Warming up (electric heating) of concrete in winter using PNSV wire: technological map

Concrete work can be greatly hampered by the winter, particularly in terms of keeping the proper temperature for curing and setting. Utilizing electric heating systems—more especially, PNSV wire—to keep concrete at the ideal temperature even during freezing weather is one practical way to solve this issue.

Concrete can be reliably heated with electric heating using PNSV wire, which keeps the material warm enough for proper hydration and strength development. Using this technique, the wire is embedded in the concrete mixture, which heats up when an electric current flows through it. The heat produced speeds up the curing process and keeps the concrete from freezing.

This post will explain how to heat concrete in the winter with PNSV wire and provide a thorough technological overview. We’ll go over the detailed procedure, advantages of this approach, and useful advice to guarantee the greatest outcomes. Knowing how to use this technique will help you accomplish high-quality concrete work even in inclement weather, whether you’re a contractor or a do-it-yourself enthusiast.

Technological map and methods of heating concrete

A map of technology needs to be created in order to heat concrete during the winter. Ensuring the efficient, effective, and safe completion of all tasks requires strict adherence to technology and standards. Examples of the document are available online, but a unique warm-up plan is created for each unique object.

The process map, which is created using SNiP, ENiR, and GESN, contains crucial reference information about the right temperature, the preferred heating technique, the locations of all required equipment, the process as a whole, etc.

• Scope of application of the heating method
• Technology, organization and stages of work
• Calculation of labor costs
• Basic requirements for the quality of work
• Schedule for the implementation of all tasks
• Necessary material resources
• Occupational health and safety
• All important technical and economic indicators
• Schemes for laying, connecting wires, electrodes, length of heating elements, control of time/temperature conditions, etc..

There must be drawings and diagrams with every piece of data. Calculations and tables for common designs used to carry out a specific plan are pertinent.

Warm up with a welding machine

Using an incandescent light, thermometer, and reinforcement pieces, this technique involves heating. An incandescent lamp is positioned between the straight and adjacent wires that run through the pieces of reinforcement that are installed parallel to the circuit to measure the voltage.

The temperature is measured with a thermometer. This procedure typically takes two months or more. The concrete structure must be dependable shielded from the effects of water and cold during the entire warming-up process. Generally speaking, small amounts of concrete need to be heated, and favorable weather is required for the use of welding machine heating.

Infrared method

The basic working principle of this technique is the conversion of radiation from an infrared device into thermal energy. Electromagnetic oscillations, with a wavelength of 0.76-1000 μm and a propagation speed of 2.98 x 108 m / s, are the cause of this type of heating. Quartz and metal tubes are frequently used as generators.

This technology’s primary advantage is its capacity to run the gadget on regular alternating current. Assuming control over power is possible, infrared heating is contingent upon the target temperature range.

Because of the rays, the energy is able to permeate deeper concrete layers, allowing the process to proceed smoothly and gradually. High power indicators are not recommended because they will not work properly because the upper layer of concrete will warm up while the lower layer stays cold, leading to the spread of deformations, destruction, etc. In order to accelerate the adhesion time, the technique is most frequently used to heat thin layers of a structure and prepare a solution.

Induction method

At below-freezing temperatures, reinforced concrete can acquire the necessary strength more quickly thanks to induction heating technology. The technology can only be applied to reinforced structures, or any structure with internal metal elements that serve as a core.

Magnetic induction, a principle of electrodynamics, serves as the foundation for the technology. An insulated cable is looped around the poured element (commonly used for columns, for example) to serve as an inductor. The computation method determines the wire cross-section and number of coils. When an electromagnetic field is created inside the structure by an alternating current flowing through the cable, heat is transferred from the internal reinforcing elements to the concrete.

Another option for a core is metal formwork, which they warm up outside. This technique is rarely employed because heating formwork performs better under these circumstances.

To stop heat loss, materials that insulate against heat must be placed over any exposed concrete sections. By periodically disconnecting the power supply, the thermos method or isometric holding is applied once the mixture reaches the design temperature. With this technology, the electric heating of concrete is assumed to consume 120–150 kW-h/m3 of concrete.

