Strength of gas silicate blocks. Efficiency of gas silicate blocks in the construction of low-rise buildings

Gas silicate blocks are a building material of universal importance. It is an artificial porous stone. This structure is formed through a natural chemical reaction between aluminum and lime. During the reaction, these two components break down and form hydrogen.

In conditions of constant rise in energy prices, the need for building materials with high thermal characteristics. To reduce heat loss in modern projects Aerated concrete and gas silicate blocks are increasingly being used - materials of the class of thermal insulating cellular concrete. They are often confused due to their common properties and the same scope of application. Even specialists cannot always immediately tell a potential customer which material is in front of him - gas silicate or aerated concrete, which is better, what is the difference between them and whether there is any at all. Partly, the confusion is caused by the manufacturers themselves when they define aerated concrete as a type of gas silicate or vice versa.

What is the difference between aerated concrete and gas silicate? In particular, when producing aerated concrete, natural hardening of the block in the open air is allowed; for gas silicate, autoclave ovens are a prerequisite. In addition, for aerated concrete blocks the main binding component is cement, while for silicate analogues it is lime. The use of different components affects the color of the finished blocks.

If we talk about specific characteristics, you can notice the following differences:

Gas silicate blocks have a uniform distribution of hollow cells, which ensures high strength.
The weight of aerated concrete blocks is much greater, which requires a reinforced foundation during construction.
In terms of thermal insulation, gas silicate blocks outperform aerated concrete blocks.
Aerated concrete absorbs moisture better, which provides a greater number of freezing cycles.
Gas silicate blocks have a more consistent geometry, which makes it easier to finishing wall structures.

Externally finished products distinguished by color: gas silicate or autoclaved aerated concrete is almost white, grey colour typical for non-autoclaved aerated concrete.

The average values for each parameter are shown in the following table:

In terms of durability, the materials are identical and can last more than 50 years.

If you answer the question: “What is better, aerated concrete or gas silicate?”, gas silicate blocks have much more technical advantages. However, manufacturing technology forces an increase in the cost of finished products, so aerated concrete blocks are cheaper. Therefore, those who want to build a house from high-quality and modern material choose aerated silicate; those who want to save money on construction give preference to aerated concrete.

In this case, it is necessary to take into account the region of application: in areas with high air humidity, the service life of gas silicate blocks is noticeably reduced.

Composition and production technology of gas silicate blocks

The mixture for the production of gas silicate blocks has the following composition:

binder (Portland cement according to GOST 10178-76, calcium lime (according to GOST 9179-77);
silicate or siliceous filler (quartz sand with 85% quartz content, fly ash, etc.);
lime, with a content of magnesium and calcium oxides of more than 70%, and a slaking speed of up to 15 minutes;
technical water;
gas-forming additive (aluminum powder and others).

Gas silicate belongs to the class of lightweight cellular concrete. This material is a mixture consisting of 3 main components: cement, water and fillers. Lime and quartz sand in a ratio of 0.62:0.24 can act as fillers. We should also talk about the additives that give gas silicate its individual characteristics. Fine aluminum powder acts as an additive. All these components are thoroughly mixed, and under certain conditions, foaming of all these materials occurs. When aluminum powder reacts with lime, hydrogen is released. The huge number of hydrogen bubbles released makes up the porous structure, which is the main distinguishing feature of gas silicate. Its structure resembles a concrete “sponge”, since the entire volume of the block consists of cells (bubbles with a diameter of 1-3 mm).

Gas silicate blocks

The cellular structure makes up almost 85% of the volume of the entire block, so this material is very light in weight. First, a mixture of components is prepared in a special mixer for 5 minutes, which includes Portland cement, fine sand (quartz), water, lime and a gasifier (most often, this is an aluminum suspension). Hydrogen produced by the reaction between aluminum paste (powder) and lime forms pores. Bubbles ranging in size from 0.6 to 3 mm are evenly distributed throughout the material.

Basic fluids flow in metal containers or molds. chemical reactions. The mixture is subjected to vibration, which promotes swelling and setting. After hardening, all surface irregularities are removed with a steel string. The formation is divided into blocks, and then they are sent to an autoclave unit. The final calibration of the finished blocks is carried out by a milling machine.

Gas silicate blocks are manufactured only using the autoclave method. Aerated concrete blocks can be produced both by autoclave and non-autoclave methods (natural hardening of the mixture):

Autoclave processing. This stage significantly improves the technical characteristics of gas silicate. Here for 12 hours at high blood pressure steam treatment is carried out, the temperature of which is almost 200°C. This heating process makes the texture more uniform, thereby improving the strength properties (at least 28 kgf/m²). Its thermal conductivity is 0.09-0.18 W (m∙K), which makes it possible to erect walls in one row (400 cm) in almost any climatic conditions, but excluding the northern regions.
Non-autoclave technology. It consists in the natural hardening of the mixture: moistening and drying under natural conditions. In this case, it is quite possible to do it yourself, since there is no need for special equipment. The strength of blocks in such production does not exceed 12 kgf/m².

