Gas silicate blocks: disadvantages, advantages, characteristics

As practice shows, the construction of partitions and load-bearing walls takes almost 50% of the building materials needed to build the entire building. To reduce construction costs, consumers choose materials with similar performance characteristics, but at a lower cost. Among these materials are gas silicate blocks.

Knowing the properties of these products, their disadvantages and advantages will help to avoid errors that can affect the quality of a residential building and its durability.

Product Features

Low cost is the main advantage of gas silicate blocks, a square meter of them costs half the price than when using brick. The ability to produce products of complex shape is also very important, due to which the speed of building construction is significantly increased.

Gas silicate is a subspecies of cellular concrete. For its manufacture, an industrial autoclave is used, but it is possible to manufacture products at home. The following components are used as raw materials:

1. Portland cement.
2. Aluminum powder.
3. Siliceous aggregate.
4. Water.

The catalyst is quicklime, it reacts with aluminum and foams the mixture. As a result of this, hydrogen is released, forming tiny bubbles. In the production in an autoclave, after mixing, the mass is steamed and poured into a mold. After hardening, the plate is cut into elements of the desired size and shape.

Types of block designs

Products by density are divided into several subspecies:

1. Silica blocks with compressive strength D700. This material is the best option for the construction of multi-storey buildings, both industrial and residential. In low-rise construction it is used for the construction of load-bearing walls and partitions.
2. Products with strength indicators D500-D600. They are used in the construction of low-rise (maximum - three floors) structures. In areas with a warm climate, such buildings do not need insulation.
3. Thermal insulation products. The strength of the plates of this brand is D400. They are used for warming constructed or newly constructed facilities or for the construction of non-bearing partitions.
4. Blocks with a density below 400 kg / cu. m. The distribution of such structures is very limited. They can be used only as a heat-insulating material, for example, for heating systems. Due to the low density, the plates do not allow heat and cold at all, therefore they represent the most effective example of thermal insulation.

Note: regardless of the strength of the products they are used in the construction of multi-story buildings and industrial facilities only as a heater.

Material characteristics

The main technical characteristics are the following indicators:

1. Specific heat. The indicator is measured in kJ / kg * ° C. In gas silicate, it is equal to unity, while in reinforced concrete structures it corresponds to 0.84.
2. Thermal conductivity. The density of gas silicate (0.14 W / m * ° C) is similar to the density of spruce or pine wood, therefore it conducts heat just as poorly as materials from wood of the named species. For comparison, the density of reinforced concrete is 2.04, so in buildings made of this material it is hot in summer and cold in winter.
3. Sound absorption. Due to the presence of voids inside the blocks, the sound is poorly transmitted.
4. Cyclic frost resistance. Depends on the density of the material - the higher it is, the more freezing / thawing cycles the building can withstand. So, blocks with a density index above 600 can withstand up to 50 cycles, that is, years. If they are protected from the effects of winds and moisture, the duration of operation can be increased by 50%.

Product Weight

To build a house, it is very important to know the weight of the products in order to choose a reliable foundation. Although gas silicate weighs less than brick and stone, it also has its own weight. This parameter depends primarily on the brand of products. For example, a cube of gas-silicate blocks of the D300 brand weighs 300 kg, the D500 brand - half a ton, the D800 brand - 0.8 tons. The weight of an individual block depends not only on the brand of aerated concrete, but also on its size.

To calculate the mass of one block, the weight of a cubic meter is divided by the number of elements in it. So, for example, a cube of block structures measuring 25x40x60 cm weighs 500 kg and consists of 16 elements. It is easy to calculate that 500: 16 = 31.25 kg. Products of similar dimensions of brand 400 weigh 25 kg, brand 600 - 37.5 kg.

How to make calculations?

It is not difficult to find out how many gas silicate blocks are needed to build a building of certain sizes - the dimensions of the products are adjusted to the standards of building materials, in particular brick. In this case, the thickness of the solution layer was also taken into account. To find out the exact number of blocks needed for operation, you should calculate the volume of one block, specify the number of elements that are needed for laying 1 sq. m and then calculate the total.

In the prepared draft, the dimensions of all partitions and walls are necessarily indicated. Multiplying their total length by the desired height, they get the desired result. Just do not forget that from the figure you need to take away the area of ​​windows and doors. Next, 10-15% is added to the result. This is a calculation for battle, chips, other defects that may appear during transportation and installation.

Material advantages

The advantages are the following characteristics of the blocks:

1. Light weight, so it will not be necessary to build a reinforced foundation, as for brick walls - you can build a columnar structure or a shallow foundation of a strip type.
2. Poor thermal conductivity. A house made of gas-silicate blocks holds heat 5 times better than a brick building of the same type.
3. The ability to erect structures of complex and unusual geometric shapes. Moreover, this can be done without much effort, while when working with bricks it will be necessary to spend a lot of time on giving the individual elements the desired shape.
4. High vapor permeability. With high humidity, gas silicate absorbs moisture, and when the air becomes too dry, gives it away. Thanks to this, a microclimate is created in the house, which is cozy and comfortable for a person.
5. Fire safety. Gas silicate belongs to the low-combustible materials of group G1.
6. The ability to engage in construction work at any time. Today, there is glue for gas silicate blocks on sale, with which you can work even in winter.

An important detail: there is one caveat - it is unacceptable to work in rain or snow, since moisture, getting into the pores, collects in them and begins to destroy the structure from the inside.

Disadvantages. What are the disadvantages of gas silicate products?

Although today projects from gas silicate blocks are a profitable, justified and modern solution, this material does not occupy a leading place in demand. This is due to its shortcomings:

1. High water-absorbing properties. Having gained moisture, structures lose their strength, so buildings must be protected from water or snow. Moreover, in a humid environment, a fungus quickly appears, which will be impossible to remove from the porous structure of the material.
2. Shrinkage in the first year after laying the walls. Because of this, it is necessary to postpone the finishing work.
3. Low mechanical strength. If the brick walls were able to withstand even the sieges of the troops in the Middle Ages, gas silicate blocks can easily crumble during mild impacts. Because of this, when arranging a house, nails under all the shelves must be fixed to the wall with glue so that they do not slip out.
4. Inadmissibility of the use of sand-cement plaster. Instead, a gypsum mixture is used.

Construction sizes

The standard size of the manufactured structures is 60x30x20 cm. Blocks of such dimensions are considered optimal for the construction of low-rise buildings. But these sizes specified in GOST 21520-89 are not mandatory, so manufacturers can produce products of other sizes that exceed those specified in length and height.

In addition, products are available in different types, the sizes of which differ from the standard. It:

1. Direct blocks. Dimensions 20x25x62.5 cm, 30x25x62.5 cm or 20x30x62.5 cm.
2. Products equipped with a groove-comb system and gripping handles. Dimensions 37.5 / 40x25x62.5 cm.
3. Tongue-and-groove designs. Sizes 30 / 37.5 / 40x25x62.5 cm.
4. Products for partitions. Dimensions 15 / 10x25x62.5 cm.
5. Designs for U-shaped jumpers. Dimensions 20/30 / 40x25x50 cm.

Cost

Like the mass of products, their cost depends on the brand.

Based on the above parameters, it is possible to calculate the price of gas silicate blocks per unit. For example, if there are 33 pieces in a cubic meter with a total value of 3,150 rubles, then one element will cost about 97 rubles.