Many know that there is a sandy pillow under the foundation, however, not everyone can say exactly why it is needed and how it is created. As a result, newcomers in construction business often raw sand into the trench without any understanding and eventually only harm the whole design.
The pillow under the basement sole can perform three functions:
- Leveling. If the soil is not poured and not movable, then the only task of sand is to align the bottom of the trench or pit for uniform placement of the solution or the correct load distribution from the FBS.
Compensating. Bunched soils under the support of the house in winter can strongly affect the load distribution, leading in difficult cases to the destruction of the concrete tape or plate.
In this case, the object's task is to compensate for deformation, reduce them to an acceptable level for this foundation.
Replacing if an organometallic or organic soil (for example is a peat), then you have to put up with continued decomposition processes.
In this case, the soil will necessarily be movable, bunched and characterized by a low bearing capacity. It has to be removed on a greater depth, until the end of the organic layer and fall asleep with sand trench.
Which thickness need a pillow under the foundation, depends on which function it performs in this particular case.
Cushion device
The easiest way to create a subtype that performs an aligning role. As a rule, its thickness in this case does not exceed 15-20 cm. It is enough to fall asleep sand, carefully align, shed it with a small amount of water - moisturize and then ravage.
But this minimum you can do either on non-empty soils, or in the case of a deep linkage of the foundation, below the level of friction and support for non-deformable soil layers. In other cases, it is necessary to lay a compensation pillow. Its dimensions depend on the width of the soles of the foundation. The exact data can be calculated on the table.
| 50-70 | 2.4 * B. | 1,2 * B. |
| 70-100 | 2 * B. | 1,15 * B. |
| 100-120 | 1.8 * B. | 1.1 * B. |
For example, if the foundation is laid with a width of 60 cm, then the pillow width will be 60 * 2.4 \u003d 144 cm, and the height is 60 * 1.2 \u003d 72 cm. Ribbon foundation with a ribbon width Over 120 cm in a compensating pillow does not need .
A compensating sand pillow is laid as follows:
Sand is considered not a bunched material, also due to its structure, it prevents the capillary increase in moisture from the underlying layers to concrete. But this is all characteristic only for sand, not filled with water.
If a lot of moisture falls under the foundation, then it can radically change the properties of the pillow.
Therefore, in the area with a high level of groundwater or where there is a chance of getting under the concrete of sedimentary waters, it is mandatory to provide a moisture dreament system - drainage.
The process of bookmarking under the foundation of the replacement pillow fundamentally from compensating is not different. Only the role of geotextiles and water removal system increases. In any case, an important point is the correct traam. It is worth considering more.
See our video selection on the topic:
How to compact?
Pure sand practically does not give a shrinkage, but only after the proper seal. If you neglect this procedure and fulfill it unfair, high risk of drawdown with the subsequent destruction of the foundation.
So that everything turned out properly, the following rules should be followed:
It is more convenient and faster on sealing using vibrating lips or a special construction vibrator.
In some cases, you can use road construction techniques, and sometimes it turns out to be traaming manually.
What a way to choose is depends on the characteristics of the site and capabilities.
Selection of sand
Few people think about what sand is to choose for a pillow under the foundation. Take the one that will bring. However, the properties of this material affect the properties of the intake to a no less degree than the correctness of its bookmark.
For the foundation pillow, a washing career or river material is best suited.
The perfect choice is grave. Do not forget that other materials that meet the requirements presented are allowed.
However, it is difficult to correctly determine the loads and properties of one or another soil at home, so the easiest way to take the material that is guaranteed to fulfill its task.
See our video selection on the creation of a sandy pillow:
PROFFU »Records» Materials and Tools »Sandwife under the foundation
Before starting construction work, many pre-calculate the required amount of material. This is the right approach to such a serious cause. But at this stage, many questions arise. One of them: What sand is needed for the foundation?
The choice of such a material should be paid to special attention, since it is an important component, one of the main components used in the manufacture of concrete. From the quality of the mixture of the mixture and will depend on the durability of the foundation - the future foundation of the house. The modern market offers a huge range of sand, both natural and artificial. How to decide on the choice so that the foundation does not suffer from it, the article will tell.
Even inseparable in matters of construction, a person will be able to guess that for the foundation it is suitable exceptionally pure sand. Initially, various organic elements may be present in it: small twigs, grass and so on. For construction work, such material is not suitable, so there must be a seeded sand, cleaned of extraneous garbage.
However, simple shift cannot do if we are talking about such impurities as lime or clay. It is much more complicated to clean like sand, so when buying building materials, it is necessary to immediately pay attention. Permissible clay content in the sand is not more than five percent of the total mass, especially if a solution is made for the foundation. Otherwise, the building after a while will give shrinkage, cracks and will not be particularly reliable.
