Sand is free-flowing natural material, obtained as a result of the natural destruction of rocks under the influence of external factors. May contain small amounts of various impurities. It is used in almost all types of construction. To properly mix the solution, you need to know the density of the sand, since the proportions of the other components depend on it. It also affects the volume of purchases, for example, for arranging a cushion for the foundation.

What is density and what does it depend on?

Density shows how many grains of sand in kilograms fit into 1 m3. It is measured in kg/m3, sometimes in t/m3 or g/cm3 (this indicator affects). But this value is not always constant, as it can change depending on the following conditions:

1. Grain size. It can be fine-, medium- and coarse-grained. The larger the grain of sand, the lower the density, and, conversely, small ones fit more tightly. Coarse- and medium-fraction sands are used for the production of building materials and masonry mortars, and fine-fraction sands are used for the production of dry construction mixtures.

2. Porosity. Shows the number of voids. The high porosity option has lower density. If it is loose, then the value is 47%, if compacted - 37%. The degree of porosity decreases when sand grains are saturated with moisture, as they are enveloped in water and the voids between them disappear. It also decreases after transportation, since during movement everything is compacted due to vibration. Different fractions have different degrees of porosity. For construction sand made from large and medium grains it is 0.55, for fine sand it is 0.75. The denser it is laid, the greater the load from the foundation it can withstand and distribute it more evenly.

3. Humidity coefficient. You should definitely check the degree before purchasing. The more water it contains, the lower the density. The weight of 1 m3 of wet sand differs significantly from the same amount of dry sand.

4. Impurities. Depending on their volume, the density of sand kg/m3 also changes. It may contain clay, dust, salt, gypsum and much more. The density of pure material is about 1300 kg/m3, with clay impurities - 1800 kg/m3. To remove contaminants, it is washed, but because of this, the cost increases significantly.

Types and prices

There are several types of densities:

• true;
• bulk (medium).

The first type is also called specific gravity and is also measured in kg/m3. True density shows how much is in one cubic meter of bulk building material, without taking into account the voids between the grains. It is calculated experimentally in laboratories. Its value for non-metallic sand rock is 2500 kg/m3.

Bulk density shows the quantity in one cubic meter, taking into account voids and gaps. Its value is always less than the true value. To measure it, you will need a 10 liter bucket. Sand in its usual uncompacted state is poured from a height of 10 cm from the edge of the container until a slide appears above it. As soon as the bucket is full, the excess is leveled metal ruler, without compacting the sand, after which the container is placed on the scales. The result obtained must be divided by the number 0.01, which means the volume of the bucket, converted into cubic meters. For example, sand weighs 16.5 kg, it is equal to: 16.5/0.01 = 1650 kg/m3. In this case, it is convenient to use the formula P=M/V, where P is density, M is mass, V is volume. And, conversely, knowing the compaction indicator, it is calculated how much the bulk building material weighs, for this it is multiplied by the volume of the container - M = P * V.

The true density of construction sand is a constant value. The average value is used for calculations. Prices vary depending on its type, purity and fraction size. Uncleaned is noticeably cheaper than washed. Therefore, if a small batch is required, you can purchase unwashed sand and clean it of impurities yourself, especially if it is needed for the construction of a non-load-bearing structure. If you need it for making a foundation, you should purchase only clean and quality material. Clay and other impurities reduce the degree of adhesion of sand grains to cement, which is why the strength grade of concrete decreases.

Table with prices at which you can buy construction sand:

When choosing sand, you should consider: the lower its density, the more binding powder will be required to fill the voids between the sand grains and connect all the components, resulting in cost mortar rises.

The degree of radioactivity of most bulk building materials is first, but it is better to check the quality certificates, especially if it will be used to build a house, in which case it should only be class one.

Almost no construction can be completed without the use of sand. This is, in fact, a universal material, extracted from various deposits and, accordingly, having different characteristics(density, humidity, etc.) and names: dune, river, sea, quarry.

Below we will talk about the last type of sand from the list.

What is quarry sand?

This is one of the most common types sand used in various areas– construction, road work, territory development and other areas.

It is extracted from the bowels of the earth by developing quarries, the location of which determines the structure, composition and fraction of the material.

In this case, the building material does not shrink, and the finished product is flexible and elastic.

Species

According to the method of processing to which the product is subjected after extraction, sand is also divided into several types.

Alluvial – extracted from flooded deposits using hydromechanical equipment for this purpose. This processing method allows you to remove foreign impurities and components from sand and ultimately obtain a pure, high-quality product.

It is used for the production of mortar and bricks, as well as in the construction of roads and in the manufacture of reinforced concrete products.

Screened – the material is sifted through special equipment, equipped with a system of sieves and cells. During the cleaning process, clay particles, dust and small pebbles are separated from the sand. As a result, the material is freed from foreign impurities and large fractions.

