Everyone knows that concreting is impossible in winter. But it is not so. Using some technology, you can achieve a positive result even at low temperatures. One of them is the use of electrical cable for heating concrete, which will be discussed in this article.
The reasons for the need for heating
What is happening from a technical point of view with the process of concreting in frosty weather interfering with the quality of the setting?
Let's get a look:
- One of the constituent components of concrete is water.. The subzero temperature causes its crystallization, with the result that the ice pieces literally plow the cement structure from the inside. As a result, you get a loose substance that has nothing to do with the desired result other than color. In this case, you do not even need to cut the concrete with diamond circles, it can be broken manually.
- Also, the icy film interferes with bonding.that further aggravates the situation.
Advice: do not fall prey to the delusion that concrete, without any special treatment, achieved the required strength only because of its solid state. This effect is due to icing, but in the spring, when the liquid melts, you will get a mushy substance.
The implementation of the heating cable
The technology of electric heating of concrete with the PNSV wire implies its transmission within the structure, or along the formwork, depending on the situation. It is worth noting that a sample with a steel core with a diameter of 1.2-3 mm and PVC insulation is best suited for this. At the same time the cord is securely fixed to the bars of the reinforcement.
Next, the following happens:
- The design is filled with the finished solution.
- Included transformers supply electrical current through the designed system.
- Its temperature from this quickly rises to +80 degrees Celsius.
- All components of concrete have high thermal conductivity, so that the heat produced by concrete from the wire quickly spreads throughout the volume.
- Warming up is made until the cement has reached the required strength.
Tip: if construction work is carried out in a suburban area without access to electricity, it is recommended to use special antifrosty additives. Although they will not protect against such low temperatures as cable heating, they will still significantly improve the result.
The advantages of the system
- Versatility. Equally perfect for the foundation, and for the wall, and for any other structure.
- Copes with the protection of the binder, even at -40 degrees Celsius.
- Flexible price of operation of the system. You can freely adjust the power of the transformers used, thereby controlling the cost of electricity.
- The ability to connect to multiple transformers. This allows you to increase the power of heating and accelerate the setting of concrete.
- Easy to use do-it-yourself. Having dealt with the basic principles of this technology, you can easily apply it yourself.
The calculation of the electric heating of concrete with wires is made in accordance with the characteristics of the materials and equipment used.
The following data will be useful for you:
- The power of the heat released for structures reinforced with reinforcement is about thirty-five Watts per linear meter, and for casting without the use of metal rods - up to forty Watts.
- The resistance of the steel base of the wire with a diameter of 1.2 mm is 0.15 Ohm / m, and for a diameter of 1.4 mm - 0.1 Ohm.
Wire laying instructions:
- Install at a temperature not lower than -25 degrees Celsius.
- For cable, choose intermittent or long-term operation.
- The turning radius of the wire should be more than fifteen millimeters.
- Avoid intersecting and touching sections.
- The minimum distance between the cables is also fifteen millimeters.
- Do not turn on the system without confidence in its reliable fixation.
- Power connection is via cold ends. Take care that their joints with the heating structure are outside the heating zone.
- Strictly observe the safety regulations during operation of the heating equipment, which are regulated by SNiP 111-4-80 / ch.11.
Follow all the recommendations, and the strength of the concrete structure will reach its maximum even in severe frosts.
Concreting can be carried out in the winter. The main thing is to ensure a sufficiently high temperature of the solution, sufficient for setting. This task perfectly cope heating cables.
The video in this article will provide you with an additional amount of information regarding the materials presented.
Pour concrete at any time convenient for you.