Arbolite blocks. Arbolite blocks from a mixture of sawdust and cement Wall blocks from chips and cement

Two kilometers from Lake Naroch, 20 years ago, a unique type of settlement for Belarus appeared - the ecological village of Druzhny. By its very existence, it proves that high-quality and budget housing can be built from the simplest materials: wood, straw, wood chips and clay. And this option for solving housing issues in the countryside may well become an alternative to construction in agro-towns.

Helped all over the world

The Germans, who first visited our country in the early 90s, were so impressed by the scale of environmental and economic problems that they had the idea to help families who lived in the contaminated territories move to more favorable regions of Belarus.

The first houses in Druzhny on Naroch began to be built by a group of German volunteers in 1993. Land for a settlement for migrants was allocated by the authorities in the Myadel district of the Minsk region. There was also an agreement with the chairman of the local collective farm, who wanted to attract labor to his farm in this way.

When choosing materials for construction, the Germans focused on their environmental friendliness and availability in this area. With the shortage of everything at that time, including building materials, there was practically nothing to choose from. But wood, straw and clay were in abundance.

Yuri Suprinovich

From the Belarusian side, the International Charitable Public Association Ecodom (in 2014 it was renamed EcoStroitel) also took part in the project “A House Instead of Chernobyl”. Its representative, Yuri Suprinovich, says that then, according to the goals of the project and the existing material base, it was necessary to choose a construction technology that would allow people to build a house without any special skills. As a result, a German frame house with walls filled with a mixture of straw and clay was chosen as the model.

Volunteers from Germany came to build the first houses. Among the German volunteers were specialists who performed two tasks: supervised the construction and taught others the technology: now Druzhny probably has more specialists in adobe construction than in the whole country.

At first they built houses with straw filling, later they switched to wood chips: it turned out to be easier to work with, the material itself is just as cheap and affordable.

The combination of free labor of volunteers and the low cost of “grassroots” building materials made it possible to build 14 houses by the official opening of the ecovillage in 1997 (now there are 31).

In order to move from a radiation-contaminated area to a clean one and at the same time get a new house for free, applicants were selected. One of the main criteria is the desire to contribute to the construction of the village.

“My family and I moved here from the Khoiniki district in 1994,” says Valentine, one of the earliest eco-settlers. — We saw an advertisement in the newspaper, which said that a German charitable organization would build houses on Naroch for migrants from contaminated areas, and there would be a selection among those wishing to resettle. We did not count on something much, but the letter was written. Two weeks later the answer came: come.

Valentin's family was among the first eight who passed the selection. But only two of them remained here. The rest got scared and refused to move.

“They can be understood,” Valentine says. - We arrived here on March 20, 1994, and here is an open field. It is now here the road, trees, houses, and then it was slush, dirt, a collective farm ... Many looked at all this and immediately left. Because it was not clear whether there would be a kindergarten, a school, a shop, a job. It was a difficult moment. This is not the same as coming to Minsk and they gave you an apartment.

The settlers first built their houses, then helped others. The collective farm paid them wages as builders.

We were told that the houses would be built of mud and straw. We thought that the straw would be only for the bundle, and the rest would be clay to make it stronger. But everything turned out to be wrong. First, clay is mixed with water in a concrete mixer, “sour cream” is obtained. It was poured into a dug hole 3 × 3 m and straw was added, which was brought by the collective farm. And all this was mixed up and trampled under foot. Then the straw in the clay was thrown onto wooden decks so that it flowed around, dried up. Then it was sent to the formwork, fixed to a wooden frame, and rammed. Immediately, to be honest, I did not believe that something normal would turn out. But when the formwork was removed, I saw that the walls were even and neat. And now 22 years have passed - nothing has rotted. I also remember that everyone was afraid that the mice would stretch the straw. But they are not in the walls. It's nonsense that someone will gnaw through the moves there.

Clay and straw inside the wall of one of the first houses: after 20 years it is dry inside, there are no mice

Valentin said that they worked side by side with the Germans at the construction site. Our people were greatly impressed by their technical equipment.

- In 1993, German carpenters arrived, so they had so many tools - for all occasions. We have never seen such things before our eyes: circular saws, tools for studding the details of the frame ... We were immediately afraid to take them into our hands, before that we only knew axes and hand saws. Then the Stihl chainsaw was first seen!

Valentin says that he made the first repair two years ago - he repaired the facade.

Previously, the facades were sheathed with clapboard. Now many are changing it - in 20 years the paint has peeled off them, in some places the wood has begun to rot. But the walls themselves are in excellent condition. They are insulated and plastered. In the first houses, clay plaster was applied without reinforcement, so it cracked in some places - greased it, and we continue to live. I decided not to change the staircase that the Germans made for me, even though it creaks. Then in the 90s it was not possible to find dry lumber, so it was assembled from raw boards. Well, she creaks, but it's not scary. The second floors are minimally insulated - only 15 cm of straw and clay between the rafters. I had to warm it up over time. But this is in our first homes. Now they are building warm attics. But what no one in the village will complain about is the dampness. In our homes, there is always normal humidity - at least heat it, at least keep it in the cold.

