Reinforced concrete wall panels

PZhS reinforced concrete wall panels are used in the construction of walls of buildings. Moreover, they are used both for the construction of internal and external walls. Depending on the type of construction, they are divided into bearing, mounted and self-supporting.

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Additional Information

  The technology of using wall reinforced concrete panels

A modern building must meet the highest requirements for heat saving, architectural expressiveness, comfort, etc. For this, new materials and new technologies are being introduced. Bearing walls in panel buildings consist of reinforced concrete panels whose height is the floor. Reinforced concrete wall panels  not self-stable, unlike large blocks: their stability during construction is ensured by mounting devices and special structures of connections and joints during operation. Overlapping panels are made of products the size of a structural planning cell or reinforced concrete flooring.
Structures with this technology of building construction perform several functions at once: internal walls - load-bearing and soundproofing functions, external walls - load-bearing and heat-shielding, etc.
Reinforced concrete panels can be either prefabricated structures (in this case, the layers are connected during the production process at the factory, and the panels are mounted at the construction site of the finished wall element), as well as prefabricated - during installation, each layer is installed separately (three-layer reinforced concrete panels).

  Reinforced concrete wall panels manufacturing technology

Wall panels are produced in accordance with GOST 11024-84 - for external panels and GOST 12504-80 - for internal panels, in addition, local and industry standards, technical specifications, Construction Norms and Regulations are applied.
According to GOST 11024-84 "Wall panels, exterior concrete and reinforced concrete for residential and public buildings" for the production of exterior walls use products from light and heavy concrete, and autoclaved cellular.
The division into types occurs in connection with the different purpose of the reinforced concrete panels, the number of layers and design. Depending on the number of main layers, they are divided into single-layer, two- and three-layer, which in turn can also be with or without air layers.
Single-layer are made of a homogeneous material with low thermal conductivity. For reinforcement, a welded frame and mesh are used. Two-layer include bearing and insulation layers. The bearing layer is made of dense heavy or light concrete. This layer is located on the inside of the building. The insulation layer is made of lightweight, cellular heat-insulating concrete and of heat-insulating rigid plates.
Three-layer reinforced concrete panels (Sandwich-panel) includes two layers of concrete, between which is a layer of effective insulation. Concrete layers are connected with each other by diagonal stainless steel bonds through a layer of insulation, due to which the outer layer of concrete hangs on the inner one. As a result, the absence of cold bridges is achieved.
You can change the thickness of the layers, which achieves good results in the heat resistance of panels

  Features of three-layer wall panels

Among the features of three-layer reinforced concrete panels  factory-made can be identified:

• good heat resistance;
• profitability (relative to the speed of construction of the building);
• sound and wind resistance;
• low installation costs;
• relatively little dependence of construction work on weather conditions;
• panel size accuracy.

It is also worth noting an important feature of modern reinforced concrete panels, which relates to production technology. These are modern formwork: they allow the manufacture of products of the necessary configurations and sizes for each individual project. Due to this, an architect can create a unique image of each building.
When choosing the design of wall reinforced concrete panels, it is necessary to pay attention to the following details: appearance, ease of installation, functionality, economic indicators, strength requirements, after-installation care. Wrong choice of construction and material can lead to additional significant costs during the operation and maintenance of buildings. Preservation is also one of the most important criteria in the design of concrete facades. Therefore, we recommend using only high-quality floor panels, which in any quantity can be ordered from us.

  Specifications

  PS wall panels

Name	Length mm	Width mm	Height mm		Volume, cubic meters
PS60.15.3,0-3.l-31
PS60.12.3,5-6.l-31
PS60.12.3,0-3.l-31
PS60.12.3,0-6.l-31
PS60.15.3,5-6l-31
PS60.15.3,0-3.l-31
PS60.15.3,0-6.l-31
PS60.18.3,5-6l-31
PS60.18.3,0-3l-31
PS60.6.3,5-6l-31

Metal Profile Three Layer Sandwich Panels - Represent:

• steel cladding coated on both sides with polymer;
• mineral wool or polystyrene foam boards used as a core (insulation);
• strong and reliable two-component glue connecting them.

Marking three-layer sandwich panels Metal Profile

Materials for three-layer sandwich panels Metal Profile

In the production of three-layer sandwich panels, cold-rolled, hot-dip-galvanized steel, 0.5 - 0.7 mm thick with different types of polymer coatings is taken as the basis. Production: NLMK, MMK, Severstal (Russia), ArcelorMittal, Corus, Ruukki (Europe).

Types of polymer coatings:

• prism (PFP),
• polyester (PE),
• plastisol (PL),
• polyvinyl fluoride (PVF).

   The cost of sandwich panels is laid by the type of coating.
   During the manufacture of sandwich panels, both sides are covered with a protective film.

Types of insulation for three-layer sandwich panels Metal Profile

Mineral wool (MV)

Mineral wool plates are a fibrous material that is obtained from a melt of rocks of a basalt group on a synthetic binder. The main advantage of mineral wool is its: incombustibility environmental friendliness high thermal and sound insulation characteristics, chemical and biological resistance.    From mineral wool slabs are cut with vertical orientation of the fibers, which gives special mechanical and strength characteristics of the TSP. Mineral wool guarantees high heat-shielding properties of panels under different weather and climatic conditions. The thing is that mineral wool is non-hygroscopic.

Expanded polystyrene (PP)

Expanded polystyrene is an environmentally friendly material that has low thermal conductivity and low weight. The advantage of expanded polystyrene in high strength, it is chemically stable and also durable. Expanded polystyrene has the ability to withstand significant loads for a long time. Expanded polystyrene does not support the combustion process, in the event that there is no contact with an open flame. The fact is that polystyrene foam is a self-extinguishing material. Due to the minimum weight, polystyrene foam sandwich panels are easy to install.

Two-component adhesive

In order for the joint of the cladding and insulation to be strong and reliable, it is necessary to use high-quality two-component adhesive based on polyurethane, European production. The glue composition was specially designed for high-strength properties - to connect the core with metal cladding throughout the life of the panels. The Metal Profile company offers glue for a sandwich of panels having all necessary certificates of quality and safety.

Types of Three-Layer Sandwich Panels Metal Profile

Wall three-layer sandwich panel Metal Profile with open fastening Z-LOCK MP TSP – Z

Wall three-layer sandwich panel Metal Profile with open fastening Z-LOCK (hereinafter MP TSP-Z) is a universal and practical solution that differs from similar panels in more favorable qualities. As a rule, the Z-LOCK lock is endowed with a design, which in turn has been modernized by Metal Profile specialists. Such a design absolutely eliminates the possibility of moisture penetrating into the insulation. Such a unique solution allows not only to increase the level of thermal insulation, but also to increase the density and reliability of the material, guaranteeing a long service life of the products while maintaining all operational characteristics. There are no “cold bridges” in the sandwich panels of MP TSP-Z, which indicates the excellent thermal insulation properties of the material and the possibility of using these sandwich panels in the construction of buildings in any climatic conditions.

Wall three-layer sandwich panel Metal Profile with hidden fastening SECRET FIX MP TSP-S

The METAL PROFILE three-layer wall sandwich panel with hidden fastening SECRET FIX (hereinafter referred to as MP TSP-S) is a material that provides a seamless surface of the building wall. The uniqueness of such panels consists in the use of an improved hidden lock providing reliable connection to the metal structure. Also, such a castle improves the aesthetics of the building due to the lack of external fastening. The design of the lock has been modernized by the Company's specialists, thereby guaranteeing the material superior quality without additional reinforcement compared to peers in various price categories. Installation of a structure using a three-layer wall sandwich panel METAL PROFILE with hidden fastening SECRET FIX MP TSP-S as a cladding is quite easy and in a very short time, thereby reducing construction time. The formation of any through holes that can affect the performance of the material are absolutely excluded. This makes it possible to use a three-layer sandwich panel in almost all climatic conditions, guaranteeing unrivaled protection against cold and moisture. Structurally, Wall panels Metal Profile of this type are ideal for horizontal installation.

Roofing three-layer sandwich panel Metal Profile MP TSP-K

The roofing three-layer sandwich panel METALL PROFILE MP TSP-K is endowed with high strength, which is provided by the five-rib design of the TSP and a significant height of each rib. The design of the roofing three-layer sandwich panel METALL PROFILE MP TSP is highly resistant to bending, due to which it is able to withstand heavy loads. The core of mineral wool or polyisocyanurate foam allows the use of the material even in the extreme north. Locks of the structure have a deep geometry, giving the structure reliability, integrity and protection against the penetration of cold and moisture into the panel. Installation of MP TSP-K roofing sandwich panels is possible at any time of the year and takes less time when compared with other roofing systems. Different types of cladding and a wide range of colors can solve even the most difficult architectural problem.

