Expanded clay: thermal conductivity, properties and technical characteristics

Ceramsite, whose thermal conductivity is largely determined by raw materials, also has a low specific gravity, as well as high strength. It is these qualities that determine the wide scope of use of this material in construction.

Thermal conductivity

For those materials that are designed to perform a protective function, the characteristic of thermal conductivity is particularly important. Claydite acts as a natural material, which is why this parameter depends on many qualities.

Among the first should be allocated the size of the granules. The more impressive the faction will be, the more insulation will be needed. The porosity and humidity of expanded clay will also affect the thermal conductivity. The average coefficient of thermal conductivity is difficult to determine, because there are many deviations. Ceramsite, whose thermal conductivity in the reference literature is indicated in the range of 0.07 W / m, has a high hygroscopicity. But it would be fair to indicate the maximum value of thermal conductivity - it is reached at the level of 0.16.

It is important to choose the right material. If the coefficient of thermal conductivity is higher, the amount of heat that passes through the insulator layer will be impressive. This indicates that the heat protection is reduced. Pay attention to the porosity of expanded clay, which affects the density and thermal conductivity. The higher the first parameter, the lower the last two.

What affects the main characteristic of expanded clay

As studies show, the thermal conductivity of claydite is determined by the absence of quartz, but only at a particular stage of production. Technologists must take into account the specifics of production. After all, silica contained in expanded clay increases the thermal conductivity, while other oxides lower this value.

This does not apply to gases formed when heated to swelling temperature. It has been established that if pores contain H ₂ + CO in a volume larger than 55%, then the thermal conductivity of expanded clay is two times higher than if the filling is carried out by air. Thermal conductivity can also be affected by micropores. The less they are, the lower the thermal conductivity, but the porosity on this characteristic does not affect.

Basic properties

Ceramsite, the thermal conductivity of which was mentioned above, has certain properties, among them:

• High strength;
• Frost resistance;
• durability;
• Refractoriness;
• Optimal ratio of quality and cost.

Considering this material, it is impossible not to distinguish good thermal insulation qualities, acid resistance and chemical inertness. Claydite is considered a natural material and is an environmentally friendly heat insulator.

Key Features

Ceramsite, whose thermal conductivity you need to know before purchasing this material, has excellent qualities. It is made of slate and clay and is suitable for environmentally friendly and modern house-building.

Apply claydite also for decorative purposes, and at home it is suitable for solving problems of growing cultivated plants. With the help of this material it is possible to exclude increased evaporation of moisture, which helps to control the water balance of plants.

Specifications

The coefficient of thermal conductivity of expanded clay is established by state standards 9757-90, as well as other technical characteristics, among them it is necessary to distinguish the fractional composition. On sale you can find material in three fractions:

• 5-10;
• 10-20;
• 20-40 mm.

We can not fail to mention another category of factions, which is rarely used in construction work. Here you can include crushed stone and granules, the sizes of which vary from 2.5 to 10 mm. Quite often when buying a consumer is interested in bulk density, in this issue 7 values for brands are established:

• Up to 250 kg / m ³ - brand 250;
• From 250 to 300 kg / m ³ - brand 300;
• Similarly - brands 350, 400, 450, 500, 600.

For the general sale, the following two brands are not produced, they are manufactured only with the approval of the consumer. The claydite, the characteristics whose thermal conductivity is mentioned in the article and should be of interest to the consumer, has a certain compaction factor, which is agreed individually, but this value does not exceed 1.15. An important parameter that determines the behavior of expanded clay when exposed to moisture is water absorption. It can vary from 8 to 20%.

Comparison of the thermal conductivity of expanded clay with some other materials

Claydite, thermal conductivity (comparison of this characteristic with other materials should also be carried out prior to material selection), which has already been mentioned above, is often preferred by consumers of mineral wool or expanded perlite. In the first case, the coefficient is 0.04, which indicates that with the same thickness, cotton wool will release less heat compared to claydite.

Another alternative is expanded perlite. Its water absorption is lower than that of expanded clay and is only 5%, while the thermal conductivity coefficient is only 0.04.

Claydite, whose properties, the thermal conductivity of which makes it sometimes an indispensable material in the performance of work, is sometimes even compared with expanded vermiculite. It is the most optimal option that could replace claydite, and is produced from rock, which makes it environmentally safe. Thermal conductivity of expanded vermiculite is 0.08, which is 2 times less than mineral wool. If you use this material, you can form a thinner layer of backfill, which will load the overlap less. This suggests that this insulation can also be used as a basis for screeding.

Conclusion

Thermal conductivity acts as one of the important characteristics of expanded clay. But it does not depend much on the mode of production. If you use conventional technology, you will not be able to change the qualities of expanded clay. However, when applying modern techniques for the type of co-firing or the plastic method, it is possible to increase the heat-insulating properties of expanded clay.