11 MATERIALS OF SPECIAL PURPOSE

11.1. Thermal insulation building materials and products

General information

Thermal insulation materials are materials that have a thermal conductivity of not more than 0.175 W / (m ° C) at 20 ° C and are intended for thermal insulation of buildings, process equipment, pipelines, thermal and refrigeration industrial installations. The use of such materials in the construction allows to significantly save thermal energy, the scarcity and cost of which is growing. It is believed that 1 m3 of effective thermal insulation materials saves 1.45 tons of fuel equivalent.

Classification

Materials and products are divided according to the following main features: by type of the main feedstock (inorganic and organic); on structure (fibrous, cellular, granular (loose));

the content of the binder (containing and not containing a binder

property); in a form (friable (cotton wool, perlite, etc.); flat (plates, mats, felt, etc.); shaped

(cylinders, semi-cylinders, segments, etc.); laced; flammability (combustible) (incombustible, non-combustible, combustible).

General principles of technology of thermal insulation materials

The thermal conductivity of a material is a function of the thermal conductivity of the skeleton of a material, the thermal conductivity of air, and moisture in the pore space. Dry air, enclosed in small closed pores, has a thermal conductivity of λ = 0.023 W / (m · ° C). Consequently, the structure of the heat-insulating material and product must have a skeleton of amorphous structure, extremely saturated with small closed pores or thin air layers. From this it follows that thermal conductivity directly depends on the density of the material - λ = f (ρт). Therefore, heat-insulating materials and products have a limit on the average density (not more than 500 kg / m3) and are marked by it. The brands of thermal insulation materials (kg / m3): D15, D25, D35, D50, D100, D125, D150, D175, D200, D250, D300, D350, D400, D500. Material having an intermediate average density is referred to the nearest larger grade.

In practice, use the following basic ways to create a highly porous structure of the material. To obtain materials of cellular structure (cellular concrete, foam glass, porous plastics (foams)) use the methods of gas evolution and foaming. Closed-cell materials, such as foam glass, have a slight water absorption. To reduce water absorption in the manufacture of materials are introduced water-repellent additives.

The method of high water mixing consists in the use of a large amount of water in obtaining molding masses (for example, from tripoli, diatomite); subsequent evaporation of water during drying and firing of molding products contributes to the formation of air pores. This method is often combined with the introduction of burnable additives (carbonaceous man-made waste, sawdust, etc.).

The creation of a fibrous skeleton is the main method for the formation of porosity in fibrous materials (mineral wool, fibreboard, etc.). Highly porous structure is fixed mainly by heat treatment of products.

Nomenclature and application of TIM

In Russia, the production of thermal insulation materials is distributed as follows:

mineral wool - 65%, glass wool - 9.3%, foams - 6.6%, cellular concrete - 6.6%, basalt, perlite and vermiculite products - 12.5%. Materials based on basalt and glass fibers, slow-burning foams, moisture-resistant foam-foam boards, cellular concrete with a density of up to 400 kg / m3 prevail abroad.

Mineral wool - a formless fibrous material, consists of thin vitreous fibers with a diameter of 5-15 microns, obtained from a melt of low-melting rocks (marls, dolomites, etc.), metallurgical and fuel slags, and their mixtures.

Mineral-cotton hard plates with increased rigidity are made on a synthetic binder. Slabs from the mass of flowable consistency are molded in vacuum presses and subjected to heat treatment at 150 ... 180 ° С. Get the plate density of 180 ... 200 kg / m3, a thickness of 30 ... 70 mm.

Mineral- cotton semi-rigid and soft plates are made with synthetic, bitumen

starch and binder. Products (plates, cylinders, segments, mats) with a synthetic binder have a lower density, are more durable and attractive in appearance compared to products on a bitumen binder. The density of the plates is 35 ... 250 kg / m3, thermal conductivity - 0.041 ... 0.07 W / (m '° C).

Steklopor obtained by granulation and swelling of liquid glass with mineral additives (chalk, ground sand, ash TPP, etc.). The technological process includes the production of granulate - "glass-bead" and its low-temperature (at 320 ... 360 ° C) swelling. Glass clamps are produced with a density of ρm = 15 ... 120 kg / m3, λ = 0.028 ... 0.05 W / (m · ° C). In combination with various binders, glass bars are used for the manufacture of piece, mastic and potting insulation.

