New, and in in this case, forgotten old, wood concrete is returning to the building materials market. As practice has shown, building a house from wood concrete blocks with your own hands is a good prospect for building a strong, warm and reliable private house.
Disadvantages of brick and concrete walls known to everyone wooden houses Not everyone can afford it. An alternative to the above is wood concrete. Containing 80-90% wood chips, combined with a cement binder and modified with chemical additives, wood concrete eliminates the shortcomings and enhances the advantages of wood and concrete.
Wood concrete was created and tested in the middle of the last century, and its production is regulated by GOST 19222-84.
Technologies for the construction of private houses from wood concrete
A house can be built in two ways:
- Construction from arbolite blocks. In this case, industrially manufactured ready-made wood concrete blocks are used;
- Monolithic construction from wood concrete. The use of this technology involves the formation of permanent formwork and subsequent pouring of wood concrete mortar into it.
Often the decision is made to make wood concrete with your own hands. Before starting work, it is important to make sure that the blocks have gained the strength and hardness necessary for work.
To build a house from monolithic wood concrete you need to study the technology of the device monolithic walls. The remaining stages will be identical to block construction.
In this article we will focus on detailed description first option.
How to build a house from wood concrete blocks with your own hands
The main stages of work in the form of successive steps from A to Z.
Stage 1. Design of houses made of wood concrete
The development of the project precedes the start of work due to the need for its coordination and approval by the licensing authorities. In addition to the house plan itself, the cottage project contains information about the materials used, places and methods of connecting to communications, electrical and gas supplies, type of foundation, etc. The project makes it possible to further calculate the amount of material and the load it creates.
For your information, the design of a house made of wood concrete is no different from the design of a house made of foam concrete, and therefore a typical project can be used, taking into account the absence of the reinforcing belts necessary for foam blocks.
Stage 2. Selection of material for construction
Before you start construction work, you need to make sure you make the right choice wall material.
Arbolite certainly has a number of advantages. But! Only if it is of high quality and is used for its intended purpose.
You should know that wood concrete is used in the construction of buildings with a height not exceeding 7 meters. (height self-supporting wall). This makes it attractive when constructing a 2-3-story private house or cottage with an attic. In combination with columns or other structural elements(support pillars) that take on part of the load, more storey construction is allowed.
Which wood concrete is suitable for building a house
To purchase a high-quality block, professionals advise paying attention to the determining factors:
- price. Homemade wood concrete is much cheaper;
- fullness and uniformity of the block. The chips should be of more or less the same fraction, densely packed. The looseness of the block indicates its low compressive and bending strength;
Note: the use of sawdust increases the thermal conductivity of the block. Large chips are not completely saturated. As a result, the adhesion of wood to cement is disrupted and the block loses strength.
- block geometry. GOST allows a deviation from the specified size not exceeding 5-7 mm. The use of a special weight during the manufacturing process allows us to reduce deviations to zero.
Note: the unevenness of the blocks can increase the consumption of masonry mortar by 40%, makes the use of special adhesive mixtures inappropriate, and increases the consumption of plaster when finishing, increases the complexity and duration of work.
- color and impurities. Insertion of impurities or differences in color within the block indicate a violation of the manufacturing and drying processes.
- certificates that will indicate: cement quality, complete chemical composition, test results.
Stage 3. Construction of a foundation for a house made of wood concrete
A distinctive feature of wood concrete is good indicator bending strength, regardless of the purpose of the block. This gives the block the ability to recover from stress. In practice, this removes restrictions when choosing the type of foundation, which is an integral part of any structure. To a large extent, it is the quality of the foundation that determines the lifespan of the house.
What is the best foundation for a house made of wood concrete?
In practice, any can be used. Most often it is tape or combined.
Foundation technology for an arbolite house:
- marking for the foundation;
- removing the soil layer to the required depth;
- arrangement of sand and crushed stone cushion;
- compaction (recommended with watering to achieve greater density);
- installation of formwork;
- reinforcement;
- pouring the foundation.
- waterproofing the foundation strip;
- backfilling of sand inside the squares formed by the foundation strip followed by compaction;
- complete waterproofing of the foundation.
Note: during the pouring process, the channels provided for by the project are left for further installation of communications.
Before starting work, you need to decide on the size of the foundation.
- depth of placement. Depends on the type of soil, distance to groundwater, number of storeys of the building. The dependence of the parameters on the type of soil is shown in the table;
- foundation thickness. Depends on the total (static and dynamic) load on it.
