Cement-asbestos pipes: prices and reviews
In industry, they have long been used. The main material for the manufacture of products is cement, whose content is 80-85%. The rest is asbestos, intended for pipe reinforcement.Its fibrous structure increases the strength of the composition. But the material remains fragile and care should be taken when transporting, moving, storing and installing it.
Previously, cement-asbestos pipes were produced mainly for irrigation systems.At construction sites, they began to be used recently, since their properties fully comply with the requirements of modern regulatory documents.
Production of cement and asbestos pipes
Asbestos fiber is mined as a natural material. No complicated technological processes are used to obtain it. For the manufacture of pipes, it must first be fluffed, and then mixed with water and cement. Adding to the cement up to 40% fine sand makes it possible to reduce the cost of production, without reducing its quality.
The main technologies are molding with curing on production lines.After the pipe is kept in the open air, and then in pools with warm water.
Asbestos fiber has extremely high strength, the level of which is close to some steel grades. So that they work in the cement mass, they are positioned in the direction of rotation of the molding drum, inflicting in layers with removal of excess water.
Types of pipes
Asbestos-cement has the following advantages:
- non-toxicity and fire safety;
- resistance to high and low temperature, as well as aggressive media;
- high strength;
- low price.
The disadvantage is fragility. At displacement of the laid pipeline, its destruction may occur. Therefore, laying should be carefully done on a sand pillow.
It is also believed that asbestos is harmful to health. However, being in the mass of cement, it does not cause any harm, since the fibers are chemically bound to the substrate. The main danger is asbestos dust, if it enters the lungs during breathing.
Pipes do pressure and non-pressure. The latter are used in systems where the liquid flows by gravity: in pipelines, hydraulic structures and drainage systems. Their connection is made through couplings with filling of the gap by winding.They provide a tight connection. Holes are made in the sleeves into which heated bitumen is poured after installation. After it hardens, the joint is sealed. If the coupling is made of polyethylene, it is heated in hot water and put on the pipe. Due to the elasticity of the joints, a slight distortion during the installation of the pipeline is allowed.
Pipes used for laying underground cables and as a shell of reinforced concrete piles in construction. In some heating systems, non-pressure asbestos pipes can be used as a chimney, if the temperature of the exhaust gases does not exceed 3000FROM.
Pressure pipes are used where the liquid is supplied under pressure up to 6-9 atm: in irrigation systems, water and gas pipelines, with the construction of wells and boreholes. They are divided into classes, on which pressure depends (6-9 atm). With the increase in the permissible load on asbestos pipes, the price increases. For example, one non-pressure pipe with a diameter of 100 mm costs 310 rubles, and pressure classes VT6 and VT9, respectively, 555 rubles and 634 rubles. The price also significantly depends on the diameter of the pipe.
The connection is made by means of couplings from a similar material or cast iron. Inside they are equipped with two grooves in which rubber rings are inserted.To facilitate assembly, the ends of the pipes are lubricated with graphite with glycerin. The final fastening of the coupling is performed using cement mortar or special sealants.
For gas pipelines, asbestos pipes are coated with resins from the inside, which prevents leakage.
Temperature deformation does not threaten asbestos pipelines, as the installation is done with gaps. In addition, compared with steel, thermal expansion is 12 times less.
Sizes of pipes
The diameter of asbestos pipes supplied for sale ranges from 100 to 500 mm.By special orders they are made up to 1000 mm in size.
The length of the products is limited by the brittleness of the material and does not exceed 5 m. To achieve the required strength, the wall thickness must be significant, which increases the weight. To work with large pipes, it is necessary to use special lifting equipment.
The use of cement-asbestos pipes in the construction of the foundation
Every home should have a reliable and durable base. If you decide to build a foundation of bored piles, cement-asbestos pipe can be used as a fixed formwork. This method has the following advantages:
- production speed;
- high quality and low cost;
- possibility of making piles by yourself.
The foundation of asbestos pipes with their own hands can be erected as follows.
- A well is drilled and sand is poured to the bottom.
- A pipe is installed in the well with fittings inside.
- Concrete is poured.
- After hardening, a tip is installed on the upper parts of the piles and all the piles are fastened with a grillage.
The foundation of asbestos pipes is used in private housing construction. It can be built by hand and guarantees a long service life.
In the villages, an asbestos chimney is used everywhere.It can be used in a small heating system. But many do not attach any importance to this, which can create big problems. The pipe material actively absorbs condensate, soot builds up on it, as a result of which the chimney quickly collapses in the area of the battens and rafters of the roof. Through the cracks in the room can get gaseous products of combustion of fuel. A worn pipe can cause a fire.
Soot accumulates on the rough walls of the pipe, and then ignites.At the same time its temperature significantly exceeds the allowable. Deposits should be periodically removed, but cleaning the pipe is difficult due to the difficulty of creating inspection windows.
Condensate is a mixture of oxides of combustion and moisture, which is actually a solution of hydrochloric acid that can destroy any material, not to mention a cement-asbestos pipe. When it collapses, shells form on the walls. The loss of smoothness worsens the craving, which reduces the flow of air into the furnace.
Condensate is transferred to the entire structure, and the destruction of the brickwork of the chimney occurs. This can be noticed by the appearance of stains on the walls and unpleasant smell in the room.
Thus, incorrectly selected asbestos pipes can cause disassembly and alteration of the entire furnace and adjacent walls. Therefore, you should immediately find more reliable materials for the chimney, which are always commercially available.
Pipes are delivered and laid out along the trench. It is important to plan its bottom well to provide the necessary bias. The pipe should rest on the ground for a quarter of the outer circumference. In the area of the junction is equipped with a pit.Laying is made on the tensioned cord.
On one side, a coupling is put on the pipe, after which it is lowered into the trench and a connection is made to the main line. Similarly, the entire assembly is performed.
Cement-asbestos pipes are used mostly in water supply and in the construction of pile foundations in low-rise construction. Numerous reviews suggest that, when used as intended, asbestos pipelines work reliably. Homeowners are also satisfied with using pipes as formwork for reinforced concrete piles.
The widespread use of asbestos pipes in the villages as chimneys is not always justified, since they are only effective in working with low-power heating systems. The reviews are contradictory, since everyone drowns in different ways and not always the products are destroyed by heat. It would be better to find another solution for the chimney.