German pellet boiler

By the way, in almost all the houses of immigrants, in addition to the modern water heating system, there are also stoves. Just in case.

Now the houses in the village are heated by natural gas. But the public house, also known as the "office" and the house of creativity in combination, is heated by a pellet boiler with automatic feed. Valentin says that 3 tons of pellets are purchased for the season. The heating system has solar collectors that work in tandem with the boiler. Thus, the house is heated, and hot water is always available.

There are not as many children in the village as before - they grew up and left. But the local house of children's creativity is not idle. Valentin says that many families have adopted adopted children. Clubs have been set up for them.

Ecovillage public house

Now Valentin looks after the common house, maintains wind farms, which stand on a hill near the village. He is not going to leave Druzhnaya.

- The houses passed into our ownership after 10 years, before that we did not have the right to sell them. It was believed that if you lived here for so many years, it means that you got accustomed. Most of the settlers stayed here. And I took root, although I sometimes go home. I can say that people live better here. There are many drunkards, there is practically no work ...

There are houses for sale in the village of Druzhnoy, but there are no options for a penny.

- The houses here are excellent - all communications, large plots, near Naroch. A neighbor recently sold it to someone for a dacha for $26,000.

New settlement in Stary Lepel

A similar settlement appeared in the Vitebsk region - in the village of Stary Lepel.

— Representatives of the local authorities came to Druzhny — they liked this model of the settlement, and in 2001 they invited them to their place, allocated a site, — says Yury Suprinovich. — By this time, the legislation had already changed, new requirements for the energy efficiency of buildings under construction had appeared. Therefore, new houses have already been built with additional insulation.

All of our constructed public buildings - an outpatient clinic in the village of Zanaroch and a social rehabilitation center for the disabled - are heated by pellet boilers and solar collectors. This increases the initial costs, but with further operation they pay for themselves.

Photo from www.oekodomstroj.by

Yuri says that mineral wool or expanded polystyrene are non-environmentally friendly materials, and there were no others on our market at that time. Focused on Europe. There were already options from flax fiber, reed, cork, hemp, ecowool.

As a result, we decided to make reed insulation - there is plenty of it in the country. In addition, it is a constantly renewable resource. This is how the first Belarusian production of reed slabs appeared.

“We learned how to harvest reed ourselves and now we use it as thermal insulation in our houses. The most interesting thing is that we did not come up with anything new - even in the USSR there was a building material called "reed". Today, the EcoDomStroy enterprise provides not only our facilities with reed mats, but also sends them for export, uses them when insulating houses on orders from the population

Reed is harvested in winter on the ice on Lake Naroch. There is a special self-propelled harvester for this. Local residents also have additional earnings, harvesting and selling cane to the manufacturer.

Reed plates are made on special German machines. They are very old, 1948 release.

"I know what I'm building"

Wood chips and clay are now being built not only according to social programs. They are also ordered privately. One of these houses is currently being erected on the banks of the Vileika reservoir.

Its owner, Vyacheslav Makushinsky, heads the Belarusian-German society "Children's Rehabilitation and Health Center" Nadezhda ". He told the site that he is familiar with the technology and, in his opinion, it has proven itself well.

Vyacheslav Makushinsky, Head of HICC "Nadezhda"

- I first got acquainted with this technology during the construction of two guest houses in the institution that I manage. We built the first house using frame technology with the walls filled with ecowool, the second - with clay and wood chips. Therefore, I already have practical experience in both the construction and operation of such houses. When I decided to build myself, the choice was predetermined. It was important for me that the materials were as natural as possible. Ecowool is also a natural material, but already transformed. And clay, wood chips, wood for the frame - all these are exclusively natural materials.

Now the builders are busy filling the walls with a mixture of wood chips and clay. It is kneaded in a large concrete mixer - up to 0.8 cubic meters can be cooked in it at a time. The mixture is transported by a construction wheelbarrow to the workers, who fill it with buckets into a removable formwork and ram it. In total, 7 builders are involved in the construction.

Unlike standard frame houses, which are built from sawn timber of a small cross section, these frames use natural moisture timber with a cross section of 120 × 120 mm. After the outer walls are filled and the roof is installed, ceramic brick partitions will be erected inside. After that, construction work will stop until July next year: the house should dry out by this time, the wood chips should shrink. That is, such a frame house cannot be built in one construction season.

To build this house of 130 squares, without an attic floor, it took 25 cubic meters of wood chips. Clay was “mined” right on the site when they dug a hole for an autonomous septic tank. At first glance, the technology is simple and looks attractive in terms of financial costs: clay and wood chips are much cheaper than gas silicate.

“If a person has a desire to save money on building a house, then you need to do a lot yourself or with the involvement of volunteers - relatives, friends,” says Yury Suprinovich. - Then the benefit is really obvious, since the wages of builders will be practically zero. If you invite a construction company, then at a price a house made of wood chips and clay will come out no cheaper, and maybe even more expensive than a traditional house. During the construction, a lot of manual labor, and it is not cheap.

