This is a granular substance consisting of grains of stone or mineral rocks. Domestic standards determine the size of granules construction sand from 0.16 mm to 5.0 mm. Anything larger than 5 mm is gravel or crushed stone.

Particles smaller than 0.16 mm are practically not used in construction, since when combined with water they turn into dirt. Granules of this size are not used in filtration and drainage systems, since they no longer allow water to pass through.

Sand is obtained in two ways:

1. Extraction from natural quarries and from the bottom of reservoirs - rivers and seas.
2. By grinding and dispersing rocks, quartz and other minerals.

Since the bulk of sand is used in construction, the density becomes one of the most important characteristics this material. It depends on humidity, the percentage of clay and dust particles, the power of the compacting effect of water or vibration mechanisms, the curing time and the state of loosening.

The density of sand, unlike crushed stone, can, depending on humidity, vary within fairly wide limits. When dry sand is saturated with moisture, its density first decreases - the water increases the gaps between the grains of sand. Starting from 10 percent humidity, the density of sand begins to increase as water in pure form fills all the voids and the mass per unit volume of the substance increases. From practice, everyone knows that a bucket with wet sand weighs more than with dry sand - the density of wet sand is greater.

Clay particles and lumps of clay increase the density of sand, which is one of the signs of clogging with these pollutants. Thus, the bulk density of sand with clay can reach 1800 kg/m³, while the material purified from it has an indicator of 1500 kg/m³.

Important for economic activity are indicators of the true and bulk density of sand.

Bulk density of sand

Bulk is the density that sand has immediately after filling without any mechanical or moisture compaction. You can determine it at home. To do this, you need to take a dry measuring vessel, the volume of which has been accurately verified, weigh it, pour sand into it to the top, remove the pile with a flat object without compaction, and weigh the vessel again. If the resulting mass of sand (minus the mass of the vessel) in kilograms is divided by the volume in liters, you obtain the bulk density of sand in kg/dm³, which can easily be converted to kg/t by multiplying the number by 1000. Example. 2 kg/dm³ is 2000kg/m³ (or 2t/m³).

In laboratory conditions, bulk density is determined in a similar way, but using measuring cups and measuring device the accuracy that is regulated by GOST.

Knowledge of bulk density is necessary when ordering sand for work with dosed consumption of material, when purchasing it in volumetric or mass units. Deception of buyers by dishonest sand sellers is often based on fraud with the volume and weight of this material.

True Sand Density

The concept of this term differs significantly from the previous one.

The true density of sand is the density of the monolith that crumbled into sand over time, or that was crushed into grains of sand in a crushing plant.
Sometimes true density is called without taking into account the air gaps between grains of sand.

The true density is always higher than the bulk density. If average size the bulk density of sand is considered to be 1500-1600 kg/m³, then true density of this material will be between 2000 kg/m³ and 3000 kg/m³. The average value in the industry is conventionally considered to be the true density of sand at 2500 kg/m³.

The values ​​of the true density of sand are used in the design of critical hydraulic structures, skyscrapers and other complex concrete structures. In many cases, the functional characteristics of strength, thermal conductivity, sound insulation, and deformability of buildings depend on it.

Determination of sand density - bulk and true - is carried out by laboratory methods in accordance with GOST 8735. At sites, balloon density meters are used for these purposes.

Sand density is an important technical characteristic of the material, which must be well understood in order to be used skillfully.

For construction needs, natural sands of various origins are used - river, sea, quarry, dune, etc. Their differences lie in the extraction method, the percentage of clay and organic impurities, as well as dust particles, which negatively affect the quality of concrete mixtures and the strength of the finished ones. building structures. The degree of contamination, the shape of the grains, the cost of the material and its availability, the fractional composition and humidity play a certain role in the scope of application of a particular type of sand.

Differences and features of quarry sand

The difference between the most common types of sands - quarry and river - lies in the method of their extraction. Both of them are natural inorganic materials and are extracted as a result of mining, but in the first case sand is extracted open method, and in the second - hydromechanical from the river bottom. In turn, quarry sand is divided into:

• seeded;
• alluvial, or washed;
• unprocessed, low quality.

In the first case, it is divided into fractions by sifting, while removing large inclusions. Such sand is not pure enough, since clay, lime and soil impurities can be traced in its composition. In this regard, the use of the material is allowed at low technical requirements to the work being performed.

