Expanded clay blocks: dimensions, pros and cons, properties, characteristics of GOST

It is very difficult to choose the material for building a house. It is necessary that the house was warm, reliable, durable. And yet, it is very desirable that the material for building walls be inexpensive. It is very difficult to fit all the parameters in one material. One of the options is blocks of expanded clay concrete. The material is far from perfect, but warm, light, inexpensive. Also, the size of the expanded clay concrete block can be different, which makes it easier to choose the optimal size.

What is expanded clay concrete blocks according to GOST

Expanded clay concrete is classified as lightweight concrete. As a filler, a porous material is used – expanded clay. These are rounded granules of baked clay. The composition of expanded clay concrete is cement, sand, expanded clay and water. When composing the mixture, more water is poured than in ordinary heavy concrete, since expanded clay is hygroscopic and absorbs liquid. In the production of blocks, the finished mixture is poured into molds, left until primary hardening, after which they are removed from the mold. In principle, the blocks are ready, but they cannot be used until they gain design strength.

There are two technologies for bringing products to normal strength at the factory – in an autoclave and by vibrocompression. In the first case, the blocks are sent to an autoclave, where the material is treated with steam under pressure. This makes expanded clay concrete blocks more durable. The second method is vibration with simultaneous pressure. When vibrating, all voids disappear, the solution becomes more homogeneous and fluid, enveloping each of the expanded clay granules. The result is high strength properties.

In artisanal production, the blocks are simply left to “ripen”. In theory, a minimum of 28 days is required until the concrete gains strength. But they can sell earlier so as not to take up space. At the same time, no one guarantees durability.

The fact is that for a normal set of strength cement, it is necessary to create a certain heat and moisture regime. Expanded clay concrete in this regard is more capricious than ordinary concrete. Due to the high absorbency of expanded clay, it can pick up too much water. And the liquid will not be enough for the concrete stone to gain strength, and not just dry out. Therefore, it is advisable to water the finished blocks and cover with a film for at least several days after production. It is impossible to keep them in the sun and the temperature should not be lower than + 20 ° C. Otherwise, the expanded clay blocks will not gain the required strength and will crumble even with small loads and impacts.

If we talk about the price, factory blocks are more expensive. But still. If you are building a house, and not a hozblok or a barn, you should not save and buy blocks of “garage” production. The quality is in question here.

Pros and cons of a house made of expanded clay blocks

Expanded clay blocks are many times larger than bricks. Even double. The size of a claydite-concrete block can only be compared with ceramic building blocks. But expanded clay blocks weigh less, have better thermal conductivity characteristics. And, importantly, much lower in cost. Durability and frost resistance are comparable with ceramic bricks.

Advantages of building from expanded clay concrete

The advantages of houses from expanded clay blocks include the following items:

• Small terms for the construction of walls.
• For masonry, a conventional cement-sand mortar is used.
• Claydite block masonry is well finished with any materials.
• The house is warm. But ceramic brick is more heat-intensive – by about 20-30%, so it accumulates more heat. If compared with silicate brick, expanded clay concrete block is more heat-intensive.
  

• The walls weigh a little, which reduces the cost of the foundation.
• No shrinkage.
• They do not contain lime, which means that the reinforcement does not corrode.
• Good soundproofing properties. For external walls 47 dB to 55 dB, for internal walls – from 49 dB to 54 dB. Depends on the density and thickness of the walls.

Blocks can have a tongue-and-groove system, which improves the thermal performance of the masonry. The material is natural, breathable, so there will be no problems with the regulation of humidity in the premises.

Disadvantages

The downsides of expanded clay houses are also quite serious. They must be taken into account when choosing a building material.

• Expanded clay block is not suitable for houses without heating in winter. Remember that expanded clay is hygroscopic and blocks of expanded clay concrete too. Frost resistance is not so great, so, firstly, insulation is required, and secondly, a finish that will protect the material from water ingress. It is also necessary to maintain a positive temperature. In general, the frost resistance of blocks that are processed in an autoclave or in a vibropress is about 100 cycles and this is more than enough. But private traders have no control over this parameter.
  

• Due to hygroscopicity, it is better not to use for walls in rooms with high humidity. That is, for baths it is better to look for another material. Just when building from expanded clay concrete blocks, they must be covered with waterproofing agents from the inside.
• The size of the expanded clay concrete block can “float”. This is inconvenient during construction.
• The manufacturing technology is simple, which allows you to open a “garage” production. Everything gets in the way “by eye”, no control over the characteristics and parameters, and then the blocks crumble, the walls crack.

The main disadvantage is high hygroscopicity. Clay granules can absorb a lot of water. Blocks that are stored outdoors for a long time weigh many times more than those that remain in dry rooms. Cement from moisture only becomes stronger. But you are unlikely to like wet walls. Therefore, it is important to qualitatively waterproof the foundation, to cut off all possible sources of “suction” of moisture. It is better to make a roof with large overhangs and build a high-quality catchment system.

The size of the expanded clay concrete block according to the standard

The fact is that there is no separate standard for expanded clay concrete blocks. This type of material is described by a group of standards that standardize lightweight concrete and products made from them. So the dimensions of wall blocks made of lightweight concrete are set by GOST 6133-99.

Limit deviations are also indicated. They are ±3 mm in length, ±4 mm in height, the wall thickness between the partitions can be 3 mm thicker (it cannot be thinner).

