What sand is needed for the foundation - quarry or river? What sand is better for a pillow under a river or quarry foundation? What kind of sand is used for the foundation.

It is imperative to take care of the purchase of building materials for the preparation of concrete. It is recommended to pay special attention to the sand. Indeed, how strong the mortar for laying the foundation of the dwelling will turn out to be will largely depend on its quality and origin. What sand is better for the foundation is described below.

Sand, in the upper layer of which there are large foreign substances more than 5 mm, is not suitable for mortar on the foundation.

Material quality

Sand is a free-flowing building material that belongs to a type of sedimentary rock. Moreover, it is also obtained artificially - by crushing stone and crushed stone. But no matter what kind of sand you decide to get, first of all it must be of high quality, that is, clean. The presence of various organic matter in it - branches, grass, leaves and other things - is unacceptable. Of course, you can always clean up the contaminated building material by sieving it, but it will take a lot of time and effort to do this. In addition, do not forget that in addition to organic pollution, sand can contain various impurities: lime, clay, and so on. Their presence in bulk building material is extremely problematic to determine precisely. Moreover, to clean the sand from them. It should be remembered that only 5% of the total weight of impurities is allowed in it. If the amount of clay or lime in the sand is higher, then this will lead to a deterioration in the strength of the concrete, which, in turn, will negatively affect the durability of the finished foundation.

To determine what kind of sand the manufacturer offers you, ideally you need to go to the laboratory for an examination. Only then will it be possible to find out exact amount content of impurities. However, not everyone has the opportunity to do it, because it is expensive. Therefore, here it is proposed to go the other way and check what kind of sand the manufacturer offers you in the field. Many builders use a method, which is to put in a transparent plastic or glass bottle pour on 1/3 of the sand and fill up to half the volume with water. After that, the container is thoroughly shaken so that the bulk building material is moistened as much as possible. Then it is left for 5-7 minutes and then they look at what the water has become. If it is dirty, then you cannot make a foundation out of such sand. If, on the upper layer, there are third-party substances, the thickness of which is more than 5 mm, then such a building material is also not suitable for the construction of the base of the house. If the water remains transparent and foreign substances in it are less than 5 mm or they are completely absent, then you can make a foundation from such sand.

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Material moisture

Quarry sand is mined by breaking rocks, and the quality of this material is very low.

When buying this building material, you need to take into account its moisture content. She may have different meanings... In this case, the optimum humidity is considered to be from 1 to 5%. It is with this that you need to buy sand. To find out this parameter, you can use the following method: take a metal pan, weigh it (in kg), then measure 1 kg of sand on the scales and place it in a container, then put it on the stove and ignite over low heat for 30 minutes, stirring the mixture from time to time ... When this process is completed, immediately put the pan on the scale and look at the total weight, and then subtract the weight of the container from it and divide the result by 100. The final figure will be the moisture percentage.

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What type of sand should you choose?

When purchasing sand, you need to know exactly what kind of sand is best for building the foundation for a house. This means that you need to familiarize yourself in more detail with each of its varieties. They are as follows:

River sand, due to the size of fractions from 1.6 to 2.2 mm, is used both for concrete solutions for the foundation and for interior decoration, and to create drainage systems.

River. Extracted from the bottom of the rivers. Its builders consider it universal. The sizes of its fractions vary within the following limits: from 1.6 to 2.2 millimeters. Therefore, it can be used not only for preparing concrete for the foundation, but also for decorating premises, creating drainage systems, and so on. It is important that there are practically no clay impurities in such a building material. Therefore, as a rule, you do not need to check it for their presence. In addition, organic compounds cannot be found in it. Accordingly, such sand can be called clean. Therefore, this building material is ideal for preparing concrete. Experts recommend making a foundation on the basis of it. But it should be borne in mind that river bulk building material has a relatively high price. This means that you will need to allocate a solid budget for its purchase. If it is not provided, then you will need to make a choice in favor of a different type.
Nautical. This kind building material is mined from the bottom of the seas. It comes with particles of shells and various impurities. But before delivering it to customers, manufacturers clean it. Therefore, it can be used to erect a foundation, after making sure that the manufacturer has faithfully filtered it from impurities and organic matter.
Career. This species is inferior in quality to the first two. Its production takes place by breaking rocks. The purchase of such a building material is always very economical, since the price for it is set extremely low. And if you have allocated very little for the construction of the foundation Money, then the acquisition of quarry sand will become a great solution... But it will be necessary Special attention pay attention to its quality, as in most cases it leaves much to be desired.

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What fraction of sand to choose?

Building material such as sand is divided into several types according to fractions. The gradation looks like this:

Very fine - the fraction of grains of sand does not exceed 0.7 mm. Such a building material is unsuitable for the construction of a foundation, since it will turn out with minimal strength.
Fine - fractions from 0.7 to 1 mm. Builders do not recommend using this material for making concrete. It will not have a good density.
Very fine - size of fractions up to 1.5 mm. It can be used to create a foundation, but you need to take into account that it will not have too high performance characteristics.
Small - size of fractions from 1.5 to 2 mm. It is not well suited for the preparation of concrete, since it takes a lot of cement to create it, which leads to an increase in the cost of building a foundation.
Medium - the size of the fraction is from 2 to 2.5 mm. Ideal for building foundations. It is his experts in the field of construction that recommend using. Therefore, you should opt for such sand.
Large - fractions up to 3 mm. This material is used exclusively for the preparation of high-quality concrete. Making an ordinary solution out of it is unprofitable.
Oversized - fractions up to 3.5 mm. With the help of it, foundations are created on the sand, that is, they make pillows necessary to increase the strength of the base of the building and uniform distribution load.