  Airpanel Three Layer Sandwich Panels

Airpanel three-layer sandwich panels are three-layer sandwich panels with steel cladding and a filler made of polyurethane foam (PUF) or polyisocyanurate foam (PPI). Airpanel three-layer sandwich panels are produced on a highly automated joint production line of Henneke Polyurethane Tehnology (Germany) and Stam (Italy) with a volume of up to 2 million square meters per year and fully comply with Metal Profile quality standards. Polyurethane foam - is the most common filler for TSP in the world. It has excellent thermal insulation characteristics and is characterized by durability and minimal weight. Polyisocyanurate foam is a type of polyurethane foam with special additives that increase resistance to fire. Under the influence of fire, it is charred, and in case of elimination of the source of flame, it extinguishes itself due to the flame retardants present in its composition.

Three-layer sandwich panels Sterilium

   This new product was specially designed for the internal cladding of objects with high cleanliness requirements:

• cold rooms
• food production
• pharmaceutical warehouses, etc.

   Depending on the purpose, 2 types of Advantica coating have been developed:

• L control
• CL Clean

   The front side of L Control is a PVC laminate film applied to the primer. Such sandwich panels do not emit odors, therefore they are most optimal for oil and fat plants, meat processing plants, cheese ripening chambers, etc. Such panels are able to easily withstand the wide temperature fluctuations that occur in drying and smoking shops, bakeries.

CL Clean material is a combined coating that consists of soil, an intermediate layer of paint and a PET film. Its antistatic properties prevent dust and particles of chemical elements from settling on the walls, which in turn facilitates the sterilization of the room. Due to moisture resistance, panels can be used for flower and fruit warehouses.

  Three-layer sandwich panels Agrarium

Since June two thousand and twelve, Metal Profile Company, which is a leading manufacturer of roofing and facade systems in Russia, has launched the production of three-layer sandwich panelsAgrarium. Colorfarm ™ 15 polymer-coated steel is used in the lining of the novelty. Due to the fact that the metal has high anticorrosive properties, such panels are able to withstand the aggressive and humid environment of livestock complexes and agricultural storages. Agrarium walls are quickly cleared of pollution thanks to a smooth surface.

Agrarium - are a three-layer sandwich panel with steel cladding and a core of mineral wool, polyurethane foam or polyisocyanurate foam. Such panels are specially designed for the construction of livestock facilities.

For cladding, Agrarium TSPs use Colorfarm ™ 15 polymer-coated steel, manufactured by Tata Steel, UK, which is Europe's second largest steel producer. The development and production of an extensive series of high-tech materials with exceptional performance has helped Tata Steel gain international recognition. Close cooperation with Tata Steel, together with extensive experience in the production of modern building materials, allowed Metal Profile to give a written guarantee of up to fifteen years on the operational resistance of the inner surface of Agrarium profile sandwich panels to the effects of aggressive environments that are present indoors (depending on operating conditions of the facility and the selected panel equipment, subject to competent design of the building, taking into account adequate ventilation of the room).

Three-layer sandwich panel Industrium

Industrium - are a profile type of sandwich panels that are specially designed for the construction of industrial facilities in aggressive environments of natural or man-made nature. This type of sandwich panel is made of steel with polymer coating Colorcoat HPS200 Ultra ™, 200 microns thick, by TataSteel, and mineral wool or polyurethane, which is used as insulation.

Due to the unique properties of the cladding coatings, Industrium can be used on objects with a medium aggressive and aggressive environment (according to the CIS classification) or RC5 (according to Euro norms), which is confirmed by tests in natural conditions. Metal Profile provides a written guarantee for the operational stability of the external and internal surfaces of profile sandwich panels Industrium® to the effects of aggressive environments present inside and outside the premises, up to twenty-five years (depending on operating conditions project and the selected configuration of the panel).

In three-layer structures, normal bending forces are perceived by skins, and shear forces are perceived as a frame or middle layer. The middle layer also provides insulation functions, the perception of local loads and the stability of compressed skins. The most rational use of the properties of constituent elements in three-layer panels makes these panels extremely lightweight and at the same time quite durable, giving them the required heat, sound and waterproofing properties.

Foreign experience and features of the use of three-layer structures in the USSR. Three-layer constructions have found wide application abroad: dozens of firms in various countries produce them as mass products, including the USA, England, France, Canada, Holland, Italy, Germany, and Belgium. Some of the enterprises already have many years of experience in the production and use of three-layer panels, for example, an American company "Deri"- over 30 years and the French company" Co5 ^ More than "10 years." However, the beginning of the relatively widespread use of such structures is about to end 50s. Tests of various types of three-layer panels were conducted by many of their firms.

In the years 1955-1959. structural studies were carried out by the National Center for Construction and the Experimental Station in France, the Research Center of the National Housing Association in the United States. The panels, audited by the latest organization in 1959, were approved by the US Federal Housing Administration. Development and experimental use
  Three-layer panels in construction have begun in the socialist countries: Czechoslovakia, East Germany, Bulgaria and Poland.

Three-layer structures are used abroad mainly for curtain wall panels. In recent years, with the use of such panels, a significant number of high-rise buildings have been built. "(Such, for example, is a 32-story public building in London (Fig. 1.1) with enamelled steel paneling

And let’s reduce the kraft paper - honeycomb filled with vermiculite, the multi-storey building of the atomic energy commissariat in Paris - with fiberglass lining and a middle layer of polystyrene (polystyrene and polyurethane), multi-story administrative building  in London - with asbestos cement lining and a middle layer of expanded polystyrene, a 16-story building in Lyon, an airport building in Orly (Paris), an 11-story building in Nancy, and a high-rise building in Majerter.

Three-layer glued panels for self-supporting or bearing walls  and floor coverings of single-story buildings. For example, in the USA, several firms mass-produce prefabricated one-story prefabricated houses made using three-layer panels, which are used both in the USA and in other countries - Brazil, Australia and others. In Canada, such houses from glued panels are widely used , especially in northern areas, where difficult transportation conditions and high labor costs make these homes particularly efficient.

Some companies produce a large number of three-layer panels for partitions. For example, the French plant Monte produces monthly 20,000   m  three-layer glued partition panels with lining of sheets of dry gypsum plaster or asbestos cement and a middle layer of paper honeycomb. Already by 1958 it was established approximately 800 thousand   m2  partitions from these panels. Known examples of the use of three-layer panels for fencing spatial sanitary cabins.

Due to the ease of three-layer panels, the use of volumetric blocks of them has recently been developing. So, for example, a company<<Байер» (ФРГ) приступила к изготовлению объемных блоков, состав­ленных из панелей, имеющих обшивку из асбестоцемента, и утеплите­лей из фенольного пенопласта. Из таких блоков собирается целая квар­тира полезной площадью 50  m2.  This design has been extensively tested. For single-story buildings, no frame is required, and for buildings of higher height, a steel or iron frame is used.
  concrete. The use of three-layer panel building blocks is also provided for in the 18-storey hotel building project in New York. The fencing of these blocks are three-layer panels with a thickness of 100   mm  with a middle layer of polyurethane foam. Fiberglass is used for the inner lining, clad steel is used for the outer lining. The block has a height of one floor, a width of 3.4   m  and a length of 4-5 m. To ensure the necessary rigidity, such a volumetric block is covered by two reinforced concrete frames, which, after installation, form the frame of the building. The connection of the blocks is carried out by tensioning the ropes, which are passed into the reinforced concrete frame elements. These ropes interconnect volumetric blocks and provide prestressing of the entire structure as a whole.

The thickness of the three-layer panels used abroad as building envelopes is usually from 30 to 80   mm  The main constructive solution is the hinge of three-layer wall panels on an additional half-timbered frame, performed in high-rise buildings from light stamped steel or aluminum profiles. Fachwerk is attached to the main frame or to floors.

The solution to the architectural facades of these buildings is diverse. For example, as the main architectural elements, the lines of the main columns of buildings and floors, imposts and glazing beams are chosen, the effect of a high flat wall can be created.

In low-rise construction, wooden frames and hard PVC frames are usually used. Sometimes several three-layer plates are combined previously by a common binding in a panel, the size of two rooms, the height of two floors. Cutting of the facade for the most part is made relatively small, without wall elements, with the formation of continuous strip glazing. The ends of three-layer plates are usually included in the grooves of half-timbered profiles or (less commonly) are joined together. When designing joints and panel assemblies, various thermal expansion of the frame structure, fachwerk and wall panels themselves are taken into account. Most commonly used are bolt-on joints, joints with dowels, overlays and lap joints.

To seal the joints of the panels, various sealing mastics and elastic gaskets are used. Of the mastics, materials based on thiokol and silicone rubbers are most widely used. Elastic gaskets are most often made on the basis of elastic foams and rubbers (see chapter 3).

The information available in the literature on the types of frames and the solution to joints does not give a complete picture of them. Often, these solutions cannot be applied to the conditions of the middle zone in the USSR due to the possibility of the formation of “cold bridges” at the joints. Such designs are acceptable, apparently, tol! yo in milder climatic conditions of the middle zone of Western Europe and the USA.

Asbestos cement, aluminum, sheathed steel, less often fiberglass and wood-laminated plastic are used for trimming three-layer panels abroad. In low-rise construction, waterproof plywood, hard wood-fiber and particle boards, dry gypsum plaster, hard polyvinyl chloride (for partitions), etc. are also used.

