What are the fractions of expanded clay gravel? All about expanded clay gravel Application of expanded clay crushed stone.

Innovative technologies have already reached building materials. Expanded clay gravel became one of the innovations. It is made from clay of natural origin. It undergoes rapid firing in furnaces (about 30 minutes), while the temperature reaches 1300 degrees. Clay swells in a special way. As a result, clay grains (fractions) with a light porous structure and dark brown color are obtained at the output. If you break the granule, then inside the color will be almost black. Depending on the degree of processing, a dense crust forms on the surface of the granules. After cooling, the granules are sorted. GOST, provides for granule sizes of 5-10, 10-20 and 20-40 mm. The number of granules of the wrong size should not exceed 5%.

Characteristics of the building material

The advantages of this material are undeniable. They completely change the idea of ​​building materials. Expanded clay gravel is very light, but at the same time it perfectly retains heat, is moisture resistant and fireproof, and can withstand very low temperatures. Does not deform when they are dropped. Provides excellent sound insulation, does not rot at all, does not smell of anything. With completely environmentally friendly material. After all, it only contains clay.

Application in various fields

Russia is considered one of the largest producers of this product. Per last years gravel production in our country has increased by 30%, the demand for it is constantly growing. Expanded clay gravel is indispensable for home insulation. The foundation, floor, external floors, insulation of water supply networks - all this can be insulated with expanded clay gravel. Lightweight but bulky, it retains heat well and is durable. In order to carry out high-quality work on insulation with expanded clay, you need to take it into account. The smaller the “grains” of gravel, the greater its density per 1 sq. m. Efficiency will be higher if the height of the embankment is at least 15 cm. Gravel will help keep the heat in the house by more than 60%. The construction of new roads is no longer complete without this material. It is used to divert water when working in wet and swampy areas. For utilities, expanded clay gravel is also an assistant. It is used to maintain the desired temperature regime and soundproofing. In addition, it can be used repeatedly, which is especially important for emergency work.

The porous structure of expanded clay

Today, expanded clay material as a building material is used for thermal insulation of buildings, both residential and industrial. Comparative inexpensive price, efficiency, functionality have made it one of the most popular materials used in the repair of apartments and houses. This characteristic of expanded clay is due to the method of its manufacture by firing from fusible environmentally friendly clay.

If we compare the thermal conductivity of expanded clay with materials such as wood or mineral wool, then it has a relatively lower thermal conductivity than the above materials. In addition, the natural substance from which expanded clay is made does not have harmful chemical impurities, and due to its porous composition, expanded clay has a lighter weight than similar materials made from clay.

Expanded clay production

Rotary kiln for production of expanded clay gravel

The very name of the building material expanded clay comes from the Greek phrase "burnt dust", which already indicates that the process of manufacturing expanded clay does not do without firing. Routing the production of the material is as follows: first, the clay is subjected to a sharp thermal shock to obtain a porous structure, after which the expanded clay cools down and is sealed in its fused outer shell, acquiring high strength.

Clay intended for the production of expanded clay must have good swelling during firing, be easy to melt and have a certain melting range. If necessary, to improve swelling, special additives are introduced into the clay in the form of solar oil, fuel oil, perlite, anulite. As a result of firing, granules of a certain size and configuration are obtained, which are then cooled and dried. If the granules are large sizes they are still crushed.

Cooling of the granules occurs first in a rotating drum oven by blowing air, and then continues in drum coolers. Cooling of the granules is given Special attention, because with rapid cooling they can crack, and if the cooling is delayed, the granules can soften and lose their strength.

The use of expanded clay

Expanded clay granules have three types: crushed stone, gravel and sand. Each of these types is designed to create a heat-insulating layer in a particular building structure.

The use of expanded clay gravel

Expanded clay crushed stone

According to its properties, expanded clay crushed stone does not have high strength, however, being a porous material, it contains a lot of air in its pores. Therefore, the main application of this type of expanded clay is thermal insulation. The granules of the material have sharp edges, which allows them to create good adhesion to concrete and, therefore, expanded clay crushed stone is used as a filler for lightweight concrete to give them high strength and high thermal insulation.

