually used, which promote uniform distribution of the layer over the surface and allow air to escape. After compaction, the vibrator is removed without turning off so that a void does not appear under its cylinder. If there is no vibrator, remember the method of bayoneting the mortar; you can release air by tapping on the formwork panel.

Improper drying of concrete can cause cracks and deformations, which may then require repair of the mixture, which increases the completion time and cost of the work. Concrete takes up to 28 days to dry; at first it must be moistened with water. Much depends on the time of year.

How to choose concrete for pouring

Concrete is a building material consisting of binders (cement or others), fillers (grain screenings, slag, etc.), water and additives that allow you to improve technical characteristics and build objects at any time of the year.

! The poured concrete must be prepared no later than 4 - 6 hours before filling the formwork. !

As a rule, concrete is delivered to the construction site by mixer trucks with a volume of 2–10 m3. Occasionally, material is brought in by dump trucks. But in this case, the concrete mixture must be made no later than 60 minutes before pouring.

Since it is very difficult to track the time of shipment, it is better to refuse such a dubious delivery. After all, even an hour is enough for the mixture to thicken and lose its performance properties.

When pouring formwork for the foundation, you can also use a gravel-sand mixture. In this case, the ratio of cement (M 400) to gravel is 1: 3-8. Such concrete has low strength, but it is quite sufficient for the foundations of small buildings: garages, bathhouses, sheds, etc.

To fill the foundations of heavy buildings, it is better to use crushed stone as a filler. A larger fraction of granite crushing is taken in proportion to the same brand of cement in the ratio 1: 1.5-2.

! The smaller the size of the crushed stone, the greater the amount of it that needs to be added to the solution!

When manually pouring concrete into the formwork, it must be compacted. This is done to prevent the occurrence of air pockets and cavities that weaken the monolithic body of the foundation.

Manual compaction is performed by bayoneting. This is the name for the process when freshly poured concrete is pierced 15-50 times with a bayonet shovel or a piece of reinforcement, and to the entire depth of the pour. We perform compaction using a special industrial vibrator press.

Types and types of strip foundation

Concrete strip foundations are divided into 3 groups by type:

Not buried. It is located at ground level on a bed of crushed stone and sand.
Shallow. Designed for panel, frame, foam block or wooden houses. Depth of burial – 50-70 cm.
Recessed. Used for houses with basements, buildings with heavy weight, and in areas with heaving soil. The laying depth is below 50 cm of the soil freezing level.

The buried option is rarely used - the amount of concrete for the foundation is required very large. In places with cold climates, the laying depth can be more than 2 m.

When deciding which type to choose for construction, pay attention to 4 indicators:

the load that the base will experience;
required height of the base;
ground water level;
depth of soil freezing.

By type, concrete strip foundations are divided into prefabricated and monolithic. The first consists of individual elements produced in a factory, from which the structure of the desired configuration is assembled. With the same thickness as a monolithic one, it is inferior in strength by almost a third. Among the advantages of this option are the absence of the need to independently calculate the amount of concrete for a strip foundation, ease of assembly and the ability to install blocks at intervals to save money.

Monolithic is made directly at the construction site: cement mortar is mixed and the strip foundation formwork is concreted. The construction of this option is more labor-intensive, but it is stronger than the prefabricated one and is cheaper.

Advice! In order not to make a mistake with the amount of mortar, you can use an online calculator to calculate concrete for a strip foundation.

If you have a choice between different types of foundation, you can determine which will be better by comparing the characteristics and features of each. So, when choosing between a strip foundation or a monolithic slab, several parameters are taken into account:

Soil type. For weak and non-heaving soils, tape is optimally suited. On heaving areas, it is more advisable to use a stove.
Time. Installation of the slab is possible at any time of the year; after installation, construction can continue. It is necessary to pour a strip foundation at above-zero temperatures, after which you need to wait until the concrete gains strength.
Life time. The service life of the slab declared by the manufacturers is up to 100 years, but it can be shortened due to high load, unfavorable operating conditions and under the influence of other factors. A prefabricated strip foundation retains its integrity for an average of 50-75 years, a monolithic one - up to 150.
Budget. What will cost less – a strip foundation or a monolithic slab? The cost of the tape is several times lower than the slab.

It is impossible to unequivocally answer which is better - a strip foundation or a monolithic slab. To build a house on heaving soils in a short time, the second option would be preferable. On slightly heaving soil, tape is used, which is cheaper and easier, since installation does not require special equipment.

The construction process consists of 5 main stages - preparatory work, installation of formwork, reinforcement and concreting and maintenance of concrete. In order for the resulting structure to have the necessary strength, it is important to know what grade of concrete can be used for a strip foundation, as well as to follow the construction technology.

Features of summer concrete formwork pouring

Pouring formwork in Rostov-on-Don can be done all year round (if the concrete contains the recommended additives). However, it should be remembered that the hardening (and therefore the strength) of a concrete body is influenced not only by the ambient temperature, but also by humidity, wind and even the direction of the sun's rays.

! The optimal hardening environment for concrete stone is considered to be an environment with high humidity and a temperature of 20-35 degrees!

Frankly, the price of pouring formwork in summer is much less than in winter. After all, you can often do without additives in such a season, and it is easier to care for concrete. All you need to do is cover the open part of the concrete tape with polyethylene and, in dry weather, water the surface 1-3 times with a watering can for the first 10 days.

Dismantling the formwork

Many people wonder when it is possible to remove the formwork after pouring concrete. The answer is clear: dismantling the formwork is allowed after the poured concrete has gained full strength.

Let's consider how to properly dismantle the formwork structure.

If you are a good owner, then you plan to use formwork panels for the maximum number of work cycles. This means that you should not remove the formwork after pouring and hardening the foundation using force. You can not only damage structural elements, but also create the preconditions for deformation of the foundation base that has not had time to completely harden.

If, at the time of installation of the shields, you carefully treated their internal surfaces with a special oil composition or stole them with polyethylene, there will not be any particular difficulties during disassembly. It is best to start dismantling from the place that is loaded the least and where the concrete has hardened faster - from corner areas and open edges.

Having decided how long it takes to remove the formwork, and after waiting for this moment, perform dismantling work from above, moving gradually to the bottom. First, the external supporting posts, stops, slope elements and other parts securing the panels are removed.

In the case when the opposite formwork elements were tied together with wire or metal brackets and pins during installation, first of all they are freed from this type of fastener. Removing the formwork with armored belt elements is simple - the parts are unscrewed or cut off. As a rule, this is quite enough to dismantle the shields.

In the case when the boards are mounted in a single structure using connecting bars fixed longitudinally, first of all, these fasteners are dismantled, after which the boards are removed one at a time.

When dismantling the formwork structure, it should be remembered that the reinforced concrete structure may contain embedded parts installed to form communication channels. In such places, it is necessary to remove the shields with extreme caution.

When the shields do not give in immediately, they can be left alone. How long does it take for dismantling to continue in this case? It's simple - once you make sure that the formwork panels move freely, you can continue working. There is a second option for this case - the shield is carefully torn off the concrete surface using a wood wedge. This dismantling method is used when concreting a large-scale foundation, when formwork is needed in another area.

Removed formwork elements must be stored dry. Well ventilated place. If you have to remove the formwork in the fall, it is recommended to put it under a canopy.

It is strictly forbidden to leave formwork panels on a foundation that has been poured and has gained full strength, especially before the onset of the winter season.

Wood from exposure to moisture and temperature changes will begin to have a negative effect on the reinforced concrete surface. And there is no logic in such a plan - the concrete has gained the appropriate strength and no longer needs formwork.