9

Sheets of asbestos-cement cladding on the outside (from the side of the street) are usually enameled or protected with various kinds of plastic coatings. The outer plane of the sheet is treated with silicones or a thin layer is applied to it (less than 0.5   mm)  chloriro
  bath rubber, acrylic, epoxy or polyurethane resins. Often asbestos cement is coated with a layer of fiberglass with a thickness of 0.5   mmBased on polyester or epoxy resins. Sometimes a pre - polymerized fiberglass layer is glued onto an asbestos - cement sheet. Such protection is often covered with lining of fiberboards or plywood. Wood boards are also protected by sticking aluminum foil or film. Fiberglass is also used for the outer cladding of three-layer structures, combining in this case both supporting and insulating functions. Such panels are slightly lighter in weight than panels with asbestos cement lining. Although they are still more expensive and less fire resistant, the rapid development of the chemical industry makes their use promising. To protect steel from corrosion, coatings of vinyl plastic (metal-plated steel), porcelain enamel, waterproof paints and other methods are used. Enameled steel is relatively more expensive than clad or painted, but is particularly resistant to weathering and other influences. For example, the English company Karen guarantees enamelled steel to last for hundreds of years. Of greatest practical interest is clad and painted steel in connection with its relative low cost and at the same time good performance properties.

As the middle layer of three-layer panels abroad, various types of foams are used, kraft paper honeycomb, impregnated with phenolic resin and filled with heat-insulating material (for example, vermiculite), foam glass, asbestolux (pressed asbestos, treated with steam under pressure), hollow chipboards, extruded cork, fiberboard, holo-plast (box-section material from paper impregnated with synthetic resin), etc. Of these, foams made according to no-stress technology, especially polystyrene.

In recent years, phenolic and polyurethane foams have been increasingly developed.

Expanded polystyrene is relatively affordable and cheap. According to the English company Beckelit, obtained in 1965, they are about 2 times cheaper than phenol and 4 times cheaper than polyurethane.

Expanded polystyrene is produced by combustible and self-extinguishing, and the latter are mainly used in construction. Although self-extinguishing polystyrene is slightly more expensive than combustible (according to the well-known company Monsanto, by about 10%), many American companies sell it at the same price as combustible in order to stimulate the use of expanded polystyrene in the most material sector of the national economy - construction . It is used, in particular, for insulation insulation on stamped flooring (Fig. 1.2) of an automobile plant in Genk (Belgium) with an area of \u200b\u200b150 thousand.   m2.

Extensive studies of three-layer panels have been carried out in the USSR and experimental construction with their application has begun. Based on comprehensive studies of plastics, taking into account the time factor and temperature and humidity effects and a set of panel tests (static, heat engineering, temperature and humidity, fire, etc.), recommendations are made on the design and calculation of structures using plastics and Guidelines for the manufacture of such structures and the relevant sections of SNiP.

Leading design organizations (Kharkiv Promstroiniipro-
  project, Central Research Institute of Industrial Buildings, Project steel construction, GSPI of the Ministry of Communications of the USSR, Central Research Institute of Housing and Communal Services, MITEP, Giproniselkhoz and others) together with the Central Scientific Research Institute of Civil Engineering developed three-layer designs (mainly curtain wall panels and roof slabs) for industrial, residential, public and agricultural construction, including for outdoor fences of real objects that are already partially implemented.

Based on research and experimental design, directions for the use of three-layer structures in the USSR are determined. These are

I - a steel sheet with a thickness of 0.75   mm; 2 -   wooden beam 90X40   mm   attached to the channel with screws through I   m   by lenght; 3   - overlap 400   mm; 4   - screw 50   mm; 5   - two layers of roofing material on bitumen mastic with sanding; 6 - a layer of roofing material on bituminous mastic with sanding; 7-layer polystyrene foam 19   mm   and bulk density 40   kg / cm2   on dot gluing; 8   - steel galvanized sheet with a thickness of 1   mm; 9 -   spotted galvanized sheet steel plate; profile height 38   mm; 10   - a layer of coarse sand covering the bitumen paint;

II - wall sheets of corrugated steel with a thickness of 0.75   mm;   galvanized sheets

On both sides, outside - color painting

Boards are slightly different from those adopted abroad. Three-layer panels are used abroad mainly for residential buildings. In our country, such panels are also used in fencing of walls and roofs of industrial buildings.

In the conditions of the USSR with its vast territories, the use of light and highly transportable three-layer panels is of particular interest mainly for remote areas, due to the rationality of their delivery from industrially developed areas with significant savings in transportation costs.

Undoubtedly promising is the use of light three-layer plates in the coatings of industrial buildings for metal trusses, the use of which has been developing rapidly in recent years.

In addition to industrial construction, three-layer wall mounted curtain panels are developed here mainly for multi-

2*
Floor residential and public buildings, and especially high-rise buildings, where the lightness of the panels most effectively affects.

Although wood paneling in the USSR is relatively scarce, it is difficult to rely on the widespread use of polystyrene foams for ordinary low-rise buildings. However, their use is undoubtedly promising now in special cases, for example, for residential villages in remote areas, for inventory buildings, etc.

A direction other than abroad appeared in the practice of domestic design and construction using lightweight panels. Maximum enlargement of structures; binding of the developed panels to the existing relatively large step of the supporting structures (for industrial buildings 6-12   m);  the use of relatively thick panels (due to more severe climatic conditions and a large span); a cautious attitude to all kinds of end-to-end heat-conducting inclusions forming “thermal bridges” in the panel are the trends that can be talked about.

However, it should be noted that in comparison with simple “sandwiches” of small thickness, mainly used abroad, large-sized three-layer framing panels have a number of serious drawbacks. The manufacturing technology of the panels is complicated due to the presence of the frame and their greater thickness; Comparatively high stresses arise in the casing, making it difficult to use such relatively affordable, but less durable materials, such as asbestos cement. The consumption of materials and the cost of panels are increased.

In this regard, with regard to mass construction, where requirements as high as those in the North are not required for the thermotechnical properties of fences and their increased transportability, panels of small thickness (in some cases without a frame), more economical and simple to manufacture, were developed.

Materials for three-layer structures.  For three-layer structures, two main types of materials are used: for Layer  - materials (^ noplasts, honeycomb plastics, etc.) possessing high heat-insulating characteristics and sufficient strength necessary for the perception of shear, peeling, etc. forces; for sheathing and framing - materials (asbestos cement, aluminum, plywood, fiberglass, etc.) are relatively high strength, perceiving basic normal, and often shear forces.

The main material that affects the durability of three-layer panels are also adhesives, which are discussed in detail below.

As a middle layer  Three-layer panels in the USSR are mainly used foams. pressure-free manufacturing, foam glass "and" less often sotoplasty. Of particular interest are foams with lightness and correspondingly high thermal properties. So, in terms of thermal insulation capacity, 2.5-cm polystyrene foam is equivalent to 60-cm brick, 18-cm foam concrete, 15-cm wood and 8-cm wood-fiber insulation boards. The lower bulk density of the foams leads at the same time to a low consumption of synthetic materials per unit of production.

An important advantage of foams is their comparatively sufficient strength (with a bulk density of more than 30-50   kg / m3), and high water resistance.

Prospects for use in the construction of the coming years are dodisyrol and Phenolic nEnoplast. From the point of view of strength and technical and economic indicators, the most acceptable IstyRoll (styrofoam), which is a fine-meshed spherical particles fused into a homogeneous mass. The volume of a dense material - a polymer, depending on the bulk density of the foam, is from 1.5 to 6%, the volume of open pores and voids between particles is 3-6%. Expanded polystyrene can be obtained in any bulk density from 18 to 200   kg / m3, but for building three-layer structures, it is mainly used with a bulk density of 40-GOjce / M ^.

Due to the presence of mostly closed pores, polystyrene foam has minimal water absorption. According to the main producer of this material (BASF company in Germany), it was found that with continuous exposure to water for 150 days, the volumetric water absorption of expanded polystyrene a was about 2%, and the increase in water absorption stopped after 8-10 days. For 8 years of operation under water, polystyrene foam has not changed in relation to moisture absorption and has not lost buoyancy. According to Dow Chemical, an American company, the accumulation of moisture in styrofoam after 20 years of operation under the most severe conditions did not exceed 25%.

VNIINSM data showed, albeit a small, but relatively increased water absorption of domestic polystyrene, which, obviously, is associated with non-standard quality of raw materials.

Expanded polystyrene has low heat resistance, but sufficient for the operation of building structures in operating conditions. So, according to BASF, when heated for 8 weeks at a temperature of 75 ° C, the dimensions of expanded polystyrene remained unchanged. Approximately the same results were obtained at VNIINSM and at the Research Institute of Mos - system. Even if heated for 16   h  at a temperature of 85 ° C, the volumetric shrinkage did not exceed 0.5%.

A serious drawback of polystyrene foam is its flammability; therefore, self-extinguishing polystyrene foam, where flame retardant additives are introduced, which, however, give a limited effect, is primarily used in construction.