The use of expanded clay gravel

Expanded clay gravel is perhaps the most popular type of granules, which is widely used in construction as thermal insulation material, sometimes replacing modern views heaters. Where exactly is this type of granule used:

Expanded clay gravel

• Very often, expanded clay gravel is used for thermal insulation of floors and ceilings to improve sound insulation and retain heat.
• Gravel is used to create a heat-insulating cushion at.
• Concrete with the addition of expanded clay gravel, instead of ordinary gravel, has a relatively light weight.
• When using material to create a heat-insulating layer, the laying depth of almost any type of foundation is reduced.
• Expanded clay crushed stone is widely used for thermal insulation and removal of moisture from road embankments laid in wetlands.
• This type of expanded clay is not complete without the creation landscape design, where it is created alpine slides and terraces.
• Due to its properties to first absorb moisture and then release it, expanded clay gravel is widely used in crop production, where it serves as excellent drainage for plant roots.
• When laying water pipes expanded clay gravel is used to make a kind of "fur coat" with which pipes are wrapped, protecting them from freezing.

The use of expanded clay sand

Expanded clay sand

Expanded clay sand is obtained by fine crushing of expanded clay granules to a size of 0.1-5 mm. Therefore, it differs from other types only in size, retaining the basic qualities inherent in all types: environmental friendliness, heat resistance, durability, etc. It is used as a concrete filler, for sound and heat insulation of buildings, in landscape construction.

Characterizing expanded clay, it is impossible not to mention its high fire safety. Not only do expanded clay granules practically do not burn, the material at low temperatures retains its structure, resistance to fungi and mold, which, in turn, allows it to be used in areas with a cold climate where deep freezing of the soil is observed.

Clay was used by man in ancient times, even then it was known about its hardening properties under the influence of hot air. Today expanded clay is widely used in construction and repair work. Expanded clay is a clay rock burned in kilns, which, when rotated in a kiln, swells from the gases inside.

Expanded clay gravel is the most popular building material, unlike expanded clay gravel or sand. Expanded clay gravel has a rounded oval shape, it is used for installation of floor screed and thermal insulation of houses, communications. Bricks or slabs for construction can be made from such material.

Expanded clay gravel has a number of positive characteristics:

• almost does not absorb water, because there is a protective shell;
• has good heat and sound insulation due to its porous structure;
• non-flammable, provides fire safety;
• the strength of the material allows it to be used in construction, it can withstand loads (if mixed with concrete);
• blends well with concrete;
• withstands frost and the adverse effects of atmospheric factors;
• has a small weight;
• does not rot or corrode;
• expanded clay is available in price.

Marking

Depending on the weight of expanded clay gravel per 1 cubic meter, it is divided into 10 main grades. The M250 brand means that there are 250 kilograms of expanded clay gravel per 1 cubic meter. Its strength and density depend on its weight. The most durable expanded clay gravel is M800, it is used for the manufacture of building materials. When buying gravel, the marking is main characteristic. Expanded clay can be bought both in bags and in machine quantities cubic meters. According to GOST, expanded clay gravel is divided into large (10-20 mm), small (5-10 mm) and medium (10-20 mm) fractions in size.

Application for floor screed installation

They are used when installing floor screeds, when it is necessary to level the floors in the room or make thermal insulation. Due to its low weight, even a screed 15-20 centimeters thick will not put pressure on the ceiling. Expanded clay gravel is poured and leveled, and then poured with concrete milk. There is another technology for mounting the screed using expanded clay - when it is already laid ready mix expanded clay with concrete.

Application for roof insulation

Expanded clay gravel is used in conjunction with polystyrene foam to insulate the roof, filling various cavities on the roof with this mixture. These can be as specially made wooden trays, or other cavities. Expanded clay gravel is also used for insulation flat roof, for this, a protective layer is made on top.

Wall insulation

You can insulate the walls with expanded clay gravel by filling it between the walls of the building.

Warming of communications

So that communications do not freeze in winter, they make a special shaft into which pipes are laid and covered with expanded clay gravel.

Construction

Slabs or bricks are made from expanded clay gravel, from which you can build a house or any production room. Expanded clay is used in the construction of baths to provide enough level moisture. At the same time, the use of expanded clay together with a film for waterproofing in the construction of the foundation will protect against moisture penetration.

Use in horticulture

Expanded clay gravel is widely used in horticulture, it is mixed with the soil in which plants are planted. It maintains the necessary level of moisture and heat, helps to let air through the soil. Rodents do not start in expanded clay, it even protects plants from them.

Expanded clay is a light porous material of a cellular structure in the form of gravel, less often in the form of crushed stone, obtained by firing low-melting clayey rocks that can be pushed in when they are quickly heated to a temperature of 1050 - 1300 C for 25-45 minutes. The quality of expanded clay gravel is characterized by its grain size, bulk density and strength. Depending on the grain size, expanded clay gravel is divided into the following fractions: 5 - 10, 10 - 20 and 20 - 40 mm, grains less than 5 mm are classified as expanded clay sand. Depending on the volumetric bulk weight (in kg / m3), gravel is divided into grades from 150 to 800. Water absorption of expanded clay gravel is 8–20%.