• Relatively low price
• Uniform heating
• Independence from the electrical conductivity of concrete
• Possibility of preheating the formwork, reinforcement without additional equipment

A few of the method’s drawbacks are as follows: it requires a lot of individual calculations to be performed, and its application to structures—typically pipes, beams, columns, etc.—is restricted. The following are required for induction heating of concrete: cable (KRPT 1×25, 3×50, 3×25 + 1×16) and transformer KTPTO-80.

Application of transformers

Concrete is frequently heated using transformers. These are typically TSDZ-80, KTPTO-80, TMOB, and others.

• Increased productivity due to no downtime
• Possibility to carry out work at any time of the year
• Compliance with construction deadlines
• Rational use of equipment and transport
• Increasing the strength of concrete and compliance of the finished structure with all requirements and standards
• No additional costs for additives, plasticizers, etc.d.

One of two techniques for heating concrete with a transformer is to use electrodes or PNSV wire. Through additional methods, the installation transfers the heat produced by the conversion of electricity into the concrete mass. The mixture is heated to +80 degrees, however the amount of heat is adjustable.

Heating calls for a specific amount of time, as well as monitoring and regulation; calculations can be found in regulatory documents or in a table. The requirement for a uniform distribution of thermal energy over concrete must be considered when selecting one of the two methods.

The heating transformer is connected to the electrodes if their use is anticipated. These electrodes can be internal (rod, string) or external (sewn-on, strip, plastic). It can only be used with alternating current. Transformers of the KTPTO type work best in this situation.

Electrodes can be used to heat small objects. The electrodes can receive up to 127 V when using a metal frame; in the absence of a grid, the indicator can reach up to 220 or 380 V.

Using a cable

PNSV wires of different manufacturers with a thickness of 1.2–3 millimeters are used to heat concrete. Steel makes up the wire cores, and additional insulation surrounds them. The cable is fastened to the reinforcement and arranged around the object’s perimeter. The conductor can never come into contact with the ground or formwork again thanks to the frame. For such tasks, dry or oil transformers are employed.

It doesn’t take a lot of electricity or pricey extra equipment to heat with a cable.

• The cable is installed on a concrete base before pouring.
• Everything is securely fixed with fasteners.
• The cable is checked for damage (there should be none).
• Connecting the cable to a low-voltage electrical cabinet.

Anti-freeze additives

Concrete can withstand aggressive influences and be worked at temperatures as low as -25 degrees thanks to a variety of additives. In order to enable concrete to retain its mechanical and physical qualities at low temperatures, components are added to the additives’ composition. There is a vast array of additives available on the market today.

Given that additives do not significantly impact the progression of long-term processes, it is crucial to insulate the structure after the initial strength gain with them reaches 30%.

SNiP

As with any other situation, construction and installation in cold climates are subject to set guidelines and regulations. The following documents—SNiP 3.06.04-91 ("Bridges and pipes") and SNiP 3.03.01-87 ("Load-bearing and enclosing structures")—are followed when heating concrete structures.

Sustaining the proper temperature for concrete during winter construction is essential to guaranteeing its strength and longevity. An efficient way to do this is with electric heating using PNSV wire. The technological procedure for warming concrete with PNSV wire will be described in this article, along with instructions on how to set up and operate the heating system to avoid freezing and guarantee adequate curing.

Warming concrete in the winter is a useful application of electric heating with PNSV wire. In spite of the low temperatures, this method helps to maintain ideal curing conditions, guaranteeing that the concrete sets correctly. The application of PNSV wire is particularly beneficial in avoiding problems that could weaken the concrete’s strength and durability, such as freezing and insufficient hardening.

You can make sure the heating system is installed correctly and runs well by adhering to a thorough technological map. In order to ensure proper installation, the PNSV wire must be laid so that heat is distributed uniformly across the concrete’s surface. This lowers the possibility of temperature-related issues while assisting in the achievement of uniform curing.

All things considered, using PNSV wire to implement electric heating is a workable solution for winter concrete work. It offers a dependable method for controlling temperature and raising the caliber of the finished product. This method can support your construction projects during the winter months with careful planning and execution.

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