When calculating static loads, you need to take into account:
- materials used in construction (their weight and quantity);
- presence of a base;
- wall material;
- material and number of floors;
- roofing material used;
- presence of insulation and its type;
- number of windows and doors. Total weight of elements warm circuit. When calculating the weight of the doors, you need to remember that entrance doors usually made of metal, which affects the load they create;
- material for facade cladding;
- materials for interior decoration;
- floor covering and type of flooring.
- calculated weight of furniture (195 kg/sq.m. according to SNiP 2.01.07-85).
In addition, dynamic load is taken into account:
- snow load in the region (see map). For example: the annual snow load for Moscow is 180 kg/sq.m. (according to SNiP 2.01.07-85). By multiplying this number by the roof area we get the total load. The calculations take into account the roof configuration and the resulting result must be multiplied by the coefficient M (0.94).
- wind load is calculated by the formula = House area * (15 x House height + 40);
- soil resistance to pressure exerted on it (according to SNiP 2.02.01-83). According to this standard, the resistance must exceed the pressure on it by 30%. The pressure of a building is calculated by dividing the weight of the building by the area of the foundation (sole).
Note: if the soil type is not determined, the minimum resistance value is used for calculations.
Stage 4. Construction of the basement of a house made of wood concrete
The plinth will better protect the wood concrete block from the influence of water. The recommended plinth height is 500-600 mm (depending on the level of precipitation in the region and the availability drainage system around the house). The base is made of brick or concrete.
Stage 5. Construction of walls from wood concrete
Let us immediately note that the construction of arbolite walls is notable for the fact that it is advisable to use cement-sand mortar. The choice is due to the uneven geometry of the block, which makes it economically unprofitable to use special adhesive solutions used for masonry cellular concrete such as Ceresit CT 21. Increased consumption of the adhesive mixture will increase the budget for building a house.
Consumption of cement-sand mortar is 1 m3 per 8-10 m3 of arbolite blocks. The value is approximate, because the geometry of the blocks is not constant, the discrepancy can be from 5 mm to 1.5 cm in width and height.
What to place wood concrete blocks on?
An alternative to the classic solution can be:
- Perlite mortar for laying wood concrete. Its feature is the ability to increase the thermal insulation of masonry. How to make perlite mortar: perlite is added to the classic mortar (cement, sand, water). The ratio is 1 part cement = 3 parts perlite.
- Sawdust concrete mortar. Recipe: 3 parts of sawdust are filled with a solution of aluminum sulfate (15-25.00 rubles/kg) or calcium chloride (28-30 rubles/kg). When stirring, the sugars contained in the sawdust are neutralized. Then 1 part of cement is added.
Note. Perlite is volatile, which means you need to work with it in the absence of wind.
Good reviews has thermal insulation masonry mortar with perlite LM 21-P. The Quick-mix mixture has water-retaining ability, so the blocks do not need to be moistened separately. Supplied in 17.5 kg bags, in the form of a dry powder. The solution is easily mixed with water (stir for at least 5 minutes) by hand or with a mixer (mixer). Ready solution use within 1-2 hours.
Laying walls from arbolite blocks
The technology for laying wood concrete is identical to brick or foam concrete wall, in addition, wood concrete strongly absorbs moisture from the solution, which means that the blocks need to be moistened before starting work.
1. Laying the first row of arbolite blocks
The masonry starts from the corner and is laid out in rows, periodically checking the degree of deviation with a level. The blocks are easy to process, so there will be no difficulties with adjusting the size.
The width of the seam depends on the geometry of the block and is 10-30 mm.
The solution is applied to the block of the previous row along the edges of the block. Thus, an air thermal break is obtained, which compensates for the high thermal conductivity of the masonry mortar.
On the construction forum, according to reviews, many users use additional method insulation of masonry by laying polystyrene foam tape in the seams, wooden slats etc. The gasket creates a gap in the mortar joint and thereby eliminates the appearance of cold bridges. How expedient this is, everyone decides for themselves.
Material prepared for the website www.site
The optimal thickness of wood concrete walls is 30 cm, for houses of two floors and above - 40 cm. A simple rule applies - the thicker the wall, the warmer it is. A wood concrete wall thickness of 20 cm is possible if cladding with brick or additional insulation inside and out. How thick the wall should be depends on what region the house is in, how it will be heated, and what the construction budget is.
