How is concrete heated using a welding machine? Warming up concrete with a heating wire PNSV How to heat up concrete using a transformer.

During the construction of monolithic concrete structures V winter time Several technologies are used to create the necessary temperature conditions. This could be the installation of special greenhouses, the use of heat mats or a special wire for heating the concrete. The first method is the most energy-intensive and therefore economically unprofitable; the second option involves the installation of thermal stations that heat only the upper layers, which also introduces a number of restrictions on application. The last option is the most popular and will be discussed in this publication.

Why is concrete heating needed?

During the cold season, when the ambient temperature drops below the freezing point of water, hydration problems arise concrete mortar. Simply put, the mixture partially freezes rather than completely hardens. After hanging temperature environment the thawing process begins, the solidity of the mixture may be disrupted, which will negatively affect the solidity of the structure, its resistance to water penetration, which will lead to a decrease in durability.

Consequences of pouring mortar in the cold, in this case even the Aquabarrier waterstop or other waterproofing will not help

To avoid these consequences, it is imperative to electrically heat the concrete mixture in winter. In this isothermal process, there are no disturbances in its structure, which has a positive effect on the strength of the structure being built.

Types of heating wires and cables

Most often, PNSV wires are used for electrical heating of concrete. This is due to its relatively low cost and simple installation. Below is appearance thermal wires, its design features and decoding of markings.

As an alternative, an analogue can be used - PNSP, the main difference of which is insulation; it is made of polypropylene, which allows for a slight increase maximum power heat generation.

Table of main parameters of PNSV and PNSP wires

Please note that the wires of this type can be used as floor heaters that operate on the principle of underfloor heating.

The main difficulty associated with the use of thermal wires of this type is the need to calculate their length. Small miscalculations can be corrected by adjusting the voltage level coming from the warm-up transformer.

Details of how the PNSV is installed, as well as a description of the related procedures (calculation of wire lengths, laying diagram, drawing up technological map etc.) will be given in another section.

Types and features of KDBS and VET cables

The main disadvantage of the thermal wires described above is the need additional equipment, which allows you to regulate the heat generation power by changing the voltage. The task can be significantly simplified by using two-core sectional self-regulating thermal cables, namely the Finnish VET or the domestic KDBS. They do not require additional equipment for heating and are connected directly to a 220 volt network. The heating cable structure is shown below.

Designation:

A – Outputs of heating cores.
B – Installation cable used to connect the KDBS to a 220V network; for this purpose you can use any connecting wire, for example automatic reclosure.
C – Coupling for connecting the heating section.
D – End insulator sleeve.
E – Heating section of fixed length.

Structurally, the VET cable is practically no different from the domestic analogue discussed above, with regard to the main technical characteristics, then they are shown in the comparative table below.

Table comparative characteristics VET and KDBS cables

As for marking, domestic products of this type are coded in the following form: ХХКДБС YY, where ХХ is the linear power characteristic, and YY is the section length. An example is the marking 40KDBS 10, which indicates a power of 40 W per meter, and the section itself is ten meters long.

Warming technology using PNSV

The principle of operation is quite simple: when voltage is applied, the wire heats up, which in turn heats the concrete mixture. Since it is recommended to limit heating to a voltage of 70 V, a step-down transformer (hereinafter referred to as PT) of appropriate power will be required.

Transformer substation KTPTO 80 for working with thermal conductor

Before installation, it is necessary to calculate the length of the heating wire. In this case, it is necessary to take into account its type and characteristics, voltage transformer substation, volume of concrete mixture, ambient temperature, as well as the nature of the structure (pouring of columns, beams is expected), etc. To avoid getting confused in the calculations, you can use online calculator for calculating the heating conductor PNSV or other cable (PNBS, PTPG, etc.).

To heat a concrete mixture with a volume of one cubic meter, about 1200-1300 W are needed. If we use a wire of this brand with a cross-section of 1.20 mm, then we will need a heating device of 30-45 m (to accurately calculate the length, you need to know the temperature conditions).