The first type is more expensive. This is due to significant manufacturing costs, as well as the best technical characteristics of gas silicate blocks produced by this method. They are much stronger, their thermal conductivity coefficient is lower. The pores inside such gas silicate are distributed extremely evenly, which affects the precise compliance of the material with the specified parameters.

Gas silicate blocks: characteristics

Density of gas silicate blocks

The brand and density of gas silicate blocks is indicated in the marking and determines the purpose of the block:

structural gas silicate blocks – D1000-1200, have a density from 1000 to 1200 kg/m3;
structural- thermal insulation blocks– D500-900, have a density of 500-900 kg/m3;
thermal insulation D300-D500, the density of their materials is 300-500 kg/m3.

Blocks of different densities are easy to distinguish from each other visually.

There are several classifications of gas silicate blocks with certain technical characteristics. Today, the following grades of this material are used in construction work. The best option for low-rise construction- gas silicate block d500 and gas silicate block d600.

The digital designation of the brands listed earlier shows the density of the material. In particular, the d500 gas silicate block has a density of 500 kg/m³.

Gas silicate block d600

Gas silicate block d600 is used in construction load-bearing walls Houses. It is also recommended for use in the construction of ventilated facades, which are well attached to blocks of such density. The d600 gas silicate block has a strength of 2.5-4.5 MPa and has a thermal conductivity of 0.14-0.15 W/(m°C)

Gas silicate block d500

Gas silicate block d500 is most popular for low-rise (up to 3 floors) construction. This variety is also used in monolithic construction. Its parameters are 2-3 MPa (strength) and 0.12-0.13 W/(m°C) (thermal conductivity).

When building a house higher than three floors, you should give preference to gas silicate with a marking higher than D600 and additionally insulate the walls. Based on the value of the thermal conductivity coefficient, we can conclude that the d500 gas silicate block is 15-17% warmer than the d600 gas silicate block.

Gas silicate block d400

This type is used for arranging insulation and for working with openings during the construction of multi-storey buildings using the monolithic method. The D400 brand is also popular in private construction. With high strength, it has great heat-insulating properties. These indicators are in the range of 1 MPa to 1.5 MPa (strength), 0.10-0.11 W/(m°C) (thermal conductivity).

Gas silicate block d300

Brand D350 can only be used as insulation. This is a rather rare brand on the domestic market, due to its fragility. Strength is in the range of 0.7-1.0 MPa. But it differs in thermal conductivity, which is 0.08-0.09 W/(m°C).

Thermal conductivity of gas silicate blocks

Depending on the proportions of the starting ingredients, you can obtain a product with different performance characteristics. The thermal conductivity coefficient of a gas silicate block depends on its density and is determined by the marking: D300, D400, D500, D600, D700.

The thermal conductivity of gas silicate depends on a number of factors:

Dimensions of the building block. The greater the thickness of the wall block, the higher its thermal insulation properties.
Ambient humidity. Material that has absorbed moisture reduces its ability to store heat.
Structure and number of pores. Blocks that have a large number of large air cells in their structure have increased thermal insulation properties.
Density of concrete partitions. Higher density building materials retain heat less well.

Thermal conductivity table for gas silicate blocks

Types of gas silicate blocks

Based on appearance, there are several configurations of the gas silicate block. The classification is based on the purpose of the block.

Smooth (straight) gas silicate block with hand grip

An absolutely smooth rectangular gas silicate block with recesses for gripping by hand. The gripper is easy to use because it allows you to easily move the blocks. The presence of grip handles increases glue consumption, since the technology of laying gas silicate blocks involves filling all voids during the work process.

Wall gas silicate blocks with flat edges

The usual rectangular shape reduces glue consumption, but creates difficulties in moving the block. In practice, when constructing load-bearing walls where larger blocks are used, preference is given to a block with a grip.

Gas silicate blocks for partitions

They are blocks with flat edges. Partition blocks are thinner and lighter in weight. It's convenient to work with them.

You can cut out any designs on straight blocks using a screwdriver. But such decor is more likely to be used in finishing a site with the remains of blocks from construction rather than in the construction itself, since it is advisable to protect gas silicate with external finishing material.

Tongue-and-groove gas silicate wall blocks

The formation of a tongue-and-groove connection system, in terms of production complexity, is classified as a high-tech block processing. Therefore, they are more expensive. However, it is justified because: it increases the speed of work, reduces glue consumption ( vertical connections do not require gluing), it becomes possible to eliminate cold bridges in places of vertical connection.