2. Reinforcement of walls made of wood concrete
Craftsmen advise stiffening a wood concrete wall by reinforcing it. To reinforce wood concrete, polymer (plastic) mesh or metal rods treated with anti-corrosion compounds (for example, UR-108 enamel) are used. Thus, the corners of the building, the junction of walls, window and door openings are strengthened. Unlike aerated concrete and foam concrete, no mandatory requirement in masonry reinforcement, but many users reinforce every 3-4 rows of masonry.
3. Laying wood concrete (dressing)
Arbolite blocks are laid in a checkerboard pattern (laying with dressing). This is necessary for reliable adhesion. No more than 3 rows are laid out around the perimeter. Then there is a break for a day. During this time, the solution will dry and you can continue working. That's why it's often external walls are erected together with internal ones.
Advice. Adding additives to the solution that increase the rate of strength gain of cement will increase the speed of work.
The “Shuttle” accelerator, which provides strength gain in 12 hours (consumption of 3 liters per 100 kg of cement, price 75 rubles/100 g) and the “Virtuoso Start” accelerator, which also contains an anti-shrinkage agent, have proven themselves well. Provides 50% strength gain in 3 hours (consumption 1 liter per 100 kg of cement, price 80 rubles/100 g).
4. Lintels over window and door openings
The photo shows step by step how to make a lintel over a window and over a door in a house made of wood concrete. Two options for covering openings.
Installation of jumpers from a metal corner
(the edges of the corner are walled into the walls, blocks are installed inside)
Installation of a channel lintel
(a groove was cut out in the wood concrete blocks for inserting a channel)
5. Installation of an armored belt under the ceiling in a house made of wood concrete
After erecting the wall, before laying the floor (interfloor or attic) on the wood concrete wall, you need to pour a concrete (monolithic) reinforcing belt. Its arrangement will give the wall strength, allow it to more evenly distribute the load and securely secure the Mauerlat.
How to make an armored belt on wood concrete:
- one outer row is laid out in half a block (you can purchase a narrow block or cut a wall one). This will be the outer part of the formwork;
- With inside formwork is installed from edged boards, plywood or a narrow wood concrete block is also used;
- processed reinforcement is placed into the resulting recess (diameter 10 mm, in 6 rows) and filled with concrete (the grade of concrete is the same as that used for the foundation).
To make an armored belt, it is convenient to use a special U-shaped block (tray U-arboblock).
6. Installation of house floors made of wood concrete
A monolithic reinforced concrete slab, wooden or metal beams can be used as a flooring material.
Advice. Manufacturers of wood concrete blocks recommend producing. To do this, it is not necessary to pour a concrete belt. After all, the ability of wood concrete to “pull” moisture from concrete is not in the best possible way affects the quality of the fill. Additional supplements will be required. It is also advisable to use wooden floors for installing door and window openings. The masters completely agree with them and recommend using wooden beam as a lining of the perimeter of the wall under the ceiling.
The Mauerlat is attached to the wood concrete with the obligatory laying of a layer of waterproofing.
7. Installation of communications in a house made of wood concrete
Laying communication systems does not create difficulties. Any holes can be easily made in wood concrete blocks, so there is no need to immediately lay additional channels for sewerage, pipes, heating, etc.
Some people use a hollow block, installing it on an edge.
Stage 6. Construction of a roof for a house made of wood concrete
On arbolite walls can be installed rafter system any configuration. Choice roofing material also not regulated.
Experts advise using bitumen shingles for roofing works. They explain their choice by saying that bitumen shingles can perceive minor vibrations of wood concrete walls without the appearance of significant defects.
An important nuance when constructing a roof will be compliance with the rule - moving the roof 300-500 away from the wall, which will protect it from direct contact with rain and melt water.
I will answer your questions out of order, but I will answer everything.