Assembly asbestos materials are produced in the form of sheets and rolls of asbestos fiber; sometimes a filler and a small amount of bonding agents (starch, casein, etc.) are introduced to obtain asbestos paper, cardboard, cord. Aluminum foil is used as insulation reflectors in the air layers of layered enclosing structures of buildings and for thermal insulation of industrial equipment and pipelines at temperatures up to 300 ° C.

Granular materials are used for insulating backfill. At temperatures up to 900 ° C, they use: expanded perlite in the form of porous sand with a density of 50 ... 100 kg / m3 and thermal conductivity of 0.04 ... 0.05 W / (m · ° C); expanded vermiculite in the form of a mixture of lamellar grains with a particle size of not more than 15 mm, a density of 100 ... 120 kg / m3 and a thermal conductivity of about 0.075 W / (m · ° C): crushed diatomites and tripoli with a particle size of up to 5 mm, a density of 400700 kg / m3 and thermal conductivity 0.11-0.18 W / (m · ° C).

At temperatures up to 450 ... 600 ° C, granulated and glass wool, crushed pumice and volcanic tuff, fuel slags produced by burning lump fuel, fuel ash from the combustion of pulverized fuel, blast furnace slags are used.

Fiberboard is a slab material made from wood wool and inorganic binder. Wood wool (chips with a length of 200 ... 500, a width of 2 ... 5 and a thickness of 0.3 ... 0.5 mm) is obtained on special machines using short logs of spruce, linden, aspen or pine. Portland cement and a solution of a mineralizer - calcium chloride most often serve as astringent. Forms with a mass of consistently pass the chamber of the pile, the pressing shaft, the cutting station into plates, the curing and drying chamber. The moisture content of cement-fiber plates is limited. The plates produce a density of 300 ... 500 kg / m3, thermal conductivity 0.1 ... 0.15 W / (m · ° C), with a flexural strength of 0.4-1.2 MPa. The thickness of the plates - 25, 50,75,100 mm. Fiberboard is well processed - it can be cut, drilled, nails can be driven into it.

Arbolite products are made from Portland cement and organic short-fiber raw materials (sawdust, crushed machine chips or chips, chopped straw or reeds, fires, etc.) treated with a solution of mineralizer. Chemical additives are: calcium chloride, soluble glass, sulphate of alumina. Thermal insulating arbolite with a density of up to 500 kg / m3 and structural thermal insulation with a density of up to 700 kg / m3 is used. The strength of arbolita under compression is 0.5 ... 3.5 MPa, tensile bending - 0.4 ... 1.0 MPa; thermal conductivity - 0.08 ... 0.12 W / (m · ° C).

One of the most promising modern insulation materials is the use of recycled materials from household waste (paper and cardboard). The obtained ecowool is an ideal substitute for traditional heaters. The average value of thermal conductivity is 0.041 W / (m · ° C). Ecowool is difficult to burn, due to the addition of flame retardants, biostable, has sound-absorbing properties.

Cell plastics are made by gluing together corrugated sheets of paper, glass or cotton fabric impregnated with polymer. They serve as an effective insulation in three-layer panels. The heat-insulating properties of honeycomb are increased when the cells are filled with Mipora crumbs.

Depending on the nature of the pores, cellular plastics are subdivided into foams and foamed plastics. Foams have predominantly closed pores in the form of cells separated by thin partitions. Cellular plastics with communicating pores belong to poroplasts. There are materials with a mixed structure.

In cellular plastics, pores occupy 90-98% of the volume of the material, and walls account for only 2-10%, so cellular plastics are very light and have low heat conduction (thermal conductivity is 0.026 ... 0.058 W / (m · ° C)). At the same time, they are waterproof, do not rot; rigid foam and foam plastics are strong enough, flexible and elastic. A feature of heat-insulating plastics is the limited temperature resistance. Most of them are flammable, therefore it is necessary to provide constructive measures to protect porous plastics from direct action of fire.

Porous plastics can be sawn, cut in the usual ways, as well as with electric heated wire. They are well glued to concrete, asbestos cement, metal, wood. This greatly simplifies the manufacture of large panels of enclosing structures.

