Cement and sawdust blocks. Arbolite blocks Wood chips blocks

Arbolite blocks, otherwise wood concrete - a building material patented in the first half of the last century and successfully used in modern construction of low-rise buildings. The production is based on chips from deciduous or coniferous wood. The demand and competitiveness of wood concrete among other materials is due to its affordable cost, light weight, environmental friendliness and ease of use, optimal thermal insulation performance.

Wood chips for wood concrete is the basic component and takes from 75% to 90% of the total volume of the mixture. Depending on the quality of the main raw material, its shape and fraction, the performance characteristics of the finished material directly depend.

Chips for wood concrete according to GOST

The size of wood chips for wood concrete, the technology of creation, the percentage of the initial components are regulated by the regulatory framework for the manufacture and use of wood concrete: GOST 19222-84 “Wood concrete and products from it. General technical conditions ".

Permissible chip sizes according to GOST:

• length - up to 40 mm;
• width - up to 10 mm;
• thickness - up to 5 mm.

Chips are obtained by crushing rejected wood: tops, knots, slabs. It is preferable to use coniferous wood. GOST allows the presence of crushed bark up to 10% and needles up to 5% of the total mass composition.

The acicular shape of the wood chips will increase the strength of the finished material and create an additional reinforcing effect.

In some cases, manufacturers add cotton straw, flax, hemp, wood shavings or sawdust for wood concrete to the organic component. In this case, the finished material is less durable, but with improved thermal insulation qualities.

Before using the wood base for the production of wood concrete, it must be treated with antiseptic agents to prevent the formation of fungal infections during the operation of the blocks.

Buy or make wood chips with your own hands

As soon as a private developer decided to independently make wood concrete blocks, the question arises whether it is more profitable to buy or make wood chips for building blanks. If you plan to build a small country house, then buying ready-made raw materials will reduce working hours and financial costs.

Specialized equipment for the production of wood chips is an expensive technique. Processing with chemicals takes time.

If a decision has been made to produce wood-concrete blocks in large quantities, or to engage in construction activities, then it is more profitable to independently produce wood chips.

The process of making wood chips for wood concrete with your own hands consists in a sequence of actions:

• selection of suitable wood;
• receiving chips using special equipment;
• processing of wood chips with chemical reagents in order to remove sugars.

For self-production of wood chips, it is preferable to use pine that is not damaged by pests. Pine chips retain heat to a greater extent and are easier to handle with chemicals.

Chip requirements for wood concrete blocks:

1. Lack of impurities: stones, ice, clay, sand.
2. No rot, mold or other damage.
3. The content of bark is within 10%, needles - 5% of the total mass.
4. Standard size 40105 mm.

When making wood concrete with your own hands, the presence of sawdust up to 30% is allowed. In this case, the consumption of cement increases, and the strength indicators of the finished material decrease. Arbolite blocks with an admixture of sawdust are distinguished by increased heat-saving properties. They are used as an insulating building material.

What sawdust is needed for wood concrete? Sawdust of coniferous and deciduous woods is used, as well as for wood chips. In order to purchase it is possible to contact woodworking enterprises.

Technological equipment for the production of wood chips

A woodworking shredder is the best option for obtaining chips with the correct needle shape and acceptable particle size. Its only drawback is its high cost.

The machines differ from each other in their principle of operation. The choice of an acceptable option is determined by the volume of production, the properties of the feedstock, the possibility of placement on the construction site, and the technical features of processing.

Types of chipping equipment:

1. Disc chippers. Some of the models have an adjustable knife position and tilt. This makes it possible to obtain chips of various sizes. They are capable of processing wooden blanks of any shape.
2. Drum type chippers. They allow you to recycle both wooden beams and waste from furniture production, logging farms. The machines are equipped with a large-sized feed hopper, into which raw materials are fed. Then there is a drum mechanism with double-sided knives.
3. Hammer crushers. They are produced with one working shaft or with two shafts. They are a rotary device equipped with hammers and bumpers. Once inside, wood for arbolite moves between hammers and special dividing plates, wedges and crushed from impacts, and then sifted through a sieve into the outlet compartment. The final chip size depends on the size of the sieve mesh.

