What is sand made of? Types of sand, their characteristics, extraction and use Sandy sand.

/ Rock Sand

Sand is a fine-clastic loose sedimentary rock, consisting of grains of minerals from destroyed rocks. Natural sand is a loose mixture of grains 0.14-5 mm in size, formed as a result of the destruction of solid rocks. It consists mainly of grains of minerals (quartz, feldspar, micas, etc.), small fragments of rocks, and sometimes particles of skeletons of fossil organisms (corals, etc.).
The grain sizes in sands usually range from 0.1 to 2.0 mm.

According to the size of the grains, sands are distinguished:

coarse-grained (2.0-1.0 mm.),
coarse-grained (1.0-0.5 mm.),
medium-grained (0.5-0.25 mm.),
fine-grained (0.25-0.01 mm.).

The shape of the grains can be rounded, semi-rounded, angular and acute-angled - depending on the origin and duration of grain transfer.

By origin, sand can be river, lake, sea and bottom, and by composition - quartz, glauconite-quartz, arkose, magnetite, nepheline, micaceous, polymictic, etc. The most common are quartz and polymictic sands with a greater or lesser admixture of other mineral components (clay, micas, chlorite, iron oxides, feldspar, glauconite, carbonates).

Often the sands are monomineral quartz, and then they consist of almost pure quartz.
Depending on the conditions of occurrence, natural sands can be river, sea, mountain, ravine. River and sea sands have rounded grains, mountain sands contain acute-angled grains. Mountain sands are usually more polluted with harmful impurities than river and sea sands.

As a result of natural cementation of sands, sandstones are formed.
The term sands in geomorphology is used to refer to flat spaces covered with more or less thick sand cover.

Practical use

Sand is widely used in the composition of building materials, for washing construction sites, for sandblasting building facades and different products, in housing construction for backfilling, in the improvement of yard areas and in everyday life (backfilling of paths, the installation of children's sandboxes, toilets for cats, soils in greenhouses, etc.), in the production of mortar for masonry, plastering and foundation work. Widely used in concrete production; in the production of reinforced concrete products, concrete of high strength grades. An important material in the construction of roads, embankments, as well as in the production of paving slabs, curbs, well rings (in these cases coarse sand Mk 2.2 - 2.5 is used). Fine building sand is used for the preparation of coating solutions. River construction sand is widely used in various decorative (mixed with binders and dyes to obtain special structural coatings) and finishing works. Construction river sand is a component of asphalt concrete mixtures, which are used in the construction and laying of roads. Quartz sands are a valuable raw material for the glass industry.

Sand in construction

Most commonly used in modern construction river sand and quarry sand.
river sand is a natural material extracted from the bottom of rivers. This type of sand contains practically no clay particles, as well as stones and pebbles. The grain size modules of river sand are mostly average. River sand particles are small (up to 2 mm), medium (2.0 to 2.8 mm) and large (2.9 to 5 mm). The color of river sand can be gray or yellow. River sand is considered a universal material and is used for any type of construction work, since it does not contain various impurities. River sand has become the main ingredient needed for the production of concrete. River sand is also widely used for various finishing works. River sand is used as a component for asphalt mixes in road construction, it is also necessary during road laying. The main disadvantage of river sand is its high cost, which will significantly reduce the possible scope of its application.

Quarry sand. Unlike river sand, quarry sand usually contains various impurities, in particular clay and dust. In this regard, it is problematic to use quarry sand for the preparation of solutions. However, with the help of simple equipment, quarry sand is washed in hangars or embankments. large quantity water. After washing out, quarry sand can be used as a filler for concrete. Coarse quarry sand is used for the construction of foundations and coatings for roads and airfields.

artificial sand

Artificial sand is obtained as a result of crushing such rocks as granite, marble, limestone, as well as man-made substances - slag, etc. Artificial sand is usually used for the preparation of a decorative mortar and for the textured layer of exterior building panels.

Expanded clay sand (fine expanded clay) is a building material that is not sand in the strict sense of the word, but since such a term has taken root, it should also be mentioned. Expanded clay sand is a loose sandy material obtained artificially by firing clay fines. The firing process takes place in special rotary and shaft kilns. Expanded clay sand can also be obtained by crushing expanded clay gravel. As a rule, the particle size of such sand is from 0.14 to 5 mm. The main purpose of expanded clay sand is the filling of lightweight concrete. There are several ways to obtain expanded clay sand, but the most effective by far is firing in a fluidized bed. This technology is the least expensive, which results in a lower cost of expanded clay sand; the volume of sand produced is always less than the volume of gravel.

Sand mining

Sand is mined in an open and alluvial way. For this, various equipment is used. One or another method is chosen based on the conditions in which the material is mined. A convenient entrance is necessarily organized to the place of extraction. This is important to do for the rational use of funds.

There are sand deposits all over the world.

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Quite often, we can see how children examine sand particles under a magnifying glass, or with the naked eye, trying to answer the question - what does it consist of. But even adults cannot always answer this question. We will explain to you what sand is made of.

Looking at the grains of sand, you can determine that they are composed of different rocks, and therefore have a different color.

Sand is a mountain sedimentary rock, which is a loose mixture of particles of various minerals (quartz, calcite, mica, feldspar, etc.) with a diameter of 0.14 - 5 mm, and formed as a result of rock weathering. There are few deposits that contain virtually nothing but quartz sand. But the main part of the sand consists of a mixture of quartz with feldspar, magnetite, mica, garnet, which allows you to give the sand a variety of shades. Also on our planet there are several deposits where you can find sand that does not contain quartz. For example, there are white gypsum sands or red coral sands.

