Determination of the density of dry sand obtained by various methods. What properties of construction sand are affected by its density? Density of dry sand kg m3

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 of 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 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.

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? An increase in the volume of binders increases the costs and cost of the concrete solution. As a result, the construction of objects becomes unprofitable in terms of payback. This is important for construction firms. 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 excavation work. 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 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.

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 fields - construction, road work, landscaping 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 processing method 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 the 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.

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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 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 a reasonable price, which is also the reason why it is worth giving preference to it.

Sand extracted from the quarry is a very popular material today. As is already clear, it is mined using open-pit mining. For this, special equipment is used, but despite this, the cost of quarry sand is low.

In addition, the popularity of this material is influenced by its widespread use. The presented product is used in the production of concrete mortars, which are used when arranging the foundation or plastering surfaces.

Characteristics

Quarry sand is a material that is of natural origin. This is due to the fact that it is extracted directly from the quarry. In most cases, the deposit of material is not located at a great depth under the soil layer.

Where and how to use quarry construction sand can be found in this

Taking into account the size of the space between the granules, the specific gravity can differ many times for different fractions of the same type of material. For example, the parameter under consideration for quarry sand with small granules will reach 1700-1800 kg/m3. For sand with medium and coarse grains, the specific gravity will be 1500-1600 kg/m3.

What is the cost of river sand, indicated in this

The next parameter is the density of the material in question. This value is equal to the specific gravity. In the field of construction, the concept of bulk density has been established for bulk products. In this case, we are talking about the density of the product in its uncompacted form.

The presented parameter can change its values ​​under the influence of a variety of factors. For example, the level of humidity and mechanical influence greatly influence the parameter under consideration. The reason is that each particle is enveloped in a film of water, as a result of which the distance between the grains increases. By applying pressure, the density increases, reducing the space between the grains.

The density of the product is directly dependent on the quality composition. If it contains clay components in large quantities, then the density of the sand will be greater. In addition, the characteristics under consideration are influenced by the size of the grains, as well as their belonging to fractions. The larger the fraction, the lower the density indicators.

If we consider the radioactivity of sand, it depends on the deposit of the material. Since it is extracted from mining, this product is characterized by an increased radioactive background. When constructing residential buildings and agricultural structures, it is necessary to use sand with the first class of environmental friendliness. When constructing road surfaces, it is necessary to use sand of classes 2 and 3.

In the photo - quarry sand:

The level of humidity depends on the mass of the material. The higher this parameter, the greater the weight. For sand extracted from a quarry, the moisture level should not exceed 5-7%.
The amount of clay components and organic substances in the presented product should not be more than 3%, sulfites and sulfur - up to 1%.

The specific gravity of crushed stone 20 40 is indicated

Varieties

In the construction field, quarry sand is classified according to the size of the sand grains and the processing method. Taking into account the grain size, the material in question takes the following forms:

• small
• average
• large grains of sand

For material with fine grains, their size cannot be more than 2 mm. Medium-grained sand is characterized by dimensions of 2-2.8 mm. Granules of a large product can reach 5 mm. In addition, the material is classified according to the processing method into seeded and alluvial.

To obtain seeded quarry sand, a sifting method is used using a system of special sieves. As a result, stones and other large inclusions are removed from it. Alluvial is obtained by washing. In this case, hydromechanical equipment is used. As a result of this treatment, clay and soil impurities are removed from the composition of quarry sand, which improves the chemical composition.

Based on grain composition, they are divided into the following types:

• quartz;
• mica-quartz;
• feldspar;
• limestone;
• dolomite.

What does crushed limestone of fraction 40-70 look like?

In the field of construction, quarry stone, which arose during the destruction of mountain quartz, is in great demand.

Price

The main advantage of quarry sand remains its low price. If you purchase the material in question in a volume of 1 m3, its price will be 500 rubles. The presented product can be sold in its pure form or already processed. Of course, when purchasing the second option, you will need to spend a little more, because such a product is characterized by high quality indicators.

Quarry sand is considered the most popular material in the field of construction. The reason for this demand is that it is not expensive and can be used everywhere. But it cannot be used in its pure form in all cases, since it contains foreign impurities that negatively affect the quality characteristics.

This is a granular substance consisting of grains of stone or mineral rocks. Domestic standards define the size of construction sand granules 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, density becomes one of the most important characteristics of 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, since pure water 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.

Indicators of true and bulk density of sand are important for economic activity.

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 a measuring device of the accuracy 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 the average bulk density of sand is considered to be 1500-1600 kg/m³, then the 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.

True sand density values ​​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.

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 the preparation of cement mortars. Construction sand is used depending on its density, for example, certain types are used to create others in order to make a screed on concrete.

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 per cubic meter. The density of sand with clay content is higher and is already 1.8 tons. In the same volume.

This material has been the basis of cement and concrete compositions for many years. It is in great demand in highway paving, glass blowing and 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 a washed and calcined dry natural material. When used in construction, high hygienic characteristics of the home are ensured. The density of quartz sand is a very important parameter that is taken into account when carrying out construction work.