The name of the building material arbolit comes from the Greek words "arbo" and "lithos", which means wood and stone. In Russia, it is known as wood concrete or sawdust concrete. The peculiarity of its composition is that crushed wood, flax bonfire, crushed rice straw or cotton stalks are mixed in a cement mortar. Organic filler takes in the total volume of the product from 80 to 90%. For mineralization, calcium nitrate, water glass and other chemicals are added to the feed.
Advantages and disadvantages of wood concrete
Wood concrete products, like any building material, have a number of advantages and disadvantages.
Advantages
- High sound and heat insulation properties. Low thermal conductivity is far ahead of brick and concrete.
- The manufacturer of wood-concrete structures, such as wood concrete blocks and wood concrete panels, practically do not need special equipment. Products form in simple formwork.
- The accumulative quality of sawdust concrete allows you to keep heat inside the house for a long time, despite sudden changes in ambient temperature.
- Unlike wood, wood concrete is classified as a fire-resistant fireproof material. During the smoldering of wood filler, smoke is almost not emitted.
- Because of their high vapor impermeability, arbolite blocks are used for the construction of structures such as baths. Wood concrete does not retain absorbed moisture in its mass. Under favorable circumstances, the material quickly gets rid of water and its vapors..
- Wall structures made of wood concrete are resistant to tensile loads. When moving and shrinking the foundation, they are not covered by cracks.
- Immunity to fungal and mold formations.
- Arbolit is easily plastered and can be processed. They saw it and cut it without much effort. Product structure holds fasteners for attachments.
- The light weight of wood concrete constructions greatly simplifies installation and shortens construction time.
- Walls erected from arboblocks do not need additional insulation.
- Judging by customer reviews, the interior wall decoration can be made of any known materials:
- the plaster is laid on wood concrete without any preparation;
- wooden crate fasten with screws. Then a lining is stuffed on it;
- the moistened surface is faced with ceramic tiles in the traditional way;
- a metal profile frame is attached to the walls of arbolite, then plasterboard sheets are installed;
- plastic panels are mounted on a wooden crate or metal frame;
- high adhesion of the wall material ensures reliable fastening of any type of cladding.
Disadvantages
- The main disadvantage is the relatively low strength, which does not allow it to be used as load-bearing structures in the construction of buildings and structures above 3 floors.
- The technology for the production of wood-concrete blocks and panels is not fully automated, which affects the high cost of products.
- The outer surface of the walls is subject to mandatory coating with a protective layer of plaster or other decorative materials.
Types of wood concrete
Constructional
Structural arboblock made with a large proportion of cement. This achieves a high density indicator - from 500 to 800 kg / m3. This makes it possible to use blocks on the construction of load-bearing walls. There are no size restrictions on their manufacture. Dimensions of products are set by the owner of the production as agreed with the customer.
Arbolite construction significantly reduces the construction time of buildings and structures. The relatively high price of building materials is more than offset by the savings in the non-use of hoisting mechanisms.
Heat insulating
Arbolite panels contain up to 90% organic filler. They are used for the construction of partitions and cladding of the internal surfaces of load-bearing fences of buildings (walls and ceilings) as thermal insulation.
Monolithic
Monolithic wood concrete is prepared directly at the construction site, using the same equipment as when mixing concrete (concrete mixers, troughs, etc.). Basically, the mixture is poured formwork on the floor and walls for thermal insulation. The disadvantage of using this method is that a monolithic arbolite needs a longer curing time than is necessary for concrete to harden.
Production of wood concrete blocks
Factory technology for the manufacture of concrete blocks and slabs from wood concrete includes a number of stages.
- Woodworking waste is sent to the mill hopper. From there, the feed enters the hammer mill. Then rotten and rotten chips, bark, and also large knots are sifted out in a vibrating screen.
- Waste from the processing of wood of almost all species is used, except for larch, poplar and beech. Suitable spruce, pine, fir, aspen and birch. In the process of sorting, lamellar or needle-shaped fragments of 2–20 × 2–5 mm in size are obtained2, no more than 5 mm thick.
- In the intermediate hopper, the chips are soaked.
- Then the crusher is sent to the mixing chamber (it can be an ordinary concrete mixer). During mixing, an astringent component (cement or its equivalent), water and chemicals are added.
- The finished mixture is placed in a metal or wooden collapsible formwork. Raw materials in molds are compacted with the help of special equipment - a power vibro-distributor or a vibro-stamp.
- To achieve normative strength characteristics, wood concrete is kept in the formwork for 5 days at a temperature of at least + 15 0C or placed in a heat chamber for 24 hours at + 40 0C.