Due to restrictions on fire safety, polystyrene foam has been used so far in construction, primarily for the insulation of fences made of reinforced concrete elements. However, the most effective is the use of tiled polystyrene to create light railings, especially for combined coatings on metal trusses, which are now being increasingly used instead of reinforced concrete.

An example of such a fence is the covering of the Volga Automobile Plant in the city of Tolyatti in the form of a steel galvanized stamped flooring with a heat-insulating layer of tile polystyrene foam with an average bulk density of 35   kg / m3 and a three-layer rolled carpet along it (Fig. 1-3). It is also fundamentally possible to arrange a stamped flooring with foamed foam (glued) to it (see chapter 7). In this solution, the requirements for corrosion protection of the surface of the steel flooring are reduced and its rigidity is increased. However, it is more laborious and requires the organization of special production.

Of most interest is the use of expanded polystyrene in
  three-layer panels, where both its structural and thermal insulation properties are used. In the manufacture of these structures, especially in remote areas, it is advisable to foam polystyrene at the place of manufacture directly in the cavity of the panels, which reduces the complexity of their manufacture and improves quality, provides great savings in transportation costs, and minimizes waste of such valuable material.

The application of this method requires special equipment that has been developed at the Central Research Institute for Scientific and Technical Research and has already been partially tested (see chapter 7).

50

30

500

/ - stamped steel flooring; 2 -   polystyrene of the PSBs brand 50 thick   mm; 3   - steel truss truss; 4 - reinforced concrete frame plate; 5 -   wall; 6   - rolled carpet with a protective layer of gravel

Basically, three-layer constructions have been made up to now from tile foam plastic of non-pressured manufacture of the PS-B and PS-Bs grades. Compressed polystyrene foam (grade PS-1 and PS-4), which have relatively high strength, have found only very limited use in construction due to relative scarcity and high cost. Phenolic foam has much better fire retardant properties than expanded polystyrene. There are a number of methods for its manufacture, differing both in composition and in the nature of the heat treatment, but in all cases its main component is phenolic resins.

In the USSR, phenolic foam of the FRP brand, made from phenolic resin and hardener (VaG-3), is mainly used. A serious advantage of phenolic foam, along with fire resistance, is also increased heat resistance, a wide raw material base and the relative simplicity of the process. Unlike polystyrene foam, it does not require heating during manufacturing, which in this case occurs due to a chemical reaction when mixing the starting components.

The main disadvantages of phenol foam are fragility and increased water absorption. According to these and some other indicators, it is significantly inferior to expanded polystyrene. In connection with these shortcomings, phenolic foam is used mainly in wall panels with thick asbestos-cement claddings, where the tearing forces are relatively small. To make it possible to use phenolic polystyrene in roofing panels, including those with thin skin (made of metal, etc.), we carried out a number of design measures (prestressing, etc.), which made it possible to localize its shortcomings to a large extent (see. chapter b).

Polyurethane foams (rigid) are the best type of non-pressurized foam used as the middle layer of three-layer panels. They combine most of the benefits of other types of foams. Compared to polystyrene foam, they have a greater simplicity of manufacturing technology (casting composition) and higher heat resistance. However, they have a relatively high (close to polystyrene) strength and are not fragile. A significant advantage of polyurethane foam is its high adhesion to most materials (including metals), which is why it is often used in three-layer panels without additional adhesives. Polyurethane foam is made by mixing (without heating) the starting components: dilosociates and polyesters or alkyd resins.

The disadvantages of polyurethane foam - its still high cost and scarcity. In addition, polyurethane foam burns, and therefore various additives are introduced into it. Polyurethane foam has found relatively limited use in three-layer panels; nevertheless, there is a clear tendency for its rapid growth (especially in the USA). In the USSR, rigid polyurethane foam for three-layer building panels is not yet used due to its scarcity and high cost. The prospects for its development in the coming years are also limited. The Vladimir Institute of Synthetic Resins (VNIISS) developed rigid polyurethane foam that hardens after pouring into the cavity of structures. Its bulk weight ranges from 45-180   kg / m6.

Preliminary tests of this foam gave good results, although they revealed that it is inferior to foreign samples in a number of indicators.

Given the high advantages of polyurethane foam, it is necessary to speed up work to expand its production and achieve cost reduction.

Polyvinyl chloride is usually produced by the press method; there are no-stress methods. It consists of: polyvinyl chloride resin, plasticizer, stabilizer and surfactant. The bulk density of polyvinyl chloride varies significantly - from 50 to 300   kg / m3 and more. Its production is organized in the USA, Germany, England, France and other countries. Its use in construction is small, despite increased fire resistance and relatively high physical and mechanical properties. This is due to its high cost and complexity of the technology.

In the USSR, polyvinyl chloride for many years was produced only by press manufacture (PVC grade). It has a relatively large bulk density of 100   kg / m3  and more. A well-known prospect for construction is represented by polyvinylchloride foam plastic of non-pressurized manufacture of the PV-1 brand, which is much cheaper than the foam of the PVC brand, and having a lower bulk weight - 50-60   kg / m3 (the corresponding value for PVC is 100   kg / mg)  with high physical and mechanical properties. However, it is produced in limited quantities so far and its fire resistance is less than that of PVC foam.

Sotoplasts are plastics with regularly repeating voids having a cross-sectional shape close to a hexagon, which gives them the appearance of a honeycomb. The distance between the parallel sides of the hexagon of the cell is usually 12   mm  For construction, predominantly kraft paper honeycombs are used, impregnated with phenolic or urea resins and flame retardants.

Sotoplasts impregnated with urea resins are brittle and significantly inferior in this respect to phenotypic based sotoplasts that have found primary use abroad as the middle layer of three-layer structures. Studies have shown that the strength of sotoplasts on phenolic resins is approximately two times higher than on urea resins.

The main advantage of honeycombs compared to foams is the increased strength (see below) and relatively high fire resistance. However, to obtain thermal insulation properties, honeycombs should be filled with effective heat insulators (phenolic polystyrene, vermiculite, etc.) - The production of three-layer panels with a middle layer of honeycomb is organized in France, the USA and other countries.

In the USSR, the honeycomb is still being manufactured in experimental form in Kuibyshev as a middle layer for panels, roofing and walls of collapsible buildings. Sotoplast manufacturing technology was developed by the Research Institute of Plastics, VNIIKeramzit and SLE Strommashina.

Sotoplast is a promising material for the middle layer of three-layer structures. The organization of the production of such panels requires, first of all, the adjustment of the mass production of honeycomb of the required quality and rather economical primarily on the basis of kraft paper and phenolic resins.

Foam glass is one of the few inorganic materials that are quite widely used as the middle layer of three-layer panels. This is explained by the comparatively small (for inorganic material) bulk density (7 \u003d 200   kg / mg)  and satisfactory heat engineering properties (I \u003d 0.08 ^ -0.09), in connection with which such panels are 3-5 times lighter than expanded clay concrete.

Foam glass is significantly inferior to foams in terms of weight and heat engineering indicators (for polystyrene 7 \u003d 40- ^ 60   kg / m "6, X  \u003d 0.03 - t - n - 0.04), according to mechanical and technological properties (brittleness, difficult to process); therefore, it cannot be considered as a promising material as the middle layer of three-layer panels.

As outer skin  Three-layer panels in the USSR are mainly used asbestos cement and aluminum, less often - stemite - and fiberglass, and for panels of lightweight buildings (low-rise residential, agricultural, etc.) and partitions - also wood boards (plywood, fiberboard and chipboards), protected against moisture (see chap. 3). Stemalite is usually used for external cladding in buildings of high capital with high architectural requirements. Dry gypsum plaster is also used for interior wall and wall cladding.

Panels with asbestos-cement cladding are relatively the cheapest and have increased fire resistance. However, due to the fragility and relatively low strength, they can be used mainly in wall fencing, as well as as roof tiles with a span of up to 3 m. The absence of a sufficiently effective finishing layer seriously inhibits the use of such panels, especially in civil engineering. In this regard, in a number of capital buildings in Moscow, an additional finishing layer (relative) of stemalite or aluminum is used (see chapter 4). It is more advisable to combine the finishing layer with the outer skin. As indicated, for this purpose, asbestos cement coated with fiberglass, protected steel, aluminum is used abroad.

Our country ranks first in the world in the production of asbestos - cement products and asbestos reserves. Asbestos cement output should increase even more in the short term. The five-year plan of the national economy for 1966-1970. It is planned to achieve in 1970 the production of sheet asbestos-cement products in the amount of 6.8 billion conventional tiles, or 7360 thousand g, which is 2.3 times higher than the level of 1958. In 1941, our industry produced mainly small-sized corrugated sheets and extruded tiles; in the post-war years, the production of large-sized corrugated and flat sheets, hollow and chute plates for coating industrial buildings began.

For three-layer structures, large-sized flat asbestos-cement sheets are of primary interest. Existing sheet-forming machines still allow obtaining asbestos-cement non-pressed sheets of 5X1.5 size   m  and 6-10 thick   mm  Sheets of up to 6 m in length are also produced on an experimental basis.

In the near future, it is planned to organize production at the Glavmospromstroymaterialy plant at st. Railway near Moscow large-sized pressed sheets and three-layer panels based on them (including sandwiches), for which special equipment was purchased.