If the house is not exposed exterior decoration. It is better to apply a thin layer of glue to the joint from the front side of the masonry. This will provide additional insulation to the seam.

U-shaped gas silicate blocks

The purpose of U-shaped blocks is to install hidden construction elements (for lintels and monolithic belts). According to the technology, masonry of walls made of gas silicate blocks requires mandatory reinforcement of the first and every fourth of the subsequent rows. It is precisely in order to conveniently hide the reinforcement that the voids in the U-shaped blocks are intended. After laying the reinforcing metal, the space must be filled concrete mortar or glue. In this case, you should use more cheap material for filling.

What are the sizes of gas silicate blocks?

Of course, manufacturers produce gas silicate blocks of different sizes. However, most enterprises try to follow the established standards of GOST No. 31360 of 2007. Here are the dimensions of the finished products:

250*250*600.
250*400*600.
500*200*300.
600*100*300.
600*200*300.

It is important to understand that according to GOST, deviations in length and diagonal values are allowed, which classify finished products into the 1st or 2nd category.

Deviations in the dimensions of gas silicate blocks reduce installation time due to the absence of the need for grinding and adjustment.

Thickness of gas silicate blocks: 200, 250, 300, 350, 375, 400, 500 mm;
The thickness of the partition blocks is 100-150 mm;
Length of gas silicate blocks: 600, 625 mm;
Height of gas silicate blocks: 200, 250, 300 mm;
Weight of gas silicate blocks: 14-34 kg;
In 1 cubic meter from 13 to 33 pcs. (depending on thickness);
Consumption per 1 sq.m. walls is 6.7-7 pcs.

The exact parameters are shown in the tables below:

Dimensions of a U-shaped gas block The size of a gas silicate block for walls (LxWxH) from different manufacturers and the number of pieces on a pallet.

Number of blocks in a pallet

Weight of gas silicate block

The structural mass of the block varies depending on the density of the finished product. Judging by the markings, we can distinguish the following weight:

D400. Weight 5-21 kg.
D500/D600. Weight – 9-30 kg.
D700. Weight – 10-40 kg.

In addition to density, the fundamental factor in weight change is the overall size of the finished block.

Pros and cons of gas silicate blocks

Like any building material, gas silicate blocks have strengths and weaknesses. TO positive characteristics The following points can be mentioned:

Gas silicate concrete belongs to the category of non-combustible materials and can withstand exposure to an open flame for up to 5 hours, without changing its shape and properties.
Large dimensions ensure rapid construction of wall structures.
The blocks have a specific low weight, which greatly simplifies the work process.
Only used in production natural materials, therefore gas silicate blocks are environmentally friendly.
The porous structure provides high thermal insulation values for rooms.
The material is easy to process, which helps to build walls with complex geometries.

The disadvantages include the following:

They absorb moisture well, which reduces their service life.
Application for adhesion of special adhesive compositions.
Mandatory external finishing.

It is worth noting that gas silicate blocks require a solid foundation. In most cases, a reinforcing belt is required.

Another popular material that has captured a significant share in the building materials market is gas silicate. Pre-molded blocks have much in common with artificial stone, and have noticeable advantages. For this reason, gas silicate blocks have gained such wide popularity in the construction of houses.

Where are gas silicate blocks used?

The scope of application of gas silicate lies in the following areas:

thermal insulation of buildings,
construction of buildings and load-bearing walls,
insulation of heating networks.

In terms of their qualities, gas silicate blocks have much in common with foam concrete, but at the same time they surpass them in mechanical strength.

Depending on the density of the material. There are several areas of application:

The density of the blocks from 300 to 400 kg/m3 greatly limits their distribution, and such blocks are more often used as insulation for walls. Their low density does not allow them to be used as a basis for walls, since they will collapse under significant mechanical load. But low density plays a role as insulation, since the more tightly the molecules adhere to each other, the higher the thermal conductivity becomes and it is easier for the cold to penetrate into the room. Therefore, blocks with low thermal conductivity provide more effective thermal insulation,
blocks with a density of 400 kg/m3 have found their use in the construction of one-story buildings and work premises. Due to the increased strength of the blocks and their lower weight, the cost of arranging the foundation is significantly reduced,
blocks with a density of 500 kg/m3 are more often used in the construction of buildings several floors high. As a rule, the height of the building should not exceed three floors. Such blocks, directly depending on the climate, either are not insulated at all or require traditional methods insulation.
most the best option for the construction of high-rise buildings is the use of blocks with a density of 700 kg/m3. This indicator allows the construction of high-rise residential and industrial buildings. Due to their lower cost, walls constructed from gas silicate blocks are replacing traditional brick and reinforced concrete walls.