Knowledge and experience can be obtained completely free of charge. It is enough to be a volunteer in the construction of such houses.

Yuri Suprinovich says that compared to agro-houses, the construction of which was financed by agricultural enterprises, houses using German technology were somewhat cheaper. And this is without saving on the quality of finishes and the level of equipment with internal engineering systems. For example, a ready-to-live-in house of 130 square meters in Old Lepel cost about 50 thousand dollars (without landscaping the adjacent territory).

Wood concrete, as a building material, was known back in the days of the USSR, factories worked, houses were 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 turns out to be warm, light, durable, conducts sounds poorly, and its cost is also low. Therefore, wood concrete and wood concrete blocks (arboblocks) are increasingly interested in private developers.

Let us immediately determine that wood concrete and sawdust concrete are different materials with different characteristics. The composition of the wood concrete includes waste from the woodworking industry, but only of a strictly regulated size. There is no other placeholder. And everything is spelled out in GOSTs and instructions. And the filler is not sawdust, but wood chips with dimensions not exceeding 40 * 10 * 5 mm recommended by the standard.

Properties, advantages and disadvantages

For a private developer, when choosing a building material, the technical characteristics of the material are important. Let's look at wood concrete blocks from this side. So, the characteristics and their brief decoding:

The properties are very good. Another thing is that they will only be subject to exact observance of proportions and technology. This is what arblelite blocks are dangerous for: you don't know how well they are made.

Performance characteristics

As you can see, the characteristics of the arboblock are not bad. Pluses still need to add light weight, large size and good ability to absorb sounds. A very big plus is that the blocks are easy to cut, it is easy to give them the desired shape. Another positive point is that nails and screws hold well in wood concrete. From this side, too, no problems.

• Shrinkage - 0.5-0.6%. This parameter shows how the geometric dimensions of the wall will change under load. Arbolite has one of the lowest rates.
• Water absorption 40-85%. This figure is very high. If you put the wood concrete block in water, it can absorb a lot of water. For the developer, this means that you need to take care of a good cut-off waterproofing between the foundation and the first row of blocks. Also, the wood concrete house needs an exterior finish that 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 passes vapors through itself, regulating the humidity in the room.
• Fire resistance - class G1. Arbolit refers to materials that do not support combustion. This is their definite plus.

If we talk about technical characteristics, then there is essentially one serious minus - high water absorption. There is another drawback, but it is from the field of operation. Arbolite is very fond of mice. The material is natural and warm. You can solve the problem by making a high base - not lower than 50 cm.

Production technology of wood concrete blocks

Arbolit belongs to lightweight concrete, the technology is almost standard, with the exception of some nuances: the need for pressing and using not a conventional gravity concrete mixer, but a forced one when mixing. It mixes wood chips with other components better.

Compound

The composition of the arbolite includes four components:

• high-quality cement (M 400 or M 500);
• wood chips;
• water;
• chemical additives.

The cement must be dry and fresh. Chips - a certain size. The less regrading, 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 chips, mixed. Any drinking water is allowed, but not technical, without pollution. After the chips are evenly wet, cement is added. Any other sequence is not allowed.

Types and sizes of blocks

Depending on the density, arbolite blocks are divided into heat-insulating (up to 500 kg / m 3) and structural (from 500 kg / m 3 to 850 kg / m 3). For the construction of one-story houses, you can use the lightest of the structural ones with a density of 500 kg / m 3. For mansions of 1.5 and 2 floors, the minimum density is 600 kg / m 3 and above.

The sizes of wood concrete blocks can be different. The most common - 500 * 200 mm and different thicknesses - from 100 mm to 400-500 mm. But different factories and workshops produce blocks of different sizes. Forms 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 the thickness is from 100 to 500 mm. You can choose the appropriate ones for load-bearing walls and for interior partitions. Also, for self-production of wood concrete blocks, it will be possible to make a 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, the required strength class is B 2.5.

The amount of materials needed per cubic meter of arbolite solution is in the table (photo above).

Pressing technologies

All these components are mixed, blocks are formed from them. There are several technologies:

• just pressing:
  • manual on the floor (requires great effort);
  • manual tamper on a vibrating table.
• pressing with vibration on a vibrating machine.

The easiest way to implement manual 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 the production is that after the block is molded, at least 2-3 weeks must pass before it can be used. During this time, cement will gain about 50-60% strength (depending on temperature) and it is already possible to work with blocks. That is, it is necessary to make blocks long before the start of construction. Given that the wood chips must be aged for at least 4 months before use, then you can start a year before construction.

Another practical point: if you are going to make arbolite blocks with your own hands, in addition to the 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.