Polyurethane foam is obtained as a result of chemical reactions that occur when the starting components are mixed (polyester, diisocyanite, water, catalysts and emulsifiers). Produce hard and elastic polyurethane. Density is 25 ... 45 kg / m3, strength at 10% compression is 0.3 ... 0.7 MPa.

Hard polyurethane is used in a wide range of temperatures, it is easy and cost-effective processing, high mechanical strength, wear resistance and chemical and biological resistance. It is characterized by the lowest thermal conductivity in comparison with other insulating materials, thermal conductivity at a temperature of 10 ° С below 0.019 W / (m · ° С). It can be used at temperatures from -50 ° C to +110 ° C. Zero capillarity. Volume water absorption of 0.2%. Resistance to the action of fungi and microorganisms makes it not rotting or decaying. Hard polyurethane foam is used in the form of slabs and shells. Elastic polyurethane foam serves to seal the joints of the panels. Formulations of potting compositions have been developed that can foam even in the cold. The material "self-extinguishing" on fire resistance. When using polyurethane foam materials, it is necessary to take into account their insufficient lightfastness, which can be enhanced by protecting (laminating) the surface with metal foil, roll materials and fiberglass.

In recent years, a cheaper substitute for polyurethane foam plates requiring the use of imported components has appeared on the Russian market - urea foam, which has received the trade name penoizol . This material is characterized by the following properties: noise resistance, thermal conductivity of 0.02 W / (m · K), density 15 kg / m3, non-toxic, grade for Flammability - G2, flammability - B2. Boards with a thickness of 50 mm can, by thermal conductivity, replace a brick wall with a thickness of 1000 mm. Penoizol is a material made in a bass-free way and without heat treatment from a foaming composition that includes a polymer resin, a foaming agent, water, and special modifiers.

Expanded polystyrene - lightweight plastic, made from polystyrene with a blowing agent. Expanded polystyrene is light, has a density of up to 25 kg / m3, is resistant to abrasion, water absorption is a fraction of %, it is difficult to ignite. The disadvantage of the material is shrinkage, which can be reduced by keeping the material in place before using and using flexible and elastic materials such as bitumen-elastomeric welded fabric as a waterproofing layer. It is used in three-layer wall panels on flexible connections together with hard mineral wool plates, for thermal insulation of walls and roofs.

The main indicators of polystyrene concrete and, consequently, its purpose as a block insulation material can be significantly varied by regulating the structure of the intergranular space: dense, porous or large-pore. The goal is solved by selecting the cement consumption (120 ... 500 kg / m3), granule size and bulk density of expanded polystyrene (8 ... 15 kg / m3), by introducing effective foam and gas-forming additives. This material imposes strict requirements on the content of free monomer (styrene), which should not exceed 0.002% by weight. This is achieved by special treatment (detoxification) of polystyrene aggregate, concrete mix or products and structures.

Polyurethane foam and polystyrene foam are produced as highly effective heat-insulating materials, and in combination with shrink-film packaging under pressure or by other methods as new hydro-thermal insulation materials.

Penopolivinyl chloride release hard and elastic. Hard polyvinyl chloride is a heat-insulating material that slightly changes its properties when the temperature changes from +60 ° C to -60 ° C. It is less flammable than expanded polystyrene.

Mipor is made by foaming a urea formaldehyde resin, hardening the blocks molded from the foam and then drying them. Mipora is the lightest (10 ... 20 kg / m3) and least heat-conducting of all thermal insulation materials - λ = 0.026 ... 0.03 W / (m- ° С).

Along with the stick, roll, loose bulk materials employed monolithic insulation using special sprayed polyurethane and polystyrene mixture and gypsum plaster, in which as fine aggregate (filler) includes inorganic or organic fibrous materials (asbestos, vegetable raw waste treated liquid glass, synthetic fibers).

12.2. A KUSTIC MATERIALS

Acoustic materials are materials that can reduce the energy of a sound wave, reduce the volume of internal or external sound. For most buildings, the task of acoustics, acoustic improvement is to reduce the levels of external noise to the permissible silence in the relative mode in the premises of industrial, educational, residential, cultural and residential buildings. For public buildings, it is also important to ensure good audibility and intelligibility in the main rooms, and in the music rooms - also the natural sound of instruments and voice. These tasks are solved by a set of constructive, planning and preventive measures. The main one is the proper purpose of building materials in the construction, especially in enclosing (walls, partitions), interfloor ceilings and roofing. The choice of materials is based on their different ability to retain (absorb) the sound wave, which can spread both in air and in solids and liquids.