The higher the density, the worse the thermal insulation performance, so such buildings will require additional insulation. More often, the external one is provided with the help of foam or polystyrene foam boards. This material has a low price and at the same time provides good thermal insulation premises at any time of the year.

Recently, the position of gas silicate as one of the most popular materials in construction has strengthened significantly.

The relatively light weight of the finished blocks will significantly speed up the construction of the building. For example, gas silicate blocks, the sizes of which have standard values, according to some estimates, reduce the complexity of installation by up to 10 times compared to brick.

A standard block with a density of 500 kg/m3 and a weight of 20 kg can replace 30 bricks, the total mass of which will be 120 kg. Thus, installation of blocks on low-rise buildings will not require special equipment and will reduce labor costs and time spent on building construction. According to some estimates, time savings reach a 4-fold reduction in time costs.

Material characteristics

It makes sense to list the main technical characteristics of gas silicate blocks:

The specific heat capacity of blocks produced by autoclave is 1 kJ/kg*°C. For example, a similar indicator for reinforced concrete is at the level of 0.84,
the density of reinforced concrete is 5 times higher, but the thermal conductivity coefficient of gas silicate is only 0.14 W/m*°C, which is approximately the same as that of pine or spruce wood. Reinforced concrete has a significantly higher coefficient, 2.04,
the sound absorption characteristics of the material are at the coefficient level of 0.2, at a sound frequency of 1000 Hz,
The cycle of frost resistance for gas silicate blocks with a material density below 400 kg/m3 is not standardized; for blocks with a density up to 600 kg/m3 it is up to 35 cycles. Blocks with a density above 600 kg/m3 are able to withstand 50 freezing and thawing cycles, which is equal to 50 climatic years.

If we compare gas silicate blocks with brick, the indicators are not in favor of the latter. Thus, the required wall thickness to ensure sufficient thermal conductivity for blocks is up to 500 mm, while for bricks a similar masonry thickness of 2000 mm will be required. The consumption of mortar for laying the material will be 0.12 m3 for brick and 0.008 m3 for gas silicate blocks per 1 m2 of masonry.

Weight of one square meter the walls will be up to 250 kg for gas silicate material, and up to two tons of brick. In this case, an appropriate foundation thickness will be required for the load-bearing walls of the building under construction. Brickwork will require a foundation thickness of at least 2 meters, while for gas silicate blocks a thickness of only 500 mm is sufficient. The labor intensity of laying blocks is much lower, which will reduce labor costs.

Among other things, gas silicate blocks are much more environmentally friendly. The coefficient of this material is two points, bringing it closer to natural wood. At the same time, the environmental friendliness of bricks is at a level of 8 to 10 units.

Advantages and disadvantages of gas silicate blocks

Gas silicate blocks, the price of which will significantly reduce the cost of building a house, have the following number of undeniable advantages:

Light weight of finished blocks. A gas silicate block weighs 5 times less compared to a similar concrete block. This will significantly reduce delivery and installation costs.
High mechanical compressive strength. Gas silicate with the D500 index, indicating that its density is 500 kg/m3, demonstrates an indicator of up to 40 kg/cm3.

The thermal resistance indicator is 8 times higher than that of heavy concrete. Thanks to its porous structure, good thermal insulation performance is ensured.
Gas silicate blocks have heat-storing properties. They are able to release accumulated heat indoors, which will reduce heating costs.
Thanks to the porous structure, the degree of sound insulation is 10 times higher than that of brick.
The material does not contain any toxins and has good environmental performance.
Gas silicate is distinguished by its non-flammability and does not propagate combustion. HE endures direct impact flame for at least three hours, due to which the situation with the spread of fire is almost completely eliminated.
The vapor permeability of the blocks is significantly higher than that of competitors. It is believed that the material is able to “breathe” well, while creating a comfortable indoor microclimate.

However, gas silicate blocks are currently not capable of delivering a crushing blow to all competitors. This material also has significant disadvantages:

Gas silicate has low mechanical strength. When a dowel is screwed into it, it begins to crumble and crumble, and is not able to provide effective retention. Roughly speaking, it is still possible to hang a clock or a picture on a wall made of gas silicate blocks. But the shelf may already collapse, since the fasteners can simply slide out of the wall.
The blocks do not have good frost resistance. Despite the manufacturer’s declared cycle of 50 years for brands with increased strength, there is no reliable information about the durability of blocks of the D300 brands.
The main disadvantage of gas silicate is its high moisture absorption. It penetrates the structure, gradually destroying it and the material loses its strength.
From the above disadvantage comes the following: the accumulation and absorption of moisture leads to the appearance of fungus. In this case, the porous structure serves good condition for its distribution.
The material can shrink significantly, as a result of which cracks often appear in the blocks. Moreover, after just two years, cracks can appear on 20% of the stacked blocks.
It is not recommended to apply cement-sand plasters. They can simply fall off the wall. The gypsum plaster recommended by many sellers is also not an effective remedy. When applied to a wall made of gas silicate blocks, it is not able to hide the seams between the blocks, and when cold weather sets in, noticeable cracks appear on it. This occurs due to temperature differences and changes in the tightness of the material.
Due to its high moisture absorption, the plaster will require at least two coats. Moreover, due to strong shrinkage, the plaster will become covered with cracks. They will not affect the tightness, but will greatly disturb the aesthetic component. Gypsum mixture holds well on gas silicate blocks, and despite the appearance of cracks, it does not come off.