Let's start with the film. It does not change matters whether this film will be vapor-permeable or vapor-proof. If it is vapor-permeable, then behind it (towards the street) there should be a ventilation gap. If it is not there, then the moisture remains in the first layer of reed. But technologically there is no way to create a gap there. If the film is vapor-proof, then everything is the same - the moisture remains in the first layer of reed. The fact that manufacturers put it there, but at the same time cannot clearly explain either its operation or its properties, suggests that the manufacturers, unfortunately, have not understood the operation of this design. Further. If, as you write, you install the film from the inside. Yes, this will protect the wall from vapors from the room. But this has nothing to do with moisture accumulating in the wall due to the dew point. There are two reasons for moisture in the wall. One is moisture from the room (we can protect against this with film). And the second is moisture that arises from the fact that there is a moisture condensation point (dew point) in the wall. This condensation occurs due to the difference in temperature and pressure, and if there is no vacuum in the structure, and there is no vacuum there, then this condensation will occur, even if the inside is closed with a film. Even if the wall is “wrapped with film” both outside and inside, there will still be condensation there. because there is air inside, and there is a difference in pressure and temperature. Long-winded, but I hope I explained it.
A vapor-permeable (breathable) wall or a vapor-tight (non-breathable) wall, there really is not much difference. And in terms of ventilation power too. Have you seen the numbers, the difference is within 15-20% maximum. It’s just that, to be honest, I’m surprised by the combination of non-breathable walls and clay. And, as I understand it, plastic windows, So? If a house is built with such walls for reasons of ecology, naturalness, naturalness, then something is not logical for me :-). And if clay with wood chips is just a way to make the structure cheaper, then it’s logical.
In general, regarding films (or membranes), I would not use them in this wall at all.
On the plaster wall. I have never seen this reed (straw) mat in person. If you have seen how they are plastered, then great. In fact, if they are cut and the fibers are located perpendicular to the plaster layer, then they should hold up normally. Mineral wool for plastering works. In ordinary cotton wool, the fibers are parallel to the wall, while in wool for plaster they are perpendicular, so that the mixture holds better.
By dew point. I consider the thermal conductivity for clay to be 0.1 (rounded to 0.095), for a reed mat the thermal conductivity is 0.7 (rounded to 0.065). Dew point in the second layer of reeds (counted from the outside). Therefore, even more so, you cannot cover it with any film. All moisture from there should be evaporated freely through the reed and plaster. In terms of heat, by the way, if you count clay as 0.1, then 300 mm is almost enough for Minsk. 300 mm clay + 10 mm reed, - with a margin. And 300 mm of clay + 200 mm of reed - with a large margin. But I would not remove the “extra” from the design, since these are thermal conductivity coefficients “on paper”, and in life, in my opinion, they have not yet been fully tested.
It seems to have answered everything, ask away.
Sawdust and cement blocks
Nowadays in construction you won’t surprise anyone composite materials. What only coexisted peacefully yesterday, today, thanks to new technologies, complements each other and mixes. And the result is materials that have acquired better quality characteristics from the mixed components, and even new properties altogether. These materials also include wood-cement. We know that when mixing solutions, fillers are needed. So why shouldn’t wood waste be used as a filler? The benefit is double: the waste will be used, solving the problem of its disposal, and the concrete will become much lighter.
Types of wood-cement materials
Since wood materials of different sizes and structures can be added as filler, and the addition of cement and other components can be in different proportions, there can be several wood-cement materials. Here are the main ones:
- - wood concrete;
- - fiberboard;
- - sawdust concrete;
- - CSP (cement particle boards);
- - xylolite.
And since differences in composition lead to differences in properties, materials with different performance characteristics are obtained. This allows the use of wood-cement materials in construction quite widely.
Arbolit
This is lightweight concrete made from crushed wood, water, chemical additives and a mineral binder, most often Portland cement. Crushed wood is obtained from both deciduous and coniferous trees; it is even possible to fill the concrete with flax or hemp husks, chaffed straw, and crushed cotton stalks.
The wood concrete production technology is as follows:
- 1. Wood waste is fed by conveyors into the chipper.
- 2. The resulting chips are sent to a hammer crusher.
- 3. A pneumatic conveyor feeds the resulting material into a vibrating screen, from where dust and fine crushed material go into the waste hopper, and large crushed material is sent for re-crushing.
- 4. The required crushed fraction enters the soaking bath, and from there through the dispenser into the mixer.
- 5. Through other different dispensers, cement, water and chemical additives are supplied to the mixer.
- 6. The resulting mixture in molds is compacted with presses or vibratory compaction units.
- 7. Forms with wood concrete are subjected to heat treatment and drying.
Use of wood concrete: partitions, slabs for floors, floors and coverings, large-format wall panels, wall blocks and so on.