To combat noise and sound transfer, sound absorbing (actively absorbing sound) and soundproofing (noise reduction) materials are used. They can be finishing and gasketing.

Finishing materials partially absorb sound indoors, such as industrial workshops, a typewriting bureau, etc., or technical devices, such as ventilation ducts, etc. Finishing sound-absorbing materials also optimize the conditions of audibility in rooms, for example, in auditoriums, lecture halls, broadcasting studios and etc. Most or less of the sound waves are usually reflected from structures made of finishing sound-absorbing materials. As a result, the sound is preserved in the room even after the termination of the sound source. This phenomenon is called reverb.

Cushioning materials are used under the elastic floors of interfloor ceilings, thereby protecting the premises from the spread of material (impact) sound transfer. Often these materials are combined with finishing.

The numerical value of sound absorption is estimated by a coefficient that indicates the fraction of the energy of the sound wave absorbed by 1 m2 of the material surface in an open aperture. The larger the value of sound absorption coefficient, the higher the corresponding efficiency of building material in the structure, and the frequency of sound is also taken into account, on which the value of sound absorption coefficient depends.

Sound-absorbing materials are divided according to various criteria: the nature of sound absorption, the type and technology of production, the nature of the surface of products. All these materials are usually also finishing, as they contribute to the creation of the external architectural expressiveness of the premises.

By the nature of sound absorption, materials are divided into porous, membrane and perforated. The most common are porous. Sound energy is absorbed in these materials mainly due to friction of air particles in the pores and capillaries, which are highly developed and of different diameter. With increasing porosity, sound absorption increases, although there is some porosity limit (about 80%), above which sound absorption does not increase and even there is a tendency to decrease. Важен также размер диаметра пор. При малых размерах пор проникновение звуковой энергии в толщу материала затруднено, а звукопоглощение оказывается незначительным. Оптимальным может быть принят диаметр пор до 1 мм. При мембранном типе материала сила звука снижается вследствие затраты энергии на вынужденные колебание достаточно массивных и жестких мембран (плиты, фанерные листы, плотный картон, некоторые ткани и др.). Перфорированные панели и другие материалы имеют отверстия, в которых задерживается воздух, создающий тормоз на пути воздушного переноса звука, что создает лучший эффект звукопоглощения.

К звукопоглощающим материалам, отличающимся внешним видом и технологией изготовления, относятся плитные, рулонные и комбинированные. По характеру поверхности изделии эти материалы разделяются на плиты с естественной фактурой, с порами и раковинами, с рифленой поверхностью, с перфорированной поверхностью, т. е. с отверстиями одного или разного диаметров, расположенными симметрично или бессистемно.

К сравнительно эффективным относятся акустические плиты на основе стеклянной и минеральной ваты, плиты из легких бетонов на основе неорганических вяжущих и с применением пемзы, керамзита, вспученного перлита или вермикулита и др.; плиты из фибролита; древесноволокнистые плиты; гипсовые плиты (перфорированные и сплошные); древесностружечные плиты и некоторые другие. Практическую пользу приносят акустические звукопоглощающие штукатурки. Эффективно выполняют функции звукопоглощения конструкции из пористых волокнистых материалов, покрытых различными тонкими перфорированными листами и сетками. Перфорация в плитах и листах может быть сквозной и несквозной в зависимости от типа и назначения конструкций.

Звукоизоляционные материалы применяют для изоляции помещений от распространения материального (ударного) переноса звука. В отличие от звукопоглощающих эти материалы остаются практически в скрытом от взора состоянии в виде прокладочных слоев в конструкциях внутренних стен (перегородок) и междуэтажных перекрытий зданий. Они располагаются между наружными оболочками (панелей, щитов и др.), находясь в свободном (не сжатом) или даже подвешенном состоянии (например, подвешенные маты). Возможно и некоторое обжатие звукоизолирующей прослойки, например, между несущими панелями потолка и конструкцией пола на упругом основании.

