Density of quarry sand kg m3. Bulk density of bulk materials. True Sand Density

Without sand, the construction industry will simply stop. It is required for mixing mortar, installing drainage, making bricks, concrete, plaster, and glass. It is mined in three ways: washing, sifting, and the open method. It has physical parameters. For example, the bulk density of construction sand affects the amount of sand that is not compacted during delivery in bags or in bulk in the back of a dump truck.

Distinctive characteristic

Sand is divided into 2 types:

• career,
• river.

An important indicator good quality is the degree of density. It determines how much sand is contained in 1 m³. This, in turn, depends on humidity and porosity.

For one-time home construction, this indicator is not calculated separately, but the average number accepted according to the norm is taken. However, in the professional sphere, the strength and durability of the constructed objects depends on this parameter. In addition, it can be used to determine the total amount of bulk building material. The density of natural construction sand is 1.3-1.8 t/m³. This difference is due to the admixture of clay (the more of it, the higher the indicator), as well as its quarry origin. This figure helps determine the quality grain composition

, For example:

How to calculate quantity using density?

Mass is calculated by the formula: m=Vxp (m - mass, V - volume, p - density). Let’s say we need to find out its quantity in 10 m³, then the data is substituted this way:

m = 10 x 1.3 = 13 t.

Here, an average density p of 1.3 t/m³ was used. Always keep in mind that insufficient density means increased voidness. Then preparing the solution will require increasing the amount of binders. Why is this disadvantageous for construction? Increasing the volume of binders increases costs and costs concrete mortar

An increase in humidity will lead to a decrease in density. This is explained by the clumping of fractions. In this case, the decrease continues until the humidity reaches 10%. Further growth increases the volume of liquid, it fills the free space, and the density begins to increase. Constantly changing the parameter changes the quality concrete mixture. It is important here that the standards are observed during deliveries.

How to measure it manually? Sand is poured into a 10-liter bucket from a height of 10 cm. The bucket should be filled completely to form a slide. It is cut strictly horizontally to ensure guaranteed flat surface filled bucket. This amount of sand is weighed, then the density is calculated. To do this, divide the mass by volume: the resulting kilograms are converted into tons, divided by 0.01 m3. An even more accurate calculation is obtained if measurements are taken twice. Then they are summed and divided by 2.

Other calculation methods

This characteristic is taken into account when drawing up a project for carrying out earthworks. The loose type of soil allows you to use the pit method. To do this, the soil is dug out in the form of a small pit (pit), and the displaced sand is placed in a special container for weighing. A tin cone is placed above the pit, determining the density of construction sand, which is filled with dry sand. Next, the volume of the pit is determined, from which the volume of suspended sand is subtracted. This method is quite simple, it gives only tentative calculations, so the radiometric method is sometimes used. It is based on the use of radioactive radiation. This parameter is assessed by the ability of sand to absorb and scatter this radiation.

Average additional values ​​of quarry sand:

• radioactivity - class 1;
• bulk density 1.4 t/m³;
• grain density 2.6 g/cm³;
• clay content 1.9%.

Average additional characteristics of river sand:

• class A radioactivity (47 BC/kg);
• bulk density is 1.4±0.1 t/m³;
• amount of impurities 0.1%.

Voids are determined by bulk density. This value can be measured independently in the following way: a sample is poured into a 1-liter measuring vessel and weighed. If the humidity is too high, the sample is placed in a 10-liter vessel, then the values ​​are converted to the required values. The content of clay impurities reduces the bulk density and deteriorates the quality of the material. It is impossible to make plasters, high-quality concrete, and various mortars from sand with a high clay content, because their frost resistance and strength are reduced.

Humanity has been using sand for construction needs for a long time; without it, one certainly cannot build a house. It is actively used in dry construction mixtures, which are sold in stores or as a component for preparing cement mortars. Construction sand is used depending on its density, e.g. individual species are used to create others in order to make a concrete screed.

Sand is a non-metallic, free-flowing building material. As a rule, this is a mixture of grains measuring 0.14-5 mm, which were formed during the natural destruction of rocks. There are several. They are characterized by a different content of small particles of clay or simply dusty elements.

The purest of them and the highest quality is river sand. Sea water is worse, since it already contains salts, from which it must be purified. Quarry sand and mountain sand are distinguished by the presence of undesirable clay, which means the quality of the product is lower. Sand mainly has the following composition: quartz and also impurities in the form of silicates and the same clay.