Popular size of expanded clay concrete block for walls and partitions

Most often, expanded clay concrete blocks measuring 390 * 190 * 188 mm are used for laying walls. It turns out very convenient, since for central Russia a wall thickness of 400 mm is considered optimal. That is, the laying is carried out “in one block.” Partitions usually require a smaller thickness – 90 mm. The length and height remain the same. That is, the size of the expanded clay concrete block for partitions is 390 * 90 * 188 mm. This does not mean that partitions cannot be made from longer or shorter partition boards. It is possible, but shorter ones – more seams, more solution consumption, and longer ones are harder, more difficult to work with.

If you want to have the best sound insulation parameters between rooms, partitions can also be folded from wall blocks. Either the standard width – 190 mm, or those that are thinner – 138 mm. But the costs are more.

Custom dimensions

There is an addition in the standard that, in agreement with the customer, the size of the expanded clay concrete block can be any. So you can find products of any format.

In addition, there are also technical conditions (TS), which are developed and registered by the enterprises themselves. If you are going to buy a large batch and the marking is not GOST 6133-99, but TU, it is better to familiarize yourself with this document so that there are no surprises.

Types of expanded clay blocks

The ends of the blocks can be grooved, flat or tongue/groove. For corner use, one edge may be smooth. In addition, the corners can be rounded or straight. On the supporting surfaces (where the mortar is placed), grooves can be formed for laying reinforcement. These grooves should be located at a distance of at least 20 mm from the corner.

Blocks come with and without voids. The voids can be through or not, arrange them evenly, perpendicular to the working surface. The maximum allowable weight of a lightweight concrete building block is 31 kg. The standard normalizes the thickness of the walls that enclose voids:

• outer walls – at least 20 mm;
• partition over blind voids – at least 10 mm;
• between two voids – 20 mm.

Voids are often made flat – in the form of cracks. The number of “lines” with voids determines the thermal conductivity of the material. The more lines of voids, the warmer (and “quieter”) the wall will be. Air is known to be a poor conductor of heat. In any case, worse than concrete. Therefore, splitting the block with voids gives a good result.

Grades by density and compressive strength

In terms of strength and thermal conductivity, expanded clay concrete blocks are divided into two categories: structural and structural and heat-insulating. In each of the groups there may be products of different densities. Density is the mass of one cubic meter of material in a dry state. The approximate value is after the letter D. For example, D600 – the mass of a cubic meter is 600 kg, D900 – 900 kg. And so on.

• Structural and thermal insulation:
  • D500 V0,75 to V1,75;
  • D600 V1,0 to V2,5;
  • D700 V1,5 to V3,5;
  • D800 V2,0 to V3,5;
  • D900 V2,5 to V7,5;
  • D1000, 1100 V3,5 to V10;
  • D1200, 1300, 1400 B5 to B10.
    

• Structural:
  • D1100 V 12,5;
  • D1200. 1300 V12,5 to V20;
  • D1400. 1500 V12,5 to V30.

In private housing construction, structural and heat-insulating blocks are usually used. For the construction of external walls of one-story houses, claydite-concrete blocks of the D700 or D800 brand are used; lower grades can be taken for internal unloaded partitions.

Standard midrange solutions

When building a house, it is best to order a project. Here everything will be taken into account for you, all nodes, materials will be prescribed, including the size of the expanded clay concrete block, its parameters and quantity. It remains only to buy everything on the list. But few do it. The project is a cost, and there is so little money. Therefore, they themselves try to roughly “estimate” without calculation. The position is also understandable, but it does not always lead to savings, because “standard solutions” are made with a margin of safety, and this is an overrun of material. But, in general, there are well-established options for the composition of the pie of the outer walls of expanded clay blocks for Russia.

• Only blocks without insulation. Wall thickness – 600 mm. The size of the expanded clay concrete block for the outer wall is 590*290*200 mm, the blocks are hollow, structural and heat-insulating. Place the blocks with voids up, fill them with heat-insulating material. It is most convenient with polystyrene foam chips. Finishing from the inside – plaster or drywall, outside – plaster.
  

• Expanded clay block 400 mm + insulation. For the outer wall, it is more convenient to use an expanded clay concrete block with a size of 390 * 190 * 200 mm. When laying in a dressing, we get 40 mm thick. The insulation layer must have a thermal conductivity coefficient of 0,05 W / m ° C. For mineral wool and polystyrene foam – this is about 50 mm.
• Multi-slot block of expanded clay concrete 500 mm thick without insulation. The dimensions of the expanded clay concrete block must be selected, since they often come in non-standard sizes. Can be found 500mm long and 250mm wide. It will be convenient to put the usual scheme with dressing. Or you can use other formats, but you will need to develop a masonry scheme.
  

• Expanded clay wall 290 mm thick + insulation. For this option, you can use a large-format block. According to GOST, its size is 288 * 288 * 138 mm, but it weighs a lot, it is more difficult to work. You can use a narrower one – 138 mm wide, which will almost give the required thickness. Insulation needs about 100 mm, interior decoration – plaster or drywall.

When choosing expanded clay blocks, we look at two indicators: the compressive strength class – for load-bearing walls, it must be at least B3,0 (with a margin). The second indicator is the coefficient of thermal conductivity. The lower it is, the better.