- After the aforementioned time, the finished products are freed from the formwork and sent to the warehouse.
Specifications
Despite the predominant content of organic matter (wood) as a filler, arbolite in its technical characteristics is referred not to wood products, but to a variety of concrete. Therefore, they classify the material by strength and assign the brand, like concrete.
Type of wood concrete | Strength class | Brand | Density, kg / m3 |
Constructional | At 1.5 | M 15 | 500–650 |
AT 2 | M 25 | 500–700 | |
At 2.5 | M 35 | 600–750 | |
At 3.5 | M 50 | 700–850 | |
Heat insulating | At 0.35 | M 5 | 400–500 |
At 0.75 | M 10 | 500–650 | |
IN 1 | M 15 | 500 |
Application
Wood-concrete products are used in construction in the form of blocks, panels, coating slabs for combining roofs and ceilings with reinforced concrete rods. Arbolit is used as sound and heat insulation structures for walls and floors. It is especially popular for the formation of sections of livestock complexes.
Monolithic material is laid between two reinforced concrete panels, thereby obtaining wall fencing (sandwich) with high thermal insulation performance.
Features of structures made of wood concrete blocks
Arbolit is a special building material, therefore, when using it, it is necessary to take into account the limited bearing capacity. Each type of structural elements from wood concrete needs its own approach.
Walls
Vertical enclosing surfaces are erected from arblocks. From the magnitude of the load, the walls are divided into 3 types:
- Bearing - use structural wood concrete in the form of blocks. Their thickness is 500 mm for two-story buildings and 300 mm for baths, garages and cottages;
- self-supporting - fences 300 mm thick are erected from arboblocks with a size of 200x300x500 mm;
- partitions - internal piers with a thickness of 200 mm are laid from arboblocks with a size of 200x200x500 mm.
Masonry is performed on a cement-sand or perlite solution. Before this, the surface of the blocks of wood concrete is moistened, otherwise the hygroscopic mass of the arbolite will absorb the moisture of the masonry mortar, not allowing it to shut.
For the same reason, the surfaces of finished floors must be plastered, having previously moistened them. Manufacturers often sell wall material with exterior decoration with decorative concrete.
Masonry technology for load-bearing walls
The installation of supporting structures from wood-concrete blocks is carried out in the following order:
- The surface of the foundation is covered with a layer of waterproofing. Then pour a layer of cement mortar.
- In the corners of the foundation lay beacons from the blocks. Mandatory equality of diagonals between opposite angles.
- The first rows of blocks are carefully checked for horizontalness. The slightest violation of the even surface of the first can adversely affect the quality of the subsequent masonry.
- Masonry arblocks usually perform a width of half a block. The vertical butt joint of the lower row should be in the middle of the upper block.
- To strengthen the walls produce horizontal reinforcement. Every 3-4 rows are laid with reinforcing mesh. As an option, steel rods ø 8–10 mm are placed in the longitudinal cuts.
Floors
For floors, wood concrete is used as insulation. Armolith coating is performed in two ways:
1 option
- a cement screed 40-50 mm thick is arranged on a soil base;
- then lay a crate of reinforcement ø 10–12 mm, forming cells 25x25 mm;
- the intersection is fixed with a knitting wire;
- the frame is poured with liquid concrete M 200;
- lay waterproofing (roofing material, roofing, etc.);
- after the solution hardens, the surface is filled with liquid wood concrete. Otherwise, arbolite plates with a thickness of 50–70 mm are laid;
- the floors are finally finished with finishing (laminate, linoleum, carpet, tile, etc.).
Option 2
- on a concrete base of the floor, firstly, 70 mm thick arbolite slabs are laid;
- then put more durable - 30 mm thick;
- the floor is covered with a finish lining.
Overlap
Floor slabs are combined designs. They consist of 3 layers:
- lower - monolithic concrete panel М 25 or М 35 with reinforcing mesh ø 10–12 mm;
- medium - heat-insulating wood concrete;
- upper - cement screed.
Average price for wood concrete
Based on the analysis of proposals in the building materials market, a table is compiled of the average cost of arbolite blocks.
Block sizes | Price, rub / pcs. | Price, rub / m3 | Quantity pcs / m3 |
160x370x500 | 142 | 5000 | 33,78 |
200x300x600 | 172 | 5000 | 28 |
200x370x500 | 178 | 5000 | 27 |
150x200x600 | 99 | 5700 | 55,5 |
200x300x600 | 182 | 6000 | 28 |
Conclusion
There are many factories producing arbolite building materials in the country. Basically, they are located next to woodworking enterprises. The simplicity of technology makes it possible to manufacture arbolitic blocks and plates in any private household.