Can be used for preparing mortars and mixtures.

Ground sand is an unrefined product containing foreign components (up to 40%). The material is low in cost and is more suitable for roughing procedures - leveling land plots and filling trenches.

Density

There are several types of material in question.

But the most useful include two types:

• true;
• bulk.

The true density of a material is the density of the grains of sand themselves.

When determining the true density, the amount of air between the grains is not taken into account, which can be 35-40% of the total volume, as well as the density of dust particles and clay components.

It follows that true density always more (1.5-1.9 times) than bulk. According to technical requirements specified in GOST 8736-2014, this parameter should be 2-2.8 g/cm3.

Determination of density

Possible methods, their essence, necessary equipment and instruments for measuring procedures are designated in GOST 8735-88. The same standard specifies the stages of test actions and methods for processing the obtained data.

The bulk density of the material is determined by weighing it in special cylindrical metal containers.

For this purpose, vessels with a volume of 1 dm3 and 10 dm3 are used. A small container is used for weighing dry and sifted sand, a larger container is used for unsifted material with natural moisture.

Sand is rightfully the most common and popular building material due to its excellent qualities and properties. find out how much a cube of sand weighs.

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Empty and filled vessels are weighed, after which the bulk density is calculated using a formula. To perform calculation procedures in everyday life, use a ten-liter bucket, into which sand is poured “with the top” from a small height (about 10 cm).

After this, the “slide” is removed, comparing the material with the edge of the bucket, the sand remaining in it is weighed and the net weight in kilograms, without container, is determined. The resulting figure is divided by 0.01 m3, thanks to which it is possible to calculate the bulk density of sand or the weight of 1 m3 of product in tons.

The true density of sand grains is determined in the laboratory using one of two methods:

• pincometrically - using a pincometer (special glass container);
• accelerated method, which uses the Le Chalier device - a glass vessel with a funnel-shaped top and a scale on the neck.

For more information on determining pitch density, watch the video:

Characteristics

In addition to density, there are other characteristics, by which the properties of sand can be assessed:

• presence of foreign impurities. There should be as few of them in the material as possible. Thus, the permissible content of organic components is 3%, and sulfur and sulfides – up to 1%;
• humidity. The mass of sand depends on it. The wetter the material, the greater the weight, and vice versa. According to standards, this parameter should not exceed 7%;
• level of radioactivity (depending on deposits). Material with a high degree of radioactivity cannot be used in residential construction;
• coefficient This refers to the ability of the material to pass water. U quarry sand this figure is 0.5-0.7 meters per day.
• coefficient;

Conclusion

To summarize, we can say that Quarry sand is a product that can be used in a variety of areas: agricultural industry, road development and building construction, for preparing solutions and decorating summer cottages.

At the same time, the material has reasonable price, which is also the reason why you should give it preference.

Construction or renovation work are often produced using various sand-cement mortars prepared independently. The quality of any mixture depends on the condition of its components. While all parameters are known for cement, the situation with sand is more complicated. Density of dry sand - important parameter, which largely determines the quality and consistency of the solution. The ability to calculate this value is just as necessary for the builder as the ability to calculate the amount of materials.

Why is it necessary to determine the density of dry sand?

Types of sand

Sand is a dry bulk material consisting of finely crushed rocks. The fraction size ranges from 0.05 to 5 mm, which creates problems in calculations. The composition of building mixtures requires fairly careful adherence to proportions, otherwise the strength of the materials will not meet the requirements of SNiP.

Determining the density of sand in practice is a very difficult task. The gaps between individual grains of sand are practically impossible to measure, since the shape of the grains of sand obtained by different conditions crushing rocks, has a complex and irregular configuration. There may be gaps between the corners and edges of individual particles that are significantly larger than the gaps between natural grains of sand, whose shape is closer to spherical.

Dry sand of natural origin (river) has a more dense structure, so the use of the same volume of material of different origins or fraction size will give mixtures that differ from each other in their parameters. Therefore, it is very important to have the most correct knowledge of all parameters of the components of the mixture, the mass of the material, its density and other indicators.

Main types and parameters of sand

The difficulty in definition forced the introduction of the concept of bulk density of sand, which determines the amount of mass per unit volume. There are three types of density:

• True. This is an indicator of extremely compressed sand, which has no voids between the grains.
• Bulk. Value in weighed and dry form.
• Average. This is a value that takes into account the presence of moisture and the porous structure of the grain. The average density is higher than the bulk density, but less than the true density.

Humidity is one of the most important factors that constantly changes the condition and bulk weight. Sand is stored, as a rule, in the open air, as a result of which the degree of humidity begins to depend on weather conditions. The compositions of all mortars assume the presence of dry material, and the sand in the mixture has other, non-ideal parameters. The change in density forces the use of compaction factors that correct the value that dry sand has.