All three types of machines have manual loading of raw materials. To ensure safety at work, it is preferable to use long timber pieces. Use a shovel or other suitable long-handled tool to load smaller material.

Raw wood is used to make chips. Only in this case, the shape and size of the fraction of the resulting product meets the regulatory requirements. The use of dry wood is fraught with the formation of small chips, which will require an increased consumption of the cement mixture.

Preparation of wood chips for the manufacture of wood concrete blocks

Wood raw materials contain harmful substances - sugars, which can increase the setting time of the cement mixture, reduce the strength of finished wood concrete blocks. The primary task of preparing the wood concrete mixture is the processing and preparation of wood chips.

Basic processing methods for organic filler:

Having studied the theory of how to make wood chips for wood concrete and having mastered practical skills, it is enough just to set up an independent production of wood chips for wood concrete. It is preferable to purchase the original organic raw materials at logging and woodworking enterprises. If the wood component is required for the construction of one house, it would be wiser to purchase wood chips, or ready-made wood concrete blocks from manufacturers. To obtain a quality assurance for the purchased materials, it is worth contacting licensed manufacturers who are ready to provide the necessary certificates and documents.

Concrete when using sawdust as filler on line of concrete closer to the classics than arbolite.

It's all about the presence of sand in the sawdust concrete composition.

No matter how similar in composition arbolite and sawdust concrete are - there is a difference, and it is, at times, essential.

We will not analyze the differences, we will consider in detail only the sawdust concrete itself.

There are types of sawdust concrete:

• heat insulating (average density from 400 to 800 kg / m3);
• structural (average density from 800 to 1200kg / m3).

Like any other concrete, sawdust concrete best of all gains strength in heat and humidity, since moisture does not quickly evaporate and goes to the formation of cement stone.

pros

The main advantages of sawdust concrete are:

1. The cheapness of the main components.
2. Ease of manufacture.
3. Durability of buildings.
4. Environmental friendliness.
5. Excellent thermal protection.
6. Manufacturing and application technique developed over decades of use.

Minuses

The main drawback is only one: not all sawdust will fit for this stuff. If, in the case of sugar, the chips were removed from the chips during maturation, and according to the ratio of the volume of chips and the specific area of \u200b\u200bchips, the decomposition of sugars did not greatly affect the cement, then in the case of sawdust concrete, the process of decomposition of sugars strongly affects the cement itself inside the block.

Manufacturing

In the process of production of sawdust concrete, it is important to take only the most suitable sawdust from those types of wood in which the sugar content is minimal... Optimal candidates for the second life of waste in sawdust concrete:

• pine;
• birch;
• poplar.

Larch, despite its high characteristics in terms of density and strength is in the very last place, with the highest sugar content.

If a spruce begins to gain strength two weeks after setting, then the end occurs somewhere on the fortieth day after production. But for larch, this period is much longer: from thirty days at the beginning of strength gain to one hundred and forty at the end.

All work on monolithic sawdust concrete need to be done in springso that everything is over by the fall. Because of the emitted sugars, it is better to condition the sawdust in the fresh air, including sprinkling the sawdust with water in order to wash away the remaining sugar breakdown.

A couple of water rinses will already provide the sawdust with an acceptable condition for use in the process of making sawdust concrete. Sawdust structure when storing in bulk, it will not allow the processes of decay and combustion to begin. Since they are not compressed, there is no need to be afraid of moisture.

Composition

Any brand of sawdust concrete contains:

• cement;
• sand;
• slaked lime;
• sawdust.

Differences in proportions observed only in the ratio of the components of the mixture.

Each brand of sawdust concrete has its own proportions.

Components

We prepare sawdust concrete with our own hands. The proportions of the components per 1m3 of the finished mixture are displayed in the form of a table:

As you can see, with an increase in the amount of cement, the purpose of the blocks is more limited to the construction of non-residential buildings. This is due to the change in the coefficient thermal conductivity of blocks, negating all efforts to heat the building. When using blocks of the M10 brand, the coefficient is 0.21, which is a very good indicator.