Звукоизоляция всегда связана с характером конструкции, а не только со структурой и свойством материала, как при звукопоглощении.

Звукоизоляционными акустическими материалами служат полужесткие минераловатные и стекловатные маты и плиты на синтетической связке, древесноволокнистые изоляционные и асбестоцементные изоляционные плиты (последние используют в местах опирания конструктивных элементов перекрытий на стены зданий). Для звукоизоляции используют также плиты из полистирольного пенопласта, а из засыпных материалов - кварцевый песок, керамзит, шлак.

12.3. Г ИДРОИЗОЛЯЦИОННЫЕ МАТЕРИАЛЫ

The general task of waterproofing is to prevent the penetration of aggressive groundwater containing acids, sulfates, hydrogen sulfide, chlorine, which cause the destruction of concrete and metal, to the insulated material (anti-corrosion waterproofing) or water migration through the building envelope (anti-filtration waterproofing). To do this, you need to either create a waterproof layer between the water and the surface of the material, or make the material itself waterproof. Waterproofing is performed primarily for underground structures and structures that experience during operation the effect of direct hydraulic head or filtering groundwater. These are foundations, basement walls, floors. Sometimes waterproofing is used to prevent leakage of water or other liquid from tanks.

Waterproofing materials must have a high degree of water resistance, chemical resistance, biostability, be flexible enough, have a high deformability (not give cracks and gaps during temperature shrinkable deformations of the insulated structure), etc.

Currently, the following methods of waterproofing are used: painting, pasting, plaster-monolithic, facing, membrane, injection. For each uses its own materials.

The paint waterproofing recommended for protection against capillary filtering water (free-flow) is a monolithic waterproof coating with a thickness of 3 ... 6 mm, obtained by applying bitumen, bitumen-polymer, polymer and polymer-cement compositions (mastic) on the surface to be protected. Waterproofing coated should have a high adhesion to concrete of at least 100 kPa and tensile strength from 3 to 12 MPa.

Gluing , plastering and facing coatings are used for direct action of water on the surface under a pressure of up to 10 m. To perform glued waterproofing, they use both special roll waterproof and waterproof materials and a wide range of coatings that can be used as roofing. Roll materials are produced in the form of rolls with a size of 10 ... 20 m2 and are divided into basic and baseless.

The main materials, which are mainly used as roofing materials, but can also be used for waterproofing, include glassine, roofing material, hydroisol, glass fiber, roofing sheet. In the manufacture of these products, the base, which is roofing or asbestos cardboard, fiberglass canvas, is impregnated with low-melting oil roofing bitumen or tar. Then, in some cases, covering the layers of solid road bitumen. In order to increase the weather resistance of the ruberoid, up to 35% of fine-ground filler, obtained during the grinding of shale, dolomite, mica and talc rocks, is introduced into the composition of covering masses. In addition, all products (with the exception of glassine) on one or two sides are covered with sprinkling masses (talc, efel — waste from mica shale, sand). The dressing protects the surface from premature destruction by atmospheric factors. After this, the product is dried and rolled.

Plaster monolithic coating is made of asphalt (cold or hot), polymer, polymer cement and cement mortars with a thickness depending on the size of the hydrostatic pressure (up to 10 m) 6 ... 50 mm. This coating is relatively fragile, so this waterproofing in order to avoid cracking is used only for rigid non-deformable surfaces of building structures. The conditions limiting the use of asphalt solutions are exposure to petroleum products and hot water (with temperatures above 50 ° C). Strengthen monolithic waterproofing can be either through additional reinforcement with fiberglass (fiberglass).

In recent years, the use of waterproofing dry building mixes based on Portland cement has been expanding. Depending on the composition of dry mixes, waterproof concrete (W12) or coating compositions can be obtained by mixing them with water at the construction site. The high density of the coating is achieved due to the careful selection of the granulometric composition of the washed aggregates and the introduction of sealing additives.

Plaster compositions are applied to the surface in layers (no more than three layers) by hand or by pneumomechanical means. Mineral compositions (based on cement) contain sand of a certain fraction (cement-sand mortars) or fine ground aggregates (colloid-cement mortars). To ensure the desired plasticity of the mixture and impermeability of the coating, plasticizing and sealing additives are introduced.