In addition, it is necessary to take into account the current strength, for normal operation 14.0 - 18.0 Amperes permissible for a cable immersed in a solution (depending on the connection diagram).

Electrical diagram PNSV connections A) star B) triangle

Installation of PNSV

Here is a brief guide to the standard methodology:

Please note that the principle and layout of PNSP, PNBS, PTPG are practically no different from PNSV.

Using a welding machine as a PT.

This method of heating is quite possible; we will give an example of how this method can be implemented. Let's say we need to fill a slab with a volume of 3.7 cubic meters, at an outside temperature of 10°C. For this purpose, you will need a 200.0-250 ampere welding machine, current measuring clamps, PNSV wire, cold ends and fabric insulating tape.

We cut eight segments of 18.0 meters each, each of which can withstand a current of up to 25.0 A. We will leave a small margin and take eight such segments to connect to a 250.0 A welding machine.

We connect a twisted installation wire to each output of the segment (we connect the cold ends). We are laying the PNSV, its diagram will be given below. It is advisable to connect the cold ends (plus and minus separately) using a terminal block placed on a textolite or any other insulating material.

Having completed the filling, we connect the direct and reverse output of the device (the polarity does not matter), having previously set the current to a minimum. We measure the load current on the segments; it should be about 20.0 A. During the heating process, the current strength may “sag” a little; when this happens, we increase it during welding.

Pros and cons of PNSV

Heating concrete in this way is quite beneficial. This is explained by both the low cost of the wire and the relatively low electricity consumption. Separately, it is necessary to note the resistance of the wire to alkaline and acidic influences, which allows the use this method when adding various additives to the mixture.

Main disadvantages:

complexity of calculations when calculating the length of the wire;
the need to use PT.

Step-down stations are quite expensive, and given the length of the process, it is not profitable to rent them (such services cost 10% of the cost of the product). The use of welding machines makes it possible to heat small structures, but since it is not designed for this mode of operation, its failure and subsequent expensive repairs are quite likely.

Installation of sectional heating cable

Since such concrete heaters are supplied not in coils, but in ready-made sections, the issue of cutting is eliminated. All that is needed to assemble a winter concreting installation is to calculate the power of the segment based on how many cubes of concrete are in the structure, and then select a cable of the appropriate length.

Let's start with quick guide according to calculations and small installation recommendations:

The instructions for the concrete TMT technology indicate that heating a cubic meter of mixture requires from 500 to 1500 W (depending on the air temperature). Electricity consumption can be significantly reduced if you use a few simple technical techniques:

Use special additives for the mixture to lower the freezing point of the solution.
Insulate the formwork.

If a beam or ceiling is being poured, the heating cable is calculated from 4 linear meters per 1 m 2 surface area. When constructing volumetric elements such as I-beams concrete beams, electric heating is laid in tiers, with a distance between them of no more than 40.0 cm.
The cable protection allows it to be wound to the fittings.
The distance from the surface of the structure to the electric heater placed inside must be at least 20.0 cm.
In order for the concrete mixture to heat up evenly, the heaters must be placed at the same distance.
Between different contours must be at least 40.0 mm.
Crossing heating conductors is prohibited.

Advantages and features of segmented cable

To the undoubted positive qualities Products of this type should include:

To organize concrete heating using this method, you do not need expensive additional equipment (ET).
Unlike drying with electrodes, the likelihood of electric shock is minimal.
Easy installation and simple calculation of segment length.

Peculiarities:

VET cable is significantly more expensive than the wire for heating concrete PNSV. Domestic KDBS, for example, produced by the ETM company in Krasnoyarsk, improves the situation somewhat, but not by much. That is why these cables are used in the construction of small concrete and reinforced concrete structures.

As a conclusion.

We have described only one method of heating concrete; in fact, there are many more. These will be discussed in other publications.

In conclusion, we consider it necessary to answer the question that appears repeatedly on the Internet, why it is impossible to use nichrome wires to heat concrete. Firstly, this pleasure would be very expensive, and secondly, it is prohibited by safety regulations. This is why there is no need for a calculator to calculate the number of turns of nichrome to heat a pipe or concrete.