How gas silicate blocks are produced

It is more advisable to buy gas silicate blocks from those dealers who represent products of well-known manufacturers. Modern quality equipment on factory lines allows for proper control over the quality of produced gas silicate blocks, thanks to which the buyer is confident in the durability of the purchased products.

The production process itself is divided into several stages, and, characteristically, each of them is fully automated. This eliminates the intervention of the human factor, on which the quality of the products often depends. Especially on Fridays and Mondays. Anyone who has worked in production will understand.

Lime, sand and gypsum are crushed, which forms the basis for the production of blocks. By adding water, the sand is ground to a liquid mixture. It is sent to a mixer, into which cement, gypsum and lime are added. Next, the components are mixed, and during this process an aluminum suspension is added to them.

After all the components have been thoroughly mixed together, the mixture is poured into molds, which are moved to the maturation zone. When exposed to a temperature of 40°C for four hours, swelling of the material occurs. In this case, hydrogen is actively released. Thanks to this, the final mass acquires the necessary porous structure.

Using a turning grip and a cutting machine, the blocks are cut into required sizes. At the same time, automation controls accurate and defect-free cutting of products.

Following this, the blocks are sent to an autoclave to gain their final strength. This process takes place in a chamber exposed to a temperature of 180°C for 12 hours. In this case, the steam pressure on the gas silicate should be at least 12 atmospheres. Thanks to this mode, the finished blocks gain the optimal value of final strength.

Thanks to the crane-divider and equipment for final quality control, the blocks are laid for their subsequent natural cooling. After that, possible contamination is removed from the blocks on an automatic line and the blocks are packaged and labeled.

What is noteworthy is that the production process is waste-free, since at the time of cutting, still at the hardening stage, the waste of the raw mass is sent for recycling, adding material to other blocks.

Pallets with packaged gas silicate blocks receive their technical certificate with detailed physical properties and technical characteristics of the product, so that the buyer can ensure compliance with the declared characteristics.

Further work is up to dealers and marketers, on whom the success of product sales will depend.

Gas silicate products are used in the construction industry. The block production process is carried out under high pressure, as well as under natural conditions. Thanks to their porous structure, they retain heat well. The D500 gas silicate block is popular, the characteristics of which make it possible to use of this material during the construction of houses. As a result of the use of blocks of increased sizes, the building construction cycle is shortened. Let's look at the main technical characteristics that need to be taken into account when choosing a material.

What are gas silicate blocks?

Gas silicate block products are a modern building material made from the following raw materials:

Portland cement, which is a binding ingredient;
quartz sand introduced into the composition as a filler;
lime involved in the gas formation reaction;
powdered aluminum added to foam the mass.

When mixing the components, the working mixture increases in volume as a result of an actively occurring chemical reaction.

Gas silicate blocks are widely used in the construction industry

Molding containers filled with silicate mixture harden under various conditions:

naturally at ambient temperature. The hardening process lasts 15-30 days. The resulting products are characterized by a reduced cost, but have insufficiently high strength;
in autoclaves, where products are heated at high pressure. Steaming improves strength characteristics and specific gravity gas silicate products.

Density and strength indicators change depending on the manufacturing method. The specified characteristics of the materials determine the area of use.

Blocks are divided into the following types:

products for structural purposes. They are marked D700 and are in demand for the construction of permanent walls, the height of which is no more than three floors;
thermal insulation and structural products. Brand D500 corresponds to these blocks. They are used for construction internal partitions and construction of load-bearing walls of small buildings;
thermal insulation products. They are characterized by increased porosity and density reduced to D400. This allows the use of gas silicate material for reliable thermal insulation of walls.

The digital index in the block markings corresponds to the mass of one cubic meter of gas silicate, indicated in kilograms. As the density of the material increases, its thermal insulation properties. Products of the D700 brand are gradually replacing traditional brick, and products with a density of D400 are not inferior in thermal insulation properties to modern insulation materials.