Check purity of sand
Before you choose which sand is needed for the foundation, you should check its purity. For this, a simple method is usually used. It will take any empty transparent bottle (glass or plastic). On one third, sand is falling asleep and filled with water half. Then the bottle is then intensely, so that the components are pretty mixed with each other. After that, they put it and wait five minutes for about ten minutes. If the water in the bottle became muddy and dirty, then such sand is not suitable for the foundation. If a foreign substance appeared on the surface, the layer of which exceeds the half-meter, then such a material cannot be taken too.
Now consider what kind of sand varieties exist.
Sand species for mounds
To ensure the reliability of the construction under construction, according to the standards, it is necessary to use bulk mixtures. The market realizes sedimentary rocks in three types, depending on the place of their extraction. This is the sand:
- career;
- river;
- nautical.
To answer the question of which one is most suitable for the foundation pillow, you should familiarize yourself with the characteristics and nuances of using each type.
Career sand
This raw material is mined in quarries, breaking rocks. An important indicator of reliability and strength of career sand is the parameter of its humidity. Admissible is the ratio from one to five percent. Suitable humidity can be determined visually. From the sand it will not be possible to blind a tight lump - he simply crushes.
The cheapest material is considered precisely the career sand. The price of it hesitates from three hundred to seven scores per cube. This is due to its low quality due to the large amount of clay impurities and other substances. Nevertheless, this raw material is considerable in demand.
Types of career sand
Depending on the type of processing, quartz raw materials is classified as follows.
1. Sand soil. This is a crude mixture with various impurities. As a rule, it align the country areas and fall asleep trenches.
2. Mooked sand. It is produced from waterfront deposits using hydromechanical equipment. The technology allows you to assemble the mixture without any impurities and unnecessary components. This material is used in the production of roads, paving slabs, concrete, bricks and reinforced concrete products.
3. Sedane sand. It is purified by a technical and mechanical method from large particles and stones. Typically, such raw materials are used to prepare the mass of plaster, laying solutions and in the casting of stone products.
River sand
This raw material is mined from the bottom of freshwater rivers. It rarely contains organic compounds and impurities. Therefore, river sand is considered a clean and natural product, which is designed for multipurpose use. This is the perfect material for laying the foundation, creating drainage and dilution of the solutions required for the interior decoration of the house. Due to the natural grinding of river sand, has a perfectly smooth shape and a small fraction within two millimeters.
Thanks to all listed advantages, this material becomes universal and desirable, but rather expensive raw materials for the foundation. Thus, the price of building sand, mined from the river, may vary from seven hundred to one thousand rubles per cube.
Classification of river sand
The raw material from the bottom of the river can be very different from each other. Therefore, it should be sorted out with a variety of grains. They can be several fractions: from 0.7 to 5 millimeters. The saturation of small sands is very sitting and tamped, so it is suitable only for lightweight buildings. Also distinguish the following types of bulk river material.
1. Large sand. These are pebbles of about five millimeters. They are obtained by splitting rocks with special crushing and grinding equipment.
2. Coarse sand. It has unobtrusive neutral color, is mined in dry rivers. Ideal for decoration and decoration of the room.
3. Mytoy river sand. These are medium-sized grains. They have gray or yellow, since they include iron and silicon oxides.
Positive sides of river sand
River sedimentary breeds have several positive qualities that are of great importance for the construction of the foundation. They meet technical and aesthetic requirements, do not rot and are not exposed to an aggressive environment. River sand is characterized by high moisture resistance and excellent noise insulation. It is also safe and environmentally friendly material.
For the construction of multi-storey buildings, only a large-phrase type is used, and the average baby will be suitable for sieves. Also, river sand is ideal for landscaping, playgrounds, landscape works and room decoration.
Sea sand
Sea crumb is also exactly the material as needed for the foundation. The sand is not very better than the river, but sometimes worse. This is explained by the presence of organic impurities (algae, seashells) and foreign objects. But the sea sand is necessarily purified from strangers and washed, so it is considered clean and high-quality. Due to this, this material is the most expensive, and not everyone is ready to pay for it. It is more appropriate to use sea crumb for construction where it is sold and cheaper.
Sand fractions
Any sand can be classified by its size. Experts allocate the following varieties of fractions.
- Very thin. It is a grain of a size of about 0.7 millimeters. They are suitable for the arrangement of playgrounds and are unsuitable for construction.
- Thin. Crupines in size reach from 0.7 to 1.0 millimeters. This is a loose material. You can not use such sand for construction, but it will be not bad for the preparation of skinny concrete.
- Small fraction. It is a grapple size of 1.5-2.0 millimeters. When it is used, the consumption of cement mixture increases.