For the M15 grade, this coefficient is 0.24, which is caused only by a slight increase in strength requirements, respectively, and an increase in the amount of cement to obtain a solid block for the construction of a two-story house. For the M25 block, the coefficient is already almost 0.39, which is two times higher than for the M10 block. This means that the M25 block is twice as cold, but from it large rooms can be built.

The golden mean for sawdust concrete is one-story buildings.

Proportions

The proportions of sawdust concrete are shown in the table:

In terms of volume, this means the following. When making sawdust concrete:

1. M10 brands:
   • cement 0.5 buckets;
   • sand a little more than 1 bucket (bucket with a slide);
   • sawdust a little more than 3 buckets.
2. M15 brands:
   • a little more than 0.5 buckets of cement;
   • sand 1.5 buckets;
   • sawdust almost 4 buckets.
3. M25 brands:
   • cement 0.5 buckets;
   • sand a little less than 1.5 buckets;
   • sawdust 3 buckets with two slides.

It is important to follow exactly this recipe, because it was worked out for decades, much earlier than wood concrete. The lack of progression in quantity and proportion should not be confusing. The components work differently in each case.

Slaked lime as a component is used both as a means of de-sugaring sawdust, and bypassing this stage, by introducing the required amount of fluff into the mixture.

Mix preparation

Surprisingly, the easiest way to prepare the mixture is by hand. When preparing sawdust concrete with your own hands, ordinary concrete mixers will not work... Due to the lightness of some components, they risk remaining on the walls of the concrete mixer, or simply float on top of the water. Any loading order.

You can first:

1. dilute cement in water;
2. add sand, sawdust and lime.

Another variant:

1. mix sawdust with lime;
2. add sand and cement;
3. dilute with water.

No matter what other people say, there is absolutely no difference in which option you choose.

As a result of the work, a homogeneous mixture is formed, in the structure of which there is sand and cement. It is these two components that form cement stone... Lime neutralizes sugars as they are released from the sawdust, and the sawdust itself is the filler. Lightweight concrete classic.

Machine mixing of sawdust concrete possible functionally if a forced-type mixer is available, as in the production of polystyrene concrete. But even in that case, the sequence does not matter, since if the sawdust has already been treated with lime during preparation, then they are no longer afraid of water.

Sawdust concrete based on gypsum binder

We should also mention a little about mixture where stucco is used instead of cement.

And let people not be afraid of the rate of setting of gypsum in combination with water, since these moments have already found a popular solution.

The problem is solved by adding an ordinary detergent to the water, and it is known to give water in a metered dose to the gypsum molecules in an unhydrated state.

Explanation: stucco as sold in stores has ability to connect with water, forming a formula already with it, and which is already a solid formation, which is not particularly afraid of water.

There is still no point in disputes - whether it is possible to build external walls from gypsum-based blocks.

According to some reports, with a proven technology (on hand) and when protecting blocks from atmospheric influences, it is quite possible to use these blocks for building external walls... Internal ones can definitely be built.

The only question is in the price for the binder, but in terms of the volume of sawdust and the strength of the setting, we can say that the costs will be slightly higher, and the rate of curing is four to five times higher.

About the size of sawdust

The size of the sawdust does not matter if the binder is available in sufficient quantity.

As a rule, the sawdust is taken from the sawmill, and the differences in the sawdust of the band and circular sawmill are so negligible that they are not taken into account at all.

Here the shavings from the cylindering and calibration machines will no longer go.

A homogeneous mixture will not work if in one volume there are fractions that differ from each other in volume by several hundred times.

Of the features of the process - it is important to mix so that when a lump of the mixture is held in hands and squeezed with hands, then water does not flow from it. Although everyone's strength is different, and you need to approach this issue logically. And after the lump has formed - so that it does not crumble in your hands.

Including for these nuances, lime is present in the solution. It provides mutual adhesion both between sand and cement, and between them and sawdust.