When choosing sand, you need to pay attention to its edges. They need to be sharp, as this shape increases the knitting properties. concrete mortar.

Before starting the construction of the foundation, take care of the purchase suitable materials, from which high-quality concrete can be prepared.

The greatest attention should be paid to sand, since the strength of the solution depends on it.

Sand is a free-flowing material belonging to the category of sedimentary rocks. It can be mined from quarries or created artificial method by crushing crushed stone and stone.

Regardless of how the selected variety is made, the main criterion that it must have is purity. It is important that there are no admixtures of organic and inorganic materials, stones, leaves, grass.

If you bought a low-grade building material, you will need to clean it by sieving, which is labor intensive and time-consuming. Cleaning will not rid the sand of fine litter - particles of clay and lime.

According to technical standards, a content of up to 5% of impurities is allowed. When the number of particles is higher than this value, make the maximum durable concrete impossible. And the foundation, built from low-quality raw materials, is short-lived.

To understand how good the raw materials are, it is best to send them for expert laboratory analysis. This is the only way to know for sure all the characteristics. True, you will have to pay money for the procedure. But there is economical way independently analyze the raw materials. You will need:

Pour sand up to a third of the volume into a transparent container;
To fill with water;
Shake the container thoroughly so that the contents are saturated with moisture as much as possible;
Do not touch the bottle for 10 minutes so that all fine grains of sand settle.

If the water remains dirty or upper layer clogged with third-party substances with a thickness of 5 mm or more, such material cannot be taken for the foundation.

If the water "cap" remains transparent, and there are no foreign particles, feel free to mix concrete from this sand.

Suitable humidity

The moisture content of the building material is of great importance. The best indicator it is considered 1-5%.

You can find out if your raw materials have normal moisture content like this:

Take a metal pan, weigh it;
Add exactly 1 kilogram of sand there;
Using a stove, heat the pot for half an hour, stirring occasionally;
Then measure the weight of the container. Subtract the weight of the pan from the available value. Divide the result by one hundred;
The final number is the percentage of moisture.

Choosing the type of sand

According to the mining method, the following types of this building material are distinguished:

River. As the name implies, it is mined from the bottom of the rivers. It is considered universal. Ideal for foundations and interior decoration. Allows you to create drainage systems... An important plus is the absence of clay impurities and organic matter. But it's expensive.

Nautical. Since it is mined from the bottom of the seas, fragments of shells and other objects may come across. Manufacturers usually clean this sand thoroughly before delivering it to customers. It is recommended to analyze a certain amount in the laboratory before purchasing a large batch.

Career. The quality is lower than that of the sea and river. It is obtained through the destruction of rocks. Clay and other impurities are often found in the composition of quarry sand. This is an economical option, but the quality is usually not high enough to build a solid foundation.

Expertise will help you choose what kind of sand better fit for your area.

Quality comes at a price. If you do not have a large budget, you better dig up more money and postpone construction. After all, the foundation is too important a part of the house to save on it.

What size of grains of sand is better

There are several types of sand by fractions:

Very thin (less than 0.7 mm). Cannot be used in foundations, even when building a small cottage... Such sand does not allow to obtain sufficiently strong concrete.

Thin (thinner than 1 mm). You cannot make concrete from it. This fraction does not allow achieving the required level of density.

Small (up to 0.15 cm). It is used for foundations when it is necessary to build a small-sized building (up to 1-2 floors).

Medium (0.2 - 0.25 cm). This fraction is suitable for pouring foundations, therefore experts recommend using it.

With grains of sand up to 0.3 centimeters thick. These varieties are too expensive. High-quality concrete is made of them, and it is impractical to use it in household construction. Suitable for the foundation of high-rise buildings.

Extra large. The size of the fraction is less than 0.35 cm. Suitable for increasing the strength of the building and helping to evenly distribute the loads. The varieties are suitable for the construction of skyscrapers.

Do not forget to examine the edges of the grains of sand with a magnifying glass. The sharper they are, the better the binding properties of the concrete.

How much sand is required

5 parts of sand to 1 part of cement is considered suitable. If you want to use crushed stone, then the ratio will be as follows: 4 shares of sand, 2 - crushed stone and 1 part of cement. There is no point in trying to find another perfect recipe. The proportions have been tested over decades of practice.

The quality of the cement is also important. Some brands have such characteristics that they need to be added a little less or more, but on a small scale this difference is not significant.

In no case should you experiment in order to save money. There is a risk of paying off both with money and with your own safety.

If you buy a lot of cheap sand and mix it into concrete, then over time the building will sag and collapse.

Many people know that there is a sand cushion under the foundation, but not everyone can say for sure why it is needed and how it is created. As a result, novices in the construction business often pour sand into the trench without any understanding and in the end only harm the entire structure.