Facing coatings are used, as a rule, to protect monolithic structures. Metal sheet materials with a thickness of up to 4 mm are used as permanent formwork for concreting monolithic structures. In the case of the location of waterproofing from the action of groundwater, metal sheets are protected with colorful compounds from corrosion. Polymeric sheet materials, flat and profiled (polyethylene, polypropylene, vinyl plastic), 2 mm thick, are installed in the formwork upon receipt of monolithic structures or glued to the surface with a polymeric silicate composition to protect prefabricated structures.

With waterproofing foundations, builders are increasingly recognized by membrane waterproofing, which is a multilayer material consisting of a thick polyethylene film with a voluminous mesh glued to it, which is filled with granules of bentonite clay or a water-swellable polymer. When moistened, these materials, increasing several times in volume, create a waterproof layer.

If necessary, waterproofing the foundation of a building in use is drilling through holes in the walls and basement of the basement through which special waterproofing solutions are injected, consisting of portland cement, clay, water glass and sealing additives — injection waterproofing. For waterproofing walls from capillary moisture raising, drilling in a wall of a network of inclined small diameter wells followed by injection of impregnating solutions through them: silicone, water-repellent liquids or monomers with special additives, which, polymerizing in the pores of the material, increase the water resistance and load bearing capacity of the structure.

Impregnating waterproofing is effectively performed using a penetrating material such as "Kolmatron", developed in Russia. With it, the design not only acquires waterproofing properties, but also restores its strength and frost resistance to the brand F150.

For concrete porous surfaces, it is also effective to use compositions that include easily penetrating chemicals that interact with calcium hydroxide of cement stone, forming compounds that clog pores and increase the density of the surface layer.

12.4. ROOFING MATERIALS

Roofing materials are intended for building roofing. Depending on the type of raw materials, roofing materials can be metal, ceramic, cement-containing, polymeric, bitumen-polymeric and bitumen. When choosing roofing materials, criteria are used based on the compliance of the material with the following roof characteristics: configuration, planned durability, taking into account aesthetic perception and economic opportunities of the developer.

The roof covering during the whole period of operation is exposed to numerous adverse environmental factors: humidity and temperature changes, exposure to ultraviolet rays. Under the influence of the load, the temperature deforms both the roofing material itself and the rigid base of the roof. The quality of roofing materials is checked according to the main general indicators (water resistance, water resistance, frost resistance, resistance to ultraviolet rays) and properties depending on the composition of the material (flammability, toxicity, etc.).

Silicate roofing materials include: asbestos-cement roofing materials, clay, cement-sand and glass tiles (which is still limited in use), natural slate

The bitumen include: roofing material, asphalt, bitumen mastic, waterproofing; to tarry - roofing roofing, roofless roofing, roofing with large mineral dressing and tar mastic

The materials on the basis of plastics include flat and wavy plates of fiberglass, brizol - roll material produced from crushed waste rubber, bitumen, asbestos and plasticizers, and organic glass (plexiglas) with a thickness of 0.5 mm to 24 mm.

Metal roofing materials include steel roofing (galvanized and non-galvanized). Metal, aluminum or galvanized steel, is a stamped corrugated sheet in the form of a section of a tiled roof. Increased durability (up to 50 years), as well as imitation of a ceramic material is achieved by protecting the surface with a transparent acrylic composition with colored mineral filler. To perform the roof, also use flat sheets of aluminum and galvanized steel with colored polymer coatings.

Roofing sheet materials also include the most popular slate in individual construction, which is a profiled asbestos cement sheet. To increase durability (up to 50 years) and make them decorative, they are protected with paint formulations that reduce water absorption and increase frost resistance. Compared to metal, this "breathing" material has a lower thermal conductivity and sound insulation capacity.

The new materials conquering their market include “ondulite” - flexible corrugated sheets formed from cellulose fibers impregnated with bitumen. On the front side, the sheets are coated with a protective and decorative paint layer based on a thermosetting (vinyl-acrylic) polymer and light-resistant pigments.

Cement-sand tile (CHP), which can be tongue-and-groove and ridge, is obtained from hard cement-sand mixtures with pigments using high-pressure forging to impart desired hydrophysical properties.

Ceramic ordinary and ridge tiles can be glazed and unglazed.