Chips for wood concrete: how to get or where to buy

The best wood chips for wood concrete are obtained from pine and spruce. You can also use larch, but when mixing it is necessary to double the amount of chemical additives. From hardwoods, GOST allows the use of aspen, beech, birch, poplar. The rest of the requirements are:

The best wood chips are obtained from lumpy waste wood. It is first passed through chippers, and then crushed in a hammer mill. The following mechanisms can be used for this:

• Disc chippers with adjustable blades. Not all of them can be adjusted to obtain chips of the required size, but the sizes will be close.
• Rotary knife crushers. Narrow and narrow chips come out of them, and the length is adjustable. I mean, it's a good option. There is only one “but”: there are a lot of knives and with prolonged use they need to be changed or welded on (they do not sharpen). We add to the pluses that crushers of this type can be used for re-crushing technological chips obtained during the first crushing (after reconfiguration).
• Shredders or roller grinders. This is expensive equipment (about 1 million rubles), and mostly imported, but it is excellent, as it is made for certain sizes of wood chips.

If you make arbolite chips yourself - not an option, you can buy it. If it works out, you can negotiate at the factory where wood concrete is produced. Just check the parameters of the chips. If there is none nearby, you can take chips from under the sizing machines. Some of them can be adjusted so that the chips are not thick.

Features of the manufacture of mortar for wood concrete blocks

Wood waste contains sugars. If fresh raw materials are used, sugars may begin to ferment, which will cause the integrity of the block to be destroyed. When kneading, chemical additives are added to the solution, which neutralize their effects (liquid glass, calcium chloride, alumina sulphate, lime). They can be added in combinations: calcium chloride with liquid glass or alumina sulphate with lime. The total weight 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 withstand the chips for at least 90 days in a pile in the air. If there is no way to wait, the chips are soaked for 3 days in lime milk, stirring occasionally. Then it is filtered, not dried, in this form it is used for kneading. Only in this case, it must be taken into account that much less water will be required. This method works well, but is very troublesome. It is easier to find an opportunity to purchase chemical additives.

The procedure and features of mixing the solution

For mixing the mortar, a forced-type concrete mixer is used. You can also use an ordinary 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 (raised, it almost does not mix).

First, sawdust is poured, a certain amount of water is added. While sawdust gets wet, chemical additives are diluted in a small amount of water, then they are unloaded into a concrete mixer. When all the wood is evenly wet, pour cement. It is loaded in portions, waiting for a uniform distribution throughout the volume. 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, they are a box with handles without a bottom. The form is placed on a flat surface (a board, for example). During manual tamping, the molds are filled with arbolite 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, after which it is pressed again. This procedure can be repeated several times until you reach the desired density of the layer, after which you can fill up the next one. Layers are poured up to the upper edge of the block, after the final tamping, the top is leveled, cutting off the excess with a metal bar.

You can use a lever - mechanical or driven. In this case, the force develops significant and you can load the entire volume at once, if necessary, adding to the edge. To achieve a high density, you can press several times, then increasing, then weakening the pressure. Experience shows that with this principle of manufacturing arbolite blocks, they turn out to be more durable, pressing out (restoring the shape due to the elastic force of the chips) appears much less.

The best blocks in terms of strength and with less effort are obtained if vibration is added to the pressing process. In this case, the efforts that are necessary to obtain the desired strength are reduced significantly. For these purposes, vibrating tables are made. And the process is called vibrating with a load.

The molded block on a stand is transferred to the place of drying. If the solution allows and the block holds its shape, the frame can be removed. But sometimes home-made arbolite blocks sin in that the solution turns out to be too liquid - it's easier to tamp. In this case, the blocks are left in the form for a day. The use and transportation of blocks is possible no earlier than 2-3 weeks after molding.

Features of the construction of their wood concrete blocks

The laying of blocks is carried out according to the type of brick - with dressing of seams, on a cement-sand mortar. Of the features - 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 eliminates the suction of moisture through the foundation from the ground. We make a combined waterproofing - first we impregnate with bituminous mastic or any other coated waterproofing, we lay a rolled waterproofing on top. Previously, roofing material was always used, but today it is of poor quality and will collapse in a couple of years. And it is important to exclude moisture leakage (due to the high water absorption of wood concrete), so use a hydroisol or something similar. It is possible, in two layers, also smeared with bituminous mastic.

The next nuance is laying over window and door openings. It is best to use special U-shaped blocks, in which to lay a reinforcing frame and 4 bars of reinforcement 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 notches are installed above the opening. They can be supported from below with a board and spacers. Then the frame is laid, everything is poured with concrete. Leave the structure for a day, after which the supports can be removed and laying can continue.

There are many nuances of building a house from wood concrete blocks in the video.

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

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

No matter how similar in composition to each other arbolite and sawdust concrete - there is a difference, and it is, at times, significant.

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 gains strength best in heat and humidity, since moisture does not evaporate quickly and goes to the formation of cement stone.

pros

The main advantages of sawdust concrete are:

1. Cheapness of the main components.
2. Ease of manufacture.
3. The durability of buildings.
4. Environmental friendliness.
5. Excellent thermal protection.
6. A method of manufacture and application developed over decades of use.

Minuses

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

Manufacturing

In the process of producing sawdust concrete, it is important to take only the most suitable sawdust from those types of wood that have minimum sugar content. Optimal contenders for the second life of waste in sawdust concrete:

• pine;
• Birch tree;
• poplar.