Manual mixing of sawdust concrete with a shovel:

Application of sawdust concrete

A truly popular building material, as it is the most affordable of materials by the complexity of production. Perhaps people notice a wave-like interest in such materials for themselves. If earlier sawdust concrete was a good option for the whole country, then with the wave of Western marketing, people in pursuit of fashion have moved away from the reasonable framework of choice.

Only now, many have begun to pay for environmental friendliness and practicality building materials, and not something that was designed for completely different climatic conditions. From sawdust concrete they are successfully built:

• houses with up to three storeys;
• garages;
• sheds;
• outbuildings;
• technological buildings.

Like any moderately hygroscopic material, sawdust concrete needs external finishing, just like aerated concrete and foam concrete.

If we consider sawdust concrete in comparison with autoclaved aerated concrete, then the water absorption of the latter is generally 200% of the mass of the block. Therefore, do not be embarrassed by the presence of sawdust in the blocks. A popular insulation that was produced in Germany at the beginning of the last century - ecowool - is generally made from what is collected in landfills.

Therefore, it is still worth figuring out which is more environmentally friendly - sawdust concrete with natural ingredients, or ecowool with a hyper content of bromine salts.

You can buy wood concrete blocks in Moscow at a price of 28 rubles apiece. The cost of a cubic meter of wood concrete blocks is from 2200 rubles.

Today, the attitude of builders to wood concrete blocks is ambiguous, although the products have a number of positive qualities. She, of course, also has disadvantages, like any building material. Before buying such blocks, you should study all their properties in order to use the products for their intended purpose and be prepared for the consequences.

Description and production features

To choose a reliable manufacturer that has all the certificates for the product - it is worth starting with this. Such enterprises follow all those requirements that ultimately affect the quality of products.

1. These products are made from cement (less often - gypsum), wood chips, water and synthetic components. The cement composition (in the professional language is called "dough") binds together wood particles, which are subject to special requirements. Their length according to GOST should not exceed 4 cm, width 1 cm, thickness - 0.5 cm. The finer the chips, the higher the quality of the building material. However, sawdust or shavings in the mixture drastically reduce the quality of the blocks.
2. Wood particles are treated with a special composition - for better adhesion to cement and increasing the water-repellent properties of wood. This component is also subject to the requirements of GOST.
3. The blocks have the shape of a large rectangular parallelepiped and are molded in two ways: manually or on a special machine. In this case, wood particles are evenly distributed inside the product. Of course, products obtained by a mechanized method have a higher quality and a clear geometry of the edges. And only large manufacturers can afford reliable block making machines.
4. The production technology requires strict adherence to the proportions of the composition, which is also possible only at specialized enterprises.
5. The finished product must pass a series of tests.

Arbolite blocks belong to the class of large-cell lightweight concrete. Manufacturers offer these products in various sizes, the most popular option is 250x300x500 mm.

Using wood concrete blocks

The products are applicable in the construction of civil and industrial buildings, namely:

• to create curtain exterior walls,
• when constructing internal partitions,
• for the construction of load-bearing walls in buildings not higher than two floors,
• as sound and heat insulating material.

The operation of wood concrete blocks is possible in rooms with a normal or low level of humidity, in other cases a special impregnation is required.

Practical characteristics

1. Strength. Today manufacturers are ready to offer wood concrete blocks with different strength classes. The scope of application of the products also depends on this value. A characteristic feature of such products is their high bending strength. Unlike bricks, foam and aerated concrete blocks, wood concrete products do not form cracks during operation.
2. Thermal conductivity. This indicator for wood concrete blocks is extremely low, which favorably distinguishes such products from many other types of wall and heat-insulating building materials.
3. Density. Due to their low density, such products are not able to withstand heavy loads, and are not suitable for the construction of eaves of buildings, the laying of basements and basements.
4. Moisture absorption. Arbolite does not accumulate moisture inside, but passes through itself. Structures made of this material must be plastering or finished with hinged facade materials.
5. Frost resistance. Since wood concrete walls are to be finished, they are additionally protected from the effects of low temperatures.
6. Fire resistance. These products can be called practically non-combustible material.
7. Biological resistance. The products are immune to mold, rot, fungi and insects.
8. Soundproofing. By this parameter, wood concrete blocks are superior to many traditional and modern building materials (silicate and ceramic bricks, wood, various types of aerated concrete).
9. Water vapor permeability. Steam passes freely through this material, which guarantees a comfortable climate at any temperature.
10. Environmental friendliness. The components included in the raw materials do not emit substances harmful to humans.
11. Ease and simplicity in work. The blocks are lightweight and do not put pressure on the foundation. Products fit into the desired structure rather quickly, with them you can carry out the same manipulations as with wood: sawing and cutting, driving in nails and screwing in self-tapping screws.