The cushion under the foot of the foundation can serve three functions:

Leveling. If the soil is not heaving and not mobile, then the only task of the sand is to level the bottom of the trench or foundation pit for even placement of the solution or the correct distribution of the load from the FBS.

Compensating. Heaving soils under the support of a house in winter can greatly affect the distribution of loads, leading in difficult cases to the destruction of a concrete tape or slab.

In this case, the task of the sand is to compensate for deformations, to reduce them to an acceptable level for a given foundation.

Substituting If there is organic-mineral or organic soil under the house (for example, peat), then you have to put up with the continuing decomposition processes.

In this case, the soil will necessarily be mobile, heaving and characterized by low bearing capacity... It has to be taken out to a great depth, until the end of the organic layer and covered with sand in the trench.

How thick a foundation pillow is needed depends on what function it performs in this particular case.

Pillow device

The easiest way is to create a bedding that performs a leveling role. As a rule, its thickness in this case does not exceed 15-20 cm. It is enough to fill up the sand once, carefully level it, spill it with a small amount of water - moisten it and then tamp it.

But such a minimum can be dispensed with either on non-porous soils, or in the case of a deep foundation, below the freezing level and relying on non-deformable soil layers. In other cases, it is necessary to lay a compensating pillow. Its dimensions depend on the width of the foundation sole. The exact data can be calculated from 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 a foundation is laid with a base width of 60 cm, then the width of the pillow will be 60 * 2.4 = 144 cm, and the height 60 * 1.2 = 72 cm. Strip foundation with a tape width over 120 cm, no compensating pillow is needed.

The compensating sand cushion is laid as follows:

Sand is considered a non-heaving material; also, due to its structure, it prevents the capillary rise of moisture from the underlying layers to the concrete. But all this is typical only for sand not filled with water.

If a lot of moisture gets under the foundation, then it can radically change the properties of the pillow.

Therefore, in an area with high level groundwater or where there is a likelihood of sediment water getting under the concrete, it is imperative to provide for a moisture removal system - drainage.

The process of laying a replacement pillow under the foundation does not fundamentally differ from the compensating one. The role of geotextiles and water drainage systems is only increasing. In any case, the correct ramming is essential. It is worth considering in more detail.

Watch our video selection on the topic:

How to seal correctly?

Clean sand practically does not shrink, but only after proper compaction. If you neglect this procedure and perform it in bad faith, there is a high risk of subsidence with subsequent destruction of the foundation.

In order for everything to work out properly, you should adhere to the following rules:

It is more convenient and faster to perform compaction work using a vibrating plate or a special construction vibrator.

In some cases, you can use road construction equipment, and sometimes it is good to tamp it by hand.

Which method to choose depends on the characteristics of the site and the possibilities.

Selection of sand

Few people think about what kind of sand to choose for a pillow under the foundation. They take the one that will be brought. However, the properties of this material affect the properties of the bedding no less than the correctness of its filling.

Washed quarry or river material is best suited for cushioning the foundation.

The ideal choice is gravel. Do not forget that it is allowed to use other materials that meet the presented requirements.

However, it is difficult to correctly determine the loads and properties of a particular soil at home, so the easiest way is to take the material that is guaranteed to fulfill its task.

Watch our video tutorial on creating a sand pillow:

Proffu »Records» Materials and tools »Sand bedding under the foundation

Before starting construction work, many pre-calculate required amount material. This is the right approach to such a serious matter. But at this stage, many questions arise. One of them: what kind of sand is needed for the foundation?

The choice of such a material should be given special attention, since it is an important component, one of the main components used in the manufacture of concrete. The durability of the foundation - the future foundation of the house - will depend on the quality of the mixture obtained. The modern market offers a huge range of sand, both natural and artificial. How to make a choice so that the foundation does not suffer from it, the article will tell.

Even a person who is ignorant of construction issues will be able to guess that exceptionally clean sand is suitable for the foundation. Initially, various organic elements may be present in it: small twigs, grass, etc. Such material is not suitable for construction work, therefore, there must be sown sand, cleaned of foreign debris.

However, simple pouring is not enough if it comes about impurities such as lime or clay. It is much more difficult to clean such sand, so when buying building materials, you need to immediately pay attention to this. The content of clay in the sand is not more than five percent of the total mass, especially if a solution is being made for the foundation. Otherwise, the structure after some time will shrink, crack and will not be particularly reliable.

Checking the purity of the sand

Before choosing what kind of sand is needed for the foundation, you should check its purity. For this, a simple method is usually used. Any empty clear bottle (glass or plastic) will be needed. Sand is poured into it by one third and half filled with water. Then shake the bottle vigorously so that the components mix well with each other. After that, they put it and wait for five to ten minutes. If the water in the bottle has become cloudy and dirty, then this sand is not suitable for the foundation. If a foreign substance appears on the surface, the layer of which exceeds half a centimeter, then such material cannot be taken either.

Now let's consider what types of sand exist.

Types of sand for embankment under the base

To ensure the reliability of the structure under construction, in accordance with SNiP standards, it is necessary to use bulk mixtures. The market sells sedimentary rocks in three types, depending on where they are mined. This is sand:

career;
river;
nautical.

