Expanded clay: thermal conductivity, properties and technical characteristics

2024 Author: Howard Calhoun | [email protected]. Last modified: 2024-01-02 13:48

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

Thermal conductivity

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

Among the first is the size of the granules. The more impressive the fraction, the more insulation will be needed. The porosity and moisture content of expanded clay will also affect the thermal conductivity. It is quite difficult to determine the average coefficient of thermal conductivity, because there are many deviations. Expanded clay, the thermal conductivity of which 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 reaches the mark 0, 16.

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

What affects the main characteristic of expanded clay

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

This does not apply to gases produced when heated to the swelling temperature. It has been established that if the pores contain H_{2 + CO in a volume greater than 55%, then the thermal conductivity of expanded clay will be 2 times higher than if the filling is carried out by air. Micropores can also affect thermal conductivity. The smaller they are, the lower the thermal conductivity will be, however, porosity does not affect this characteristic.}

Basic Features

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

• high strength;
• frost resistance;
• durability;
• fire resistance;
• optimal ratio of quality and cost.

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

Main Features

Expanded clay, the thermal conductivity of which must be known before purchasing this material, has excellent qualities. It is made from slate and clay and is suitable for sustainable and modern home construction.

Expanded clay is also used for decorative purposes, and at home it is suitable for solving the 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 thermal conductivity of expanded clay is established by state standards 9757-90, like other technical characteristics, among them it is necessary to highlight the fractional composition. On sale you can find material in three fractions:

• 5-10;
• 10-20;
• 20-40mm.

It is impossible not to mention another category of fractions, which is rarely used in construction work. This includes expanded clay crushed stone and granules, the sizes of which vary from 2.5 to 10 mm. Quite often, when buying, the consumer is interested in bulk density, 7 values \u200b\u200bare set in this matterby brand:

• up to 250 kg/m3 – grade 250;
• 250 to 300 kg/m3 – Grade 300;
• similarly - grades 350, 400, 450, 500, 600.

The following two brands are not produced for general sale, they are produced only upon agreement with the consumer. Expanded clay, the characteristics, the thermal conductivity of which is mentioned in the article and should be of interest to the consumer, has a certain compaction coefficient, 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 expanded clay thermal conductivity with some other materials

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

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.

Expanded clay, whose thermal conductivity properties make it sometimes an indispensable material for work, is sometimes compared with expanded vermiculite. Heis the best option that could replace expanded clay, and is produced from rock, which makes it environmentally friendly. The thermal conductivity of expanded vermiculite is 0.08, which is 2 times less compared to mineral wool. If this material is used, then a thinner layer of backfill can be formed, which will load the floor less. This suggests that this insulation can also be used as the basis for a screed.

Conclusion

Thermal conductivity acts as one of the important characteristics of expanded clay. But it does not strongly depend on the mode of production. If you use conventional technology, then it will not be possible to change the qualities of expanded clay. However, with the use of modern techniques such as joint firing or the plastic method, it is possible to increase the thermal insulation properties of expanded clay.