LWA Blocks (“K-BLOKS”)
LWA (lightweight expanded clay aggregate) block is one of most popular materials in masonry and is widely used in construction of private houses, public and industrial buildings as well as is applied as a structure for load-carrying (walls, foundation) and non-carrying (walls, filling of columns and gaps) stone elements of buildings.
Positive properties of LWA block include its mechanical strength (3 MPa and 5 MPa in most popular blocks) as well as good moisture resistance, acoustic isolation and machinability: the blocks can be easily cut, allow making holes and slots therein, and also be used in various fastenings, with screws, nails, while at the same time they are not fragile. Various sizes of blocks are available: 100, 150, 200, 250, 300 mm.
LWA block is an ideal choice of wall and masonry materials since it excellently combines parameters that often are mutually contradicting, such as strength, thermal conductivity, vapour permeability and acoustic comfort.
K-BlOKS 3 mpa
K-BlOKS 5 mpa
|Pressure strength||3 MPa||5 MPa||SKC|
|Unit weight||750 kg/m3||1000 kg/m3||750 kg/m3|
|Heat conductivity||0,20 W/mK||0,30 W/mK||0,34-0,56 W/mK|
|Acoustic isolation||18-20 dB||18-20 dB||20-25 dB|
|Name||Width (mm)||Height (mm)||Length (mm)||pcs/m3||m2/m3||Weight (kg, net)||Pallet|
Use of LWA Blocks
- Construction of foundation (depth should be not lower than the ground water level)
- Interior walls
- Carrying walls
- Partition walls
- Vertical joints are used:
- if the wall is left unprocessed from one side;
- If sound isolation of walls is necessary;
- If an arch is projected.
Positive Properties of LWA Blocks
- Damp resistance, frost resistance, fire resistance
- Strength, regardless of lightweight of material
- Very good thermal conductivity and acoustic isolation
- Fast and easy processing
- Precise shape and size
- Light weight
- Ecologically clean.
Factory equipment is designed for production of LWA blocks with ± 1 mm precision. Lightweight expanded clay aggregate (hereinafter referred to as the claydite) of high quality (fraction 0-4, 4-10) is used in production process.
LWA block is made by vibrocompression of cement, water and lightweight claydite of which weight share is 350 kg/m. Claydite is in the form of clay granules that are baked under high temperatures and are four times lighter than natural fillers, distinguishing with good thermal insulating properties. Cement is a binding agent, dampproof and having excellent cohesion with plaster.
LWA block is made of claydite and cement (in blown clay granules) without chemical impurities. The blocks are formed in a semi-dry vibrocompression process with the use of precise metal moulds. This procedure ensures the mass uniformity and excludes the possibility of peeling. The obtained material is lightweight, resistant towards high temperatures, non-frosting, excellently cohesive with plaster and having good thermal properties. The filled-up wall has good acoustic isolation and high fire resistance.
With changing temperature, all building materials change their volumes to lesser or grater extent. These changes are expressed by thermal expansion ratio which value for LWA block is 0.008 mm/VC. This thermal deformation is not visible on a separate component but over large area of walls can cause adverse forces which, in turn, lead to formation of cracks. To avoid wall cracking, all building materials should be reinforced.
LWA block is non-freezing and due to it suited for northern weather conditions. Claydite micropores are closed and water does not get inside while large outside pores between granules stop the water and are never filled completely. That is why even a wet block that is frozen gives the ice a space for expansion and the structure of materials is not destroyed. Tests have proved that the durability of LWA block is 50 cycles (F 50). This magnitude exceeds many other characteristics of the block and allows its transportation and assembly not requiring special conditions. Unfinished walls of a house can be left for winter months not worrying that they will start being destroyed.
Heat insulating properties of a wall depend on its moisture content. Therefore it is necessary to consider the difference between the laboratory value and the estimated value of heat conductivity of a material (lambda). If the material has a tendency towards absorption of water and slow water drying, then the wall water-content coefficient is high. Since LWA blocks dry out perfectly, this value changes insignificantly.
Moisture in Walls
Due to a special structure of capillaries in LWA block, the masonry does not retain moisture. During the construction, water that has got inside is going through not accumulating in the wall. With such interior structures, the buildings dry out quickly, their walls are resistant towards both rain and frost. Vapour permeability of 3 MPa blocks is: d * 8.3 * 10_5 g/l.
Water amount retained in 3 MPa blocks at different relative humidity (Rh) values is as follows::
- at Rh = 50%, kw = 2% (weight %);
- at Rh = 90%, kw = 7% (weight %).
Normally, humidity of external wall structures is about 4% and upon dry atmospheric air such level can be reached in 3 to 4 weeks after commencement of construction
Use of LWA blocks
|Type of block||Width (mm)||Field of use||Haydite pressure strength (MPa)|
|K-bloks||100||Interior partition walls||3 and 5|
|150||Interior partition walls, filling of openings in skeleton structures||3 and 5|
|200||Exterior and interior carrying walls, filling of openings in skeleton structures, foundation.||3 and 5|
|250||Exterior and interior carrying walls, filling of openings in skeleton structures, foundation||3 and 5|
|300||Exterior and interior walls, carrying cross walls, walls on reinforced concrete structures, foundation||3 and 5|
|SKC-bloks||190||Interior partition walls, exterior and interior carrying walls, filling of openings in skeleton structures||3,0|
|240||Exterior and interior carrying walls, filling of openings in skeleton structures||3,0|
|Type of block||Thickness of course (mm)||Acoustic isolation (dB)||Plastering||Fire resistance||Acoustic isolation with plastering 20mm(dB)|
|3 MPa||5 MPa||3 MPa||5 MPa|
|K-bloks||100||41||43||+5-8 mm||120 REI||45||47|
|150||45||46||+5-8 mm||240 REI||49||50|
|200||48||49||+5-8 mm||240 REI||52||54|
|250||51||52||+5-8 mm||240 REI||54||56|
|300||53||54||+5-8 mm||240 REI||56||58|
|SKC-bloks||190||+5-8 mm||240 REI|
Size and weight of blocks
|Type of block||Size (mm)||Weight (kg)|
|Width||Height||Length||3 MPa||5 MPa|
Recommended thickness of joints: 10 to 15 mm. nominal thickness of joint which is taken as a basis of height estimate: 15 mm. To avoid the appearance of cracks in a wall, the plastering should be carried out with least use of reinforcement: one reinforced joint per metre of wall height, each fifth joint should be reinforced, as well as the first course over the covering and the last course of masonry. Each third course should be reinforced for the base.
Note: K-blocks are transported with the use of wood pallets 1 m x 1.20 m while the blocks are packed into PE film.
Demonstrative examples of use