Expanded clay is used as a porous filler for lightweight concrete, as well as a heat-insulating material in the form of backfills.

Expanded clay gravel

Rounded particles with melted surface and pores inside. Expanded clay is obtained mainly in the form of expanded clay gravel. Its grains have a rounded shape. The structure is porous, cellular. On its surface there is often a denser crust. The color of claydite gravel is usually dark brown, in a break it is almost black. It is obtained by swelling during firing of fusible clays in rotary kilns. Such gravel with a grain size of 5 - 40 mm is frost-resistant, fire-resistant, does not absorb water and does not contain impurities harmful to cement. Expanded clay gravel is used as a filler in the manufacture of lightweight concrete structures.

Expanded clay crushed stone

Expanded clay rubble - aggregate for lightweight concrete of arbitrary shape, mostly angular with grain sizes from 5 to 40 mm, obtained by crushing large pieces of expanded expanded clay mass. (Crushed stone is crushed gravel, crushed stone has sharp angular edges, gravel is crushed into crushed stone for better adhesion concrete)

Some clays swell when fired. For example, in the production of clay bricks, one of the types of marriage - burnout - is sometimes accompanied by swelling. This phenomenon is used to obtain a porous material - expanded clay from clays.

Swelling of clay during firing is associated with two processes: gas evolution and the transition of clay to a pyroplastic state.

The sources of gas evolution are the reactions of reduction of iron oxides during their interaction with organic impurities, oxidation of these impurities, dehydration of hydromica and other water-containing clay minerals, dissociation of carbonates, etc. Clays pass into the pyroplastic state when a liquid phase (melt) is formed in them at high temperature ), as a result of which the clay softens, acquires the ability to plastic deformation, at the same time becomes gas-tight and swells with released gases.

For the manufacture of expanded clay concrete products, not only expanded clay gravel is needed, but also fine porous aggregate.

Expanded clay sand (expanded clay screening- other name ) - filler for lightweight concretes and mortars with a particle size of 0.14 to 5 mm is obtained by firing clay fines in rotary and shaft kilns, or by crushing larger pieces of expanded clay, as well as screening waste during the production of expanded clay.

Choosing expanded clay for various construction works, it is advisable to familiarize yourself with its main characteristics in advance. Physical and mechanical properties and application of this eco-friendly material largely determined by the size of the granules. Where to use expanded clay of different fractions and how it differs - this is what the conversation will go on.

Porous clay granules, expanded under the influence of high temperatures, acquire a whole range of useful qualities, while remaining as natural as possible. Expanded clay of any fraction is characterized by a high level of heat and sound insulation, strength, resistance to frost and fire, and low volumetric weight. At the same time, the material has its own characteristics, depending on the "caliber" of the particles. Detailed description you will find the expanded clay manufacturing method.

Description and characteristics

Granules are made in sizes from 0.05 to 4 cm, they are divided into 4 categories - expanded clay sand 0-5 mm and gravel of three types:

• small - 5-10 mm;
• medium - 10-20 mm;
• large - 20-40 mm.

Table 1 shows the main specifications named varieties.

Comparing the expanded clay fractions with each other, it is worth noting that the heat-saving capacity is somewhat greater for medium and coarse gravel. Given the low bulk density, they are best used for warming unloaded areas. And, on the contrary, fine-grained material is more durable - such expanded clay is most often chosen for floor screed. All species are characterized high level moisture absorption (from 8 to 20%), therefore, they need reliable waterproofing.

The use of expanded clay

Due to the variation in the values ​​of physical and technical parameters, the use of bulk material from fired clay has its own nuances.

1. Expanded clay sand (0-5 mm).

There are two types of technology for producing fine-grained expanded clay. The first method is firing small particles of clay in special furnaces with active aeration. This is an inefficient technique, since small granules stick together with large ones. Higher quality small-caliber expanded clay is obtained by crushing expanded clay gravel on special roller crushers. The price of expanded clay crushed type is much higher than granular.

Expanded clay of fine fraction is used for thermal insulation of the floor and wall masonry.