Gas silicate blocks are superior in mechanical strength to foam concrete

Gas silicate blocks - pros and cons of the material

Products made from gas silicate have a complex of serious advantages. The main advantages of gas silicate blocks:

reduced mass with increased volumes. The density of gas silicate material is 3 times less compared to brick and about 5 times lower when compared to concrete;
increased safety margin to withstand compressive loads. The strength indicator for a gas silicate block marked D500 is 0.04 t/cm³;
increased thermal insulation properties. The material successfully competes with annealed brick, the thermal conductivity of which is three times higher than that of gas silicate;
correct shape of blocks. Thanks to reduced tolerances on overall dimensions and clear geometry, the blocks are laid on a thin layer of adhesive mortar;
increased dimensions. The use of large-sized silicate blocks with low weight for the construction of building walls allows to reduce the duration of construction;
good workability. If necessary, it is easy to give the gas silicate block a given shape or cut the block material into separate pieces;
acceptable price. Using block gas silicate for the construction of a cottage, private house or cottage, it is easy to significantly reduce the estimated cost of construction activities;
fire safety. The blocks do not ignite when heated or exposed to open fire. They belong to low-flammable building materials included in the G1 flammability group;
high sound insulation properties. They are provided due to the porous structure. The ability of blocks to absorb external noise is ten times greater than that of ceramic bricks;
environmental friendliness. During production gas silicate mixture no toxic ingredients are used and no components harmful to health are released during operation;
vapor permeability. Through the air cells located inside the gas silicate mass, air exchange occurs, creating a favorable microclimate inside the building;
frost resistance. Gas silicate blocks preserve the structure of the massif and performance characteristics, withstanding more than two hundred cycles of prolonged freezing followed by thawing;
heat storage properties. Gas silicate blocks are an energy-saving material that can accumulate thermal energy and gradually release it to increase the room temperature.

Application area depends on material density

Despite many advantages, gas silicate blocks have weaknesses. The main disadvantages of the material:

increased hygroscopicity. Porous gas silicate blocks gradually absorb moisture through an unprotected surface, which destroys the structure and reduces strength;
the need to use special fasteners for fixing hanging furniture and equipment. Standard fasteners do not provide reliable fixation due to the cellular structure of the blocks;
insufficiently high mechanical strength. Block material crumbles under load, so it requires careful handling during transportation and laying;
the formation of mold and the development of fungal colonies inside and on the surface of the blocks. Due to increased moisture absorption, favorable conditions are created for the growth of microorganisms;
increased shrinkage amount. In real operating conditions, under the influence of loads, the blocks gradually shrink, which after some time causes the formation of cracks;
reduced adhesion with sand-cement plasters. It is necessary to use special finishing compounds for plastering gas silicate.

Despite the existing disadvantages, gas silicate blocks are actively used for the construction of capital walls in the field of low-rise construction, as well as for the construction of thermally insulated walls of multi-story buildings and for thermal insulation various designs. Professional builders and private developers prefer gas silicate blocks due to the significant advantages of the material.

Gas silicate block D500 - characteristics of the building material

The structural and thermal insulation block of the D500 brand is used for various purposes:

construction of boxes of low-rise buildings;
arrangement of interior partitions;
strengthening door and window openings.

Gas silicate blocks provide good thermal insulation of the room

Having decided to purchase block silicate marked D500, you should familiarize yourself in detail with operational properties popular building material. Let's look at the main characteristics.

Strength properties

The compressive strength class of the material varies depending on the method of manufacturing the blocks:

gas silicate grade D500, produced by the autoclave method, is characterized by a strength index of B2.5-B3;
The compressive strength class for similar blocks produced using non-autoclave technology is B1.5.

The strength of D500 blocks reaches 4 MPa, which is not high enough. To prevent cracking of the gas silicate material, the masonry is reinforced with mesh or reinforcement. The relatively low safety margin allows the use of block building materials in low-rise construction. When constructing multi-storey buildings, gas silicate blocks are used together with bricks for thermal insulation of the walls being built.

Specific gravity

The density of gas silicate blocks is an important performance indicator that characterizes the porosity of the block mass. Density is indicated by markings in the form of the Latin letter D and a digital index. The number in the marking characterizes the mass of one cubic meter of gas silicate. Thus, one cubic meter of gas silicate marked D500 weighs 500 kg. Knowing the marking of products by density, the size of the blocks and their number, it is easy to calculate the load on the foundation.

Gas silicate blocks - environmentally friendly material

Thermal conductivity characteristics

The thermal conductivity of gas silicate blocks is the ability to transfer thermal energy. The value of the indicator characterizes the thermal conductivity coefficient of gas silicate blocks.

The value of the coefficient varies depending on the moisture concentration in the material:

the thermal conductivity coefficient of dry gas silicate material grade D500 is 0.12 W/m⁰С;
with an increase in humidity to 5%, the thermal conductivity of D500 blocks increases to 0.47 W/m⁰С.