Today, such methods of heating concrete as heating concrete with a PNSV wire, heating cable, heating using special thermomats, transformers and stations are popular. But the most proven and, most importantly, accessible to the majority remains.

Winter concreting.

The main material used in modern construction buildings is concrete. To ensure that construction continues uninterrupted, all year round, at sub-zero temperature, concrete heating is applied. Heated concrete sets in exactly the same way as at above-zero temperatures and subsequently has the necessary strength. If concrete freezes, it does not set, therefore it has no strength, and when it freezes, it crumbles.
To heat the concrete, a step-down transformer is used - 380V/55V. Also, nichrome wire, NMPG - 1.5 sq. mm. And from the low side of the transformer, - cable large diameter, usually - 35 - 50 sq. mm. Depending on the maximum permissible load of the transformer. Usually this is 510A. Therefore, cables with a diameter of 50 sq. mm. on one phase, it is enough to fully load the transformer.
Winter concreting. Warming up the concrete. Horizontal heating is carried out as follows. Inside reinforcement cage, before pouring concrete, insulated nichrome wire is laid. The wire is laid in loops. The length of the wire of one loop should be 25 meters, then the current in the wire will be 10A, which is the optimal value for heating it. The beginning of the wire is connected to one phase of the low-voltage transformer cable, the end of the wire is connected to the other phase. It is laid out evenly over the entire area ready for pouring concrete. The distance between the stretched wire of the beginning of the loop and the stretched wire of the end of the loop, as well as between adjacent loops, should be 20 - 25 cm. This will ensure even heating of the entire surface. For the cables on the low side of the transformer, the loops are connected evenly between phases. When all the loops are connected, concrete pouring begins. After the concrete is poured, the heating area is fenced off and the transformer is turned on. Horizontal heating is used when concreting floors and interfloor ceilings.

Vertical heating of concrete for building columns and load-bearing walls, is produced in this way. Inside the vertical reinforcement frame of a column or wall, using insulators, electrodes are installed along the entire height. Usually this is steel wire with a diameter of 8mm. The electrode must not touch the reinforcement cage. Most often, the insulators, and at the same time the fastenings of the electrodes, are pieces of rigid insulated wire. The middle of the wire is wrapped around the electrode, the edges are wound on the frame reinforcement so that the electrode is in the tension of the insulated wire. Cables from the low side of the transformer are connected to the upper ends of the electrodes using leads. The load distribution must be uniform and is done as follows. Phase “A” is connected to the first electrode. Phase “B”, to the second electrode. Phase “C”, to the third electrode. Further - in the same sequence. The fourth electrode is phase “A”, the fifth is phase “B”...and so on.
After pouring the concrete and turning on the heating, you need to immediately check the amount of current in the low-side cables. If the cable, for example, has a cross-section of 35mm.sq. and the current is more than 400A, it needs to be unloaded. That is, turn off the transformer and disconnect several electrodes. Warming up is carried out for 12 – 17 hours. During this time, the water completely evaporates and the concrete sets.

Work on pouring concrete should be carried out no more than 4-6 hours after mixing the material. Most convenient way pouring concrete (including to a height) - using a special pump. In this case, you can insert an adapter into the hose to reduce the speed of concrete movement. It is recommended to first direct the jet to corners, slopes, wall branches, edges of holes, and then to the main part of the formwork. Once pouring is complete, the concrete must be compacted to eliminate voids and cavities. The material is compacted using the bayonet method. In this case, the concrete is pierced throughout its entire depth bayonet shovel or a piece of reinforcement. It is considered better to work out the mixture with a special vibrating screed or submersible vibrator.

In winter, concrete poured must contain special components - acidic or hydrochloric. It is also recommended to build polyethylene greenhouses above the work site, inside which a heat gun or air heater is placed.

Electrical heating of concrete is carried out when pouring in the winter or in situations where it is necessary to speed up the time during which the concrete will set. In this case, you must strictly adhere to the established technical regime. Otherwise, the concrete product may lose its strength or crack. After pouring, it is necessary to pour water over the concrete surface and close it plastic film to prevent moisture evaporation.