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

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

All works on monolithic sawdust concrete should be done in the spring to be finished by autumn. Due to the released sugars, it is better to bring the sawdust to the condition in the fresh air, including watering the sawdust with water in order to wash away the remnants of sugar decay.

A couple of washes with water will already provide the sawdust with an acceptable condition for use in the sawdust concrete manufacturing process. Sawdust structure when stored in bulk, it will prevent the processes of decay and combustion from starting. Since they are not compressed, there is no need to be afraid of moisture.

Compound

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 1 m3 of the finished mixture will be 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 reduced to the construction of non-residential buildings. This is due to the change in the coefficient thermal conductivity of blocks, nullifying 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 the strength requirements, respectively, and an increase in the amount of cement to obtain a durable 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 that of the M10 block. This means that the M25 block is twice as cold, but from it you can build large rooms.

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. In the manufacture of sawdust concrete:

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

It is important to follow just such a recipe, because it was worked out for decades, much earlier than wood concrete. The lack of progression in quantity and proportions should not be embarrassing. In each case, the components work differently.

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

Preparing the mixture

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 run the risk of remaining on the walls of the concrete mixer, or simply floating 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 to choose.

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

Machine kneading sawdust concrete functionally possible if there is a forced-type mixer, as in the production of polystyrene concrete. But even in that case, the order 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

It is worth mentioning a little about a mixture where building gypsum is used instead of cement.

And let people not be afraid of the setting speed 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, as you know, dispenses water in a dosed manner to gypsum molecules that are in an unhydrated state.

Explanation: building gypsum in the form in which it is sold in stores has ability to connect with water, forming a formula already with it, and which is already a solid formation that is not particularly afraid of water.

Until now, the dispute has not been put to an end - is it possible to build external walls from gypsum-based blocks.

According to some reports, with proven technology (on hand) and when protecting blocks from atmospheric influence, it is quite possible to use these blocks for building exterior walls. You can definitely build internal ones.

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

About sawdust size

The size of the sawdust does not matter if there is enough binder.

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

Here, the chips from the cylindering and calibrating machines will no longer work.

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

Of the features of the process - it is important to knead so that when a lump of the mixture was picked up and squeezed with his hands, water would not flow from it in a stream. 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 the hands.

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

Manual mixing of sawdust concrete with a shovel:

The use of sawdust concrete

A truly folk building material, as it is the most affordable of materials on the complexity of production. Perhaps people are noticing for themselves a wave-like interest in such materials. 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 a reasonable choice.

It is only now that many have begun to turn to environmental friendliness and practicality building materials, and not something that was designed for completely different climatic conditions. Successfully erected from sawdust concrete:

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

Like any moderately hygroscopic material, sawdust concrete needs an exterior finish, 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 what is more environmentally friendly - sawdust concrete with natural ingredients, or ecowool with hyper-content of bromine salts.

Today, the market for insulation materials is filled with a wide variety of materials, ranging from mineral wool to extruded polystyrene foam. However, even expensive materials do not guarantee complete heat preservation. Most of the experts in this field began to return to the long-known, but lost popularity, methods of thermal insulation of buildings. In this article we will talk about how insulation with sawdust is carried out.

sawdust types

Sawdust is small particles of recycled wood, which are obtained as a result of sawing. In appearance, they look like small dust.

Sawdust can be purchased in different fractions from 5 mm to 3 cm. The length depends on the technological process of the woodworking enterprise, namely on what type of tools is used in each case.

This material is environmentally friendly. In addition to low cost, sawdust has many other advantages, for example, excellent thermal insulation and sound-absorbing qualities, as well as a small specific gravity of the material. Mostly, sawdust is created from hardwoods such as spruce, pine or ash.

Ceiling insulation with sawdust

It is necessary to insulate the ceiling in a private house from any material, both from brick and from foam blocks. Because it is through the ceiling that significant heat loss occurs. Average heat loss through the ceiling is 20%. From an economic point of view, the most profitable is the insulation of the ceiling with sawdust.

Note that the laying of wood processing products is a laborious task. Before you start installation, you need to carry out a lot of preparatory work. First of all, such work is aimed at protecting against fire, because wood in any form is extremely flammable. It is highly flammable and has a long burning time.

What materials and tools may be needed:

• sawdust of fine and coarse fraction
• sand, clay or slag
• lime and copper sulfate (you can take boric acid)
• substrate. For this purpose, you can use corrugated cardboard or any other breathable materials that have good vapor permeability.
• sealant and mounting foam
• flame retardant and wood preservative. These compounds are necessary if the ceiling boards are not covered with a protective material against mold and fungus, fire
• construction stapler and staples to it.

Work must begin with the protection of ceiling beams and boards from possible adverse factors. Most often, high-quality buildings are already built from processed timber. However, if this procedure was missed for some reason, then it is necessary to carry it out now.

Wooden elements must be protected comprehensively, and the following sequence must be observed:

• an antiseptic is applied first, which prevents rot and protects against insects
• next come fire and bioprotective agents that increase resistance to fire and high temperatures
• the third uses water repellents that prevent moisture from entering the wood structure. In addition, such products protect the wood from washing out previously applied solutions.