Alluvial sand is subjected to hydromechanical treatment with water, which removes unnecessary components from it, which ultimately affects the purity and quality of the bulk material.

Developed quarries can be located on plains, slopes, mountains or beds of dried rivers and reservoirs. Depending on the composition of the sand grains, quarry sand is:

• quartz;
• limestone;
• feldspar;
• dolomite, etc.

Plain quarries are flat areas with thick sand layers lying just below ground level. The presence of groundwater and the depth of development directly affect the moisture content of sand, which can be either dry or waterlogged. Sloping areas are located on hills, due to which the rock always remains dry, and water quarries, although they do not have surface waters, are still distinguished by the presence of water-logged sands. Their prey is in this case, is produced using hydromechanization in the form of dredgers and rippers. Mining quarries provide the construction industry with quartz sands.

Based on the size of sand grains, the material is divided into seven groups, starting with very fine (fineness modulus up to 0.7) and ending with increased coarseness (fineness modulus 3-3.5). Table 4 of GOST 8736-2014 indicates the maximum percentage by weight of clay and dust particles in construction sand ranging from 2 to 10%, depending on the group of bulk material, as well as the presence of lumpy clay - no more than 0.25-1%.

Material characteristics

Unprocessed quarry sand is much dirtier than river sand, but 1.5-2 times cheaper, which determines its scope of application. It is indispensable in works where the technical characteristics of materials are not required high requirements, since its cost remains attractive. It should be noted that more expensive, purified quarry sand is a good alternative to its river counterpart when used in concrete mixtures, which is due to the uneven shape of the grains, which have good tenacity compared to smooth particles.

The important characteristics of quarry sand are:

• density – bulk and true;
• voidness – determines the percentage composition of air in the total volume of bulk material;
• sand grain size modulus, indicating a specific group of material;
• percentage of foreign inclusions, including clayey, organic and dusty;
• humidity;
• frost resistance;
• radioactivity;
• filtration coefficient.

What is the density of quarry sand?

From the entire list technical characteristics the subject building material can be distinguished:

• bulk density of quarry sand (kg/m3), determined for natural humidity conditions;
• true grain density (g/cm3).

Bulk density refers to the weight of one cube of bulk material in an uncompacted state. This includes not only the volume of solid particles, but also the voids between them, so the bulk density of coarse sand is always less than the corresponding values ​​​​related to fine-grained materials. In the first case, for example, the average density of sand extracted from an open pit is 1400-1500 kg/m3, and in the second - 1700-1800 kg/m3.

The bulk density of bulk building materials is often called average, which is not entirely true, since the term “average density” refers more to solid and liquid media.

The true density of the material is a constant value, depending on the structure of the sand grains and their chemical composition. Based technical specifications, presented in GOST 8736-2014, the indicator of the true density of sand grains of natural sand should be in the range of 2-2.8 g/cm3. Material with such values ​​is used in the composition of mortars, concretes and dry mixtures; it is used in the construction of foundations under roads and runways.

The density of quarry sand determines its consumption for performing certain works. With the same volume of material and a lower density, you will need to purchase less sand in weight equivalent. In other words, with a bulk density of 1400 kg/m3, there will be 1.4 tons of sand in one cube, and with a density of 1800 kg/m3 – 1.8 tons of sand. But with a lower density of the material, you will have to take into account its greater voidness, which can affect shrinkage when compacting the sand layer or increase costs when purchasing binders included in the concrete mixture. We should not forget that the density of sand is affected by its humidity and the presence of clay impurities. These factors deteriorate the quality of bulk material.

Methods for determining density

Possible methods, their essence, required equipment and tools for carrying out measurements are specified in GOST 8735-88. The stages of testing and methods for processing the results obtained are also specified here.

Bulk density sand is determined by weighing it in measuring metal vessels cylindrical. Their capacity is 1dm3 and 10dm3. The first vessel is intended for dried and sifted, and the second - for unsifted sand, which is in its natural state when normal humidity. Empty and full containers are weighed, after which the bulk density of sand is determined using the formula.

IN living conditions use a regular 10-liter bucket, into which sand is poured from a height of about 10 cm until the container is filled with a “slide”. Next, the elevation is cut off flush with the edge of the bucket, and the sand contained in the container is weighed and its net mass without the bucket is determined. The result obtained in kilograms is divided by 0.01 m3, which allows you to find out the bulk density of sand, or the mass of one cube of material in tons.

