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Protect the surface of the concrete floor
To protect the concrete floor, which is operated in the normal mode, or is subject to wear in areas with high traffic, there are several ways to protect the surface.
   Comparable ways: their cost, appearance and ability to perform the task to protect.
   In this article, we consider three ways to finish and protect the floor. Each of them has its advantages and disadvantages.
   Thin fil...

Finishing compositions based on water glass. Part 3
When used as part of exhaustion moderator comes coagulation and solidification of liquid glass. However, due to the presence in the composition of Portland cement with a finishing time is an increase strength of the coating due to hydration of cement minerals. Thus from colloids formed during the coagulation liquid glass are actively assigned to the water for hydration of cement, a porous media formed tumors filled Portland cement, which leads to...

Finishing compositions based on water glass. Part 2
Studies in Berlin Institute Federal institute for Materials Research and Testing, show that the average density of 1730 kg/m3 brick large proportion of pores having a size in excess of 1 micron is more than 90% [3] and they are responsible for the increased migration of fluids through brickwork.
   Most fully meet these requirements structure obtained by coagulation and water-soluble potassium silicate forming silica with a high sp...

Modernization and repair of self-propelled machines. (3)
Hardening electrolysis BORATING hinge pins and bushings mates working equipment hydraulic excavators EO-4121 (EA-4321) gives an increase in wear resistance 4-6 times compared to the bulk quenching details.
   Taking into account the high wear resistance of brazed blades, hardened sintered alloys (see Table 1), are recommended for carbide knives dumps graders DZ-122 and RS-98, combined machine E-405 based on KAMAZ, for front dumps a t...

Specialized exhibition Architecture. Construction (END)
Mari-lime brick and gas silicate blocks
   JSC "MZSK" produces silicate brick and a half, color (white, yellow, black, red, blue, green, brown).
   For the production of silica brick used quartz sand from quarries near the plant. Limestone enters the factory with Dobryatinskogo deposit Vladimir region. Silicate brick (Table 1) is used for masonry exterior and interior walls of buildings and structures, as well as ...

Geophysical processes primers and security. Part 5
In the center of Moscow can distinguish vertical structure comprising a crashing into the Earth`s crust magma elongated cylinder (Fig. 2) [5]. In the center section marked lack of extensive vertical zone converted waves ("blind spot"), going from the depths of 70-80 km to 7.5 km. Such "blind spots" are characteristic of the earth`s crust with the introduction of monolithic dense mantle rocks such as gabbro, diabase, etc. In such a zone Tashkent e...

Finishing compositions based on water glass. Part 1
The quality of the decoration of buildings for new construction and reconstruction depend not only on their aesthetic, but also the operational parameters, as good-quality finish - a guarantee of durable service basic designs, long maintenance-free operation, the costs for maintenance and care. Traditional binders used for the production of finishing compositions, liquid glass is widely used, but it has some drawback: coatings based on it gaining...

On possible amendments to the equation Griffiths
Griffith presented a picture of destruction allowed to formulate the problem of determining conditions of the beginning of crack propagation and find its general solution.
   As seen from the above schemes, in the process of crack propagation material directly adjacent to it "coasts" unloaded relaxes. This means that the stress and strain it decreases, and the elastic energy stored earlier in this area of ​​the body is re...

Construction skyscrapers - the requirements of modernity. Part 4
The program is a high-rise building in Moscow
   The project is now a high-rise building in Moscow is implemented in two main areas: the construction of business center "Moscow City" and implementation of the program of the Government of Moscow "New Ring of Russia."
   1. Moscow international business center "Moscow - City"
   The project includes the construction of buildings on the territory of abou...

Degree project - beginning of the road. (3)
Given the great diversity of subject matter and content of diplomas in various specialties, the jury is faced with great difficulties in determining the winners - "Who better violinist or a dancer?". Nevertheless, often based on emotional perception and can estimate the relevance and novelty, and the author`s contribution to the thesis project or job. Absolute winners in recent years have been graduates of Rostov CSO GASU St. Petersburg, Nizhny N...


 Information for builders




Polybutene [-CH2-CH (C2H5) -] - polypropylene similar to the properties of the brand "Random", but unlike a more flexible. It is promising for device system "warm floor".
Polyvinylidene fluoride (PVDF) has been applied for the manufacture of pipes for more than 15 years ago. This polymer has a high chemical resistance. Operational temperature range from PVDF pipes is very wide - from -40 to +140 C (140 C and when permitted working pressure up to 0.4 MPa). PVDF pipes are resistant to UV radiation, so the system can be run from them in the open.