The disadvantages of asbestos cement are primarily its fragility, determined by the low specific viscosity (1.5   kgf / cm2), weak work under tension and significant deformation during drying and wetting. Fiberglass coating of asbestos cement significantly improves its physical and mechanical properties.

Aluminum alloys are still scarce at present, but the volume of their production in our country is growing rapidly (from 1958 to 1965 it grew by about 3 times), which determined the expansion of the use of aluminum in a number of industries, including construction. The feasibility of using aluminum for cladding of three-layer structures, especially in remote areas, is determined primarily by its high strength and corrosion resistance.

Aluminum is nonflammable, easy to process, has a lower bulk density than steel (7 \u003d 2.7   g / cm3)  and good appearance, so that additional finishing of the front surfaces is often not required. The cost is still high, its elastic modulus is approximately three times smaller than that of steel, and twice as large as steel's linear expansion coefficient.

Given that the stresses in the skin of three-layer structures are usually low (300-400   kg / cm2), it is necessary to use mainly annealed and semi-alloyed alloys of the AMts and AMg types, as well as thermally hardened aviales AV-G, AD31-T alloys, which are relatively cheap and have high corrosion resistance. However, for prestressed flat panels (see Chapter 6), where tensile stresses can reach significant values, in some cases high-strength alloys of the AD-ZZ-T-1 type should also be used.

Increased deformability of aluminum complicates the device of butt joints of panels (see below) and causes additional stresses in adhesive joints under the influence of temperature influences.

From this point of view, it is more advisable to use protected steel (clad with vinyl plastic or coated with waterproof paints), especially considering its lower cost and increased mechanical properties compared to aluminum. In accordance with the decisions of the governing organizations, a wide production of sheltered steel was launched; in particular, at the Zaporizhstal metallurgical plant - clad steel. Preliminary test results of the first metal samples conducted at NIIICHermet and TsNIIS are positive (see chapter 3).

As cladding of three-layer panels of low-rise buildings, you can also use wood boards (primarily waterproof plywood), the production of which is rapidly developing (see chapter 3).

The main types of glued three-layer panels. Schemes, sizes and other data on three-layer panels for industrial, civil, agricultural and other types of construction are given in table. 3. They are divided into two groups - with metal (aluminum, sheathed steel) and non-metal (asbestos cement, plywood, fiberglass, etc.) claddings. As the middle layer of the panels, mainly foam plastic is used, less often sotoplast.

Three-layer panels with metal cladding  are of most interest for industrial construction, especially in metal truss coatings. Their most important advantage, especially significant for our country with a relatively harsh climate, is the possibility of installing a roll-free roof. Due to their low weight, the supporting frame of buildings, as well as the costs of their transportation and installation, are greatly facilitated.

Given the lightening of the carcass, the cost of roofing slabs with sheathed steel sheathing is lower than the cost of reinforced concrete slabs, approaching the cost of slabs with asbestos cement sheathing (see chapter 8). Due to all these advantages, plates with sheathed steel sheathing should, in our opinion, be one of the main solutions for roofing fences for metal trusses.

Slabs with aluminum cladding are significantly more expensive than slabs with steel cladding and reinforced concrete slabs (see chapter 8). Nevertheless, for remote and northern regions, their use (for roofing and walls) is beneficial: they are extremely lightweight, very transportable, their installation is relatively simple. Three-layer panels with metal plating are arranged with a frame to obtain a full joint. In wall panels, there may be no framing (see chapter 4).

The most convenient for transportation and installation of panels of increased thickness with a frame (type 4, table. 1). Such road panels,

And they are used to enclose walls and roofs mainly in remote and northern areas.

For construction in the central regions, three-layer panels of small thickness were developed (40-60   mm), usually working when flying up to 3   m  In wall fencing, these panels (type 1, Table 1) are attached directly to the half-timbered racks or are pre-assembled in an enlarged panel reinforced with a steel frame (type 1.6).

In roofing fences, they are used in the form of thin slabs, with a contour frame, supported on girders (type 2), or enlarged slabs (type 3). The main three-layer part of the enlarged plates is prepared in advance and attached to the steel frame with bolts. Each of its cells is supported on four sides.

The enlarged slabs of type 3 with dimensions ZhbiZhZzh are supported by bent profiles, and 3x12   m  - bar runs. 3x3 cooker   mDesigned mainly for hanging coatings. In panels of type 3, a three-layer package works in more favorable conditions (resting on four sides) than in panels of type 2.

The advantages of enlarged slabs also include the ability to stack them directly on farms. However, they require a slightly higher consumption of steel and are more expensive than type 2 panels stacked according to girders (see chapter 8). The main advantage of the latter is the simplicity and the minimum number of joints across the ramp or even their absence (when laying panels along the ramp of buildings of limited width).

Panels of type 2, and sometimes type 3, can also be used for remote, northern areas with laying them on the runs in steps of 3   m  At the same time, to increase transportability, their width can be reduced, and to improve the thermal properties, to increase the thickness.

By joining plates of types 2 and 4 along the length and width, spatial structures (arches, folds, shells) can be created with a span 12   m  and more (see section 4 of this chapter below). For this purpose, in the list of designs (Table 1), three-layer blocks of curvilinear outline with metal plating (type 6) are provided, from which arches and cylindrical shells can be erected.

Research and design development of these structures was carried out using the middle layer of expanded polystyrene and partially expanded polystyrene chloride (brands of PVC and PV-1). For this purpose, polyurethane foam can also be used in principle, but in practice it is not yet available for construction.

The use in these structures of relatively affordable phenolic foam, which also has increased fire resistance, is difficult due to the increased fragility of this material and its reduced tensile strength. In this regard, pre-stressed structures were developed where the polystyrene foam compresses (see chapter 6).

The use of these structures, even if somewhat more complex than those indicated, is of interest when using not only phenolic, but also other types of foams, given their increased reliability associated with the specifics of the work of adhesive joints in these structures (mainly for compression).

The main types of glued three-layer panels for

Coating plates with a sheath of metal sheets 1 middle layer 2   foam (sotoplast) and channel-shaped frame 3, supported on two sides along or across the span

6X3X0.04 \u200b\u200b(0.06)

B) Coating plates with a lining 1 of metal sheets, the middle layer 2   styrofoam, channel 3 and ribs 4   from steel profiles

Civil, agricultural and other construction Cladding material and thickness Type of middle layer Type of glue Application area Aluminum alloys 6-0.8  - g-1,2  mm Protected steel 6 \u003d 0.5 ^ 1   mm Polyfoam PSB-stY=40 Kg / m 3 and others. Polyfoam PV-1   y \u003d =50-7-60  kg / m3   sotoplast kraft-bu - important, etc. Rubber, epoxy, phenolic, etc. Also Also Also Also Aluminum alloys 6-0.8-5-1.2  mm Protected steel 6 \u003d 0.5-M   mm Polyfoam PSB-st or PV-1Y \u003d 60 Kg / m3,   sotoplast kraft paper, etc. Epoxy phenolic, etc. Industrial and public buildings with a running system, with laying of plates along or across the building Aluminum alloys 6 \u003d 0.8-I  mm   protected steel 6 \u003d 0.5   mm Polyfoam PSB-st or PV-1  y \u003d 60 kg / m3, Sotoplast kraft-bu - important Also Byte-type industrial and public buildings Also Also Industrial and public buildings

	Material  and  skin thickness	Type of middle layer	Type of glue	Application area
	Aluminum alloys 6 \u003d 0.8  - g- 1  mm Protected steel b \u003d 0.5   mm	Polyfoam PSB-st or PV-1  y \u003d 60   kg / m3 Sotoplast Kraft paper	Epoxy, phenolic, etc.	Industrial and public buildings
Aluminum alloys 6 \u003d 0.8-g-1.2  mm Steel 6 \u003d 0.8 -g-1,2  mm	Also	Also	Industrial buildings in remote and northern areas
Aluminum alloys 6 \u003d 1.2  mm   steel 6 \u003d 0.8   mm	Solid fibreboard (lattice), polystyrene, honeycomb	Epoxy, rubber phenolic	Industrial precision engineering buildings
Aluminum 6 \u003d 0.8-g-2  mm   steel b \u003d 0.8-g-1.5   mm	PSB-st or PV-1 foamsY=60 Kg / m3,   sotoplast kraft paper - woven or fabric	Epoxy, phenolic, etc.	Industrial and public buildings

Name and brief description of the panel

A) Coating plates or curtain wall panels with lining 1 of the flat sheets of asbestos cement, the middle layer 2   from foam, honeycomb or foamglass, asbestos cement framing 3 or without framing

B) Enlarged coating plates from three-layer panels /, with asbestos cement sheathing, a middle layer of foam or honeycomb and ribs from steel bent profiles 2

C) Enlarged coating plates of three-layer panels 1 with asbestos cement sheathing, a middle layer of foam and ribs in the form of steel bar runs 2

D) Wall mounted panels consisting of a supporting and framing frame 5 made of steel (or aluminum) profiles or wood, and window blocks filling it 4   and deaf three-layer piers 3 with asbestos cement lining 1 and the middle layer 2   from polystyrene, honeycomb, foamglass