Cellular concrete is a thermal insulation and structural material made on a binder mineral base. It has a porous structure, which is due to the mixing of concrete with foam and ultra-light aggregates, gas formation and air entrainment. There are several varieties cellular concrete, the most popular of which in construction are foam concrete, aerated concrete, aerated concrete, gas silicate, and expanded polystyrene concrete.

Features and applications of concrete

Concrete is the main material in the construction of buildings and structures, pouring foundations and manufacturing various building structures. In order to achieve it of proper quality, especially when pouring in conditions low temperatures, it is necessary to strictly adhere to the technology for producing concrete mixture.
The composition of concrete large quantities includes water that is not chemically combined with the other components of the solution - cement, sand and filler. Thus, when the ambient temperature drops to zero temperatures, it freezes, which leads to an increase in setting time and a decrease in the strength of concrete.

At temperatures below 0 degrees, strength finished design is reduced to 50%, which can lead to cracking and destruction of finished concrete structures.

In order to carry out uninterrupted and high-quality construction in winter, as well as to preserve the strength properties of concrete, there are several methods for warming it up:

Thermos. The technology of thermos heating of the mixture consists of insulating the formwork;

Additions of hardening accelerators, plasticizers and antifreeze additives. It differs from the creation of insulated formwork by the addition of chemical reagents that help accelerate the setting of concrete and prevent freezing of the water included in the mixture;

Preheating of concrete. It consists of delivering concrete from the plant to the pouring site in heated concrete mixers and creating double formwork into which hot air is supplied. Thus, the easiest way to solve the question is how to warm up concrete without high costs;

Heating the mixture using the electrode method. Electrodes or special fittings are installed in concrete through which electric current is passed. Thanks to this, the electrodes heat up, and from them the concrete mass heats up;

Infrared heating of concrete mixture. It consists of heating the solid concrete structure illuminated by infrared rays;

Induction heating method. When using this method, an electromagnetic inductor is used as a heating element, heating the concrete mixture using eddy currents.

Warming up concrete with a welding machine

Warming up the concrete welding machine
When conducting construction work Warming up of the concrete is often required. For this there are special devices, but you can also use a regular welding machine.

First of all, additional electrodes will be needed for warming up. As such, you can use scraps of reinforcement. They are installed as evenly as possible over the entire concrete surface, which should be covered with sawdust. These sawdust will serve as additional thermal insulation and will also prevent moisture evaporation.
After this, the arranged fittings are connected to each other with a wire so that parallel circuits are formed. The forward and return welding wires are connected to these circuits. It is very important that they do not become isolated on each other! The presence of voltage is determined by an incandescent light bulb installed between the circuits. When warming up, you should constantly monitor the temperature of the concrete to prevent overheating. Temperature control is carried out using any thermometer.

Using this method, you can heat up concrete without using any expensive and complex devices. But still, it is better to use a welding machine for not very large volumes of concrete.

You should immediately abandon the idea of “simplifying” the process by simply connecting a welding chain to the concrete reinforcement. Besides wasting time and electricity, this will not give any result.

Among the numerous brands of welding machines, LINCOLN ELECTRIC stands out. Their excellent quality, reliability, high performance, as well as ease of use, have long been recognized by both professional welders and those who use the devices for their own needs. LINCOLN ELECTRIC has recently launched devices for plasma cutting, capable of easily working with any metals and alloys.

Winter concrete and its use

What qualities are needed for concrete used in winter? At this time of year, sightings are most common negative temperatures air. Therefore, it is impossible to mix concrete under normal conditions. This is what led to the fact that all concrete production plants can be winter or summer. The former cannot produce products at negative temperature conditions. The second ones can produce winter frost-resistant concrete at temperatures down to minus twenty-five degrees. They differ from those that operate in the summer in that they are equipped with a steam generator that heats up the inert components; warm production and mixing compartment; an industrial boiler that raises the temperature hot water; work in accordance with special technologies; Fill the mixers with hot water.