Fibrolite
It consists of slabs made from wood shavings and mineral binder. Chips longer than 35 cm and width 5-10 mm is ground into wool. Next, the technological process looks like this: the shavings are mineralized with potassium chloride, moistened and mixed with cement paste, and the slabs are pressed at 0.4 MPa. This is followed by heat treatment in curing chambers and drying.
Fiberboard is used both for the construction of walls and as a filler and insulating material in frame structures. It should be noted that when using fiberboard as a wall material, it should be plastered, and where humidity is high, it cannot be used at all.
Sawdust concrete
This is lightweight concrete made from sand, Portland cement and sawdust. The technology is as follows: sawdust and small shavings are poured into the mixer, and water with mineral additives and Portland cement are also supplied there. All this is mixed, arranged into shapes and compacted. In order for sawdust concrete to harden faster, it is kept in thermal chambers for 24 hours at a temperature of 40-60°C.
Sawdust concrete is used for the production of panels and wall blocks, and is used to make clean floors.
Cement particle boards
They are the most commonly used wood-cement materials. For their productionwood shavings are used, then a cement-shaving mixture is prepared from it by mixing the shavings with water, cement and mineral additives, followed by dosing, molding, pressing and heat treatment.
Cement particle boards are frost-resistant, fire-resistant and bio-resistant. this justifies their use in prefabricated housing construction. Moreover, they can be used for facade work and interior decoration. They're not afraid high humidity, have proven themselves well in restoration work.
Have cement particle boards and disadvantages. The high density (up to 1.4 t/m³) makes it difficult to lift slabs for cladding the top floors of houses without winches andforests They also have low bending strength and the slabs can break. At the same time, they are very resistant to longitudinal deformation, for this reason they are used to strengthen house frames.
Xylolite
It consists of magnesium binder, alkali-resistant pigments and sawdust, to which finely dispersed minerals: asbestos, marble flour, talc.
During production, sawdust is sifted through two sieves (the remaining on 1 sieve and sifted through the second in technological process does not participate). The binder is prepared in mixers: first magnesite is supplied, then coloring pigments, then magnesium chloride (as a hardener). This mixture is fed into another mixer, where it is mixed with sawdust for about 5 minutes.
Next, the slabs are formed under significant pressure (up to 10 MPa), at high temperatures (up to 95°C) and harden in curing chambers. Then, to ensure complete condition, the slabs dry in warehouses for two weeks. In order to increase water resistance, the slabs are impregnated with hydrophobic compounds. Most often these slabs are used for the production of floors.
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Arbolite, as a building material, was known back in the days of the USSR, factories were operating and houses were being built. After the collapse of the country, the technology was forgotten for some time, and a few years ago it was remembered again. The material is warm, light, durable, does not conduct sound well, and is also inexpensive. Therefore, wood concrete and arbolite blocks(arboblocks) are increasingly of interest to private developers.
Let’s immediately determine that wood concrete and sawdust concrete are different materials with different characteristics. Wood concrete contains waste from the woodworking industry, but only in a strictly regulated size. There is no other filler anymore. Moreover, everything is prescribed in GOSTs and instructions. And the filler is not sawdust, but wood chips with dimensions recommended by the standard of no more than 40*10*5 mm.
Properties, advantages and disadvantages
For a private developer when choosing building material important specifications material. Let's look at wood concrete blocks from this side. So, the characteristics and their brief explanation:
The properties are very good. Another thing is that they will only be provided that the proportions and technology are strictly observed. This is why arblite blocks are dangerous: you don’t know how well they are made.
Performance characteristics
As you can see, the characteristics of the arboblock are quite good. Another plus is the low weight, big sizes and good ability to absorb sounds. A very big plus - the blocks are easy to cut and easy to shape the required form. Another positive point is that wood concrete holds nails and screws well. There are no problems on this side either.
- Shrinkage - 0.5-0.6%. This parameter shows how much the geometric dimensions walls under load. Wood concrete has one of the lowest rates.
- Water absorption 40-85%. This figure is very large. If you put an arbolite block in water, it can absorb a lot of water. For the developer, this means that care must be taken to ensure good waterproofing between the foundation and the first row of blocks. Also, an arbolite house needs exterior decoration which will protect the material from moisture. It's not all that scary. It is much more important that the hygroscopicity of wood concrete is low (the ability to accumulate vaporous moisture). Even with very humid air, it does not become damp, but allows vapor to pass through itself, regulating the humidity in the room.