	Cladding material and thickness	Type of middle layer	Glue adhesive	Application area
	Asbestos cement6 = 8-7 -10   mm   for roofing, 6 \u003d 6 - 8   mm For walls	PSB-stY=60 Kg / m *   for roofing, y \u003d 30   - t- 40 Kg / M Z   for the walls. Polyfoam FRP-1 y \u003d 60 -7 -100  kg / m3 Sotoplast Kraft - paper. Foam glass (for walls)  y \u003d = 200  kg / m *
Asbestos cement 6 \u003d \u003d 8n-10  mm   for roofing, 6 \u003d 6   - t-8  mm For walls	Also	Also	Also
Asbestos cement6=8 -7 -10   mm   for roofing, 6 \u003d 6~8   mm For walls
Asbestos cement6 = 8 -7 -10   mm   for the roof 6 =6- F-8 Mm For walls
Asbestos cement 6 \u003d 6-7 -8  mm	Polyfoam PSB-st u \u003d 30-t-40  kg / m3 FRP-1 Y = 60  kg / m * y Y = 200  kg / m3		Civil Engineering

Hinged wall panels up to b length with 1 asbestos cement sheathing, middle layer 2   from polystyrene foam or honeycomb and asbestos-edged frames - 3 profiles

	Material and thicknessCasing	Type of middle layer	Type of glue	Region  application
	Asbestos cement6 \u003d 6-i-8  mm	Polyfoam PSB-stY  \u003d 30 h - 40   kg / m * FRP-1 Y=60 Kg / m3, Sotoplast kraft-bu - important, foamglass At = 200  kg / m3	Diphenol, epoxy or rubber	Civil Engineering
Asbestos cement6 = 8-7-10   mm	Same as foam glass	Diphenol, epoxy or rubber	Industrial and civil engineering
Wood tile materials (plywood, fiberboard, etc.)0 = 4-7-12   mm   painted or protected with thin plastic or metal films, fiberglass	Polyfoam, fiberboard honeycomb or Kraft - paper with effective insulation	KB-3 and the like glues or PN-1 (only for fiberglass)	Low-rise buildings, collapsible structures, lightweight industrial and agricultural buildings
The same, 6 \u003d 8-7-1 2l £	Also	Also	Also
The same, 6 \u003d 4 - \u003d - 6  mm

Of the fencing with metal cladding, it is worth noting the slabs of suspended ceilings for the workshops of precision instrumentation of radio engineering and the like industry (type 5). They differ in high rigidity and profitability. As the middle layer of these panels are used fiber boards (grilles made of fiber boards), polystyrene and honeycomb.

Panels with non-metallic cladding (asbestos cement, as well as wood boards and fiberglass, etc.) are used both in civil and industrial construction. As the middle layer of these structures, polystyrene, foamglass (only for walls) and honeycomb are used. The area of \u200b\u200bapplication of roof slabs is mainly industrial construction, and wall panels - civil and industrial construction. Asbestos-cement roof slabs are covered with a roll carpet.

Panels span 3   m  small thicknesses (type 7, a) are used as coating plates with a run-through system or wall panels on crossbars. They are arranged with or without asbestos cement framing (see chapter 4). Framed panels with increased fire resistance, and also allowing the use of less durable types of the middle layer, are mainly used.

Unframed panels (sandwiches) can be used in less stressed parts of buildings, for example in wall panels, as well as elements of enlarged cover plates with spans 6 and 12   m(types 7, b, c) or enlarged wall panels of industrial (type 7, d) or civil (type 7, d, f) buildings.

Of particular interest is the use in civil and industrial construction of wall panels span 6   m  with as - cementless lining and frame (type 8). They have an increased thickness and require a slightly higher foam consumption, but are relatively simple and do not require metal consumption. Framing in these panels with a span 6   m  has a channel-shaped outline; in panels with a span of 3 m, where the arrangement of channel-shaped profiles is not always possible due to the small thickness of the panels, in addition to channel-shaped, zeto-shaped profiles are also used. In this case, trimming of corrugated sheets can be used. The connection of asbestos-cement sheets with the middle layer is carried out on glue, and with framing - on glue-metal fasteners.

Panels with paneling made of wood-based panels (types 9-11), primarily waterproof plywood, are of undoubted interest for low-rise, residential, lightweight agricultural construction, inventory collapsible buildings, partitions, etc. For this purpose, it can also In some cases, fiberglass is also used. Boards made of wood-based panels must be protected from moisture, for example by painting or foil-gluing (see chapter 3).

Three-layer panels are used in pilot construction for industrial and civil buildings. First of all, three-layer roofing plates and wall panels made of aluminum and polystyrene, applied to the external fencing of the processing plant (Fig. 1.4) in Yakutia under the design of the GPI Design steel construction and technical communication buildings in the northern regions according to the GPPI project of the Ministry of Communications (Fig. 1.5 and 1.6). Similar panels (designed by the Leningrad Branch of the GPI Projectstalkonstruktsiya) were used to cover the telescopic dome in Tbilisi.

The total area of \u200b\u200bpanels installed in these buildings exceeds 300 thousand.   m2.

On the basis of successful overall experience1, it is planned to use three-layer panels made of aluminum and foam for other facilities, of which buildings for prospecting for construction, fencing of an enrichment plant in the Udachnoye area, tennis court coverage in Kharkov, etc. (see Chapter 4) should be noted. .

Three-layer panels with a middle layer of foam glass, with outer sheathing made of stemalite and inner sheathing made of asbestos cement or stemalite are used for external wall fencing of the 2nd Moscow Watch Factory (Fig. 1.12). Such a solution, where the finishing layer (steemite) is simultaneously sheathing, is the most economical, but at the same time there are increased requirements for the rigidity of the panel structure, which is directly exposed to temperature influences.

In these designs, roof slabs perceive only local loads within their span. Attempts to use these panels in work on the main loads as the upper compressed belt of the combined truss - panels are noteworthy. This design span 18   m  was developed by the All-Union Institute of Light Alloys - VILS and applied to cover the sports hall (Fig. 1.7) near Moscow.

Three-layer hinged wall glued panels are also used in Moscow as window sills of buildings of increased capitalism - the Rossiya Hotel (Fig. 1.8), the Gidroproekt administrative building (Fig. 1.9), the CMEA building (Fig. 1.10) and the building of the CPSU Central Committee (Fig. 1.11). They had asbestos-cement cladding, and a decorative protective layer of stemalite or corrugated aluminum was installed on the rel. Foam glass or phenolic foam was used as the middle layer of these panels. The latter was used only in the CMEA building and on a small plot in the Central Committee building.

Panels for the CMEA building were manufactured in the Polish People's Republic, and for the Central Committee building - at the Central Scientific and Research Institute of Cinematography using casting composition FRP.

Experience has shown that panels with phenolic foam (FRP) are much easier to manufacture and cheaper than with foam glass.

Currently, preparations are underway for the use of panels with phenolic foam in the wall fences of the 13-story building of the Scientific and Technical Information Center SSTC in Moscow, as well as some industrial facilities.

Three-layer panels of suspended ceilings with a middle layer of wood fiber honeycombs (gratings) are used in production (Fig. 1.13). Compared with analogs (Fig. 1.13, d), such a design requires 5 times less aluminum and about 40% cheaper.

The manufacture of panels with metal cladding for these buildings was carried out near Moscow (on Karacharovsky and Taldomsky

3 A. B. Gubenko

Factories), in Irkutsk and other cities. Unfortunately, the production of these panels was not mechanized enough, and for the middle layers less effective types of foam plastic of the block type (PVC, foam rubber, PSB), relatively expensive and not very transportable, were used.

As tests and calculations have shown, the use of a new technology developed by TsNIISK, with foaming of foam directly inside the panel, with its foaming to the skin (see Chapter 7), can significantly reduce the cost of the panels and improve their quality. This technology has already been successfully tested at a semi-factory installation at TsNIISK and taken as the basis for organizing the production of three-layer panels of aluminum and foam IN  Magadan, Bratsk, etc.

The situation is much worse with the manufacture of three-layer panels of asbestos cement and foam. They were made near Moscow (Zheleznodorozhny and st. Kuchino) and in Saratov in semi-artisan conditions and with minimal mechanization. The introduction of the production of mechanized processes developed at the Central Scientific Research Institute for Scientific and Technical Research (see Chapter 7) will significantly reduce the cost of panels and improve their quality.

In the field of construction, reinforced concrete products are the most used products. Some samples are prepared directly at the site, but basically such structures are manufactured industrially. The use of ready-made panels significantly reduces the time of work and ensures the exact fulfillment of all the requirements specified in the design documentation.

Specifications and manufacturing are regulated by GOST, depending on the purpose and features of the technology: for external walls - No. 12504 from 1980, internal - 11024 from 1984, products with insulation, three-layer - 31310 from 2005. There are a number of other documents - SNiP, TU of enterprises and so on.

Wall Panel Classification

The division into certain groups is conditional, but it gives a more complete idea of \u200b\u200bthe specifics of the use of specific samples. All of them differ in several "parameters."