The recipe for preparing concrete in winter is different in that special additives are used to prevent the mixture from freezing, maintaining its plasticity. Company " Concrete system"has two enterprises specializing in the production of concrete in winter. These are the Concrete Plant at the Rzhevka airport and the Concrete Plant in the village of Beloostrov.
Is it possible to pour and lay concrete in winter? Yes, but two conditions are required:

1. during transportation and concreting, you need to use special frost-resistant additives in concrete
2. While the concrete is setting, it is necessary to raise the air temperature using special devices.

During concreting and before it is completely petrified, you need to create required temperature. Special additives do not affect this process in any way, so you need to cover the concrete in winter conditions with polyethylene or burlap, use heat guns or constant tension.

What technologies are used to increase temperature? This thermal curtains, which are created through the use of heat guns or construction hair dryers. This equipment supplies air jets to the area of the heated structure that must be protected. It is possible to save money by using welding machines and wire to heat concrete in winter.

When concrete is poured in winter, the required strength characteristics may differ greatly from the actual ones. The most important requirement is maintaining a certain temperature. Minimum temperature depends on the antifreeze, usually it is minus five, ten, fifteen degrees Celsius.

Warming the concrete welding transformer

This heating method is suitable for small volumes of pouring and if you have a welding transformer, it is ideal for home use. Warming up with a welding machine is the same as heating with a special step-down transformer. The principle remains the same, only the power is noticeably reduced.

Let's take a welding machine as an example. direct current with a power of 250 amperes.

I will not go into calculations for winter concreting, but will describe the heating process itself, based on personal experience when pouring concrete slab 4 by 5 meters. The article contains explanatory photographs; I don’t have my own, but I tried to select the most suitable ones so that they would clearly explain the principle of concrete heating.

We need: a welding machine 150-250 amperes, heating wire PNSV, single aluminum wire 2.5-4 sq., current clamps, HB electrical tape.

1. The heating wire must be cut into pieces of 18 meters, I calculated the length empirically. The number of such segments must be calculated based on the power of the existing welding machine. Let's take a 250 ampere device as a basis. At maximum load our loop will handle 25 amps and that's the ceiling. So you need to build on this figure. Let's not force the welding transformer, 8 loops will be just right. To warm up a concrete slab 4 by 5 meters and 19 cm thick, this amount will be normal.

2. It is necessary to attach 2 aluminum wires to the cut pieces of PNSV wire; we connect them using a twist of 3-5 cm. The length of the aluminum end is selected locally. See for yourself, these aluminum ends will need to be attached to the welding cable. There is no need to worry too much, since it is always possible to increase the required length. We carefully isolate the twist.

3. Next we need to lay out the heating loops. We arrange it wisely so that the heating cable is located just above the middle of the slab, but below the top layer of reinforcement. We tie the loops with an insulating cable so that when they warm up they do not short out to the ground. Twisting of PNSV and aluminum wire must be in concrete, otherwise it will burn. We remove the aluminum ends from the pouring area. When laying loops, mark the aluminum outlets from the loops so as not to get confused when connecting. Most best option this is to make an exit on one side of the slab + and on the other side of the exit plate to - .

4. After pouring, we need to assemble the entire heating circuit as quickly as possible. There are two cables coming out of the welder; to put it simply, this is our power supply for the warm-up loops.

We connect all the positive outputs of the loops to the positive welding cable and, accordingly, we throw the other ends of the loops to the minus. Choose the connection method yourself, I personally made a so-called “guitar”; I attached two textolite plates to the welding cables, on which bolts were welded to clamp the aluminum ends of the heating loops. In general, see for yourself what is convenient for you, in the end we get eight ends on each welding cable.

5. We turn on the welding machine and begin to heat the concrete. Before turning on, set the current regulator to minimum. Having turned it on, we measure the amperage on the welding cables with a current clamp. If it is approximately 240 amps, do not be alarmed because as the concrete heats up, the amps will begin to drop. We check the performance of each loop with pliers; to begin with, there should be 14-18 amperes on each loop. After about two hours we measure again, if the amperes have dropped, we add current to the welding. Add gradually minimum - middle - maximum, if you reach the maximum in 8 hours, this is already a good result. Be sure to check the load on the loops, remembering that they will not withstand more than 25 amperes. Depending on the temperature, the heating time of the concrete may increase or decrease. Based on my experience, I will say that at -12C I heated and dried the above-described concrete slab for 38 hours.