This type of building material "adheres" well to the plaster, this allows you to refuse additional reinforcement of structures.

The disadvantages are:

• the need to use plaster or facade panels, which must be selected especially carefully,
• cost: it is slightly higher than that of other types of cellular concrete,
• there is a large number of products on the construction market, the quality of which leaves much to be desired - as a rule, these are products produced by an almost “handicraft” method.

In accordance with the current legislation, concrete with organic aggregates in Russia can be used in low-rise construction

Wood concrete material - lightweight concrete with organic aggregates (up to 80-90% of the volume). It was invented by the Dutch around the 30s of the last century. However, in fact, the idea of \u200b\u200busing organic matter as filler in concrete - sawdust, wood chips, straw, and so on - has a longer history.

In Central Asia, houses were traditionally built from adobe - a mixture of clay and chopped straw. By the way, adobe is still produced in private farmsteads. Bricks were made from a mixture of clay and straw and dried in the sun. Melon-shaped wall blocks called "guvala" were also popular. They were made from the same material. Such bricks and "blocks" did not have sufficient strength. But in the local climate with scarce rainfall, they served long enough and reliably.

In the USSR, wood concrete became popular in the 60s. GOST was developed, copied from the technology of manufacturing Dutch material under the DURISOL trademark. By this time, wood concrete had already won a place in the markets of Europe and America due to its environmental friendliness, good heat and sound insulating properties and low specific weight of the finished wall structure. Abroad, this material is called differently: "dyurisol" - in Holland and Sweden, "woodstone" - in the USA and Canada, "sawn concrete" - in the Czech Republic, "centriboad" - in Japan, "duripanel" - in Germany, "velox " - in Austria. It is used in the construction of not only private houses, but also high-rise industrial buildings.

Types of wood concrete blocks

Arbolite composition and tenology very simple - cement, special chips, air-permeating additive. Industrial production requires equipment - wood chips, concrete mixer, molds.

The Soviet analogue of "Durisol" has passed all technical tests, was standardized and certified. More than a hundred wood concrete factories worked in the USSR. By the way, the material was used for the construction of buildings even in Antarctica. At the Molodezhnaya station, three service buildings and a canteen were built from wood concrete panels. The thickness of the walls was only 30 cm. There are practically no minuses of this material, but there are many pluses. Foundations for it are required the same as for aerated concrete.

Arbolite housesrather warm and durable, because such building blocks are made in accordance with technology. The price of such a house is comparable to the price of a house made of foam-gas concrete. But inherently these houses are more environmentally friendly.

However, in the Soviet Union, wood concrete did not become a material of mass use. A course was taken for the construction of large-scale concrete-block houses, for which arbolite was not suitable due to its characteristics. In the 90s, the wood concrete production industry in Russia fell into decay. But the condition of buildings built from wood concrete 60 years ago shows that the material is quite suitable for use in construction. Moreover, the technologies do not stand still.

Wood concrete chip cutter Wood concrete chip equipment

Today some foreign manufacturers produce wood concrete based on calibrated coniferous wood chips using special grades of concrete. There is a technology to remove sugars from organic matter, which "encourage" wood decay, special methods of drying wood chips. Special additives are used that increase the strength and durability of wood concrete and improve its consumer properties. So the initial advantages of wood concrete - the availability of components and environmental friendliness - can be supplemented with new ones. It is difficult to make a high-quality wood concrete with your own hands, but it is likely. You can buy high-quality wood concrete at a price of 3000 - 3400 rubles / m3.