To answer the question of which one is most suitable for a foundation pillow, it is worth familiarizing yourself with the characteristics and nuances of using each type.

Quarry sand

This raw material is mined in quarries, breaking rocks. An important indicator of the reliability and strength of quarry sand is its moisture content. A ratio of one to five percent is considered acceptable. Suitable humidity can be determined visually. It will not work out of the sand to form a dense lump - it will simply crumble.

The cheapest material is considered to be quarry building sand. The price for it ranges from three hundred to seven hundred rubles per cubic meter. This is due to its low quality due to the large amount of impurities of clay and other substances. Nevertheless, this raw material is in great demand.

Types of quarry sand

Depending on the type of processing, quartz raw materials are classified as follows.

1. Sandy soil. It is a crude mixture with various impurities. As a rule, it is aligned summer cottages and fill up the trenches.

2. Washed sand. It is extracted from flooded deposits using hydromechanical equipment. The technology allows you to collect a mixture without any impurities and unnecessary components. This material is used in the production of roads, paving slabs, concrete, brick and reinforced concrete products.

3. Seeded sand. It is cleaned by a technical and mechanical method from large particles and stones. Typically, such raw materials are used to prepare a mass of plaster, masonry solutions and in the casting of stone products.

River sand

This raw material is mined from the very bottom of freshwater rivers. It rarely contains organic compounds and impurities. That's why river sand considered clean and natural product, which is designed for multipurpose use. it perfect material for laying the foundation, creating drains and diluting the solutions necessary for the interior decoration of the house. Due to natural grinding, river sand has an ideally smooth shape and a fine fraction within two millimeters.

Thanks to all the listed advantages, this material becomes versatile and desirable, but rather expensive raw material for the foundation. So, the price of construction sand extracted from the river can vary from seven hundred to one thousand rubles per cubic meter.

River sand classification

Raw materials from the bottom of the river can be very different from each other. Therefore, you should deal with the variety of grains of sand. They can be of several fractions: from 0.7 to 5 millimeters. The filling of small grains of sand shrinks and compresses strongly, therefore it is suitable only for lightweight buildings. The following types of bulk river material are also distinguished.

1. Coarse sand. These are pebbles about five millimeters in size. They are obtained by splitting rocks using special crushing and grinding equipment.

2. Coarse sand. It has an unobtrusive neutral color and is obtained from dry rivers. Ideal for finishing and decorating a room.

3. Washed river sand. These are medium-sized grains. Have gray or yellow, since they include iron and silicon oxides.

Positive sides of river sand

River sedimentary rocks have several positive qualities, which are of great importance for the construction of the foundation. They meet technical and aesthetic requirements, do not rot and are not exposed to aggressive environments. River sand is characterized by high moisture resistance and excellent sound insulation. It is also a safe and environmentally friendly material.

For the construction of multi-storey buildings, only the coarse-fraction type is used, and for capital houses, an average crumb is already suitable. Also river sand is ideal for landscaping sites, playgrounds, landscape works and decorating rooms.

Sea sand

Sea chips are also exactly the material that is needed for the foundation. The sand is initially no better than river sand, and sometimes even worse. This is due to the presence of organic impurities (algae, shells) and foreign objects. But sea sand must be cleaned of strangers and washed, so it is considered clean and of high quality. Due to this, this material is the most expensive, and not everyone is willing to pay for it. It is more appropriate to use sea chips for construction where it is sold nearby and is cheaper.

Sand fractions

Any sand can be classified by its size. Experts distinguish the following types of factions.

Very thin. These are grains of sand about 0.7 millimeters in size. They are suitable for arranging playgrounds and are not suitable for construction.
Thin. Grains in size reach from 0.7 to 1.0 millimeters. This is a loose material. You cannot use such sand for construction, but it will be good for making lean concrete.
Small fraction. Represents grains of 1.5-2.0 millimeters in size. When using it, the consumption of the cement mixture increases.
Average. Nibbles (2.0-2.5 millimeters) can be used to create standard concrete.

Large. Sand particles reach three millimeters in size. This fraction is ideal for breeding high-quality concrete mix, which will be used in large-scale construction.
Very large. The particles are more than three millimeters in diameter. They are added to the foundation cushion and used to distribute the mass of the structure.

Choosing sand for the foundation

So what kind of sand is needed, river or quarry? Experts agree that the first option is most suitable for the construction of foundations. It will create a layer that will increase the strength, stability of the building, prevent "walking" and the formation of cracks.

However, river sand will not be affordable for everyone. In this case, it is allowed to use quarry crumb, but it must be washed. A sand and gravel mixture is also suitable, which improves the quality of the bedding compound.

Required amount of sand

Usually, one part of cement is taken for five parts of sand. But this calculation is suitable if the solution is made from only these two components. The ratio of sand, crushed stone and cement for the foundation will be completely different. As a rule, they are taken in following proportions: four pieces of sand, two pieces of crushed stone and one piece of cement.

As can be seen from the calculations, it is always necessary to take more sand than other components. The very amount of materials directly depends on the height of the pillow and the building itself. It is better to buy sand with a small margin so that you do not have to buy it at the wrong time. Residues can be adapted for the preparation of mortars for wall decoration or masonry.