- Average. Cruppers (2.0-2.5 millimeters) can be used to create standard concrete.
- Large. Sand particles in magnitude reach three millimeters. This fraction is ideal for breeding a high-quality concrete mix, which will be used in large-scale construction.
- Very large. Particles are more than three millimeters in diameter. They are added to the foundation pillow and are used to distribute the mass of the structure.
Sand selection for foundation
So what is the sand, river or career? Experts converge in the opinion that the first option is most suitable for the construction of foundations. It will create a layer, which will increase the strength, stability of the building, will prevent "walking" and the formation of cracks.
However, the river sand will not be for the pocket. In this case, it is allowed to use a career crumb, but must be soothing. A sandy-gravel mixture is also suitable, which improves the quality of the laying under the pillow.
Required amount of sand
Usually, one part of the cement is taken for five parts of the sand. But this calculation is suitable if the solution is made only from these two components. Sand, rubble and cement ratio for the foundation will be completely different. As a rule, they are taken in the following proportions: four parts of sand, two parts of rubble and one - cement.
As can be seen from the calculations, the sand should always be taken more than the other components. The number of materials itself directly depends on the height of the pillow and the building itself. Sand is better to buy with a small margin so that you do not have to buy it at an inappropriate moment. The remains can be accommodated for the preparation of solutions on the decoration of the walls or their masonry.
Summarizing
Answering the question of which sand is needed for the foundation, it should be noted that the ideal option is considered the river grains of the middle fraction. Such material has excellent properties for construction purposes. It allows you to build the most durable foundation that will flash for a long time and will be an excellent basis for the construction.
Purchase sand is necessary from reliable manufacturers, so as not to stumble upon poor-quality raw materials. It is recommended to check the material before purchasing the level of humidity and the number of extraneous impurities. It is also worth paying attention to the compliance of the procurement size. As a rule, in the cubic meter there should be approximately one and a half tons of sand.
When bookmarking the foundation, it is important correctly and competently choose building materials. Especially carefully you need to choose sand, as it is it depends on the strength of the solution for the foundationSo, the strength of the whole base. To the question of which sand is better to choose for the foundation, will reply in this article.
Sand selection
Sand for foundation is a bulk material obtained by from sedimentary rocks or artificial creation. The quality of sand does not depend on its method of receipt, it is important to take into account only its purity.
If you can find foreign objects in the size of a more half astimeter, it is not suitable for booking the foundation. The branches, leaves, organic trash can relate to foreign subjects.
Of course, you can try to clean the sand yourself, taking a sieve and sift it, but only imagine how much time and effort you will go to this process. Asking sand, you just remove large impurities, and what about the content of such elements that are undesirable in the sand for the construction of the foundation of the house, such as lime or clay.
Better immediately choose high-quality sand and start working. Remember that high-quality sand suitable for the manufacture of the solution should not contain more than 5% impurities. In addition, a large number of additives will worsen the strength of the sand, which will affect the foundation and house or building. Content gravel in the sand should not exceed 10%Since gravel is a constituent element of a solution for filling the foundation.
End, ideal sand you can detect only by conducting a special examination of his compliance with all standards in the laboratory, learn the percentage of impurities in the total mass and other indicators. But such an examination is a costly and long process, therefore i can determine the quality of the sand can be appropriate methods.
Fall off the sand, in a transparent bottle, by a third, and then pour up half with clean water and shake. After that, give a mixture stand for 5 minutes and look at the transparency of water. If it has become inspired and dirty, then the sand contains a lot of impurities. The emerging foreign substances, also a bad sign, and such sand is unsuitable for construction. If the water is transparent and without impurities, then the sand is ideal for booking the foundation.
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Sand origin
What sand is better - career or river, let's talk in this part.
Career sand
Career sand is mined in a quarry, destroying rocks. It is lower quality than river, but there are exceptions. When choosing a career sand an important factor in its reliability and strength is the humidity parameter. Its percentage should be from 1 to 5%. The humidity of 5% is determined on the eye in that it is impossible to make a tight ball or snowball from the sand - it crumbles.
To properly determine the humidity parameter, you can resort to the following method. To determine the humidity of the career sand, take the container, weigh it. Then, weigh 1 kg of sand in it and hold for about half an hour at a weak heating temperature, and then weigh the sand. Humidity will be calculated by the formula: the sand mass after heating is minus the mass of the container, divided by 100.
Career sand is cheaper at a price than river, since its production method is less expensive.
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River sand
The river sand is ideal for laying a foundation, and is also used in the dilution of solutions for the interior finish of the house or the creation of drainage. Therefore, such sand universal and multifunctional. Its small fraction from one and a half to two millimeters and the absence of impurities make it welcome, but expensive building material.