To characterize this building material, there is such a thing as sand density. It is estimated by the porosity coefficient. For example, fine-grained varieties have an indicator of 0.75. The density of construction sand and its quality are always determined by the presence of clay in it. Builders love to work with a uniquely pure river product. It has a density of 1.3 tons. cubic meter. The density of sand with clay content is higher and is already 1.8 tons. In the same volume.

This material has served as the basis for cement and concrete compositions. It is very popular when styling highways, when blowing glass products and in agriculture.

In construction, the concept of density is of fundamental importance, which is the ratio of the mass of sand to its volume; it has units of measurement: g/cm3 and kg/m3. Natural sand is 1300-1500 kg/m3.

For bulk building materials, this indicator is variable and depends on the degree of compaction. This means that the same amount of product occupies different volumes. The density of sand is invariably dependent on humidity, and any changes in it affect the bulk density. As humidity increases, sand grains become covered with a layer of water and, accordingly, the volume of sand increases sharply. It is sand that is taken into account during humidity fluctuations when calculating the dosage of sand according to the required volume. If this factor is not taken into account, the construction mixture will not have the necessary margin of safety and, in general, the engineering structure will be of poor quality.

Nowadays it is mainly used to extract it simply - by washing quarry sand. This is done in this way: clay and dust are washed out of it with a large volume of water.

The density of construction sand also depends on the structure of the grains. For example, a high indicator directly indicates that it contains dense, especially strong and frost-resistant grains. It is this material with an increased coefficient that is indispensable for construction in permafrost conditions. It is the basis of high-strength concrete with excellent frost resistance.

Density in a loose state is characterized by 1500 kg/m3, but can increase to 1700 kg/m3. It is characterized by the best hygienic characteristics and is washed and calcined dry natural material. When used in construction, high hygienic characteristics dwellings. Density quartz sand- this is very important parameter, which is taken into account during construction work.

Sand is a bulk material. It is difficult to measure its true density - it is almost impossible to remove gaps between grains of sand. For this reason, the concept of bulk density of sand is more applicable to sand. This is the average value of the weight of the material per unit volume.

Concept and meanings

The determination of the bulk density of sand hides the value of the dry mass of the material per unit volume, measured in cubic meters or cubic centimeters.

There are many types of sand by origin and fraction. Small grains of sand fit more tightly into the volume than large ones, therefore their mass is much greater. And vice versa.

Thus, sand extracted from the river is usually smooth and polished and has a dense structure. Its weight per cube averages 1500-1600 kg/m 3 according to GOST 8736-93. Sand grains from a quarry are often porous with sharp corners and edges; these weigh much less - about 1300 kg/m3.

Factors determining density

The bulk weight of sand depends on several factors:

• The fraction and shape of sand grains determines the density of the bulk material in to a greater extent. The larger the fragments, the longer distance the opposite remains between them. Round and square grains of sand occupy more space than flat ones.
• Breed of origin. The denser the mineral from which the sand is formed, the greater the mass.
• Remains of soil and organic impurities also affect the bulk mass of sand. Cooking technology mortars involves the use of purified fine filler, so this parameter can be adjusted by washing or sifting the fill.
• Humidity after washing or sand mining. Water penetrates the pores of sand grains and increases their weight. Bulk density dry sand is up to 30% less than wet sand. As it dries, the mass decreases and the volume increases.
• Sand compacted during placement has much more high density per unit volume than poured in the normal state.

The value of mass per cubic meter can be clearly seen in the table of bulk density of natural sand:

Calculation of changes in volume and mass

Sand is delivered to the construction site in in different forms: dry or wet, river or quarry. It may not be used immediately: the material is used as needed. If the embankment is stored under open air, grains of sand constantly change humidity depending on weather conditions. Technologists have to take these factors into account before preparing working solutions and backfilling pits.

Since the bulk density of fine and coarse sand is constantly changing, compaction coefficients are used to determine the actual mass of the volume without weighing. Some of them are reflected in the table:

The average density of the material is multiplied by the coefficient to obtain the desired result. The table shows the most popular values ​​of kу.

The bulk compaction coefficient of sand does not guarantee an accurate result - the error can be 5 percent or more. The only reliable way to determine the mass of a unit volume of material is weighing, which is not always possible or convenient. Professionals can use any of available methods determining density on site.

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.

Kinds

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 the true density is always greater (1.5-1.9 times) than the bulk density. 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 devices and tools for measurement procedures are indicated in GOST 8735-88. The same standard specifies the stages of test operations 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 thanks 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. For 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 the most various fields: 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. The density of dry sand is an important parameter that 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. Compound 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 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 accurate 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. In order 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.

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.