What is aerated concrete and what is its properties?
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In addition to load strength, external walls should provide good thermal insulation and a favorable internal microclimate, protect against noise, as well as enable the desired finish from the outside and inside.The technology of their construction is also important - affecting the labor intensity, organization of the construction site or the needed tools and equipment.
One of the wall materials used is aerated concrete and although its main advantage is high heat protection, in the currently used technology for the construction of sandwich walls, this is less important.
Requirements for wall materials
The desired features of wall materials are in many cases impossible to obtain in homogeneous products, because some of their properties are mutually exclusive.For example, high acoustic insulation requirements related to high material density are in contradiction with good thermal insulation.
For this reason, two- or three-layer walls are most often erected, where connected with each other "specialized" layers provide favorable parameters of the entire partition.
For construction materials in such partitions, important utility features are:
Wall materials used to build single -family houses do not have to meet special strength requirements, and the products used are characterized by compression resistance within 1.5 MPa for aerated concrete up to 25 MPa for silicate.
However, for utility reasons, it is important not only to fix the installed equipment, but also the structure of the material - a uniform or openwork, which requires the selection of appropriate fasteners.
Vapor permeability of external walls can be identified with the so -called.breathing the wall, understood as the ability to ventilate and drain moisture outside.In fact, even the best "breathable" wall is not able to maintain humidity at the desired level and does not replace the home ventilation system.
On the other hand, the vapor permeability of the wall layers affects the possibility of condensation of water vapor inside the wall, which can lead to permanent moisture.
In practice, this problem concerns the use of materials characterized by high vapor permeability and at the same time good thermal insulation (mineral wool, heat -proteinous blocks made of cellular concrete).They cannot be covered with vigorous layers from the outside, because it will prevent them from drying out.
Ścian z betonu komórkowego nie można pokrywać od zewnątrz paroszczelnymi powłokami, photo. L. Jampolska.Wall ability to store heat - i.e. thermal accumulation - has a positive effect on the stabilization of the room temperature and allows you to effectively use energy, e.g..from sunlight.Indirectly, thanks to the stabilization of the temperature, we also obtain more effective operation of heating devices that can work smoothly without jumping heating power changes.
High accumulation is provided by walls of high insulated mass, i.e. those in which the inner layer is made of heavy materials, and from the outside there is a thick layer of thermal insulation.
Is the heat protection of wall materials important?
Obtaining the required heat protection of external walls at the level of thermal permeability u ≤ 0.2 W/m2 K, prompts many investors to build layered partitions.The construction placed from any wall material with a 20 cm thick insulation with a surplus meets these requirements.
However, the use of homogeneous materials limits the possibilities of erecting highly energy -saving walls, because the uniform wall would have to be irrational high thickness.An additional problem will be created by thermal bridges on strength structural elements (wreaths, lintels, pillars).
Economic considerations are decisive - the equivalent improvement of heat protection - corresponding to the enlargement of the insulation layer by 1 cm requires thickening of the wall, e.g..Heat -protected aerated concrete by at least 3 cm.
Aerated concrete walls
Aerated concrete products have been used for many years to build external walls and internal partitions, and a rich range with different parameters allows you to easily select this material for specific applications.
Simply put, the production of aerated concrete, also called aerated concrete or siporek, consists in foaming cement-lime lenses, sand and additives as a result of a piano reaction with aluminum powder.As a result, a porous block of pre -hardened material is created, which is cut on blocks with the required dimensions.Then they are undergoing autoclavization (saturation with hot steam), which increases their strength.
Depending on the purpose, hardened blocks can be transferred for mechanical processing, shaping the side hooks and handles.The low hardness of this material also facilitates its processing on the construction.
The assortment of cellular concrete products includes several strength classes, depending mainly on the density of the material, in the range of 1.5-4.0 MPa.
Z betonu komórkowego buduje się zarówno ściany zewnętrzne......jak i przegrody wewnętrzne, photo. Solbet.The lightest - with a density of 300 kg/m3 - are characterized by high heat protection.LAMBDA factor manufacturers specify within 0.085-0.09 W/m K and such blocks are mainly intended for erecting single-layer walls with a heat protection at 0.2 W/m2 K.
Products with a higher density.
In addition to the materials for erecting external walls, products for erecting internal walls, creating lintels or thermal insulation cladding with good heat -protective properties, similar, e.g..for polystyrene.Standard front dimensions are usually 24x59 cm at 6-48 cm thick, depending on the variety and purpose.
Despite the low capillary ability, due to the large pores in the structure, the aerated concrete is absorbing and in the event of a coach dries for a long time, and frozen in this state is completely destroyed.
The growing labor costs, as well as striving to shorten the time of the investment process, make contractors more and more often want to use materials that allow for quick and convenient erection of the walls of buildings.
Most of the currently offered wall concrete wall materials eliminate the need to create vertical joints, thanks to the shape of the side walls in the form of a feather and a groove.Thanks to this, the embarrassing of the mortar on the sides of the blocks or blocks falls out, and it is easier to maintain the straightness of the wall.
Boczne ścianki bloczków z betonu komórkowego mają formę pióra i wpustu, dlatego nie wymagają nakładania zaprawy, photo. Solbet.New solutions on the market of cellular concrete products
It is also common to focus the manufacturers of wall materials to enlarge their dimensions - new systems allow you to put 1 m2 of walls with less than 8 elements - while facilitating their installation.Shaped handles or holes allow convenient transfer and precise setting on the wall.
Currently produced blocks also have more accurate dimensions - tolerances do not exceed 1-2 mm - which allows the use of thinner horizontal joints.Instead of traditional masonry mortars, thin -layer adhesive mortars are then used to combine.They are applied with an efficient dispenser, which at the same time ensures even thickness of the weld.
New is the use of high heat protection polyurethane foam for masonry, which definitely improves insulation, eliminating heat bridges on the joints.A great facilitation of masonry work is to extend the product offer with complementary elements - corner, half or frame, which excludes the need to cut them at the construction site, while ensuring material homogeneity over the entire surface of the wall.
The exactly placed walls with an equal surface also allow you to simplify the method of their finishing.On a smooth and even wall, you can apply shaded plasters, which limits the consumption of plastering mortars and ensures faster performance.
PoradnikCenisz nasze porady? Możesz otrzymywać najnowsze w każdy czwartek!Author: Cezary Jankowski
Prepared by: Martyna Nowak-Ciupa
photo.opening: h+h
