The density of expanded clay - what it is and what it depends on

By Admin | Construction Materials
25 April 2016

Currently expanded clay is the most popular eco-friendly insulation.This building material is characterized by its low weight and cellular structure.The density of expanded clay usually has a relatively low value.But it is noteworthy that one of its main characteristics is precisely the bulk density of expanded clay.After all, this feature allows the material in the future to choose the right faction.And for the full-quality characteristics of expanded clay just need to consider the size fractions, volume, and the proportion of this material.

What is the density of expanded clay


  1. Getting haydite
  2. fractions haydite
  3. Bulk density and brand
  4. true and specific gravity

Getting haydite

Getting haydite occursin the process of firing clay specialist.Initially, this takes all the necessary raw materials processing, and then it undergoes a drastic thermal effects.Approximately 20-40 minutes, the temperature increases from 1050 degrees to 1300 degrees.

This raw material swells and gets a new structure - cellular or, in other words, porous.The surface itself is melted pellets, resulting appears almost perfect hermetic.That is why such beads have high strength and are much less susceptible to mechanical stress.

expanded clay fractions

Despite the fact that the density of the material is small enough, the mechanical strength here is sufficiently high.Due to the special structure of the granules, expanded clay is able to withstand high loads and protects the numerous types of objects from being destroyed.And the size of the pellets themselves allow us to identify these types of raw materials:

  • clay gravel;
  • Expanded clay sand;
  • Expanded clay gravel.

Expanded clay sand, characterized this size fraction is 0-5 mm.Gravel, usually has the following fractions: from 5 to 10, from 10 to 20 mm, from 20 to 40 mm.

On the latter point, the expanded clay gravel fraction is 5-40 mm.It is obtained by crushing into small particles of gravel.The most popular faction of expanded clay gravel - from 0 to 10 mm.The common name of the gravel - crushed concrete block.

There are a number of special modes of processing of clay.It is through these modes and possible to achieve the required density of expanded clay gravel:

  • Plastic,
  • Wet,
  • Dry,
  • powder and plastic.

Bulk density and brand

As mentioned above, one of the most important characteristics of expanded clay - density (kg / m3).And it is the bulk density.Quality of expanded clay, as one of the most common heat insulator also determines the grain volume, porosity and bulk volume weight.The density of expanded clay gravel varies depending on the particular brand.But in general, it takes records from 250 to 800 kg / m3.

So if the bulk density of expanded clay gravel has an index of less than 250 kg / m3, its brand - M250.Expanded clay with a bulk density of 250-300 kg / m3 is the brand M300.A concrete block with a density of 300-350 kg / m3 - M350.Further, by analogy.But it is necessary to take into account that after the brand M450, Brand bulk density increased by 100. For example, M500, M600 and M700.

Limits brands associated with a bulk density of sets and GOST 9757-90.The most minimum grade clay gravel and crushed stone - M250.The maximum mark - M600.Although the agreement with the customer, and allowed higher values.Expanded clay sand has a slightly different figures - from M500 to M1000.It should be borne in mind that the minimum characteristics are advisory, but the maximum required for compliance.Thus, it becomes clear that the lighter the concrete block, the better its quality indicators (of course, the material when compared to the same fractions).

true and specific gravity

When performed various calculations, it is important to bear in mind two types of density of expanded clay: specific and true.

specific density of expanded clay in the first place, is variable.It depends on the specific form of the material.Thus, this feature can take values ​​stated below:

  • clay gravel - from 450 to 700 kg / m3,
  • keramsit dry mixture - 800 kg / m3,
  • Expanded clay gravel - from 600 to 1000 kg / m3.

true density of expanded clay, a constant, is the mass per unit volume of the material in the dense state (Pu).This figure is needed to determine the specific gravity.Thus, for its calculation is required to divide the weight of dry material per volume of the substance itself, but the pores are not considered.Visually display the following formula: Pu = m / Va, where Va - volume, m - mass.

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