In buildings built from gas silicate blocks, due to the reduced thermal conductivity of the material, a favorable microclimate is maintained year-round.

Frost resistance

The ability of gas silicate blocks to withstand temperature changes associated with deep freezing and thawing is characterized by markings. The frost resistance index for D500 products is F50. Compared to other types composite concrete this is a pretty good indicator. Frost resistance is affected by the moisture concentration in the blocks. As the moisture content of the material decreases, the frost resistance of the blocks increases.

Lifetime

Gas silicate has a long period of use. The structure of the gas silicate massif has maintained its integrity for more than half a century. Manufacturers of blocks guarantee a service life of products for 60-80 years, provided that the blocks are protected from moisture absorption. Plastering the material allows you to extend its service life.

Fire safety

Gas silicate blocks are a fireproof building material with fire resistance up to 400 ⁰C. Tests confirm that covered with plaster gas silicate wall can withstand exposure to open fire for three to four hours. The blocks are suitable for the construction of fire-resistant walls, partitions and chimneys.

Conclusion

Block gas silicate is a proven material for the construction of low-rise buildings. The characteristics of the blocks make it possible to ensure the stability of the buildings being erected and maintain a comfortable microclimate inside the buildings.

Practicality

Strength

Environmental friendliness

Price

final grade

Operational parameters of gas silicate blocks

Life time– the nominal value is up to 100 years in normal climates and up to 50 in humid climates. At proper care, the presence of plaster and gutters, the standard terms are quite consistent with the real ones.

Material consumption- depends on climatic conditions. Recommended wall thickness ranges from 400 mm to temperate climate up to 800 mm in the northern regions.

Strength class for compression– characterizes guaranteed pressure that will not lead to destruction. Blocks with a density of 600 kg/m3 have a strength class from B1.5 to B3.5 (2-3 times less than that of brick). Thermal insulation structures with a material density of 300 kg/m3 have a much lower strength class - B0.75-B1.5.

Note that a decrease in the strength class of gas silicate blocks does not mean a real decrease in the strength of the structure. For a porous material, the mass of the entire masonry (as a result, the pressure exerted) is 2.5-3 times lower than that of a brick structure.

Frost resistance– numerically shows the number of thawing cycles that a specific type of material can withstand without losing more than 15% of its strength. In this case, the designation that looks like F50 means that the guaranteed number of cycles is 50.

Technical tests are carried out under harsh conditions that greatly exceed environmental changes. The block is immersed in water until it is completely saturated, and then placed in freezer. In reality, such strict conditions do not exist, so the main function of the parameter is to guide the buyer to a more acceptable option for a specific climate zone.

Coefficient of thermal conductivity– depends on the density and humidity of the material. Thus, the lightest gas silicate block (300 kg/m3) has a thermal conductivity coefficient of about 0.08 W/(m??C), and the heavy one (600 kg/m3) is almost 2 times higher. An increase in material humidity by 1% increases thermal conductivity by 4-5%.

The table shows the differences different brands blocks for thermal conductivity, shrinkage, frost resistance and vapor permeability:

Gas silicate blocks are a good choice when small houses, especially in cold climates. For country houses or walls in an apartment, porous material will also be a convenient and inexpensive solution. When purchasing, you should carefully check the contents of the pallets - unscrupulous sellers may sell blocks with a large percentage of defects.

Gas silicate blocks are in great demand in residential and industrial construction. This building material is superior to concrete, brick, natural wood, etc. in many respects. It is made from environmentally friendly raw materials and is lightweight, fire-resistant, easy to use and transport. The use of this lightweight material makes it possible to reduce the cost of arranging a heavy reinforced foundation and thereby reduce the cost of building construction.

What are gas silicate blocks

Gas silicate block is a lightweight and durable wall material, which is made from cellular concrete. The products have a porous internal structure, which has a positive effect on their heat and sound insulation properties. Such building material can be used in various fields construction industry - for the construction of country houses and country houses, car garages, utility buildings, warehouse complexes, etc.

How gas silicate blocks are produced

There are two main technologies for the production of gas silicate building blocks.

Non-autoclave. With this production method, the working mixture hardens under natural conditions. Non-autoclaved gas silicate blocks have a lower cost, but have some important differences from autoclaved ones. Firstly, they are less durable. Secondly, when they dry, shrinkage occurs almost 5 times more intense than in the case of autoclaved products.
Autoclave. Autoclave production of gas silicate requires more energy and material resources, which increases the final cost of the products. Manufacturing is carried out at a certain pressure (0.8-1.2 MPa) and temperature (up to 200 degrees Celsius). The finished products are more durable and resistant to shrinkage.

Types of blocks

Depending on the density, composition and functional purpose, gas silicate blocks are divided into three main categories.