To achieve higher efficiency, it is worth purchasing all drugs from the same manufacturer.

After carrying out protective work, all seams and joints must be sealed with foam and sealant. In addition to cracks in the ceiling, any other holes that may be present in the roof structure must be sealed. This is necessary so that the insulation material does not come into contact with precipitation or strong winds, which can lift the heat-insulating layer. Don't forget about trimming the protruding parts of the foam flush with the ceiling beams, otherwise there will be voids in these places through which heat will escape.

Next, you can lay the substrate, which is needed to prevent the shedding of fine dust from sawdust from the ceiling. This dust can become a source of additional dust in the house. The substrate must have vapor-permeable qualities. If there are no such qualities, then warm air and steam, rising up, will remain between the boards and materials, and will cause additional condensate. As a result, mold may form due to excessive moisture. As a substrate, you can use any cardboard, for example, from old boxes, packaging. Most importantly, it must be completely dry.

Clean the ceiling boards from dirt and dust and lay cardboard sheets on them in several layers. Lay the underlay with an overlap of 15-30 cm so that sawdust does not get into the seams. Now you need a stapler, with which you need to fasten all the joints of the material.

Sawdust should be bought dry, without foreign odors. In advance, they should be treated with compositions of fire retardants and antiseptics. After the mass has dried, 10% lime (fluff) and a small amount of copper sulfate (or borax) can be added to it. All this must be mixed well.

There are several basic methods for installing sawdust insulation. They can be covered dry or mixed with cement and diluted with water. Sawdust can be poured both in a clean dry form, and mixed with cement and diluted with water.

With the dry method, sawdust is poured in two layers:

• coarse fraction or shavings. This layer should be 10-15 cm thick. It must be well compacted
• smallest fraction. The second layer should be the same thickness as the first. And it also needs to be well tamped.

In addition, slag, sand or clay can be laid on top of the sawdust. These materials will save your sawdust from the appearance of rodents and the development of mold.

In order to insulate the ceiling with a wet method, you need to buy sawdust, which were made at least a year ago. Such sawdust will be slightly wet. However, make sure they are free of mold.

The ratio of chips, water and cement: 20:3:2. The mixture must be done in small volumes, because it dries quickly. The resulting solution must be poured between the floor beams onto a substrate or a layer of sand and compacted. The layer thickness should be 5-10 cm. The solution completely hardens and can be walked on.

Sawdust, as a heater, is great for floor insulation. As in the case of the ceiling, sawdust for floor insulation must be pre-treated from rodents, insects and microorganisms. To do this, it is better to use special ready-made solutions.

The difference between floor insulation and ceiling insulation is that it is very difficult to add an insulator that shrinks in the floor structure. Therefore, it is necessary to choose in advance a method in which the mass will not dry out over time. In practice, this means that when dealing with thermal insulation of the floor, it is worth using not dry sawdust, but mixed with different components and subsequently hardening.

To prepare this mixture, you need to add gypsum or cement to the sawdust. Observe the following proportions: 85% sawdust, 5% gypsum and 10% fluffy lime or lime paste, which must be taken twice as much as dry lime. Do not forget that gypsum hardens very quickly, faster than cement.

It makes no sense to dry the sawdust before kneading. On the contrary, if the sawdust is dry, it is worth adding a little water. The degree of readiness of the mixture is checked in the hands - if the lump does not crumble and does not spread, then the composition is ready.

If the insulation is carried out in a building that has already been in operation, then the existing floor covering will have to be dismantled, the floors will have to be re-treated with an antiseptic with moisture-resistant mastic, and then a vapor barrier material or film substrate should be mounted.

The created mixture of sawdust is placed on the substrate and compacted well. The thickness of the layer should be approximately 10 cm. After tamping, the mass must be left to solidify, in about 2-3 weeks.

When using dry sawdust, you need to create a raised floor. All wooden parts must be covered with protective agents. Next, a rough floor is mounted on the base from boards, on which waterproofing is laid. Sawdust is poured on top of the hydraulic barrier. The layer should be 10 cm or more. Note that insulation with sawdust is not suitable if you are going to make a screed. Sawdust is characterized by low strength and serious shrinkage. Before installing the topcoat, you need to leave the floor for 2-4 days. Over these few days, the sawdust will shrink by 2-3 cm and you will need to add an additional amount.

Be sure to note that if the sawdust is not provided with good waterproofing and ventilation (the gap between the finished floor and the layer of insulating material), then they may lose their heat-shielding qualities.

The most difficult thing can be called wall insulation, because for this you need to create a frame. The frame must be filled with sawdust and compacted by hand. Large fraction sawdust is suitable for laying in a frame wall. With a dry version of the bookmark, it is worth taking care of thoroughly drying the sawdust so that there is no moisture left in them.

With the wet method, the mixture is prepared from wood chips, lime, gypsum or cement, with the obligatory addition of antiseptics. The thoroughly mixed mass is moistened, poured into the prepared frame and compacted tightly so that the material does not sag. Gypsum, like cement, after a while draws out all the available moisture, and makes the mass monolithic.