In the laboratory, two methods are used to determine the true density of grains:

• pycnometric - using a pycnometer, which is a glass vessel of a special shape and a certain capacity;
• accelerated - using the Le Chalier device, which has a peculiar shape with a funnel in the upper part and a scale marked on the neck of the glass vessel.

Preparation and conduct of tests are described in detail in the above GOST. The methods for determining true density differ significantly from each other, and the results are processed using completely different formulas. But in the end, the numbers turn out to be identical, although the duration and complexity of the processes differ markedly.

How to improve the characteristics of quarry sand

The qualitative composition of bulk material is improved in two ways - sifting and washing. The processing process removes large debris and stones, as well as clay and organic inclusions. Seeded sand is more homogeneous and in most cases is already suitable for mixing foundation and plaster mortars.

Washed sand, as the name suggests, is cleaned using large quantity water. As a rule, the process occurs in flooded quarries, but if it is necessary to process sand in dry conditions, its composition is improved by additionally installing water reservoirs. As a result of cleaning, almost all clay inclusions are washed out of the sand, and the quality of the material approaches its purer river analogue.

Alluvial sand may be used in critical monolithic structures and production of durable concrete.

Application of different compositions of quarry sand

The purpose of the material in question depends on its quality, presence or absence of impurities. For example, low-quality quarry sand, due to its low cost and versatility, is widely used in several areas, not always related to construction. In particular:

• to “lighten” the soil layer in agricultural work;
• when constructing embankments in low-lying or marshy areas;
• in landscape design;
• in road construction;
• at wastewater treatment plants;
• as backfilling of trenches or when filling ditches;
• when storing vegetables;
• for domestic and economic purposes - for growing seedlings and flowers, sprinkling icy paths, etc.

Seeded sand extracted from quarries is used in finishing works, putting it into the composition of plaster and cement mixtures. The material can be used in the construction of foundation pads and asphalt pavements. Fine-grained fractions show themselves excellently in the composition of initial putties, various grouts and decorative mixtures. Coarse quarry sand is laid as a drainage layer and added to mortars when pouring curb stones and paving slabs.

Alluvial sand is intended for concrete and reinforced concrete structures, responsible for bearing capacity buildings. It is added to dry building mixtures for various purposes.

You should not rely on the economical purchase of low-quality sand if the work requires more expensive material. Having received a one-time benefit, you can acquire a whole range of problems that will have to be solved for many years.

When calculating the volume, several are taken into account most important indicators, one of them is the density of sand. The operational properties of the mixture prepared for a particular construction project and its main parameters are influenced by the bulk density of sand (average). In the price list of the IdealTrade company, prices are indicated in rubles per m3, therefore, knowing average density sand (kg/m3), you can estimate the overall construction costs.

Factors influencing density formation

From one of physical characteristics sand, its degree of density, depends on how much volume the same amount by weight will occupy. Sand density, kg/m3, depends on following criteria:

• , that is, grain sizes: fine-grained sand fractions are denser, larger ones have a smaller size.
• and porosity of the material: this criterion shows the volume of voids in the granular substance. The reduction in looseness occurs due to several factors, such as: dynamic impacts and vibrations, moisture saturation, pressing, etc.

Sand density, kg/m3 is indicated in the table:

• Humidity indicators - the bulk density of sand (kg per m3) is formed based on humidity conditions: when it increases to 10%, the volume increases in proportion to the decrease in density; with moisture saturation up to 20%, air is displaced by water and the weight of one cubic meter increases. The density of river sand, kg m3, judging by the table, is higher than similar materials.
• Impurity content: the presence of particles of dust, clay, mica, crushed stone, gypsum, stone chips, etc. will definitely affect the characteristics and properties of the bulk material. Alluvial sand (purified with water) becomes much cleaner and a little more expensive.

Our advantages

At IdealTrade, a pro in the non-metallic materials market, all resources comply with GOST standards, since we constantly monitor product quality.

Construction Materials

Why do you need to know the density of construction sand (kg/m3)?