• Wet screed. In order to achieve real insulation with its help, small granules should not be introduced into the solution. As a result, their pores are clogged with cement, thermal insulation deteriorates. It is better to do layer-by-layer backfilling of the floor with expanded clay (4 cm each), distributing the cement-sand mixture between them. This technique allows mounting screeds with a maximum thickness of 200 mm.
• Warm solution. From the point of view of thermal resistance, the most vulnerable point in the masonry are the seams. The usual sand-cement composition has a thermal conductivity coefficient of 1.15 W / m o C (more than that of silicate brick). This indicator can be reduced several times if fine-grained expanded clay sand (0-3 mm) is used. Blocking the "cold bridges", thereby insulating the wall.

Crushed sand is also used in the production of expanded clay concrete. small particles they mix well with cement and sand concrete, so the blocks are stronger and harder than those made from expanded clay gravel (but less warm).

2. Small gravel (5-10 mm).

The use of the material of this fraction is carried out in several directions.

2.1. Expanded clay for leveling floors - dry screed. It provides insulation and perfectly levels the plane for the subsequent installation of GVL (gypsum-fiber sheets). If the screed is 10 cm thick, then you should buy fine gravel for backfilling at the rate of 35-40 kg per 1 m2. First, the floor is covered with plastic wrap, a screed level is applied, expanded clay insulation is poured over the sectors, it is leveled with the rule, GSP sheets are laid, the slots are blown with mounting foam.

2.2. Facade insulation. Gravel fraction 5-10 mm is used to create heat-insulating layers in the process of building walls. In this case, the following options are possible:

• backfilling of cavities with lightweight well masonry;
• filling the space between the inner brick wall and an external structure made of silicate or facing brick, as well as concrete blocks for plaster;
• thermal insulation of a frame or block house - backfilling of fine gravel between the wall and facade material(for this purpose, leave a gap within 10 cm).

In all cases, the insulation is rammed and spilled with cement milk. To protect porous granules from moisture, a ventilation gap is equipped. Fine gravel is widely used in the production of expanded clay concrete blocks, characterized by low thermal conductivity.

3. Medium gravel (10-20 mm).

Like a smaller counterpart, it is suitable for filling the space between the outer and interior walls. Another area of ​​application is the insulation of a flat roof or pitched roof with a slight slope. First, the rafters with the crate are lined with vapor barrier, then loose building materials are laid with a layer of 20-30 cm. In order to evenly distribute the granules along the length of the slope, transverse limiters are fixed between the rafters. Expanded clay is poured in portions, covered roll waterproofing, the joints of which are sealed with bituminous mastic. Roofing material is installed step by step.

During work, the weather must be dry. The roof structure requires additional reinforcement to support the weight of the insulation. flat roof amplify reinforced concrete slab. For a pitched roof, increase the cross section wooden elements, put additional stops, struts, bars.

4. Coarse gravel (20-40 mm).

The material of this fraction has a low bulk density, and therefore has found application as a heater attic floors, basements as well as foundations.

• Attic insulation. Due to the low weight of expanded clay of large fractions, the load on the floors is reduced, so the thickness of the insulation layer in the attic can be increased to 16 cm. First, the beams are protected with a vapor barrier (Izospan, aluminum foil, polyethylene film). Next, a layer of mashed clay is laid, coarse gravel is poured on top. To increase the strength of the surface, expanded clay is applied wet screed(if overlaps allow).
• Underfloor heating in the basement. On an earthen base, they equip a sand cushion, tamp it down. Lay polyethylene film with entry to the walls, a layer of expanded clay 10 cm thick is covered. From above it is reinforced with a steel mesh and a cement screed is laid. In the event that the floor is already covered with concrete, longitudinal and transverse logs are mounted on it. The resulting cells are covered with gravel, after which the frame is sheathed with wooden flooring.
• Thermal insulation of the finished foundation with expanded clay. This method is quite old, but still popular. The technology includes digging a trench along the perimeter of the foundation to a depth of freezing of the soil, with a width of at least 50 cm. Formwork is constructed from improvised materials (slate, used boards or bars). Its inner surface for waterproofing is lined with roofing material. After that, the space is filled with gravel of a fraction of 20-40 mm, covered with roofing material. Sand is poured on top and a concrete pavement is made.

average cost expanded clay

Price loose insulation depends on the size of the granules and the grade of strength, as well as on the form in which it is supplied - packaged in a bag or loose. Expanded clay in bulk of any fraction is cheaper than the same expanded clay in bags. You can buy material in Moscow at retail and from the manufacturer (directly or through official dealers). The absence of an intermediary, as well as buying in bulk, can significantly reduce construction costs. The average cost per cubic meter of insulation is shown in Table 2.

Often, buyers are interested in. It depends on the fraction of the material and the capacity of the container: it is 50-, 40- and 25-liter. Table 3 will help compare the cost of packaged insulation.