In addition to river sand allocate nauticalbut in modern construction it is applied there, from where it can be quickly brought, otherwise it the price exceeds even river. In quality, it is not better than the river, and sometimes even worse due to the impurities of the organicities (shells, algae) and foreign objects.
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Sand fractions
Depending on the size of the sand in the sand, the following types of fractions are distinguished:
- Very thin Contains grades size up to 0.7 mmBut due to the low fraction is unsuitable for the foundation. The foundation based on it will turn out as low as possible.
- Thin Contains sandbank sizes from 0.7 to 1 mm. Such sand is not thin, therefore it is also not suitable for the solution of the foundation. Usually thin sands are used to fill concrete.
- Very small Contains grades size to one and a halfBut still not suitable for filling the foundation, since the strength will still be optimal.
- Small Contains grades size from one and a half to 2 mm. And again it is not suitable for filling the foundation because of the large cost of cement for him.
- Middle Contains sandbank sizes from 2 to 2.5 mm And perfect for filling the foundation because of its strength and high performance properties.
- Large Contains sandbank sizes up to 3 mm and is intended for the manufacture of concrete high-quality and expensive marks. Such sand is very expensive.
- Sand increased size Contains sandbank sizes up to 3.5 mm and is used for the manufacture of sand pillows, designed to increase the strength of the base and distribute the load on all angles evenly.
Fill the foundation assumes that the verge of the middle sand you choose should be sharp. It is the sharp edges of the grace that increases the operational properties of the solution and make it as strong as possible.
And water mixed in certain proportions, create such a superfrequency building material as concrete. Each ingredient plays its important role. So, the sands act as an integral component of a concrete mix, which fills the space between the crushed. The quality of small aggregate plays a key role, since the wear resistance and strength of the final product depends on the correct distribution of internal voltage.
General requirements when choosing
Sand for concrete, which is used for the manufacture of concrete solution, must comply with the norms of the GOST. The material is suitable if it contains less than ten percent of the particles with a fraction to 0.14 mm and no more than three percent of the impurities represented by dust, il and clay. It is the presence of the latter in the mixture that can negatively affect the frost-resistant and strength of concrete, since it covers the sand, without giving them a properly connecting to the rest of the components. Also, according to the norms, the content of large-sized particles is no longer allowed, and the share of 5-10 mm particles should lie within five percent of the total mass of the bulk component. Organic enclosures in the material represented by humus or vegetable elements should be absent.
Particle size
The river is the most optimal version of the filler of concrete mixes. To figure out which sand is needed for concrete, first determined with the most important parameter when choosing a bulk building material - the size module (fraction). Distinguish:
- very large (more than 3.5 mm size);
- increased fraction (in the range of 3-3.5 mm);
- large (2.5-3 mm);
- medium size (2-2.5 mm);
- small (1.5-2 mm);
- very small (1-1.5 mm);
- subtle (0.7-1 mm);
- very thin (up to 0.7 mm).
To determine the size module, manufacturers sift the sand alternately through sieve with fractions of 10 mm, 5 mm, 2.5 mm, 1.25 mm, 0.63 mm, 0.315 mm and 0.14 mm.
Simplified classification can be presented as follows:
- small;
- middle;
- large.
The manufacture of concrete involves the use of coarse sands with a sufficient amount of smaller grains, otherwise the concrete mixture will contain many voids. The emerging empties will fill cement, which means an increase in the cost of the final product. It is noted that the grains of the same fraction are badly in contact with each other, forming more free space. Therefore, massively use a mixture of different particle sizes to obtain the highest density between the elements.
Based on the size of the particles, bulk materials are classified into two classes. The first class is characterized by the absence of microparticles of less than 1.5 millimeters in diameter. Such sandy material is considered better, since the presence of a very small aggregate negatively affects the dedication of larger fractions. The second class, respectively, includes small components. That is why for the preparation of high-quality concrete use bulk first class.
Views
Sand is a small-grained mining sedimentary breed, found in the finished form or obtained by crushing rocks. In addition to the grain size, the placement is an important indicator, which determines its properties. Allocate:
- river;
- nautical;
- career;
- quartz.
The river sand is preferred because there is no clay and there is a very small amount of stone. It is somewhat more expensive than the other types of bulk, but the best quality. Its grains are homogeneous and have a smooth oval shape, the density of their settlement is much higher than the career, the form of which is not symmetric and has irregularities on the surface. It is extracted with the help of landfinding devices that suck water along with sand and carry the mixture into the storage. At the same time, water has an outflow back in the reservoir.
According to the properties of sea sand, it looks like a river. His feature is the content of small grains of seashells and sea stone. Therefore, it needs additional cleaning. Sea salt makes grains of homogeneous size and the right shape. It is the most expensive bulk material, because mining it takes place on the seabed using costly technologies.