1. According to the implemented engineering solution.

• Compound (prefabricated).
• Monolithic.

In turn, they can be:

• three-layer - are reinforced concrete ribbed panels with a layer of insulation;
• two-layer (heat insulator + concrete with reinforcement). The insulation is fixed on the inner edge. The most common are mineral wool slabs, a layer of foam concrete or foam glass, which are covered with a cement screed on top;
• reinforced concrete single-layer panels with concrete of only one brand. Typically categorized as "light" or "especially light." Moreover, various materials can be used as filler in solutions - expanded clay, agloporite, slag, and some others. Their feature is that one face is treated with special cement, which facilitates the production of "finish" finish. During installation, the panel is placed with the expectation that this side of it “looked” inside the building.

2. In terms of resistance to load.

• Bearingless.
• Self-supporting.
• Bearing.
• Carrying floor by floor.

3. According to the specific application.

• Residential, administrative or public buildings.
• Engineering facilities.
• Wall panels for industrial buildings.
• Attic rooms.
• Basement (technical) floors.
• For installation inside or around the perimeter (external).

4. The structure.

• Hollow or solid.
• Of one or more types of concrete.

All of these differences are major. But there are others that are associated with the specifics of use or some additional characteristics of wall reinforced concrete products. Samples differ in concrete brands (from light to heavy), binders (gypsum, cement), type of reinforcement, as well as a number of other parameters (grade of metal, its preparation, location of mortgages and so on).

The range is so vast that it makes no sense to list all the varieties. Moreover, manufacturers produce designs, as a rule, for a specific order and focus on technical specifications provided by the buyer. For example, with already mounted units (window, door) or with openings prepared for a certain size.

Product Features

1. Good bearing capacity and increased strength.

2. Quick installation. All wall reinforced concrete panels are distinguished by strict geometry and exact coincidence of the locations of fasteners ("mortgages").

3. The use of multilayer products allows you to save time and materials on heat and noise insulation of buildings.

4. Resistance to thermal effects, aggressive environments, temperature fluctuations.

5. Preliminary preparation of the basis for the “finish” finish is not required, as they differ in the evenness of the edges.

6. The possibility of application in the construction of structures for any purpose.

Dimensions

They depend on several parameters: wall cuts (single row, strip, combined), the type of panel (including window sill, wall) and are tied to the module of multiplicity “M”. The limits of linear dimensions are in “mm”.

For external walls:

• length - from 300 to 8,400;
• height - from 600 to 8,400;
• thickness (for combined cutting) - from 200 to 400.

For internal:

C - technical (basement) floors;

H - (attic rooms).

The last group is also letters. They give an idea of \u200b\u200bsome design features of a wall reinforced concrete product (the location and configuration of openings, end zones, reinforcement outlets and the like).

2. Reinforced concrete panels.

Here the designation is somewhat different. We only note the differences.

Second letter:

• C - for supporting products.
• G - for non-carriers.

• In - the walls.
• P - basement (technical) floors.

Fourth: only composite reinforced concrete panels - C.

approximate cost

It’s hard to give exact numbers. And it is not only a large assortment, but also the features of the manufacturing technology that takes into account the brand of concrete, type of reinforcement (mesh or frame) and a number of other indicators. Therefore, instead of price lists, a calculator is placed on the manufacturers' websites, with which you can calculate the approximate cost of the panel only after entering the initial data. And if there is a list of products, then to clarify the price of the sample it is proposed to make a call to the specified number.

In order to have a general idea of \u200b\u200bthe price of reinforced concrete panels, you can focus on the following average (and very approximate) figures (rub / m 2):

• single layer - from 3 100;
• two-layer - from 3 650;
• three-layer - from 4 850.

Buying used wall reinforced concrete panels is cheaper because the price depends on the degree of wear. But given the specifics of the production of products, experts do not recommend using them in critical areas. Even a professional who has found signs of a hidden defect will need special equipment to conduct a complete diagnosis and give recommendations for further use of the panel.

Modern construction is impossible to imagine without prefabricated housing construction. In order for the building to meet the requirements of today in terms of heat saving, comfort, architectural expressiveness, etc., new technologies and new materials are being introduced.

The load-bearing walls of prefabricated buildings consist of floor-height panels. Unlike large blocks, wall panels are not self-stable: during construction, their stability is ensured by mounting devices, during operation, special designs of joints and connections. Overlappings are made of reinforced concrete flooring or panels the size of a structural-planning cell ("panel to room").

Most of the structures with this technology of building construction perform several functions at once: external walls - load-bearing and heat-shielding, internal - bearing and sound-proofing functions, etc.

This technology is distinguished by high spatial rigidity, which ensures earthquake resistance of structures during earthquakes.

In the sector of both civil and industrial construction, sandwich panels with mineral wool or polystyrene fillers are still widely used as enclosing structures, the cladding of which uses metal with various types of coatings. To carry out the elements, builders try to use reinforced concrete panels, as a rule, also with various kinds of insulation.

Prefabricated reinforced concrete products have been used with us for a long time and were widespread, especially in the typical development of residential areas. It was in the era of "developed socialism" that these panels were used in the projects of two- and three-story buildings of kindergartens, schools and shopping centers. Over time, the word "large-panel building" has become synonymous with poor construction. But the point is not in the panels, but in the fact that the available technical solutions for such construction have so far been used extremely insufficiently or even incorrectly. In recent years, we have already built prefabricated monolithic buildings of the most diverse appearance, impeccable from a technical point of view and meeting all modern requirements.

MODERN REINFORCED CONCRETE SANDWICH PANEL - This is a multilayer reinforced concrete structure, most often a three-layer one, with flexible connections, with an effective insulation up to 180 mm thick, which guarantees a particularly low heat consumption. The latter is also ensured by the large thermal resistance of the currently manufactured walls and roofs, which is five times higher than the thermal resistance of the previously used the same structures, as well as triple glazed windows. Thanks to all of the above, heating costs are reduced by at least two times. The thermal resistance of such structural elements is fully consistent with Russian standards (SNiP P-3-79, changes No. 3 - 4 "Construction heat engineering").

Reinforced concrete sandwich panels also have good sound insulation - thanks to the insulation and the use of well monolitizable structures of interblock connections.

In addition to serial, so to speak, standard finishes, it is possible to use the individual design of each panel and apply a wide variety of finishing options. Good appearance and leakproofness of the external joints are ensured by the use of modern elastic sealing materials and a new joint design.

Many of our manufacturers produce a wide range of these panels. They can be used for the construction of multi-storey residential buildings, schools, hotels, shopping centers, administrative, as well as industrial and warehouse buildings, multi-storey garages and others. Among the manufacturers - DSK "Block" and Gatchinsky DSK (LSR group) with an improved 137th and 121st series, Gatchinsky SSK (Optima series), DSK-3, Kirishsky DSK, DSK-5, KZHBI-211, Betoneks, Reinforced Concrete Products Plant No. 1 (Rosstroy Corporation - SU 155).

Now, manufacturers provide a wide range of services: they make up the structural part and working drawings of products according to architectural drawings, make products and deliver them to a construction site. For design, computer programs AutoCAD and "SCAD" are used, which guarantees short deadlines and good quality of design work.

The three-layer external wall panel, or Sandwich panel, consists of two layers of concrete, between which there is a layer of effective insulation. Concrete layers are interconnected through a layer of insulation with diagonal stainless steel bonds, with which the outer layer of concrete hangs on the inner layer of concrete (Fig. 1). As a result of this, a complete absence of cold bridges is achieved.

The inner layer is usually carrier. The outer concrete layer forms a facade surface with various types of finishes. You can apply surface finishes when the concrete is successfully combined with other finishing materials.

By changing the thickness of the layers, one can achieve good results in the heat resistance of panels. The thermal conductivity when using hard mineral wool as a heater, see the table above.

It is also possible to produce two-layer panels - without a facade layer. In this case, the facade layer is made at the construction site (facing with facade brick).

Advantages of using three-layer exterior wall panels:

good heat resistance (due to the lack of cold bridges);

sound and wind resistance;

climate resilience;

the speed of construction with a relatively small complexity;

the ability to install doors and windows at the factory, which allows you to start production of internal works earlier;

the ability to make channels for installing electrical wiring;

the ability to finish surfaces in whole or in part at the manufacturer;

the exception of the plaster of the inner walls, because their surfaces are smooth;

panel size accuracy;

a wide range of options for finishing the facade.

The introduction of modern technologies in enterprises and the use of new lines of technological equipment from leading manufacturers, such as Ebaw, Wiggert, allow us to create completely new products. Thanks to the development of technology, "work on errors" was carried out, as a result of which many of the previous flaws of the panels were eliminated: convenient layouts were created, problems of joints and thermal conductivity of wall panels were solved, the architectural appearance of facades was updated, flexible technological lines for the production of parts for buildings of various architectural and construction systems were introduced , including frame, precast monolithic and mixed.

The application of the technology for manufacturing the outer contour of panels using modern heaters made of foam concrete and polystyrene concrete panels makes it possible to change the overall dimensions, the configuration of both the panels and the outer walls, the binding of window openings, and use various types of finishes without any special expenses.