- Fire resistance - class G1. Arbolite refers to materials that do not support combustion. This is their undoubted advantage.
If we talk about technical characteristics, then there is essentially one serious disadvantage - high water absorption. There is one more drawback, but it is from the field of operation. Mice love arbolite very much. The material is natural and warm. The problem can be solved by making a high base - no lower than 50 cm.
Technology for the production of wood concrete blocks
Arbolite refers to lightweight concrete, the technology is almost standard, with the exception of some nuances: the need for pressing and the use of a forced concrete mixer rather than an ordinary gravity concrete mixer when mixing. It mixes the wood chips better with the other ingredients.
Compound
The composition of wood concrete includes four components:
- high-quality cement (M 400 or M 500);
- wood chips;
- water;
- chemical additives.
The cement must be dry and fresh. Chips are of a certain size. The less misgrading there is, the stronger the block will be. Chemical additives are calcium nitrate and chloride (food additive E509), liquid glass, aluminum sulfate and some other substances. Please note that they are first diluted in water and only then added to the wood chips and mixed. Any drinking water is allowed, but not industrial water, without contamination. After the wood chips are evenly wet, cement is added. Any other sequence is not allowed.
Types and sizes of blocks
Depending on the density, wood concrete blocks are divided into thermal insulation (up to 500 kg/m 3) and structural (from 500 kg/m 3 to 850 kg/m 3). For construction one-story houses you can use the lightest structural ones with a density of 500 kg/m 3. For mansions of 1.5 and 2 floors, the minimum density is 600 kg/m3 and higher.
The sizes of arbolite blocks can be different. The most common is 500*200 mm and different thicknesses - from 100 mm to 400-500 mm. But different factories and workshops produce blocks of different sizes. The molds for them can be welded from ordinary sheet iron, so this is not a problem. The photo shows an example of the assortment of one of the workshops.
As you can see, blocks of 600*200 mm and 600*250 mm are also available and thicknesses range from 100 to 500 mm. It is also possible for load-bearing walls and choose suitable ones for interior partitions. Also for self-made arbolite blocks can be made suitable shape. That is if you decide to make them yourself.
Proportions
Like any building material, wood concrete is divided into strength classes. For the construction of load-bearing walls of houses required class strength B 2.5.
The amount of necessary materials per cubic meter of wood concrete mortar is in the table (photo above).
Pressing technologies
All these components are mixed and blocks are formed from them. There are several technologies:
- just by pressing:
- manual on the floor (great effort required);
- manual rammer on a vibrating table.
- pressing with vibration on a vibrating machine.
The easiest way to do this is by hand pressing. But it is difficult to control the density and strength of the resulting blocks in this way.
Normal production conditions
For the normal process of cement hydration, a temperature of at least +12°C is required. There are no other conditions. The peculiarity of production is that after molding the block, at least 2-3 weeks must pass before it can be used. During this time, the cement will gain about 50-60% strength (depending on temperature) and you can already work with the blocks. That is, blocks must be made long before construction begins. If you consider that wood chips must be left in storage for at least 4 months before being used, then you can start a year before construction.
Another practical point: if you are going to make wood concrete blocks with your own hands, in addition to a platform for mixing and storing components, you need a platform for settling the blocks. The place should be covered, protected from rain and sun. There should be no drafts either.
Wood chips: how to get or where to buy
The best wood chips for wood concrete are made from pine and spruce. You can also use larch, but when mixing it is necessary to double the amount of chemical additives. Among hardwoods, GOST allows the use of aspen, beech, birch, and poplar. The remaining requirements are:
The best wood chips come from lump waste wood. It is first passed through chippers and then crushed in a hammer crusher. The following mechanisms can be used for this:
- Disc chippers with adjustable knives. Not all of them can be adjusted to produce chips of the required size, but the sizes will be close.
- Rotary knife crushers. They produce narrow and not wide chips, and the length is adjustable. That is, this is - a good option. There is only one “but”: there are a lot of knives and if used for a long time, they need to be changed or welded (they don’t sharpen). As an advantage, we add that crushers of this type can be used for re-crushing process chips obtained during the first crushing (after reconfiguration).
- Shredders or roller grinders. This is expensive equipment (about 1 million rubles), mostly imported, but it is excellent because it is manufactured for specific chip sizes.