From the author: Hello, dear reader. From this article you will learn how the true density of construction sand kg/m3 is determined. Why is this necessary? - first of all, so as not to be deceived when purchasing this building material. Indeed, to determine exactly how many tons of sand for construction work they brought it to you - it’s quite difficult. You won't weigh the car, will you? And so, quite often suppliers of building materials take advantage of this, simply by not adding enough sand.

But knowledge of this criterion is important not only because of possible deception. The fact is that during construction, in principle, it is important to know what will be required, say, to pour a foundation or ceiling. After all, if suddenly there is not enough, it can turn into a real disaster, especially if the object must be delivered as soon as possible.

Let's start, perhaps, with general definitions to get you up to speed. The bottom line is that the bulk density of construction sand is measured depending on how compacted the material is. The situation with cement is approximately the same: the older it is, the higher its density, since over time any bulk substance “crowds together.” An analogy can be drawn even with ordinary flour, which is used for baking.

It follows from this that the same volume of bulk substance can have different densities (and, therefore, - different quantities). In its original state (without compaction), the material can be characterized by the term “true bulk density”.

Therefore, bulk density is the density of the material in a state in which it has not been compacted. That is, - when determining this value - it is necessary to take into account not only the volume of grains of sand (or parts of other building materials), but also the distance at which they are removed from each other. From this we conclude that the bulk density is several times less than the usual density of the material.

After the material is compacted (and this depends primarily on the conditions in which it is stored and on time), its density ceases to be bulk. She's getting taller.

Why do you need to know what the density of sand (natural) is for construction work? First of all, to compare the volume and mass of the building material. The price for bulk substances can be indicated not only for 1 t (ton), but also in cubic meters. And during preparation, the proportions of the substance may be needed not in weight, but in volume.

Below is a small table in which the second column shows the bulk density of construction sand (kg/m³), and the third column shows the number of cubes per 1 ton.

Important! With increasing density, the load-bearing capacity also increases.

What does density depend on?

The density of a bulk substance (in this case, sand) primarily depends on its origin and condition. The table below shows us the fundamental differences in bulk density various types.

How to determine bulk density?

This indicator is usually determined in laboratory conditions. Essentially, the material is simply weighed using measuring vessels (1 l and 10 l). A liter container is used to determine the density in a state in which the material has not been compacted, the sand is dried to a constant mass and passed through a sieve with a hole diameter of 5 mm.

A ten-liter container is used when it is necessary to determine the indicator of the material that interests us, which is contained in the batch. In this way we can convert pass units to volume units.

In this case, the material is not specifically dried. It is taken in its natural moisture state. It is also passed through a similar sieve (hole diameter 5 mm).

The procedure for determining density looks like this: the already sifted material is poured into a measuring vessel from a height of ±10 cm. For this, you should use a scoop. When the vessel is filled, the slide should be removed using a metal ruler. The height of the sand should be level with the edges of the measuring vessel. Next, this measuring vessel along with its contents should be weighed precise scales. It goes without saying that we are only interested in the net weight of the contents, so the weight of the container should be subtracted.

To convert units of mass into units of volume, the procedure is essentially the same. As, indeed, the equipment. But you just need to pour the material not from 10 cm, but from 100 cm.

Below is the formula by which the indicator we are interested in is determined.

In this case, γn is an indicator of density, m1 is the mass of a measuring vessel without contents, m2 is the total mass, and V is, respectively, the volume.

To visually familiarize yourself with the determination procedure, watch the video below, where research is carried out in a virtual laboratory, under ideal conditions.

Conclusion

That's all, dear reader. Thank you for reading the article. Today we learned how to determine bulk density, and also found out why to do this. For convenience and clarity, we have provided a table and formula. I hope that the presented materials were useful to you.

If you are interested in another construction issue, - use the site navigation to search necessary information. I'm sure you'll find what you need here. Good luck and see you again at Seberemont, dear reader.

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 professional field 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 of the 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 in this way:

m = 10 x 1.3 = 13 t.

Used here average density p equal to 1.3 t/m³.

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. As a result, the construction of objects becomes unprofitable in terms of payback. This is important for construction companies. In private housing construction, the rise in price will not affect costs, because its scale is much smaller.

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 of the 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 obtain a guaranteed flat surface of the 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 to determine 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 application 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 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. Sand with a high clay content cannot be used to make plasters, high-quality concrete, or various mortars, because their frost resistance and strength decrease.

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