In our country, rich in forest, wood concrete can be an excellent material for low-rise individual construction

Building wall blocks made of cement and wood chips, according to GOST 19222-84, are called "wood concrete products" and, if necessary, can be made at home on their own.

Wall blocks made of shavings and cement

The technology of manufacturing building blocks from wood concrete was developed in the USSR back in the 60s of the last century. A number of factories were built and launched. However, due to the "victory" of the panel construction technology, they forgot about the arbolite and returned to it quite recently. It is a unique building material that combines excellent thermal insulation properties, low cost and ease of manufacture.

Chip and cement blockson their own - recommendations of specialists:

• A mixture of wood shavings and wood chips should be used as raw material. At the same time, the content of harmful impurities is regulated: needles and leaves no more than 5%, bark no more than 10%. It is allowed to use shavings and chips with a particle fraction of 40x10x5 millimeters and a chip: chips ratio - from 1: 1 to 2: 1;
• Fresh shavings and wood chips contain sugar, therefore, in order to avoid rotting and destruction of the block, it needs special preparation before use. There are two options - exposure in the open air for 4 months with regular shoveling, or treatment with a special solution: 200 liters of 1.5% lime solution per 1 m3 of sawdust. Process the sawdust and leave for several days with regular shoveling;
• Quality blocks can be obtained using a mechanical concrete mixer;
• As a binder, you should use ordinary Portland cement of a grade not lower than M400, and use as additives: water glass, fluff lime, calcium sulfate and aluminum sulfate. In this case, the total amount of additives should not exceed 4% by weight of the cement;
• The proven and best combination of additives for the production of wood concrete blocks: a mixture of aluminum sulfate and potassium sulfate in a 50:50 ratio, or a mixture of calcium oxide and water glass in a 50: 50% ratio.

Features of the production of blocks from chips and cement

• Before use, shavings and chips must be passed through a chipper and hammer crusher, and also sorted on a vibrating screen or through a hand sieve;
• The finished mass with additives should be thoroughly mixed with cement in a mechanical concrete mixer and only then fed into the prepared forms. The proportions of the components are different. In general, a recipe is recommended: 1 part of Portland cement, 6 parts of a mixture of shavings and chips, 2 parts of sand + additives;
• Manufacturing technology of a form or several forms. From edged boards and wooden blocks, a frame with dimensions of 600x300x240 millimeters is knocked off or twisted (with self-tapping screws). On the opposite sides of the frame, handles are nailed (bars 250x50x50 mm). To each form, from boards and bars, a pallet is knocked down or twisted. For the convenience of removing the block, the inner surface of the frame and pallet is upholstered with galvanized steel or linoleum.

Product forming technology

Before pouring, the inner surfaces of the mold are lubricated with grease, machine oil or a special separating solution. Next, a mixture of cement with sawdust and additives is loaded into the mold, layer by layer. Each successive layer is rammed with a piece of bar covered with galvanized steel or mechanical vibratory rammer.

The filled and tamped forms are left for a day, after which the blocks are carefully removed, placed in a cool place and covered with plastic wrap. On hot days, to avoid drying out, the blocks are sprayed with water. After 14-20 days (subject to an ambient temperature of 20 degrees Celsius or more), the blocks are ready for use.

Application features

• When erecting external walls of buildings from wood concrete blocks, to prevent moisture ingress, it is recommended to equip a brick or concrete base, at least 0.5 meters high from the level of the blind area. For this reason, the overhang of the roof eaves beyond the outer surface of the walls should also be at least 0.5-0.6 meters with the mandatory installation of a rain and melt water drainage system;
• For laying blocks, cement mortar with a brand of at least 10 is used;
• Interblock seams should be 10-15 mm;
• Blocks of shavings and cement can be used as an internal insulation layer by analogy with adobe (blocks made of a mixture of clay, straw and sawdust);
• Arbolite blocks or wood concrete mass can be used as a filler for well masonry. Allowed to be laid to the full height of the floor without bricking or reinforcement;
• If necessary, it is possible to build lintels of window and door openings from wood concrete. Mandatory reinforcement is required.