Why is concrete heating needed?

During the cold season, when the ambient temperature drops below the freezing point of water, problems arise with the hydration of the concrete solution. Simply put, the mixture partially freezes rather than completely hardens. After the ambient temperature rises, the thawing process begins, the solidity of the mixture may be disrupted, which will negatively affect the solidity of the structure, its resistance to water penetration, which will lead to a decrease in durability.

Consequences of pouring mortar in the cold, in this case even the Aquabarrier waterstop or other waterproofing will not help

Types of heating wires and cables

Most often, PNSV wires are used for electrical heating of concrete. This is due to its relatively low cost and simple installation. Below is the appearance of the thermal wire, its design features and the explanation of the markings.

As an alternative, an analogue can be used - PNSP, the main difference of which is insulation; it is made of polypropylene, which allows a slight increase in the maximum heat release power.

Table of main parameters of PNSV and PNSP wires

Please note that wires of this type can be used as floor heaters, which operate on the principle of a warm floor.

Details on how the installation of PNSV is carried out, as well as a description of the related procedures (calculation of the length of wires, laying diagram, drawing up a technological map, etc.) will be given in another section.

Types and features of KDBS and VET cables

The main disadvantage of the thermal wires described above is the need for additional equipment that allows you to regulate the heat generation power by changing the voltage. The task can be significantly simplified by using two-core sectional self-regulating thermal cables, namely the Finnish VET or the domestic KDBS. They do not require additional equipment for heating and are connected directly to a 220 volt network. The heating cable structure is shown below.

Designation:

A – Outputs of heating cores.
B – Installation cable used to connect the KDBS to a 220V network; for this purpose, you can use any connecting wire, for example APV.
C – Coupling for connecting the heating section.
D – End insulator sleeve.
E – Heating section of fixed length.

Structurally, the VET cable is practically no different from the domestic analogue discussed above; as for the main technical characteristics, they are shown in the comparative table below.

Table of comparative characteristics of VET and KDBS cables

Warming technology using PNSV

Transformer substation KTPTO 80 for working with thermal conductor

Before installation, it is necessary to calculate the length of the heating wire. In this case, it is necessary to take into account its type and characteristics, the voltage of the transformer substation, the volume of the concrete mixture, the ambient temperature, as well as the nature of the structure (pouring of a column, beam is expected), etc. In order not to get confused in the calculations, you can use an online calculator to calculate the heating conductor PNSV or other cable (PNBS, PTPG, etc.).

In addition, it is necessary to take into account the current strength; for normal operation of a cable immersed in a solution, 14.0 - 18.0 Amperes are permissible (depending on the connection diagram).

Electrical diagram for connecting PNSV A) star B) triangle

Installation of PNSV

Here is a brief guide to the standard methodology:

Please note that the principle and layout of PNSP, PNBS, PTPG are practically no different from PNSV.

Using a welding machine as a PT.

We cut eight segments of 18.0 meters each, each of which can withstand a current of up to 25.0 A. We will leave a small margin and take eight such segments to connect to a 250.0 A welding machine.

Pros and cons of PNSV

Heating concrete in this way is quite beneficial. This is explained by both the low cost of the wire and the relatively low electricity consumption. Separately, it is necessary to note the resistance of the wire to alkaline and acidic influences, which allows the use of this method when adding various additives to the mixture.

Main disadvantages:

complexity of calculations when calculating the length of the wire;
the need to use PT.

Installation of sectional heating cable

Let's start with a brief guide to calculations and small installation recommendations:

The instructions for the concrete TMT technology indicate that heating a cubic meter of mixture requires from 500 to 1500 W (depending on the air temperature). Electricity consumption can be significantly reduced if you use a few simple technical techniques:

Use special additives for the mixture to lower the freezing point of the solution.
Insulate the formwork.