Summarizing

Answering the question, what kind of sand is needed for the foundation, it should be noted that ideal option river grains of the middle fraction are considered. This material has excellent properties for construction purposes. It allows you to build the most durable foundation that will stand for a long time and will be an excellent foundation for construction.

It is necessary to purchase sand from reliable manufacturers so as not to stumble upon low-quality raw materials. It is recommended to check the material before purchasing for moisture levels and the amount of foreign matter. It is also worth paying attention to the consistency of the purchase size. As a rule, there should be about one and a half tons of sand in a cubic meter.

When laying the foundation, it is important to choose correctly and correctly Construction Materials... It is especially necessary to choose sand carefully, since it is the strength of the solution for the foundation depends on it, and hence the strength of the entire foundation. The question of which sand is better to choose for the foundation will be answered in this article.

Sand selection

Foundation sand is a free-flowing material obtained from sedimentary rocks or artificial creation ... The quality of the sand does not depend on its production method; it is important to consider only its purity.

If you can find foreign objects in it more than half a centimeter in size, it will not be suitable for laying a foundation. Foreign objects can include branches, leaves, organic debris.

Of course, you can try to clean the sand yourself, take a sieve and sift it, but just imagine how much time and effort it will take you for this process. By sifting through the sand, you only remove large impurities, but what about the content of such elements that are undesirable in the sand for building the foundation of a house, such as lime or clay.

Better immediately select high-quality sand and get to work... Remember that high-quality sand suitable for making a mortar should not contain more than 5% of impurities. In addition, a large number of additives will worsen the strength of the sand, which will affect the foundation and the house or building itself. Content gravel in sand should not exceed 10% since gravel is constituent element mortar for pouring the foundation.

Of course, you can only find ideal sand by conducting a special examination of its compliance with all standards in the laboratory, you will find out the percentage of impurities in the total mass and other indicators. But such an examination is a costly and time-consuming process, therefore you can determine the quality of sand using improvised methods.

Fill the sand, in a transparent bottle, one third, and then fill in half clean water and shake. Then give the mixture settle for 5 minutes and look at the transparency of the water... If it becomes cloudy and dirty, then the sand contains many impurities. Floated foreign matter is also a bad sign, and such sand is unsuitable for construction. If the water is clear and without impurities, then the sand is ideal for laying the foundation.

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The origin of the sand

Which sand is better - quarry or river, let's talk in this part.

Quarry sand

Quarry sand is mined in a quarry, destroying rocks. It is of lower quality than the river one, but there are exceptions. When choosing quarry sand important factor its reliability and strength is the parameter of humidity... Its percentage should be between 1 and 5%. The moisture content of 5% is determined by eye by the fact that you cannot mold a dense ball or snow from the sand - it crumbles.

To correctly determine the moisture parameter, you can resort to the following method. To determine the moisture content of quarry sand, take a container and weigh it. Then, weigh 1 kg of sand in it and hold it at a low heating temperature for about half an hour, and then weigh only the sand. Humidity will be calculated using the formula: the mass of sand after heating minus the mass of the container divided by 100.

Quarry sand is cheaper in price than river sand, since its method of extraction is less costly.

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River sand

River sand is ideal for laying foundations, and is also used when diluting mortars for interior decoration of a house or creating drainages. Therefore, such sand versatile and multifunctional... Its fine fraction from one and a half to two millimeters and the absence of impurities make it desirable, but expensive building material.

In addition to river sand, they also emit nautical but in modern construction it is used where it can be quickly brought, otherwise it the price even exceeds the river... In terms of quality, it is no better than a river one, and sometimes even worse due to organic matter (shells, algae) and foreign objects.

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Sand fractions

Depending on the size of the grains of sand in the composition of the sand, the following types of fractions are distinguished:

Very thin contains grains of sand up to 0.7 mm, but due to the low fraction, it is unsuitable for foundations. The foundation based on it will be as fragile as possible.
Thin contains grains of sand from 0.7 to 1 mm... Such sand is loose, therefore, it is also not suitable for foundation mortar. Usually fine sand is used for pouring concrete.
Very small contains grains of sand up to one and a half mm, but still not suitable for pouring the foundation again, as the strength will still not be optimal.
Small contains grains of sand from one and a half to 2 mm... And again, it is not suitable for pouring the foundation due to the high costs of cement for it.
Average contains grains of sand from 2 to 2.5 mm and is ideal for pouring foundations due to its strength and high performance properties.
Large contains grains of sand up to 3 mm and is intended for the manufacture of high quality and expensive concrete brands. Such sand is very expensive.
Sand increased size contains grains of sand up to 3.5 mm and is used for the manufacture of sand cushions designed to increase the strength of the base and distribute the load on all corners evenly.

Foundation fill assumes that the edges of your chosen medium sand should be sharp. It is the sharp edges of the grains of sand that increase the operational properties of the solution and make it as strong as possible.

The foundation, translated from Latin, means "foundation"; the fate of the entire structure depends on its strength and reliability. That is why it is so important for this part of the development to select quality materials... To the fortress concrete base not only the brand of the binder affects, but also the aggregates - sand and crushed stone.