The composition of the career bulk is often burdened by clay impurities and stones, so after prey, it needs washing from extraneous particles. He is the cheapest. The production of rock in sandy careers is the most massive.
Quartz sandy material is mined by artificial crushing of quartz rocks with special grinding installations. It is obtained without all sorts of impurities and is characterized by chemical neutrality. Based on processing options, there are the following methods of cleaning material:
- washing (method of purification by water washing);
- suitted (according to such a method, sieves are used for settlement).
Sandwashes occurs right at the site of mining. For this, the material is immersed in water and stirred several times. Thus, from the sands, various kinds of impurities and dust depart. Unnecessary particles float upstairs and are separated from the total mass. Such a procedure is carried out several times. True, the cost of bulk increases significantly. Sift - less costly procedure, but it does not save dust from microparticles.
Feature material
Sand can perfectly absorb and keep moisture. Miscellaneous Sand can have different both physical and chemical characteristics depending on the composition that may be:
- chemical;
- mineral;
- granulometric (mapping of particles in percentage depending on the fraction).
An important indicator acts actual weight of one meter of cubic sand. It varies within 1.5-1.8 tons. Little weight is considered better, as the mass of impurities is minimal.
Humidity plays far from a latter role. Normally, it should be 5%. The amount of water added to the concrete solution depends on this indicator. During home construction, you can check the moisture content of the material "on the eye": if the sand after compression in the fist does not crumble - it means that the normal level of humidity is exceeded, and the mixture will need a smaller amount of water.
Before starting construction work, many first calculate and harvest the material. It is right and commendable. But at this stage there are different questions, one of them, what sand is needed for the foundation. Sand choose to pay special attention, as it is one of the main and important components used when mixing concrete. And on the quality of the concrete mix, your future foundation, foundation depends on. Taking into account the fact that the market provides a large selection of various sands of both natural and obtained artificially, it is important to choose the most suitable for these work. In this article we will tell how to determine the choice.
Purely theoretically
Anyone who is not knowledgeable in building business and its nuances can guess that it is necessary to choose clean sand for the foundation. In the sand, various organic elements such as grass, branches, and so on may initially be present. For work such sand will not fit, but it can be easily cleaned. Maybe you have repeatedly seen how the workers sift the sand, cleaning it from unwanted elements.
But if we talk about such impurities, like clay, lime and other similar, then there is no simple sifting. Clear such sand is harder, so when buying you need to immediately pay attention to it. The presence of clay in the sand should not exceed 5% of the entire mass, especially if we talk about the foundation solution. Otherwise, the future structure will not differ reliability, will give a shrinkage, and this will lead to cracks. Before buying, it is important to check how clean sand is. You can use a simple way to check.
You will need a transparent bottle, be it glass or plastic. It is necessary to fall asleep sand on 1/3 and fill with water to half. Further shake the bottle intensively so that the sand is stirred with water and completely wet. After that, put it and wait 5-10 minutes. If the water has become dirty, this sand is not suitable for the foundation. If a foreign substance was formed on the surface, layer more than 5 mm, it is impossible to take such sand. Let's look at what kind of sand is what they differ and what type of sand is better to purchase for the foundation.
Sand varieties
Sands are divided into several types, depending on the place of mining:
- River.
The name of the river sand itself says that it is mined from the river bottom. This is a universal material, since it contains fractions of different sizes - from 1.6 mm to 2.2 mm. Thanks to this, it is used not only for filling the foundation, but also for different construction purposes. Name the main advantage of river sand is its natural purity and homogeneity. Clay, vegetation particles and other impurities in it are very few. Such sand is ideal for the foundation. Only here it is large enough.
The sea sand is mined from the bottom of the sea, after which it is cleaned of the sewer and other impurities. Difference of such sand is its graininess, which is about 1 mm. This size of the granules makes it possible to use it for the construction of reinforced concrete structures. It can be called quite clean, since it is cleaned before selling it, sip and washed. But for quality you need to pay, so the sea sand is the most expensive.
Career sand is mined by an open way from a career. If you compare it with river and sea sands is the worst option. And it is not surprising, as in its composition a lot of impurities - clay, vegetation and crushed stone. Because of this, the price of such sand is the lowest and is suitable for draft work at the initial stage of construction.
To unambiguously determine which sand is better suitable for concrete, it is important to consider other features. Some masters advise to buy career sand, which is cheaper, referring to the fact that it will not affect the quality of the foundation of the house. Others say the quality is above the price, so you need to choose expensive sand, which will ensure the reliability of the foundation on which it is impossible to save. Be that as it may, it is necessary to consider other features and criteria to help determine the choice.