The most common options for correction factors are shown in the table:

The average sand density is multiplied by the compaction coefficient, and the result is a value close to the real one. However, it is necessary to take into account the presence of an error (about 5%) arising from the impossibility of establishing with absolute accuracy the value of the correction for each specific case. More exact result gives a weighing method, but under conditions construction site it is not available, so estimates are most often used.

Calculation of sand density

Independent calculation of indicators can be done using the weighing method. To do this, you will need a scale or a steelyard with a capacity of 20–25 kg, and a dry container (an ordinary bucket can be used). The procedure is as follows:

• The empty container is weighed and the result is recorded separately.
• The container is completely filled with sand. The best option- pour it in a heap, then carefully remove the excess with an even strip and leave it flush with the edges.
• The full container is weighed.
• The tare weight is subtracted from the resulting value.
• The resulting value is divided by the volume of the container, the result is converted into standard units - kg/m3.

More exact indicators can be obtained by weighing several times, collecting material from different areas. It must be remembered that construction sand is stored in conditions that do not allow maintaining the same degree of humidity, so you should use it as quickly as possible, or periodically take repeated measurements and adjust the calculations.

Bulk density values ​​for different types of sand

Sand mined in different places, has a different structure, composition and fraction size. To correctly calculate the number of components in different mixtures or concrete, it is necessary to take into account the bulk density of sand of one type or another.

View	Extraction method	Dry density (bulk)
		g/cm 3	kg/m 3
River	Mined from the bottom of the river	1,5–1,52	1500–1520
River with grain size 1.6–1.8		1,5	1500
River compacted	Washed, without clay fractions	1,59	1590
River alluvium	Extracted from the river bottom using the alluvial method	1,65	1650
Career	From quarries, alluvial	1,50	1500
Quarry, fine grain	Seeded, dry	1,7–1,8	1700–1800
Building	Complies with GOST 8736-93. Mined during mining	1,68	1680
Loose		1,44	1440
Quartz	Obtained by crushing white quartz	1,4–1,9	1400–1900
Nautical	Drawn from the bottom of the sea	1,62	1,62
Ovrazhny	Mined open method, may contain many impurities	1,4	1400
gravelly	Mixed with gravel	1,7–1,9	1700–1900
Perlite	Obtained from expanded rocks	0,075–0,4	75–400
Slag	Obtained as a result of crushing sieving metallurgical waste	0,7–1,2	700–1200

The indicated values ​​are valid for dry raw materials, so when calculating, you will need to take into account the actual condition and use compaction factors. If they are neglected, excessive consumption will occur, and the composition of the mortar or concrete will be changed, which can reduce the strength of the pouring or connection of building structures.

Any without sand modern construction will be inferior. It is used to mix mortar, to create bars from baked clay, building mixture, to create thick lime mortar, as well as glass. This material is extracted in several ways: by washing and sifting. It is characterized by its physical and chemical parameters. For example, few people know that the basis of the bulk density of the building material in question is even its uncompacted mass in kg during transportation in bags. It can be different (the material was transported in bulk in the back of a dump truck or in bags).

Distinctive features of dry construction sand

The sand mixture can be conditionally divided into several types:

• the one that was mined in;

• the one that was mined from the river bottom.

A distinctive indicator of excellent quality is the degree of density of construction sand kg m3. An important role for density is played by the material’s ability to accumulate moisture and its porosity. The density of sand will differ from the density of construction sand.

If a person is interested in the one-time construction of a house, which may not be calculated separately, it is necessary to pay attention to average, which is accepted as the norm. At the same moment at professional construction The strength of the constructed structure depends on this number.

Density determines the total amount of sand. The density of construction sand is 1.3-1.8 t/m3. This indicator varies so much due to the addition of clay impurities (the more there are, the higher the number will be).

The resulting value will help you find out the quality of the grain composition, for example:

• the material that was extracted from the river bottom will have a moderate density of 1.3 t/m3; at the heart of it mineral composition geographical location. In any case, this material is considered to be of very high quality; as a rule, it does not contain any impurities;
• for material mined in quarries, this figure reaches 1.4 t/m3; in it there are some clay impurities;
• This is the reason that the material is rarely used to prepare high-quality mortar; but it is used to make the solution more affordable.

How to calculate the amount of sand in kg using the density of sand GOST 8736

This method is quite simple, but thanks to it you can only get preliminary calculations, so always check the results mathematically.

The radiometric method is also no less popular. It is based on the use of radioactive radiation.

Based on how a material can absorb and scatter radiation, this parameter is assessed.