Let's consider the main properties, advantages and disadvantages of the most common building sands - river and open pit, compare them and try to answer the question which one is more suitable for building a foundation.

Construction sand

Natural sand is a loose loose rock of sedimentary origin, has a crystalline structure with a grain size of up to 5 mm and consists of destroyed mineral remains, most often quartz with a small amount of other inclusions.

Requirements for it as a building material, according to GOST 8736-93, include parameters such as grain size, its bulk and true density, allowable limit the content of dust and clay particles, harmful impurities, radionuclides.

River sand

River sand is mined in river beds. It has a homogeneous consistency, good fluidity, and an average granule size in the range of 1.5–2.5 mm. Thanks to long-term natural washing, it is clean, the grains have the correct rounded shape.

It is believed that this is the highest quality aggregate for concrete mortar, the strength of which is especially important in the construction of load-bearing structures. The pluses of the material, as a rule, include the following features.

It does not contain clay and silt particles, which are unacceptable in cement-sand mortars and worsen their quality.
Oval-shaped crystals during the preparation of the concrete mixture do not condense, the cement milk envelops them evenly, and the finished concrete practically does not shrink.

River sand

He also has disadvantages.

Mixing with this type of filler requires more cement and more thorough mixing.
This is the most expensive building sand.

Quarry sand

The most common and affordable concrete filler... Careers with its development are everywhere, manufacturers are abundantly saturating the market with inexpensive and demanded products.

Unlike the river analogue, quarry sand has a wider range of fractions, its granules irregular shape, angular. Contains a fairly large percentage of impurities, including dust, organic matter, clay, rock debris.

There are several ways to enrich it.

Washed (alluvial) product is obtained using the technology of special directional hydraulic impact on the rock mass with its subsequent sedimentation. As a result, there is a cleaning of foreign matter, especially clay deposits.

The second method of enrichment is sifting through a sieve system, which retain large fragments of stones, lumps of clay, etc.

Sand pit development

Despite the fact that quarry sand is inferior in quality to river sand, it is in demand in the construction industry and has a number of advantages.

Much more common.
Less cement is used for the preparation of concrete - this is due to the property of crystals of irregular shape to become more compacted.
Differs in an attractive price.
The fortified product meets the highest standards.

Among the disadvantages experienced builders note the following.

Quarry sand contains a greater percentage of organic clay and dusty particles - up to 7% versus 0.05% in the river analogue.
Due to its structural composition, it settles, compresses at the time of setting and hardening of concrete. Finished construction shrinks up to 1 mm per 1 cm.

Criterias of choice

Most builders in the matter of choosing sand for the foundation agree on one thing - the fraction, the minimum percentage of foreign substances and the density are much more important than the origin or place of extraction.

A quality sand aggregate must meet the following criteria.

The most acceptable modulus of grain size is from 1.5 to 3 mm.
The limiting content of organic and clay impurities is 3-5%.
Should not contain harmful components that can enter into chemical reaction with cement alkalis - silicon dioxide, sulfur, chlorine, etc.
Have in the composition of active radionuclides no more than 370 Bq / kg, which corresponds to the I class of radioactivity.

An important point that allows you to control the quality of the supplied products is its bulk weight. The average for clean dry sand is 1500 kg / m3. A lower weight indicates the presence of foreign matter, a higher weight indicates high humidity.

In its natural form, river sand is more consistent with these criteria. A seeded or alluvial quarry is in no way inferior to him. But if the requirements for future development are low, and the foundation will not be subject to heavy loads, then an inexpensive filler from a nearby quarry is quite suitable.

The amount of sand under the house

Many people wonder how to correctly calculate the volumes of the constituents of the concrete mixture required for the construction of the base of the house.

To fill the foundation, concrete is needed at least M300. The preparation of 1 m3 takes about 650 kg of sand. Calculate the volumetric indicators of your foundation (multiply the height by the width and depth) and calculate the tonnage of sand, then convert it to volume at the rate of 1.5 t / m3.

Sand should always be bought with a small margin (15–20%) to the calculated figure - this material tends to thicken, some of it will scatter over the site during transportation, something will come in handy for backfilling.

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What sand is needed for the foundation

Before you start construction works, many first calculate everything and prepare the material. This is correct and commendable. But at this stage, different questions arise, one of them is what kind of sand is needed for the foundation. The choice of sand should be given special attention, since it is one of the main and important components used when mixing concrete. And your future foundation, foundation depends on the quality of the concrete mix. Considering that there is a large selection on the market various sand both natural and obtained artificially, it is important to choose the most suitable one for performing these works. In this article we will tell you how to make the right choice.

Purely theoretical

The main criterion is purity

Anyone who is not versed in the construction business and its nuances can guess that it is necessary to choose clean sand for the foundation. Initially, the sand may contain various organic elements, such as grass, branches, etc. Such sand is not suitable for work, but it can be easily cleaned. Perhaps you have seen more than once how workers sift the sand, cleaning it of unwanted elements.

But if we talk about such impurities as clay, lime and others like that, then simple sifting is not enough. It is more difficult to clean such sand, so when buying, you need to immediately pay attention to it. The presence of clay in the sand should not exceed 5% of the total mass, especially if we talk about the foundation solution. Otherwise, the future structure will not differ in reliability, it will shrink, and this will lead to cracks. It is important to check how clean the sand is before buying. You can use a simple method to check.