Specifications
As mentioned above, the sand should be clean. If it has vegetation or branches in it - it is not scary, they can be selected. But clay, Il, gravel and other particles can lead to a decrease in the quality of the concrete solution. The presence of clay should not exceed 5%. The presence of gravel in percentage of the entire mass should not be more than 5%, and the particle sizes are greater than 10-12 mm. If the size of gravel ranges from 5 mm to 10 mm, then more percentage is allowed - up to 10% of the entire mass.
An important moment when choosing a material is its granulometric composition, that is, the size of the granules. Based on the size of the sand pellets, it is divided into:
- very thin sand, the size of the granules of which is not more than 0.7 mm. For the manufacture of concrete such sand will be unsuitable;
- thin sand, the size of the granules of which is from 0.7 mm to 1 mm. This view is also not used for the manufacture of concrete;
- very small sand, the size of the granules of which is in the range from 1 mm to 1.5 mm. It is not necessary to choose it for concrete;
- small sand, the size of the granules of 1.5 mm to 2 mm. Not suitable for the preparation of high-quality concrete mix;
- sand of medium size, the size of the granules from 2 mm to 2.5 mm. It is the sand of such aity perfect for the preparation of a concrete mix under the foundation;
- large sand, the size of the granules of which ranges from 2.5 mm to 3 mm. It is used for the manufacture of high-quality high-quality concrete;
- sand of increased size, the size of the granules is from 3 mm to 3.5 mm. Sand such a fraction is better to use for the foundation pillow under the base of the construction.
Very large sand, the size of more than 3.5 mm can also be used for the foundation pillow.
Another important point when choosing sand for the foundation - humidity. The content of water in the sand plays the last role, since its quantity must be taken into account when the solution is made with the addition of water. The recommended sand moisture for the foundation should be no more than 5%. The dried breed may have 1% humidity. If the sand fell under precipitation, then its humidity can reach up to 10%.
If you purchased sand, you need to take care of its precipitation protection. To do this, it needs to be covered with something or unload under the canopy. Then he will not absorb excess water.
But how to determine the humidity of the sand? Take advantage of pan or iron bucket. Take the container and put it on the weight. Having learning the weight of the capacity, take 1 kg of sand and fill it with a container. Now you need to dry the sand. To do this, put it on the slab with a weak fire and "cook", stirring, 30 minutes. After expiration, everything is again needed to weigh. From the weighing result, take the weight of a bowl or bucket and multiply the result by 100. As a result, you should have a number in the percentage ratio, which indicates humidity. For clarity: a bucket or a bowl has a weight of 0.2 kg. After you dried 1 kg of sand, the total weight turned 0.9 kg. It turns out:
0.9 - 0.2 x 100 \u003d 70
Humidity of your sand is 7%. There is another method for determining humidity. It is enough just to use a special device that will show an accurate digit.
Let's summarize
So, having all the data, you need to analyze them and determine the choice. You learned that the ideal sand for the foundation is considered:
- clean sand, which consists of clay and gravel do not exceed 5% of the whole mass;
- sand with medium size, the size of the granules is from 2 mm to 2.5 mm;
- sand, whose humidity does not exceed 5%.
Buying such a building material for the foundation, you must pay attention to these indicators. The most optimal option for the price and quality is washed and dropped career sand, the size of the granules of which is 2-2.5 mm. It is better to buy it directly at the place of mining. If you have money and want your foundation to be durable and stood for a very long time, stop on the river sand of the same fraction. Then your concrete under the foundation will have the necessary qualities.
Buying sand, you should control the process of weighing a loaded and empty dump truck, as there are unscrupulous suppliers who displease sand, stating on you.
We hope that this article helped you figure out what sand to choose for the foundation.
Reliable base of construction is the key to its strength and durability. Laying is based not only on the selection of high-quality concrete and competent strapping of reinforcement, but also the correct filling of the pillow of the pit. Choosing sand for the foundation, it is necessary to take into account varieties, breeds and nuances of using the material.
Functions of sand pillows
Quartzite fractions are applied to create a fundamental basis and organization of underfers in construction. In the latter case, the sand copes with several tasks:
- lines tight soils, evenly distributing the load of the construction;
- compensates an increase in the volume of frozen water on bunched soils. The material eliminates the deformation, reduces the risk of cracking;
- eliminates damage to organic breeds - peatlands, increases the carrying ability of the substrate.
A qualitatively equipped interlayer will play the role of a barrier in the conditions of the close location of the groundwater and depreciates the weight of the multi-storey house.
What is the need for embankment?
