Today, expanded perlite is used in many industries, including construction. Being a friable material, it is useful as a filler and baking powder. Despite the fact that the material has been known in our country for a long time, perlite has been widely used only recently. What is expanded perlite? Aspects of application and production features.
Definition
Perlite is an igneous rock that is a by-product of a volcanic eruption. The material is a volcanic glass through which groundwater penetrates, thus forming a specific structure. Perlite is characterized by a structure in which it breaks up into small nuclei. It owes its name to this feature.
Production
Expanded perlite is obtained by grinding and heat-treating obsidian volcanic glass. The swelling is carried out by means of thermal shock in900-1000 degrees. When heated rapidly, gases are released inside the material, which explode and give the material a characteristic friability.
Features
In appearance, expanded perlite resembles sand or crushed stone of a fine fraction, depending on the degree of grinding. It has a color from snow-white to white with a grayish tint. The production of perlite involves its separation into various fractions - from perlite powder less than 0.14 mm in size to perlite crushed stone - 10-20 mm.
In addition, the material is divided into grades that correspond to the bulk density of expanded perlite:
- M75 - up to 75 kg/m3.
- M100 - up to 100 kg/m3.
- M150 - from 100 to 150 kg/m3.
- M200 - from 150 to 200 kg/m3.
- M250 - from 200 to 250 kg/m3.
- M300 - from 250 to 300 kg/m3.
- M350 - from 300 to 350 kg/m3.
- M400 - from 350 to 400 kg/m3.
- M500 - from 400 to 500 kg/m3.
Different grades of material are used for different needs. The thermal conductivity of expanded perlite also depends on the volumetric weight. It can vary from 0.034 W/Mk. The most common grade for use is expanded perlite M 75.
Material advantages
Perlite is often used as a heater, this is due to the fact that it has such positive characteristics:
- Natural origin. For this reason, the material isenvironmentally friendly and has no chemical impurities.
- The development of various bacteria is impossible in perlite, and rodents do not start in it.
- Perlite does not contain any binders. This means that during operation and storage, it does not change its physical properties and does not shrink.
- The material is loose and therefore vapor permeable. This makes it possible to evaporate excess moisture in the room.
- Perlite does not belong to combustible materials, which significantly increases the safety of structures in which it is used as a heater.
Thanks to these positive properties, expanded perlite is popular in construction.
Plaster
The density of expanded perlite makes it possible to use the material for the preparation of plaster solutions. They are well suited for thermal insulation of houses, since a layer of such plaster with a thickness of only 3 cm replaces brickwork in 1 brick.
The advantage of the mixture is that it can be applied to any surface - from wood to slag concrete. At the same time, such plaster does not lose its properties. For its preparation, perlite powder of fine fraction is used. After complete drying, such plaster can be subjected to any finish - it is equally good for subsequent painting and wallpapering.
Mortars
Expanded perlite is often used to make mortars that are used for laying bricks or othermaterials. Such solutions are light, at the same time durable and warm. Drying, it turns out masonry of brick, cinder block or foam concrete, which does not have cold bridges. Mortars are also used to seal various gaps, joints and other irregularities.
To prepare a dry mix, perlite sand is mixed with gypsum or cement. It is necessary to dilute with water immediately before starting work, since such a building mixture tends to harden quickly.
Wall insulation
For wall insulation, perlite sand with a fraction of about 6 mm, previously dedusted, is used. It must be laid between brickwork. The process can be carried out both manually and using a sandblasting machine. When laying, it is necessary to periodically tap the wall in order to compact the expanded perlite. The thickness of the insulating pad is usually about 5-10 cm. This is enough to keep the heat in the house.
Roof insulation
The use of expanded perlite is not limited to wall insulation, as the roof also needs additional thermal insulation. For these purposes, a fraction of the material is used, similar to that required for wall insulation. For the implementation of thermal insulation, perlite must be poured between the sheathing and the roof lathing, periodically tapping for better compaction of the material.
Oftenbituminized perlite is used, that is, mixed with bitumen. It has a sticky and durable structure. The advantage is the fact that the installation of bituminized perlite does not require heat treatment and cures itself. However, for beginners, it is more convenient to use ordinary bulk material, since it is more convenient to distribute it without some skills.
Floor insulation
Additional insulation may require not only private houses, but also dwellings in multi-apartment apartments. To do this, it is important to free the surface from the previous coating. Also, some communications or a warm floor system are often placed under the screed.
In order to insulate the floor with expanded perlite, proceed as follows:
- Completely remove the old floor covering and, if necessary, the concrete layer.
- Fine perlite is used for insulation - up to 6 mm.
- It must be poured in an even layer. Most often, it is about 3-5 cm. This is enough to hide the unevenness of the floor and perform thermal insulation.
After the perlite is poured out, it needs to be lightly tamped in order to compact it. After that, the floor is ready for pouring concrete screed.
Perlite products
Today, a large amount of material is produced, each of which has its own characteristics:
- Silicate perlite is a material that also contains lime, sand, ash or slag. At the same time, the ingredients are mixed and baked in molds in an autoclave.
- Bitumen perlite is a combination of expanded perlite with liquid bitumen. Often used for hydro and thermal insulation of roofs.
- Carboperlite is a pressed mass of expanded perlite sand and lime, followed by gas treatment. The result is products for the insulation of pipelines.
- Gypsum perlite - connection of expanded perlite with gypsum by casting or semi-dry pressing.
- Ceramoperlite is a combination of perlite and clay followed by heat treatment.
Besides this, in construction there is also application for such products as glass-perlite, bas alt-perlite fibrous material, plastperlite, perlite-containing brick, asbestos-perlite cement, perlite-cement non-combustible boards.