You will need a clear bottle, be it glass or plastic. It is necessary to fill it with sand by 1/3 and fill it with water to half. Then shake the bottle vigorously so that the sand mixes with the water and gets completely wet. Then put it on and wait 5-10 minutes. If the water becomes dirty, this sand will not work for the foundation. If a foreign substance has formed on the surface, with a layer of more than 5 mm, such sand cannot be taken. Let's look at what types of sand there are, how they differ and what kind of sand is best to purchase for the foundation.

Varieties of sand

River sand

Sand is divided into several types, depending on the place of its extraction:

River.
Nautical.
Career.

The very name of river sand suggests that it is mined from the river bottom. it universal material, since it contains fractions different sizes- from 1.6 mm to 2.2 mm. Thanks to this, it is used not only for pouring the foundation, but also for various construction purposes. The main advantage of river sand can be called its natural purity and uniformity. There is very little clay, particles of vegetation and other impurities in it. This sand is ideal for foundations. Only its price is quite high.

Nautical

Sea sand is mined from the bottom of the sea, after which it is cleaned of shell rock and other impurities. The difference between such sand is its grain size, which is approximately 1 mm. This granule size allows it to be used for the construction of reinforced concrete structures. It can be called quite clean, since it is cleaned, sifted and washed before being sold. But you have to pay for quality, so sea sand is the most expensive.

Career

Quarry sand is mined open way from the quarry. If you compare it with river and sea sand, this is the worst option. And it is not surprising, since it contains a lot of impurities - clay, vegetation and gravel. Because of this, the price for such sand is the lowest and it is suitable for rough work at the initial stage of construction.

In order to unambiguously determine which sand is best for concrete, it is important to consider other features. Some craftsmen advise buying quarry sand, which is cheaper, referring to the fact that this will not affect the quality of the foundation of the house. Others say that quality is higher than price, so you need to choose expensive sand, which will ensure the reliability of the foundation, on which you cannot save. Be that as it may, you need to consider other features and criteria that will help you make your choice.

Specifications

Better to use coarse sand

As mentioned above, the sand must be clean. If there are vegetation or branches in it, this is not scary, they can be weeded out. But clay, silt, gravel and other particles can degrade the quality of the concrete slurry. The presence of clay should not exceed 5%. The presence of gravel as a percentage of the total mass should not be more than 5%, and the particle size should not be more than 10–12 mm. If the size of the gravel ranges from 5 mm to 10 mm, then a higher percentage is allowed - up to 10% of the total mass.

A lot important point when choosing a material - its granulometric composition, that is, the size of the granules. Based on the size of the sand granules, it is divided into:

very fine 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;
fine sand, the size of the granules of which is from 0.7 mm to 1 mm. This type is also not used for making concrete;
very fine sand, the grain size of which is in the range from 1 mm to 1.5 mm. You don't need to choose it for concrete either;
fine sand, the size of the granules of which is from 1.5 mm to 2 mm. Not suitable for preparing high-quality concrete mix;
sand of medium size, the size of the granules of which is from 2 mm to 2.5 mm. It is sand of this size that is ideal for preparing a concrete mixture for a foundation;
coarse 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 quality concrete;
sand of increased coarseness, the size of granules of which ranges from 3 mm to 3.5 mm. Sand of this fraction is best used to cushion the foundation for the base of the building.

Very coarse sand, larger than 3.5 mm, can also be used for cushioning the foundation.

The sand must be dry

Another important point when choosing sand for the foundation is moisture. The water content in the sand plays an important role, since its amount must be taken into account when mixing the solution with the addition of water. The recommended moisture content of the sand for the foundation should be no more than 5%. The dried rock can have 1% moisture. If the sand gets under precipitation, then its moisture content can reach 10%.

If you purchased sand, you need to take care of its protection from precipitation. To do this, you need to cover it with something or unload it under a canopy. Then it will not absorb excess water.

But how to determine the moisture content of the sand? Use a saucepan or iron bucket. Take a container and place it on weights. Having learned the weight of the container, take 1 kg of sand and fill the container with it. Now you need to dry the sand. To do this, put it on a stove with low heat and "cook", stirring occasionally, for 30 minutes. After the time has passed, everything must be weighed again. Subtract the weight of the bowl or bucket from the weighing result and multiply the result by 100. As a result, you should get a number in percentage that indicates moisture. For clarity: a bucket or bowl has a weight of 0.2 kg. After you have dried 1 kg of sand, total weight it turned out 0.9 kg. It turns out:

0.9 - 0.2 x 100 = 70

The moisture content of your sand is 7%. There is another method for determining moisture content. It is enough just to use a special device that will show the exact figure.

Let's summarize

Better to buy sand at the mining site

So, having all the data, you need to analyze them and make a choice. You learned that the ideal foundation sand is:

clean sand, in the composition of which clay and gravel do not exceed 5% of the total mass;
sand with a medium size, the size of the granules of which ranges from 2 mm to 2.5 mm;
sand, the moisture content of which does not exceed 5%.