Between the wall and the insulation material, it is imperative to lay a waterproofing material that has vapor-permeable qualities. It is from the quality of the tamping and the density of the bookmark that the effectiveness of the insulation and the level of shrinkage depend. If the ramming is not tight, voids will appear and heat loss will begin.

The mixture is laid in layers 20-30 cm high and rammed. After that, a second similar layer is poured. And so they repeat the actions at all heights. The thickness of the insulation depends on climatic conditions. For example, in a seasonal residence, a thickness of 15 cm is enough, but in a permanent building, a thickness of 25-30 cm is needed. The frame is created from wooden boards with a section of 100x50 mm.

The mass hardens in about 1-2 weeks, and finally sets in about a month. All this time it is worth monitoring that the air humidity does not exceed 60-70%, and the temperature does not rise above 20-25 degrees. In addition, you need to regularly ventilate the room. After that, you can start finishing work.

Houses insulated with sawdust are a great option. They combine high heat retention rates with low labor costs.

sawdust house

In addition to insulation, sawdust is used for the full-fledged construction of buildings. However, buildings made of sawdust concrete are rare today. Nevertheless, experts assure that sawdust concrete is a very promising material that allows you to build economical housing with decent performance.

The manufacturing technology of such material involves the addition of binding components, for example, clay, lime, liquid glass. These additives reduce shrinkage phenomena and reduce the cost of modules. By adjusting the proportions of individual components, in relation to the total weight, it is possible to change the density, porosity and strength of the final product.

Practice shows that optimal protection is achieved after cladding, however, for example, a sawdust bath can also be used without cladding.

The advantages of sawdust concrete include:

• thermal conductivity 0.20-0.30 W/m°C. Wall, 40.00 cm thick, similar in warmth to a 90 cm brick wall
• strength 20.0-50.0 kg/cm². Such material perfectly resists deformations and shock loads, so it can be used for construction in areas with probable seismic activity.
• easy processing. Modules can be milled, nailed, drilled, processed with a hacksaw and saw. Consequently, material consumption is reduced, almost no waste
• shrinkage 0.50 - 1.00 %mm/m
• frost resistance - 25 cycles
• density 300-1200 kg/m³.

Of the shortcomings, we note:

• moisture absorption. This disadvantage can be combated by processing blocks with special compounds.
• the impossibility of building multi-storey buildings
• not very attractive appearance without finishing.

Material calculation

Consider an example to find out the average number of blocks needed to construct a building. For example, you need to build a house with dimensions of 15x10 m, with a wall height of 3.00 m. The perimeter of the building will be the sum of the lengths of all sides = 15 + 15 + 10 + 10 = 50 m. The area of ​​\u200b\u200bthe building is the perimeter times the height = 50 * 3 = 150 m². It is worth considering the thickness of the masonry, and the number of blocks in 1 m2.

The search for a universal building material, optimal in terms of its thermal, strength and environmental characteristics, was crowned with the invention of wood concrete. It happened in the 50s of the last century in the former USSR.

Having comprehensively studied the unique properties of wood concrete (the second name of wood concrete), Soviet scientists gave it a "green light". The main customer of the new structural and heat-insulating material was the northern regions of the Soviet Union, where the construction of houses from wood concrete advanced at an accelerated pace.

Unfortunately, in the late 90s of the 20th century, the use of this unique material began to decline, since it became more profitable to build residential buildings from large-sized expanded clay concrete panels.

Today, wood concrete is experiencing a rebirth and every year it is increasingly used in individual construction. Therefore, we have no right to pass by this interesting material and not consider in detail all its pros and cons.

Advantages and disadvantages of wood concrete blocks

It should be noted that in the last century, wood concrete was used not only for the manufacture of wall blocks, but also produced in the form of sheets, which were used for insulation and soundproofing floors.

Today, wood concrete is practically not used in this capacity, because its main advantages are revealed during the construction of low-rise buildings. Let's list them in more detail.

- low thermal conductivity

Wood concrete wall blocks belong to the category of effective heat-insulating materials. This is evidenced by the following fact: a wall of arbolite with a thickness of only 30 cm retains heat just as well as a meter-thick brickwork.

Therefore, in the reviews of the owners of houses from wood concrete blocks, first of all, significant fuel savings are noted even in the coldest winters.

- Durability

The strength of wood concrete blocks directly depends on their density. For structural and heat-insulating wood concrete with a density of 600-650 kg/m3, it ranges from 20 to 35 kg/cm2. According to this indicator, wood concrete practically does not differ from its main competitors - foam and aerated concrete.

An important advantage is the plasticity of this material. This fact is explained by the fact that wood chips, which reinforce this material, are part of the wood concrete blocks. Therefore, under load, wood concrete does not crack, but only slightly deforms without loss of integrity.

When building a house from wood concrete, you do not have to spend extra money and time on pouring a concrete reinforced belt, which is necessary for fragile walls made of gas and foam concrete blocks.