The residential building should be built on a solid capital basis. The monolithic design, located on a special bulk support, has good strength indicators. After preparing the territory (cleaning from garbage, markup), determining the depth, the digging of the pit is lined with a pillow of sand. When is it better to build it? Speakers are recommended in the following cases:
- when erecting dwellings on bubbly soils. The sandy layer prevents the design and deformation of the design during freezing and thawing;
- if there are soil irregularities. The mound ensures the distribution and leveling of the construction site;
- with increased dampness from undergoing groundwater. The layer performs a barrier;
- with the possible sediment of the building. The pillow is opposed to the compression forces in the soil;
- when building buildings in several floors. Running is lined up for the depreciation of the structure.
The sand under the foundation is laid by uniform layers, at a depth of no more than 20 cm, followed by a rambling and a watering of each. 
What type of material is satuled for the basis?
The correct arrangement of the bottom of the bottom, according to the standards and rules of SNiP, 3.02.01 - 87 "Earth structures, grounds and foundations", requires the use of a bulk mixture to ensure reliability of the structure. Pick out which sand is needed for the foundation - river or career, it is worth focusing on the assortment line of modern producers.
The building market market realizes the sedimentary breed for the construction of the base in 2 types: career and river. Which one is better to apply for the pillow? Responding to this question, you should decide on the nuances of using each. 
Career sand: characteristics, features of application
Raw materials are extracted from a quarry formed by the destruction of rocks. It has low quality due to large volumes of clay impurities and other substances. It is used to arrange the kittlers, but not in natural form. Before use, for the construction base, it is washed, dried and sifted from impurities. Popularity is due to low cost of raw materials.
The cushion from the career mound should have an important factor determining the reliability and strength of the future design - humidity. Its percentage of raw materials should be 1-5%. 
Varieties of material
By type, the processing quartz raw materials is divided into:
- washed. It is produced using hydromechanical equipment from waterfront deposits. Technology allows you to get the composition without impurities and various components. Washing type is used in the production of bricks, concrete, reinforced concrete products, paving slabs and roads;
- sown. Receive as a result of technical and mechanical sifting from stones and large particles. It is used in the casting of stone products, preparation of masonry solutions and for the formation of the mass of plaster;
- sand soil. It is a crude mixture with a plurality of impurities. They, as a rule, fall asleep trenches and leveled the relief of summer sites.
The career crumb, offered in the construction markets, has exceptional quality according to GOST 8736-93. Materials mined in quarries are characterized by cheap price. To check the quality, i.e. Humidity, it is recommended to weigh wet sand and hold it in the sun for about 30 minutes, and then repeatedly weighed. Humidity is calculated as a mass of raw materials after heating, from which a mass of the container was detected, separating it to 100. The optimal indicator of humidity is from 1 to 5%. 
River sediment - universal material
Universal type of quartzite raw materials is mined from the bottom of freshwater rivers. The composition is considered a natural, pure product designed for multipurpose applications according to GOST - 8736-93. It rarely be impurities and other organic compounds. Due to the natural grinding, the river breed fractions are perfect. Specialists celebrate the fact that it is better to use it for the construction of foundations.
The small-phrase product is relevant for internal and exterior finishes, for brickwork and plaster walls, as well as to create a drainage system. 
Graduation of breed
Raw materials mined from the bottom of the river is characterized by heterogeneity. Choosing the desired size of pebbles under the base, it is worth dealing with a fractional variety.
There are the following types of river bulk material:
- Mytoy - is the grave, gray or yellow grave grave grave. In their composition of silicon and iron oxides.
- Coarse-grained - mined in the rivers of dry rivers. It has an unobtrusive neutral color. It is used to decorate and finishing the premises.
- Large - pebbles reach dimensions up to 5 mm. Get it on specialized crushing and grinding equipment, by splitting rock.
River bulk material is a few fractions. Sizes range from 0.7 mm to 3.5 mm. The pillow, equipped with a mound from small grains, is intended only for lightweight buildings. Small-phrastructive fusion is strongly tamped and seated. 
Positive River Sand Characteristics
For residential inadial houses, it is better to use a church of medium and large size - 2-3 mm, and for multi-storey buildings, an exceptionally large-phrase type is used.
The river sedimentary breed has a number of positive qualities:
- meets aesthetic and technical requirements;
- has increased moisture resistance;
- not exposed to an aggressive environment, does not rot;
- characterized by excellent noise insulation qualities;
- environmentally friendly and safe.
It is popular not only in construction sites. Bumping breed is used to arrange playgrounds, for the manufacture of concrete products, landscaping, in decorating rooms and in landscape works. 