Average additional sand indicators, which is extracted from quarries:

• first class radioactivity;
• density in uncompacted state – 1.4 t/m3;
• mass of particles per unit volume – 2.6 g/cm3;
• content of crushed rock – 1,9%;

Average additional features , which is mined from the river bottom:

• the ability of atoms of some isotopes to spontaneously decay, emitting radiation A (47 BC/kg);
• density in an uncompacted state – 1.4±0.1 t/m3;
• quantity chemical elements , transferred into the composition of the alloy during its production as a technological additive - 0.1%.

The number of voids should be determined by the density of the material in the uncompacted state. On your own, this value can be measured in this way: a little sample material is poured into a measuring liter container and weighed.

If the material has accumulated moisture very strongly, then the sample can be placed in a ten-liter container, then the values ​​​​are converted to the required value.

If there are clay impurities, this negatively affects the quality of the material.

From the sand that contains high percentage clay is prohibited from making, high-quality mortar, various for construction.

All this is due to low frost resistance and strength.

How to determine density - true and bulk

It is necessary to understand that The true density of construction sand differs from bulk sand. The first value consists of the indicators of the material in dry form, the density is based on the specific sand that is used during construction work.

These are extremely necessary indicators, for example, to dose building material before mixing concrete.

Density, as previously written, is based on the moisture content of the building material. So, if the sand has accumulated ten percent moisture, lumps appear in it, which causes voids to appear.

Despite the visual increase in the material (its volumes seem larger), the density becomes lower, that is, to knead, you need to take more material. With higher humidity, water will begin to displace air bubbles between the grains, as a result the sand will become denser.

When the density of a material in an uncompacted state is calculated, this makes it possible to understand and imagine its future volumes in cubic meters, which will depend on mass.

By making accurate calculations, you can find out exactly how much material you need to order for a specific construction. And this indicator does not depend on how the cost of the product is determined: for cubic meter or per tonnage.

For more information on determining density, watch the video:

Density of the material in an uncompacted state - significance from the technological and commercial side

Mass in construction practice is the ratio of mass to volume that a material occupies in a compacted or non-compacted state. This number is especially significant from the economic and technological side.

To make concrete mixture or solution for the purpose of creating sand cushion, it is necessary to use material with known indicators.

From an economic point of view, it is advisable to calculate several basic criteria - weight per volume unit and density under individual conditions.

Determining the density of sand is important from the point of view of the ratio of its mass and the actual volume occupied. From an economic point of view, density affects the money that the customer is willing to spend - he must purchase usable material of sufficient volume.

To do this, it is advisable to establish the number of particles in a volumetric unit without compactions and take into account humidity indicators, which significantly affect the weight.

Determination of the density of a material in an uncompacted state in accordance with GOST should be carried out according to a standard procedure.

Taken required quantity material, the specified ability to accumulate moisture is taken into account, sent to a measuring container and weighed repeatedly.

The value of measuring the density of river sand in an uncompacted state

Why is it so important to determine this indicator before future construction of real estate? It is he who is able to display the real amount of materials in a single volume - a cubic meter. Thanks to it, it is possible to use the material in terms of the ratio of resources expended and functionality.

The building material discussed in the article is subject to the standards of a separate GOST 8735-88, and this indicates:

• material with such indicators is fully compliant with construction technologies;
• material properties during work and after construction of the house are quite predictable;
• the method for determining the mass of a material per unit volume has been tested and approved as a reference, allowing one to obtain a long-awaited and truthful result;
• During the material testing stage, only approved methods and technical recommendations were used.

You must remember that when purchasing sand, its bulk density will be 1600 kg/m3, which fully meets construction standards. In addition, this material can be stored for a long time, it does not accumulate moisture, and lumps and voids do not form in it over time.

Excessive indicators of the mass of sand per unit volume at high humidity- indicates a decrease in its characteristics; it can only be used in limited areas. An increase in humidity causes a decrease in the percentage of quality.

This indicator is critically important for many non-metallic elements. To clarify this indicator in a specific batch of material, the manufacturer uses correction values. Such numbers make it possible to determine values ​​from the technological and economic side.

When purchasing a large batch coefficient allows you to level out deviations, which is caused by the dispersion of indicators. For example, at the stage of purchasing ten tons of material, the amendment will allow you to determine the amount of material up to 2 tons per batch.

Conclusion

There are often situations when the need for sand is limited, in addition, there is no need to constantly purchase and arrange delivery to the site of large quantities.

The most optimal solution will be the purchase of one batch of the required size, which has passed several basic tests for the ability to accumulate moisture and bulk density.

Remember that The density of sand depends a lot on the ability of the material to accumulate moisture and its porosity. The indicators for each specific type of sand will differ, so it is important to take into account the specifics of the material, the method of its extraction, etc.