— Frost resistance

Wood concrete has frost resistance (the number of freeze-thaw cycles in a water-saturated state) ranges from 25 to 50. In practice, this means that a house made of this material will last at least 50 years (confirmed by studies of existing buildings). In foam blocks, the resistance to freezing and thawing does not exceed 35 cycles.

Speaking about the advantages of wood concrete, it should also be said about its low carbonization shrinkage. This term refers to the process of loss of strength of cement stone due to the reaction with atmospheric carbon dioxide, which results in soft chalk.

- Good soundproofing

For wood concrete blocks in the acoustic range from 125 to 2000 Hz, the sound absorption coefficient is from 0.17 - 0.6. For brick, this figure is almost four times worse. For wood, it is in the range from 0.06 to 0.1, which is also significantly less than for wood concrete.

- A light weight

1 m3 of blocks made of structural and heat-insulating wood concrete weighs almost 3 times less than a brick and almost 1.5 times less than expanded clay concrete. This allows you to significantly reduce the cost of building foundations for wood concrete walls.

- Environmental friendliness and durability

Wood concrete is one of the most environmentally friendly building materials, since it contains only natural ingredients - cement stone, wood chips, water, calcium chloride (used in the food industry) or ordinary milk of lime.

In the wall, this material behaves excellently, because it does not rot, is not afraid of mold fungi and does not burn. In addition, wood concrete breathes well and regulates the humidity in the room, absorbing excess moisture and releasing it when there is a shortage.

— Fire resistance

Arbolit belongs to the group of slow-burning materials (combustibility group G1). In addition, wood concrete is difficult to ignite (flammability group B1) and low-smoke-forming material (D1).

- Ease of processing

Wood concrete is easily processed with any mechanical tool. It can be sawn and drilled and holds nails and screws well. The rough surface of the blocks is an ideal basis for applying plaster solutions without the use of reinforcing meshes.

The disadvantages of arbolite blocks include low dimensional accuracy. Therefore, walls made of this material require leveling with plaster mortars or sheet finishing materials (drywall, magnesite, lining, siding).

Since the technology for the manufacture of wood concrete is based on the use of wood chips - a rather expensive material, the cost of wood concrete blocks exceeds the price of aerated concrete by an average of 15-20%.

1 m3 of wood concrete blocks (500x250x400 mm) costs from 4000 to 5200 rubles, while manufacturers offer aerated concrete blocks at a price of 3400 to 3800 rubles.

The wood concrete production business is one of the most interesting at the moment. This is due to the high (and growing) popularity of the material among end customers, the ease of manufacture of wood concrete blocks, and finally, the lack of time-tested manufacturers plays an important role.

Federal retail " " invites you to consider purchasing. At the same time, we will not only supply you with the best equipment currently on the market (we have been producing it for 10 years already, the former name of the Russian Arbolit company is the Experimental Design Bureau Sfera), but we will also ensure that your capacities are fully loaded with our orders.

We make arbolite blocks ourselves

Considering the rather high price of high-quality wood concrete, many developers have a natural question about the possibility of its self-production. At first glance, it seems that there is nothing complicated in this process: I mixed cement with wood chips, added water and formed blocks for myself.

However, making wood concrete with your own hands on your site will be much more difficult than in theoretical reasoning.

Firstly, almost all home craftsmen presenting their own technologies the manufacture of blocks with the addition of chopped wood, in fact, they are not talking about wood concrete, but about sawdust concrete. This is a fundamental difference. Sawdust concrete not only differs significantly in composition from wood concrete, but is also worse in terms of its strength and thermal characteristics.

Secondly, wood chips for wood concrete must meet fairly stringent requirements.. Its thickness should not exceed 5 mm, and its length - 25 mm.

Therefore, in production, all wood is first passed through a crusher and only then mixed with cement.

Thirdly, sucrose is a serious enemy of the strength of wood concrete blocks.. It is contained in wood and must be neutralized. To do this, enterprises use safe calcium chloride or aluminum sulfate. At home, you may not have these substances.

If you nevertheless found wood chips suitable for wood concrete fraction, then the sucrose neutralizer can be replaced with a solution of slaked lime. In it, chips must be kept for at least 3 hours. Another option to replace sucrose neutralizers is to store the crushed wood pulp outdoors for 3 months.

The simplest equipment for the production of wood concrete blocks includes a mortar mixer and a forming vibrating machine. The cost of such a kit is about 58,000 rubles, so it will pay off only if there is a large volume of production (building a house or a private business).

The initial mixture for the manufacture of wood concrete blocks is prepared in a ratio of 4: 3: 3 (water, wood chips, cement). Sawdust and shavings can be added to wood concrete, but their amount should not exceed 5-10% of the total volume of wood raw materials.

The wood-cement mortar is mixed in a concrete mixer until a homogeneous mass is formed. It should not be watery, but crumbly. When squeezing it in a fist, the resulting lump should keep its shape well and not fall apart.

After laying the mixture in a metal mold, it is vibrated on the machine, after which the finished block is placed under a canopy for 3 weeks to gain brand strength.

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