One cannot but pay attention to the best practices in the manufacture of concrete sandwich panels directly at the construction site. The manufacturing method is based on the shotcrete method. In this case, a seamless monolith effect is achieved. But consider it in more detail.

This method of building walling is well known in the West, the technology has been known for about 40 years. It was introduced in the Russian Federation quite recently - about 6 years ago, the Russian Wall company is the pioneer of this technology.

The basis of such a construction technology (using a three-layer panel) is the use of wall panels (3D panel), which is a spatial truss structure. The basis of the panel is a frame of reinforcing nets and galvanized or stainless rods welded at an angle to the nets; polystyrene foam is used as a heater, it is protected by two layers of concrete applied by shotcrete.

Shotcrete [from lat. (tec) tor (ium) - plaster and (con) cret (us) - compacted] - concrete work method, in which the concrete mixture is applied layer-by-layer to the concrete surface under the pressure of compressed air, that is, mechanical application of concrete is used. Shotcrete is carried out using shotcrete installations, the basis is a cement gun or concrete syringe, machine and compressor.

Compressed air mix, consisting of cement, sand, powder additives, is fed through a hose to the nozzle, moistened with water in it and at high speed (130-170 m / sec.) Is thrown onto the shotcrete surface. The layer thickness obtained in one shotcrete cycle is 10-15 mm.

The most important advantages of shotcrete, in addition to a small layer, are:

high mechanical strength (for 28 days - 40-60 MPa);

density (2.4 kg / dm3);

frost resistance (not less than Мрз 300);

water resistance (not less than B12);

high adhesion to the applied surface.

In addition, there are increased physical and mechanical properties of the final product:

bending strength is increased by 40%;

compressive strength is increased by 15%;

modulus of elasticity increases by 5%;

shrinkage is reduced by 30%.

As a result, and this was mentioned earlier, good economic efficiency and high speed of work are noted.

As an alternative, fiber-shotcrete-concrete with minimal core reinforcement can be used, and polyurethane foam can be used as insulation. At the same time, the entire process is not limited to certain geometric characteristics, but allows us to produce walls in a continuous way. Thus, we avoid cold bridges and get a virtually insulated, self-supporting monolithic structure.

In the case of the use of fiber-shotcrete concrete and polyurethane foam, the processes associated with the manufacture of meshes fall out, but, as mentioned earlier, reinforcement cannot be completely avoided, since with it the geometry of the entire building frame is set.

It is especially important that this scheme can be used in the manufacture of complex architectural forms. In principle, this will no longer be a sandwich panel in its accepted sense. But where structural reinforcement for one reason or another cannot be used, fiber is an alternative way of reinforcing shotcrete. It is well known how difficult it is to ensure the full lining of conventional reinforcement - rods or mesh. Moreover, this question arises and is important in the case of monolithic construction, where vibrators are used to remove excess air or self-compacting concrete is used, and this is also critical when using thick, power reinforcement. But this problem is solved precisely by using fiber. In many cases, the use of reinforcing mesh in ground and underground structures to strengthen the soil is an expensive and very difficult task. Typically, the mesh is laid so that it connects the two protrusions, especially if the terrain is not very even.

Therefore, in order to fill deeper sections (during its lining), a greater amount of shotcrete is required compared to fiber reinforced shotcrete technology, in which concrete is poured only on the required surface, regardless of its shape. In many projects, fiber reinforcement prevents cracking during plastic shrinkage under conditions not suitable for the proper exposure of concrete. In projects to strengthen walls under conditions of significant deformation, the latest reinforcement made of macrosynthetic fiber is perhaps an alternative to using a mesh, because its load-bearing capacity increases with growing deformation.

Summarizing all of the above, the following can be noted: if fiber were used in the manufacture of panels, then we would not have seen those ugly cracks and crumbling concrete that so often “decorate” the facades of our buildings.

Now low-rise construction is expanding in Russia, new retail and warehouse space is being massively erected. I would like to hope that this technology will be applied and have a future, and the facades made on it will last a long time. Moreover, it has every chance to be widely used in the program "Affordable Housing ...", and not only in industrial construction.

Reinforced Concrete Panels

The requirements of SNiP I-3-79 * correspond to three-layer panels with outer and inner reinforced concrete layers and effective thermal insulation located between them (Fig. 2.2.29).

Reinforced concrete panels can be either prefabricated structures (the layers are joined in the manufacturing process at the factory, and the panels are mounted on the construction site as a finished wall element), and prefabricated - the installation is carried out by installing each layer separately.

Prefabricated reinforced concrete three-layer panels

Design features of prefabricated three-layer reinforced concrete panels are:

profitability in terms of speed of construction of the building and installation costs;

less dependence of construction work on weather conditions, subject to the principle of non-penetration of moisture into insulating structures;

rigid thermal insulation, perceiving tensile and shear forces, redistributing loads between concrete layers, as a result of which the load-bearing capacity of the panel increases significantly.

It is also necessary to note one more feature of modern reinforced concrete panels regarding production technology. Modern (mobile changeable) formwork allows to produce panels of the required sizes and configurations for each specific project. Thanks to this, the architect, using industrial panels, can create a memorable unique look for each building.

Reinforced concrete panels can be load-bearing, self-supporting and hinged (non-bearing). In residential buildings, for the most part, load-bearing wall panels are used, on the inner layer of which floor slabs are supported. In office buildings, the following exterior wall solutions are usually used: curtain panels and supporting frame.

When choosing a design, it is necessary to pay attention to such details as appearance, functionality, strength requirements, post-installation care, ease of installation and economic indicators.

The wrong choice of material and design can lead to significant costs during operation and maintenance of the facades.

For prefabricated reinforced concrete structures, all main types of concrete are used: heavy, lightweight on porous aggregates and cellular. The concrete grade is selected based on the requirements for durability and strength.

Reinforced concrete panel has working reinforcement, as a rule, structural, but also may have design reinforcement designed to absorb the forces arising from the manufacture, transportation of panels and during wall mounting. As reinforcement, welded mesh and spatial frames are used.

The fittings are calculated based on the loads arising during its operation. The edges of the outer layer of the panel and the edges of the openings are equipped with ring reinforcement in order to avoid the formation of cracks caused by uneven shrinkage. At the edges of the inner layer of the panel and the edges of the openings, the reinforcement is used on the basis of structural necessity.

As a heat-insulating layer of three-layer panels, currently most often used are plates made of polystyrene foam and hard mineral wool. Other thermal insulation materials may also be used. The thickness of the insulating layer is set in accordance with the heat engineering calculation.

The connection of the outer and inner layers of three-layer panels is carried out using bonds. The main functions of the bonds fastening the concrete layers of a multilayer panel are to ensure interaction between the layers; transfer of loads of the outer layer to the inner layer; minimizing forced forces; prevention of bending of layers.

Types of bonds can be as follows: flexible metal bonds; separate reinforced concrete ties (dowels); reinforced concrete ribs.

The outer layer of the panel is designed to protect the main layers during operation from external climatic influences and perform decorative functions (Fig. 2.2.30). The types of exterior finish of the panels can be divided into the following main categories: firstly, surfaces treated with fresh concrete, secondly surfaces treated with hardened concrete, and thirdly, tile lining itself.

Installation of "sandwich panels"

The supporting structure of buildings on which the panels are mounted can be wooden, metal or reinforced concrete frames. The small weight of the products, as mentioned above, allows you to reduce the cost of the foundation during the construction of the building, as well as save on the use of expensive hoisting equipment (one or two people can work with panels).

High operational characteristics of buildings and structures using "sandwich panels" in many respects depend on the successfully solved joint of the panels. As in the case of reinforced concrete panels, manufacturers pay special attention to the solution of the “castle”.

The joints of the panels should provide: the strength of the structure; lack of "bridges of cold"; prevent moisture vapor from entering the insulation; perceive thermal changes in the size of "sandwich panels". To solve these problems, manufacturers of "sandwich panels" have developed various design solutions for "locks". Usually, panels are docked with a tongue-and-groove connection, which provides protection against moisture and a sufficient degree of strength. Thick panels can have a double tongue-and-groove connection. The gap in the lining in the middle of the end of the panels is done to interrupt the "cold bridge". A special bend of the metal sheet provides moisture resistance and durability of the connection.

Seams and joints can be additionally filled with sealing mastic, gaskets made of polyurethane, polyurethane tape or polyurethane foam. Some systems also optionally install aluminum foil. The aluminum foil at the junction protects against gas diffusion and vapor penetration into the insulation.

The end seams of the panels are filled with polyurethane foam or mineral wool and closed with a stripper.

The fastening of the panels themselves to the frame elements can be visible and hidden. Self-tapping screws or special fasteners (clamps) are used for fastening.

When installing panels, shaped elements are also used, which are metal products used to close possible joints obtained during the installation of panels.

The design of the corners of the building, door and window openings, parts adjacent to the base and the roof is carried out using special cold-formed profiles or corner panels.

To increase design capabilities, panels with false joints are produced both in length and in width of panels.