Our time - time hobbies composite materials: fiberglass, carbon fiber, etc. Metal-tube are also among such composites. They constitute a multilayer structure consisting of a thin aluminum pipe (wall thickness of 0.5 ... 2 mm), the outside and inside of the coated layer of crosslinked polyethylene (PE-X). Polyethylene is fixed on an aluminum substrate with adhesive.
Such layered tube structure ensures its reliability and life (50 years and more), each cell performs a specific function.

Aluminum Core:
ensures protection against the diffusion of oxygen and hence corrosion of metal parts in the system;
provides low CTE - 0.024 ... 0.026 mm / m. K;
ensures long-term strength at elevated temperatures.
Layers of polyethylene:
provide a smooth inner surface of the pipe, and protect it against fouling;
protect the aluminum core of education galvanic couples with brass and steel network;
reduce the thermal conductivity of the pipe (not more than 0.45 W / m. K), which protects it from fogging;
purity and provide decorative outer surface.
Metal-pipe manufactured with an outer diameter of 16 mm to 63 mm. They are supplied in coils, ranging in length from 200 to 50 m Metal-pipe bend easily, even-handed, cut and fit together with a set of special coupling and fitting parts. Metal-pipe are lightweight. Depending on the diameter of it is from 0.1 to 0.3 kg / rm. Operating temperature range - from -40 to +95 oC.
A disadvantage of this type of pipe relative to the polymer is sensitive to freezing of water in a filled condition.
Metal-pipe also produced using polypropylene. In such pipes obtained by extrusion of polypropylene fibers joined to the aluminum core through openings in the latter without the use of any adhesive.

Asbestos cement pipes
Asbestos cement (AC) - a type of fiber concrete. Asbestos in it plays the role of reinforcement, evenly distributed over the volume of the material and the hardened cement paste forms a dense matrix in which asbestos is enclosed. The ratio of asbestos and Portland cement materials in AC-15: 85. Asbestos in such material is tied up and practically not released into the environment. AC-strength materials in tension is quite high, which allows their use for the manufacture of pressure pipes. In the aquatic environment AC does not corrode, but on the contrary, compacted and hardened as a result of continuing hydration of portland cement.
Asbestos cement pipes - one of the most promising types of pipes for wide purposes, possessing valuable properties. In a world built more than 2.5 million km of AC pipes. They are not susceptible to corrosion, including provoked by stray currents, and a much easier for them are not prone to fouling. Due to the low thermal conductivity (0.8 W / m. K), AC pipes smaller problems with freezing.
Connect asbestos pipes using couplings with special rubber seals quickly and reliably. Plastic pipes lose AC-pipes to heat resistance, durability and environmental friendliness.
Asbestos cement pipes can be unconfined and pressure, different wall thickness and strength characteristics.
Non-pressure pipes with a diameter of 100 mm and 150 mm (can be made in diameters up to 500 mm) in length and 4 to 5 meters are used for non-pressure drainage, flues, cables and drainage collectors. When using the AC-tubes for chimneys need to consider that when heated to asbestos 500 ... 600 C with an explosion destroyed material.
Pressure release tube with a diameter of 100 to 500 mm and a length of 5 meters and 4 under the pressure of 0.6, 0.9 and 1.2 MPa (6, 9 and 12 kg/cm2, respectively). Pressure pipes used for water, gas and heating, pumping oil, device wells and chutes. Water networks of asbestos cement pipes for decades successfully exploited in several Western European countries.
Very promising area of ​​application of AC pressure pipes - the device of heating systems, water is supplied at a temperature up to 130 C and pressure up to 1.2 MPa. Hot water does not cause corrosion of AC pipes, but instead promotes their hardening.
On AC heating mains using prefabricated self-sealing joints: couplings (CAM type) with rubber seals (such as TM). This connection of pipes due to the presence of the gap and the possibility of mounting the tube shifts in the joint completely eliminates the problem of compensation of thermal deformation (CTE asbestos at 0,017 mm / m). Flexible couplings: enable progress 3 ... 5 degrees without loss of sealing, they are resistant to vibration and allow for quick assembly and disassembly of the pipeline.
AC-pipe heating systems outperform metal in terms of thermal insulation: thermal conductivity of asbestos almost 100 times lower than that of steel. Russia has a positive experience of heating mains of asbestos for 25 years without repair. With a good set of technological and operational performance, as well as high durability essential dignity cement pipes is their low cost (3-4 times lower than that of polymer and steel).