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How to heat concrete: methods of heating by wire, welding - Blog about repair

How to heat concrete: methods of heating by wire, welding

13-05-2018
Building

Concrete is a popular, inexpensive and widely used material, without which processes such as construction and the repair of buildings and structures become impossible. In order for a solution of this kind to create high-quality, durable, and most importantly, durable structures, it is important to know not only the recipe and technology of its preparation, but also to have information on how to warm the concrete and at what temperature the heating of the concrete is necessary and necessary.

Concrete heating for winter construction

Why warm the solution

Thermomats for heating

Negative temperature has a negative effect on the process of hydration or hardening of the concrete mix. A solution of this type consists of cement, sand, water and crushed stone.

In this mixture, it is water that is the catalyst for the solidification process of the solution. But at a negative temperature, the moisture freezes, which jeopardizes not only the process of mortar strength building, but also further construction work.

The main task of the development of the connection scheme is how to warm up the concrete during the concreting production during the winter period to ensure the optimum temperature for the solidification process.

Note! If the moisture in the solution still has time to crystallize, the solution will not save anything. You should not wait for the thaw, mistakenly assuming that the solution will acquire the necessary characteristics when the water in it melts.

Recommended microclimatic parameters for concreting production in winter:

  • The optimum temperature for setting concrete without additives and heating + 10 ... + 20 degrees;
  • Concreting at a temperature of -20 to +10 degrees will make you think about how to properly heat the concrete;
  • If the temperature is below -20 degrees, all work with the solution is prohibited.

Basic heating methods

Laying the heating cable

There are three main methods of heating the solution in low temperature mode:

  1. Using wire;
  2. With cable;
  3. With the help of a welding machine.

Heating calculation

Now that you know at what temperature you need to heat the concrete, you need to figure out how to calculate the heating.

Calculations of this kind for each method should take into account the following parameters:

  • Type of concrete structure;
  • The total area of ​​the product requiring heating;
  • Solution volume;
  • Required electrical power.

Heating solution with wire

In the photo - an example of laying wires

For the implementation of this method of heating you need a cable PNSV, the price of which is low.

This wire consists of only two structural elements:

  1. Single-conductor round conductor made of steel;
  2. Insulation made of PVC or polyethylene.

This method is based on the transfer of heat to the concrete mass from the heated wire. The heating of the wires themselves is realized with the help of transformer substations with an adjustment system. This system allows in the process of working with a solution to adjust the heating temperature depending on the ambient temperature.

Technology of heating the solution by wire

The instruction specifying how to connect the heating of concrete, provides for the execution of the following stages of work:

  1. The wire fits into the design, before it is filled with the solution, so that it does not come into contact with the formwork. The ends of the wire must go out of the concrete surface to be able to connect;
  2. Soldering method produces the output of the ends of the heating wires;

Council To preserve the thermal field of the soldering point should be wrapped with metal foil..

  1. The number of heating wires and the length of each of them is taken from the calculations made and technological maps;
  2. To ensure uniform load, a test check of the heating structure is carried out using a megohmmeter;
  3. Current is supplied to the wires through a step-down transformer substation..
The location of the heating wire

For the implementation of this method, it is necessary to draw up a flow chart for each individual design.

Cable heating

The advantage of heating with this method is that there is no need to use additional equipment. In addition, the presented method does not require large amounts of electricity.

Technology of heating solution by cable

Cable layout

The process that answers the question of how to warm up concrete at home with a cable consists of the following steps:

  • The cable is located at the base of the concrete structure just before pouring the solution;
  • The cable is fixed by fasteners;
  • During installation, the cable should not be damaged, and its individual sections should not be in contact;
  • The cable is connected through an electrical low-voltage cabinet.
Cable heating scheme

 

Note! When implementing this method, it is necessary to develop a cable layout scheme and produce temperature tests.

Heated solution using a welding machine

Implementation of the method using welding equipment

Knowing at what temperature the concrete is heated, it is possible to use a welding machine for heating.

To implement this method, you will need the following equipment and materials:

  • Several pieces of reinforcement;
  • Incandescent lamps;
  • Thermometer.

The armature in this case is located parallel to the circuit consisting of straight and reverse wires. Incandescent lamps are placed between them, with the help of which voltage measurements will be made. The most ordinary thermometer is used to measure the temperature.

The process of solidification of the solution is quite long and can take about a month. In the process of warming up and hardening of the solution, the construction should in no case be flooded with water and subject to cold.

This method is applicable when it is necessary to heat small concrete inlet structures and acceptable weather conditions.

Concrete heating in winter

In winter, the most topical is the question of how and at what temperature the concrete is heated. This is due to the fact that at this time the phenomenon of crystallization of water in solution is most often observed, which excludes its participation in the chemical reaction associated with solidification of the mass.

That is why the heating of concrete in winter is a very important procedure that can be implemented by the following methods:

  • Introduction to the solution of antifreeze additives;
  • Heating by the Thermos method.

Antifreeze additives

Antifreeze based additives

Antifreeze additives can withstand the strongest cold even at a temperature of -30 degrees. The composition of such additives may be different, but the main component is antifreeze - a substance that does not allow water to freeze.

Any builder with his own hands can add antifreeze to the solution.

For reinforced concrete products or reinforcement slabs, it is better to use additives with the addition of nitrite or sodium format. It is these additives that will provide the constructions with the preservation of physical and chemical properties and will become an anticorrosive protection for reinforced concrete at low temperatures.

Council If, after solidification of such monolithic structures, you need to drill a hole or flatten the edges, you can use methods such as diamond drilling holes in concrete or cutting reinforced concrete with diamond circles.

Thermos method

The essence of this method lies in the laying of concrete in a warm heated formwork, which will keep the temperature of 20-25 degrees for the entire period of hardening. Due to this heating design and will retain strength.

Council To speed up the hardening process, you can pour heated solution into the pre-heated formwork.

Finally

Concrete pouring in winter

Heated concrete solution during the winter period is a necessary component of the construction work. Methods of heating the concrete mass can be quite a lot and the choice of a scheme should be made individually for each structure in accordance with its basic parameters.

A video in this article will reveal to you even more features and nuances of the process of heating the solution to create monolithic concrete products.