If making wood chips yourself is not an option, you can buy it. If possible, you can negotiate at the factory where wood concrete is produced. Just check the chip parameters. If there is none nearby, you can take chips from under the calibration machines. Some of them can be adjusted so that the chips are not thick.
Features of making mortar for arbolite blocks
Wood waste contains sugars. If you use fresh raw materials, the sugars may begin to ferment, which will cause the destruction of the integrity of the block. When mixing, chemical additives are added to the solution that neutralize their effects (liquid glass, calcium chloride, alumina sulfate, lime). They can be added in combinations: calcium chloride with liquid glass or alumina sulfate with lime. The total mass of additives should not exceed 8%.
There are other ways to break down sugars. The simplest, but requiring a long period of time, is to keep the wood chips in a pile for at least 90 days in the air. If it is not possible to wait, the wood chips are soaked in lime milk for 3 days, stirring occasionally. Then it is strained, not dried, and used in this form for kneading. Only in this case it is necessary to take into account that significantly less water will be required. This method works well, but it is very troublesome. It is easier to find an opportunity to purchase chemical additives.
The procedure and features of mixing the solution
To mix the solution, use a forced-type concrete mixer. You can also use a regular gravity or “pear”, but you have to knead in it for a long time, although you can adapt - tilt the pear as low as possible when kneading (it hardly mixes when raised).
First, sawdust is poured in and a certain amount of water is added. While the sawdust is getting wet, chemical additives are diluted in a small amount of water, then they are unloaded into a concrete mixer. When all the wood is uniformly wet, cement is poured. It is loaded in portions, waiting for uniform distribution throughout the entire volume. The cement should envelop each chip from all sides. This is only possible if the sawdust is well wet, so we monitor this stage carefully.
Block molding
The solution is poured into molds. Most often they are made of metal and are a box with handles without a bottom. The form is placed on flat surface(board, for example). When manually tamping, the molds are filled with wood concrete mortar, layer by layer, each of which is pressed with a metal platform with a handle. In order for the air to escape better, the thickness of the material is pierced several times with a metal rod, and then pressed again. This procedure can be repeated several times until the desired layer density is reached, after which the next one can be poured. The layers are poured to the upper edge of the block, after final compaction the top is leveled, cutting off the excess with a metal strip.
You can use a lever - mechanical or driven. In this case, the force develops significant and the entire volume can be loaded at once, if necessary, adding to the edge. To achieve high density, you can press several times, now increasing and then loosening the pressure. Experience shows that with this principle of manufacturing arbolite blocks, they are more durable, and depressing (restoring shape due to the elastic force of the chips) is much less pronounced.
Better blocks in terms of strength and with less effort are obtained if vibration is added during the pressing process. In this case, the efforts required to obtain the required strength are reduced significantly. Vibrating tables are made for these purposes. And the process is called vibration with a weight.
The formed block on a stand is transferred to the drying place. If the solution allows and the block holds its shape, the frame can be removed. But sometimes homemade wood concrete blocks suffer from the fact that the solution turns out to be too liquid - this makes it easier to compact. In this case, the blocks are left in the mold for a day. Use and transportation of blocks is possible no earlier than 2-3 weeks after molding.
Features of the construction of their arbolite blocks
The masonry of blocks is carried out according to the brick type - with ligation of seams, on cement-sand mortar. One of the features is the thickness of the seam - about 8-10 mm. Between the foundation and the first row of blocks it is necessary to make a very high-quality cut-off waterproofing. This will prevent moisture from leaking through the foundation from the soil. We do a combination of waterproofing - first we impregnate bitumen mastic or any other coating waterproofing, we lay it on top roll waterproofing. In the past, roofing felt was always used, but today it is of low quality and will collapse in a couple of years. And it is important to prevent moisture leakage (due to the high water absorption of wood concrete), so use waterproofing or something similar. It is possible, in two layers, also coated with bitumen mastic.
The next nuance is the masonry above the window and doorways. It is best to use special U-shaped blocks in which to lay a reinforcing frame and 4 reinforcement bars with a diameter of 10-12 mm. It is better to tie it down so that there is less chance of corrosion. First, blocks with recesses are installed above the opening. They can be supported from below with a board and spacers. Then the frame is laid, everything is filled with concrete. Leave the structure for a day, after which the supports can be removed and masonry can continue.
There are many nuances of building a house from wood concrete blocks in the video.
