Concrete heating in winter: infrared, induction, thermos

If you need to fill the foundation or carry out other similar work at low temperatures, then you can not do without heating procedures. Moreover, they should be carried out according to construction standards. About how the concrete is heated in the winter, according to SNIP No. 3_03_01-87, you will find out now.

Why do you need to heat the concrete

As already noted, the pouring of concrete is made not only in summer, but also in winter. The difference is that in winter, the cement composition requires heating, the price of which can be quite high.

This process is necessary for the following reasons:

• at negative temperatures, concrete does not gain strength;
• there is a destruction of the structure of the material, because of which it forms deformed areas, and it eventually becomes less durable.

Tip! To remove the protruding bumps will help you cutting the concrete with diamond circles. In this case, be sure to use protective equipment in the form of a respirator and special glasses. As for the small depressions, they will require diamond drilling of holes in the concrete and subsequent filling of the recesses with cement mortar.

These processes can be avoided, but this will require equipment for heating the concrete in winter. You can do without it only if, before the appearance of low temperatures, the composition managed to gain a certain strength. For convenience, the data is entered in the table:

Types of concrete heating

SNiP number 3_03_01-87 establishes which methods of heating concrete in winter should be used for certain structures.

These methods include:

• thermos;
• preheating composition;
• heating in the formwork;
• induction method;
• electrode heating;

• use of heating wires;
• thermos with antifreeze components;
• infrared heating.

We will look at the most common ones.

Concrete heating with heating wire

To minimize the warm-up time of concrete in the winter, a special heating wire is used - PNSV.

Its components are:

1. steel conductor consisting of one wire;
2. insulating layer made of polyethylene or PVC.

This method of heating is based on the use of transformer substations, which strongly heat the wires. From them there is a transfer of heat to the concrete composition. It should be noted that this method is very convenient, since it allows you to adjust the heating level depending on weather conditions.

To mount such a system will require a technological map of the heating of concrete in the winter. She is usually an energy specialist who is an employee of a construction organization. There are also typical samples of such a document.

This map determines the number and location of warm-up stations, as well as the order of placement and the number of heating wires. How does the calculation of the heating of concrete in winter, for heating 1m? The solution required an average of 50-60 meters of cable.

This technology is implemented as follows:

1. the heating wire is placed inside the erected structure - this is done so that the conductors are placed evenly, do not touch the formwork, do not extend beyond the edges of the concrete and do not touch each other;

1. cold ends are soldered to the heating wire - after that they are brought out of the heating zone;

  Tip! To keep the thermal field in the soldering zone, you should wrap this area with foil.

1. wire leads are connected to transformer equipment in accordance with the prescriptions contained in the flow diagrams:
2. the assembled electrical circuit is checked by a megohm meter;
3. voltage is supplied to the created system and the heating process begins, for the correct implementation of which a temperature schedule of concrete heating in winter time is required, which is contained in the flow chart.

Method "thermos"

As the name implies, this method is not designed to transfer, but to preserve heat. It is to protect the concrete with thermal insulation materials placed outside it. Thanks to them, the applied mixture loses heat more slowly and gains strength faster (learn here how to use a concrete preheating transformer when working in the winter).

The advantage of this method is its affordable cost, because even ordinary sawdust can be used as a heater. However, it should be noted that passive heat conservation alone may not be enough. In this case, it is necessary in addition to him to apply additional methods of heating concrete in winter.

Infrared heating of concrete structures

This method is based on the use of infrared heaters. They are installed in such a way that the radiation emanating from them is directed to an open concrete surface or to a formwork. The energy transferred by them causes the cement mortar to heat up and accelerate its hardening.

Tip! Do not use this method for heating a structure with a large volume. Infrared rays will not be able to heat it evenly, which will reduce the strength of the material. Therefore, for massive products, it is better to use other types of concrete heating in winter.

Induction heating

In this method, in order to obtain heat, the phenomenon of electromagnetic induction is used. With its help, the energy of the electromagnetic field is modified and becomes thermal radiation, which is transmitted to the material being processed. The specified transformation occurs in steel formwork or on reinforcement.

Instructions for the implementation of this method establishes that it can be used only in those structures that have a closed loop. In addition, they should have thick reinforcement, in which the coefficient of reinforcement is over 0.5. Another prerequisite is the presence of metal formwork or the ability to wrap the structure with a cable in order to create an inductor.

Conclusion

When conducting reinforced concrete work in frosty weather, it is imperative to use warming up. Without it, the resulting construction will be less solid and durable (also find out how the transformer works to heat the concrete).

The most common methods of heating include the use of heating wires, infrared emitters, the use of electromagnetic induction, as well as thermal insulation. More information about how to heat concrete in the winter, you will tell the video in this article.