Sand material fractions
Career and river variety are classified by the size of the elements. Experts identify several quartz fractions:
- very thin. The gradation of 0.7 mm is unsuitable for the construction of the foundation. They can be used in the arrangement of children's game zones;
- thin. Dimensions of grains reaches 0.7-1 mm. The loose sand is not suitable as a component of the base, but not bad to create a skinny concrete;
- very small. Elements are 1.5 mm, but it is not enough to fill the foundation;
- small. It is characterized by the presence of fractions of 1.5 - 2 mm. The use of this type of material increases the consumption of the cement mixture;
- middle. Cruppers from 2 to 2.5 mm diameter are suitable as a component of standard concrete;
- large. Peschins up to 3 mm magnitude - ideal for performing a high-quality concrete mix, designed for large-scale construction;
- the composition of increased particleness with sands up to 3.5 mm is needed for the foundation pillow and the mass distribution of the structure on it.
For the pouring, only particles are needed with sharp edges that increase the adhesion of the concrete dough with the surface. 
Features of the sandy pillow
For the construction of a reliable basis, it is necessary to properly make a mound and align the surface of the pit. The arrangement of the embankment implies the following indicators:
- The pillow is constructed by 1/3 of the width of the foundation. The depth of the mound layer should not exceed 20 cm.
- Before the flooring, a geotextile cannon is stacked on the bottom of the bottom. It will provide additional drainage and keeps the mound from the mixing with the soil.
- Mound fell by parts. After laying each layer of bulk material, it needs to be well moistened and seal. Framing sand is better with the help of vibrating plates.
- The trimmer of sand under the foundation is performed until then. While on the surface there will be no traces from the legs.
- Upon completion of the forage, check the surface level. It must be smooth. This indicator depends on the correctness of the subsequent building building.
After the bottom of the bottom, the strapping is placed from the reinforcement, the formwork is stacked and concrete is poured.
To build a good and reliable foundation, it is necessary, first of all, take care of the arrangement of a sand pillow. It plays an important role in the construction of the foundation, especially on bubbly soils.
Before starting construction, many are wondering - what sand is needed for the foundation. The sand mix is \u200b\u200bthe main component of the concrete mix and the strength of the foundation and the entire future building depends on its choice. Let's look through the main questions that will help cope with the choice.
Let's talk pursuit
Even a person injecting in construction is clear one thing: high-quality foundation will not work out of dirty sand. And therefore, first of all, it should not be different impurities. These include:
- Grass, or branches. With such garbage, it is easy to cope, just asking sand for the foundation.
- Clay. There are more difficult things here, no more than 5% of clay from the whole mass is permissible in the sand mass, otherwise the concrete strength will be lower.
- Gravel. On this component, in principle, it is possible to close the eyes, but only if its component of the proportion is equal to no more than 0.5-0.7%, and the fraction is not more than 10 mm.
Of course, you can save on the purity of the material, and, by purchasing poor-quality sand, sift it before work. But think: do you need it, because such work will take enough long time, and take away a lot of your strength.
Quality Material - Strong Foundation
For self-checking for purity, you will need a transparent bottle. In her 1/3 of the part, you need to pour sand, selected for the foundation, and, in bulk water, shake it carefully. Then leave a bottle for 5-7 minutes, and check the purity of water. If it is dirty, the quality of the sand is not at the best level.
It is also necessary to pay attention to the size of the fractions of the sandy mixture. And not all the sand is suitable for kneading concrete under the foundation. Sand is like this:
- Very small. The size of the fraction is within 1.0-1.7.
- Small. Particles of such sand 1.5-2.2.
- Middle size. Granules 2.0-2.6 - this is the best option for the preparation of concrete under the foundation.
- Large. Particles of this material make up 3.5 such sand is well suitable for the pillow.
- Thin and very thin. Such sand is not recommended for the preparation of concrete under the foundation.
So, the trench is ready, we figured out the purity and size of the sandy mixture, it remains to talk about the types. The sand is conditionally divided into four types and each of them is better suited for a particular work.
Wascious sand
It is produced from the bottom of large lakes and the largest organic impurities is in the first place. In this regard, before mixing the concrete under the foundation it needs to be washed.
In principle, a good option, but the fact that it is necessary to rinse the consumer before applying it in front of another choice.
This option is cleaner, because it is washed in a natural way. Its composition is homogeneous and balanced, and the relatively small dimensions of the fractions talk about the feasibility of its use to prepare the foundation.
Sea sand
This material is mined from the bottom of the sea, and therefore its price is relatively high. But in composition and cleanliness is the best option.
Career sand
It is the cheapest material, it is mined in quarries natural by or crushing. This is not the best option for the foundation, because before working it, as well as lazy, requires pre-cleaning. The main advantage is low cost.
Based on the above qualities of materials, it can be said that the river type of sand mix is \u200b\u200bthe most optimal option to prepare a concrete mix for the foundation.
If you have some additions to this article, then you can leave them below and help readers with a choice of material.