If a beam or ceiling is being poured, the heating cable is calculated using 4 linear meters per 1 m2 of surface area. When constructing volumetric elements, such as I-beams, electric heating is laid in tiers, with a distance between them of no more than 40.0 cm.
The cable protection allows it to be wound to the fittings.
The distance from the surface of the structure to the electric heater placed inside must be at least 20.0 cm.
In order for the concrete mixture to heat up evenly, the heaters must be placed at the same distance.
There must be at least 40.0 mm between different contours.
Crossing heating conductors is prohibited.

Advantages and features of segmented cable

The undoubted positive qualities of products of this type include:

To organize concrete heating using this method, you do not need expensive additional equipment (ET).
Unlike drying with electrodes, the likelihood of electric shock is minimal.
Easy installation and simple calculation of segment length.

Peculiarities:

As a conclusion.

We have described only one method of heating concrete; in fact, there are many more. These will be discussed in other publications.

Concrete screed is poured not only in summer, when the weather is warm, but also in winter, when the temperature rarely rises above zero. As you know from a school physics course, water at sub-zero air temperatures transforms from a liquid state into a solid state, and therefore in winter you will need to warm up the concrete with a welding machine, since the composition of this material water comes in.

Today, methods of heating concrete are actively used, such as heating using a PNSV cable specializing in this procedure, heating using specialized thermomats, but the welding machine continues to be the most popular, the action of which we will consider.

Briefly about the main thing

The welding machine is offline installation to implement welding work above metal parts, cutting materials through electric arc welding. Welding units have, in addition to the main elements for welding work, additional elements.

Auxiliary elements of the welding unit:

Welding current generator;
A device used for air plasma cutting of metals;
Voltage block idle move installations;
Heating block for concrete and other solid materials.

Properties of concrete

Many people believe that concrete hardens in just a few days, but this widespread opinion is very erroneous, since the material in question is aged for almost a month, namely 28 days. However, even during this period, according to experienced professionals, concrete does not harden completely, since the hardening process can continue for years.

It has been proven that concrete after 28 days receives the main quality characteristics: strength, frost resistance, water resistance. That is why it is not recommended to subject the concrete screed of the foundation or floor to any loads during the above-mentioned time.

Warming up using a welding device

To warm up concrete base On a construction site, builders often use special devices, but ordinary welding machines can get in the way of realizing this need. The primary issue in solving the problem is additional electrodes, the role of which can be perfectly fulfilled by pieces of reinforcement.

The reinforcement, in turn, is installed evenly throughout the entire work area, which is covered with sawdust. Sawdust serves as an excellent addition to the thermal insulation layer of a concrete surface. In addition, sawdust will reduce moisture evaporation to a minimum. Next, the fittings are connected to each other by wire in such a way that parallel circuits emerge.

The forward and return welding wires are connected to the circuits, but you should pay attention to the fact that they are connected to each other. Using an incandescent light bulb, we find out about the presence of voltage, and the light bulb must be installed between the circuits. When heating the reinforcement, it is necessary to diligently monitor the heating temperature of the concrete itself so that overheating does not occur. Temperature control is done by using any thermometer.

The above method of heating a concrete surface contributes to excellent heating of the material, without requiring the use of any additional material during the procedure. complex equipment. Despite everything, it is preferable to use a welding machine for small concrete working surfaces.

It is strongly not recommended to close the welding circuit to concrete reinforcement, since this method will not bring the expected result, and the electricity bill will not be very attractive. There are several ways to warm up.

Other methods of heating concrete:

Warming up with electrodes;
Warming up by using infrared waves.

Warming up a concrete surface with electrodes

The method of heating a concrete surface using electrodes is based on passing electric current. In turn, there are several types of electrodes that can provide excellent service during heating of the concrete surface.

Types of electrodes:

Strip;
Lamellar;
Strings;
Rod.

Heating of concrete should be carried out taking into account the area work surface, safety rules and safe handling specifically with the welding machine. Before using the welding fixture to warm up the working surface, whether concrete screed floors, foundation or anything else, it is necessary to consult with competent and experienced professionals.