When buying such a building material for a foundation, you must definitely pay attention to these indicators. Most the best option in terms of price and quality, it is washed and screened open pit sand, the size of granules of which is 2–2.5 mm. Better to buy it directly at the place of production. If you have money and want your foundation to be strong and stand for a very long time, stop on river sand of the same faction. Then your concrete for the foundation will have the necessary qualities.

When buying sand, you should control the weighing process of a loaded and empty dump truck, as there are unscrupulous suppliers who do not weigh the sand, profiting from you.

We hope this article helped you figure out what kind of sand to choose for the foundation.

Video

Tips for choosing sand below:

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How to choose the right sand for the foundation

When laying the foundation, it is important to correctly and correctly choose building materials. It is especially necessary to choose sand, since it is on it that the strength of the solution for the foundation depends, and therefore the strength of the entire base. The question of which sand is better to choose for the foundation will be answered in this article.

Sand selection

Foundation sand is a free-flowing material obtained from sedimentary rocks or artificial creation. The quality of the sand does not depend on its production method; it is important to consider only its purity.

If you can find foreign objects in it more than half a centimeter in size, it will not be suitable for laying a foundation. Foreign objects can include branches, leaves, organic debris.

It is better to immediately choose high-quality sand and get to work. Remember that high-quality sand suitable for making a mortar should not contain more than 5% of impurities. In addition, a large number of additives will worsen the strength of the sand, which will affect the foundation and the house or building itself. The gravel content in the sand should not exceed 10%, since gravel is an integral element of the foundation grout.

Of course, you can only find ideal sand by conducting a special examination of its compliance with all standards in the laboratory, you will find out the percentage of impurities in the total mass and other indicators. But such an examination is a costly and time-consuming process, therefore, the quality of the sand can be determined using improvised methods.

Fill the sand, in a transparent bottle, a third, and then fill in half with clean water and shake. After that, let the mixture stand for 5 minutes and look at the transparency of the water. If it becomes cloudy and dirty, then the sand contains many impurities. Floated foreign matter is also a bad sign, and such sand is unsuitable for construction. If the water is clear and without impurities, then the sand is ideal for laying the foundation.

When laying the foundation, it is important to correctly and correctly choose building materials. It is especially necessary to choose sand carefully, since it is the strength of the solution for the foundation depends on it, and hence the strength of the entire foundation. The question of which sand is better to choose for the foundation will be answered in this article.

Sand selection

Foundation sand is a free-flowing material obtained from sedimentary rocks or artificial creation... The quality of the sand does not depend on its production method; it is important to consider only its purity.

If you can find foreign objects in it more than half a centimeter in size, it will not be suitable for laying a foundation. Foreign objects can include branches, leaves, organic debris.

Better immediately select high-quality sand and get to work... Remember that high-quality sand suitable for making a mortar should not contain more than 5% of impurities. In addition, a large number of additives will worsen the strength of the sand, which will affect the foundation and the house or building itself. Content gravel in sand should not exceed 10%, since gravel is an integral element of the foundation grout.

Fill the sand, in a transparent bottle, a third, and then fill in half with clean water and shake. Then give the mixture settle for 5 minutes and look at the transparency of the water... If it becomes cloudy and dirty, then the sand contains many impurities. Floated foreign matter is also a bad sign, and such sand is unsuitable for construction. If the water is clear and without impurities, then the sand is ideal for laying the foundation.

The origin of the sand

Which sand is better - quarry or river, let's talk in this part.

Quarry sand

Quarry sand is mined in a quarry, destroying rocks. It is of lower quality than the river one, but there are exceptions. When choosing quarry sand an important factor in its reliability and strength is the moisture parameter... Its percentage should be between 1 and 5%. The moisture content of 5% is determined by eye by the fact that you cannot mold a dense ball or snow from the sand - it crumbles.

Quarry sand is cheaper in price than river sand, since its method of extraction is less costly.

River sand

In addition to river sand, they also emit nautical, but in modern construction, it is used where it can be quickly brought, otherwise it the price even exceeds the river... In terms of quality, it is no better than a river one, and sometimes even worse due to organic matter (shells, algae) and foreign objects.

Sand fractions

Depending on the size of the grains of sand in the composition of the sand, the following types of fractions are distinguished:

Choosing sand for the foundation cushion

The sand foundation pillow is a special layer that needed to impart increased durability and stability of the building, increased strength and uniform load. Sand pillow prevents "walking" of the building in the spring due to the increased level of groundwater and prevents the formation of cracks in it. Such a pillow is essential facilitates construction on soils with high humidity.

The choice of sand for the foundation cushion is quite simple: use sand with the size of grains of sand 0.25 to 2 mm, river sand is better, or, if you cannot afford river sand because of its high cost, washed quarry sand. Sand or sand and gravel mix is also great for a pillow.

Sand-gravel mix, as the name suggests, contains gravel, which only improves the mix for bedding. The most popular foundation cushion height is height up to 15 centimeters, but not less than 10, otherwise the meaning of the pillow will disappear. If the construction of the building is being built on soils with a high level of groundwater, drainage can also be done with sand, and only then a pillow and a foundation. So the base will become even more reliable and stronger.

Backfilling under the foundation - another name for the pillow, is made on the basis of sand or crushed stone.