Structural. They have high strength characteristics. The density of the products is at least 700 kg/m3. Used in construction high-rise buildings(up to three floors). Capable of withstanding large mechanical loads. Thermal conductivity is 0.18-0.2 W/(m °C).
Structural and thermal insulation. Blocks with a density of 500-700 kg/m 3 are used in the construction of load-bearing walls in low-rise buildings. They are distinguished by a balanced ratio of strength and thermal insulation characteristics[(0.12-0.18 W/(m °C)].
Thermal insulation. They are distinguished by increased thermal insulation properties [(0.08-0.1 W/(m ° C)]. Due to their low density (less than 400 kg/m 3), they are not suitable for creating load-bearing walls, therefore they are used exclusively for insulation.

Dimensions and weight

Wall blocks from gas silicate have standard sizes 600 x 200 x 300 mm. The overall dimensions of the semi-blocks are 600 x 100 x 300 mm. Depending on the manufacturing company, product sizes may vary slightly: 500 x 200 x 300, 588 x 300 x 288 mm, etc.

The mass of one block depends on its density:

structural blocks weigh 20-40 kg, half-blocks - 10-16 kg;
structural and thermal insulation blocks and semi-blocks - 17-30 kg and 9-13 kg, respectively;
heat-insulating blocks weigh 14-21 kg, half-blocks - 5-10 kg.

Composition of gas silicate blocks

Gas silicate is an environmentally friendly building material that is made from non-toxic raw materials of natural origin. The blocks contain cement, sand, lime and water. Aluminum chips are used as a foaming agent, which helps to increase the void ratio of the blocks. Also in the production of the material, a surfactant is used - sulfonol C.

Material characteristics

Building blocks made of gas silicate have the following characteristics.

Heat capacity. Products manufactured using autoclave technology have a thermal conductivity coefficient of 1 kJ/(kg °C).
Thermal conductivity. Structural and thermal insulating gas silicate has an average thermal conductivity of about 0.14 W/(m °C), while for reinforced concrete this parameter reaches 2.04.
Sound absorption. Gas silicate blocks significantly reduce the amplitude of external noise; the sound absorption index for this material is 0.2.
Frost resistance. Material with a density of 600 kg/m 3 can withstand up to 35 freezing and thawing cycles (which corresponds to the F35 index). Products with a higher density are assigned frost resistance class F50.

Advantages and disadvantages of gas silicate blocks

The main advantages of gas silicate are the following.

Ease. Gas silicate blocks weigh almost 5 times less than concrete products of the same size. It makes it easier construction works and allows you to reduce the cost of transporting building materials.
Effective heat and sound insulation. Due to the presence of internal micropores, high heat and noise insulation characteristics of gas silicate are achieved. This allows you to create a comfortable indoor microclimate.
Environmental friendliness. The building materials do not contain dangerous toxins and carcinogens that can cause harm environment and human health.
Fire resistance. Gas silicate is made from non-flammable raw materials, therefore it does not collapse under intense heating and does not contribute to the spread of flame in a fire.

How critical are the shortcomings?

Like any other building material, gas silicate has some disadvantages.

Low safety factor. Material with low density (300-400 kg/m3) has relatively low strength characteristics. Therefore, during construction it is imperative to carry out work on reinforcing the walls.
Smooth surfaces. The front parts of gas silicate blocks have a smooth surface with a low roughness coefficient. Because of this, adhesion with finishing materials, which complicates the process of finishing walls with plaster and other coatings.
Low moisture resistance. Due to the increased porosity, the material is sensitive to high humidity. Water and water vapor penetrate the internal micropores and, when frozen, increase in volume, destroying the blocks from the inside. Therefore, walls made of gas silicate require additional waterproofing.

Where are gas silicate blocks used?

Gas silicate blocks are used in residential and industrial construction. This material is used not only for construction load-bearing elements buildings, but also to increase thermal insulation, as well as to protect utility networks(in particular, heating ones).

The scope of application of gas silicate is determined by its characteristics, primarily density.

Products whose density is 300-400 kg/m 3 have a low safety margin, so they are used primarily for wall insulation.
Gas silicate with a density of 400 kg/m 3 is suitable for the construction one-story houses, garages, service and outbuildings. Due to its higher strength, the material can withstand significant loads.
Blocks with a density of 500 kg/m 3 are optimal in terms of strength and thermal insulation properties. They are often used to build cottages, country houses and other buildings up to 3 floors high.

The most durable are gas silicate blocks with a density of 700 kg/m 3. They are used for the construction of high-rise residential and industrial buildings. But due to the increased density, the porosity coefficient of the material decreases and, consequently, its thermal insulation properties. Therefore, walls built from such blocks require additional insulation.

The process of building and testing blocks.