In French perlite means pearl. Perlite is really similar to this gem in its texture, but it is not used at all in jewelry. Visually, perlite is similar to crushed stone or sand, fractions can be of different sizes, the color is white, sometimes slightly grayish. This rock is used in medicine, energy, metallurgy, but we are more interested, of course, in agriculture and construction.
Regarding the use in horticulture and horticulture, a special type can be distinguished – agroperlite. It is an expanded perlite which has the following applications:
- It can be added to clay soils to improve soil composition and reduce the risk of plant rot and crust formation in the beds..
- In sandy soils, perlite helps to retain moisture.
- Perlite’s neutral pH helps to deal with excess soil acidity.
- Seeds can be germinated in perlite, and if you mix them with fine fraction agroperlite, they will be evenly distributed over the garden during sowing.
- Agroperlite helps to cope with fungal diseases of plants, prevent the appearance of mold and algae.
- Perlite is used in hydroponics as a substrate or one of its components. And large fractions are often used together with expanded clay to create bottom drainage.
- Perlite will ensure a uniform flow of fertilizers to the roots, as it absorbs water and substances dissolved in it.
- Due to its low thermal conductivity, agroperlite will protect plant roots from frost in winter, and from overheating in summer..
- Perlite can store corms, tubers and bulbs, which will be protected from rotting and temperature extremes.
Having dealt with the wide scope of application of perlite in gardening and horticulture, let’s move on to construction. In this area, in 60% of cases, perlite sand or crushed stone is used as a heater, due to its low thermal conductivity. There is GOST 10832-2009, which is called “Expanded perlite sand and crushed stone”. It is he who sets the technical conditions for the use of these materials..
According to GOST, expanded crushed stone is used as an aggregate in the process of making lightweight concrete. Expanded sand can also be used for the production of lightweight concrete, sound and heat insulating materials, dry building mixtures, plaster mortars, and also as heat insulating backfill.
At the same time, GOST indicates that expanded perlite sand as a heat-insulating backfill can be used on surfaces with temperatures from minus 200 to plus 875 degrees Celsius.
So, let’s consider several options for using perlite sand or crushed stone:
- Backfilling the space between the main building envelope and the facing brick. Typically, this gap does not exceed 100 millimeters. It is an inexpensive and effective way to warm up walls..
- A layer of perlite sand can be used in the process of creating a dry floor screed. A reinforced screed should be laid on top of the perlite or floor slabs should be laid.
- Expanded perlite sand is also used for backfilling ceilings, including thermal insulation of an attic space or base under a soft roof.
- You can also fill in perlite holes in ceramic blocks used in the construction of houses..
Important! Dry perlite is extremely volatile, fine dust will enter the eyes and nose, sealed glasses and a respirator are required!
Experts advise to wet the perlite with water directly in the bags in which it is sold, and then work calmly without dust.
To create a mortar, the following proportions are usually used: a bucket of cement, two buckets of perlite, and two buckets of sand. Craftsmen advise to add literally 20 grams of dishwashing detergent, for example, “Fairy”, to this solution as an air entrainer and plasticizer. Such a solution is used, for example, when laying wood concrete blocks..
Let’s talk separately about perlite concrete, in which expanded perlite sand is used as a filler. Perlite-concrete blocks in our country are still a new building material, although they have many advantages and great prospects. Perlite concrete blocks are environmentally friendly, the walls are lighter, the masonry process is simple. One such block replaces three or four bricks. Suitable for construction are perlite-concrete blocks with a density of 600-800 kg / m3.
On the basis of perlite, heat and sound insulating plasters are also produced, which have a low heat transfer coefficient, high frost resistance, and excellent sound-absorbing properties. In this case, the volumetric weight of the plaster layer is lower, because expanded perlite is a light material. The addition of cement allows the use of perlite plasters as facades, for arranging slopes. For interior work, perlite plasters with gypsum additives can be used..
As you can see, the scope of application of perlite is very wide. As for the cost, the price of a cubic meter of perlite sand in Moscow will be from 1,300 to 2,300 rubles, depending on the fraction. The most popular are perlites with a density of 75 and 100 kg / m3, fractions from 0.16 to 2.5 mm.