Blocks made of cement and sawdust
When producing products for construction, cement and wood chips are mixed. The technology is accessible and does not require application special equipment. Independent production using sawdust blocks allows you to significantly reduce the estimated cost of construction and prepare a material with your own hands that is environmentally friendly. The increased performance characteristics of products made from Portland cement and sawdust make it possible to construct residential buildings, cottages, as well as outbuildings. For correct application of the material, it is necessary to study the characteristics, recipe, become familiar with the advantages and disadvantages, and also master the technology for manufacturing products from cement and wood waste.
Sawdust concrete blocks - characteristics
Sawdust blocks are a lightweight building material. They are a type of concrete products characterized by a reduced specific gravity. Thanks to unique properties, the material is in demand in the construction industry.
Arbolite is light variety sawdust-based concrete and high-quality cement
Differs in the following characteristics:
- thermal properties. In buildings based on sawdust concrete blocks, it is easy to maintain a comfortable temperature regime;
- environmental safety. Sawdust blocks are made from raw materials of natural origin;
- increased safety margin. Sawdust concrete blocks ensure the stability of the buildings being erected;
- fire safety. The manufacturing technology and the components used ensure the fire resistance of the concrete composite;
- increased vapor permeability. The structure of the array helps maintain favorable room humidity;
- resistance to temperature fluctuations. Blocks made of shavings and cement can withstand repeated cycles of freezing followed by thawing;
- affordable price level. By using building blocks based on cement and wood chips, you can significantly reduce the estimated cost of construction.
Depending on the specific gravity sawdust blocks are divided into the following types:
- thermal insulation, characterized by a density of 0.4–0.8 t/m3;
- structural, the specific gravity of which is 0.8–1.2 t/m3.
High technical characteristics ensure the popularity of products made on the basis of cement binder and sawdust.
Sawdust concrete belongs to the category of lightweight materials
Blocks made of sawdust and cement - advantages and disadvantages
Sawdust blocks have the following advantages:
- increased degree of sound insulation. The sawdust concrete composite absorbs extraneous noise, which makes you feel comfortable in the room;
- harmlessness to others. When using products made from environmentally friendly natural raw materials, no harmful substances are released;
- fire resistance. Blocks of sawdust and cement do not ignite when exposed to temperatures up to 1100 °C for two and a half hours;
- ease of processing. The material is quickly processed by the tool and maintains its integrity under mechanical stress;
- accessibility. Chips are a waste product from wood processing enterprises and are available at an affordable price;
- simplicity of masonry. Building blocks, characterized by an increased volume with a low weight, allow you to quickly erect walls;
- long service life. Products made with high quality and protected from moisture absorption are durable.
Blocks made from these materials are widely used in the construction of houses, cottages, and outbuildings.
Along with the advantages, the material also has weaknesses:
- Long production cycle. Acquisition performance characteristics occurs within three months from the moment of pouring into molds.
- Increased moisture absorption. Sawdust concrete needs reliable moisture protection from all sides.
- Possibility of using wood chips only from certain types of wood. Sawdust with a reduced sugar content is used, the decomposition process of which affects the strength of the material.
Having assessed the advantages and analyzed the disadvantages, many developers prefer products based on cement and wood chips.
Making blocks from sawdust and cement with your own hands
The production of sawdust blocks involves the following steps:
- Procurement of raw materials for the manufacture of sawdust concrete products. The presence of the necessary materials in construction warehouses allows you to purchase all components before starting production.
- Preparation the necessary tool or mixing equipment. You can use a concrete mixer to prepare the mixture in larger volumes or manually mix it in a container using shovels.
The undoubted advantage of sawdust concrete is that you can make it yourself
- Mixing components in accordance with the recipe. The use of concrete mixers for automation helps to improve the quality of mixing, productivity, and improves the quality of sawdust concrete.
- Pouring the solution into molds. Collapsible wooden containers made from 20 mm thick boards lined with plastic sheets or metal are used.
- Drying sawdust concrete under natural conditions. Acquisition of operational hardness and evaporation of moisture occurs within 90 days after molding of sawdust concrete products.
Block composition
Sawdust blocks are made based on the following ingredients:
- Portland cement;
- sand;
- clay or slaked lime;
- wood chips;
- water.
Components
Waste is used for production various types wood:
- pine trees;
- fir;
To make wood concrete, you need clean wood chips (wood particles), not bark or leaves.
- poplars;
- ash;
- birch;
- beech;
- oak;
- hornbeam;
- larches.