Sands can be both natural and artificial.
Natural sands are usually divided into sea, river and mountain (ravine), it depends on the conditions of occurrence. River and sea sand have rounded particles, and mountain sands consist of acute-angled particles. Mountain sand is often contaminated with harmful impurities, unlike river and sea sand. Natural sand is a product of weathering (or wind erosion). The weathering process contributes to the destruction of the source material into particles of various diameters, including sand. The wind, together with water, can move sand hundreds and thousands of kilometers. In this connection, over time, sand deposits can form in the lowlands or near elevations. The texture of such sand is very dependent on the way in which the small grains of sand were delivered to the deposits. Water is able to move particles of different sizes at the same time. Therefore, very often we can see how deposits with an incredibly colorful pattern and texture are formed next to some kind of natural barrier. At the same time, the wind performs the function of filtering particles. Wind with different strengths and at different distances carries different grains of sand. Thus, deposits are formed, which consist of approximately the same size grains of sand.

Where does sand come from in deserts? The main part of the sand is carried by the wind to the deserts. But there are also cases when desert grains are formed by the destruction of mountains. Some deserts were originally the seabed, but many thousands of years ago the water left, receded.

Sand is also made artificially. This is done by crushing hard materials such as stone or slag.

Sand is a useful and necessary material. It is used to make glass, concrete, water filters, sandpaper.

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Rock Sand

English name: Sand

Minerals in the composition of the rock Sand: Quartz

Sedimentary rock, consisting of grains of mountain fossils, was called "sand". Most often, sand consists of a practically purified quartz mineral, it can have both unnatural and natural origin. The grain size of natural material is 0.16-5 millimeters.

Varieties of material

Sand is of the following types.

Mined from the bottom - material that is mined from the riverbed.
Seeded - sifted from a quarry, cleaned of large particles and stones.
Washed sand is a rock that is extracted from a quarry by washing with a huge volume of water. This washing removes dust particles and clay.
Construction - loose rock, the grains of which have a particle size of up to 5 millimeters.
Heavy artificial - a material that is mined by crushing rocks.

History of the breed

The grains of sand appeared as a result of crushing the stone. Due to various external natural factors, weathering of rocks occurred. Sand existed even when life on Earth was just emerging.

Today, sand is one of the indispensable materials. This is a universal rock, as it differs in technical characteristics.

What does sand look like?

The material has a soft yellow color. In terms of shade, it is very different. Much depends on the field. Sand grains can be rounded or angular in shape.

Sand mining

There are sand deposits all over the world. The largest sand deposits of them are located in Russia - in St. Petersburg and the Leningrad region.

Features of use

In the manufacture of various building materials, including reinforced concrete products and building mixtures, including concrete of various grades, sand is indispensable. It is also suitable for creating construction sites, for the construction of embankments and roads, for the improvement of adjacent plots. Sand is also used in the implementation of foundation, plastering, a variety of finishing and decorative works, in sandblasting. Sand is the most important ingredient for making glass. This breed is also suitable for purifying and filtering water.

Rock Properties

Rock type: sedimentary rock
Color: yellow
Color 2: Yellow

The term "sand" is commonly understood as loose material of non-metallic origin used at various stages of construction. The group of sands includes loose substrates various kinds, differing from each other in the method of production, the size of the fractions and the amount of impurities.

Construction sand can be of natural or artificial origin. The first variety is formed as a result of the destruction of rocks of the rocky type, which occurs naturally, and is mined by the development of sand and sand and gravel deposits.

In the second case, granite, marble, tuff, as well as limestone rocks are used as the starting material for its creation, which are crushed to obtain the necessary structure. This type of sand is used to create textured mortars.

The strength of sand is determined based on the stability of the rock that serves as the basis for its production.

Depending on the degree of strength different kinds It is customary to divide into the following brands:

grade 800, corresponding to rocks of the igneous type;
stamp 400 denoting rocks of a metamorphic character;
grade 300 belonging to sedimentary rocks.

These designations are used for marking building sands intended for exterior and interior work related to the finishing of concrete and reinforced concrete structures.

The most important indicator characterizing the quality of this material and the possibility of its use in various areas of production is the group of sand, determined by the level of its fineness, as well as its grain composition, in which there are divisions into the following fractions:

large, the particle size of which is from 2.0 to 5.0 mm.
medium, having grains ranging in size from 0.5 to 2.0 mm.
fine, with grain sizes up to 0.5 mm.

The grain size of building sand is a fundamental factor that has a direct impact on the further use of this material. In accordance with this parameter, all building sands are divided into two main classes: the first and second.

As part of various solutions, sand of fine and medium fractions is more often used, and coarse sand is one of the main components of concrete and is used in the construction of foundations for buildings under construction.

Classification of sands by type and their characteristics

The main technical parameters characterizing the quality and composition of this material include the following.

Size modulus

This indicator reflects the size of the sand fractions and includes the following varieties:

dusty. This type of sand has a very fine structure, resembling dust in appearance. The grain size of such material is in the range from 0.05 to 0.14 mm. In turn, silty sands are usually divided into several subspecies: unimportant, wet and saturated with water.
fine sand, the grain size of which is from 1.5 to 2.0 mm.
medium-sized, which includes fractions from 2 to 2.5 mm.
large, having grains of 2.5 - 3.0 mm.
increased size - from 3.0 to 3.5 mm.
very large, having grains of 3.5 mm or more.

This is how quartz sand with a fraction of 1-2 mm looks like:

Filtration coefficient

Another important characteristic that describes the physical and technical properties of the material is the filtration coefficient. This parameter shows how much water is needed to pass a cubic meter of sand per unit of time (hour). The porosity of the material has a direct influence on the value of this indicator.

Bulk density

The value of this indicator for a material of natural origin is about 1300 -1500 kg / m?. When the humidity changes, its volume changes, which directly affects the bulk density. At the same time, regardless of the origin and method of production, building sand must comply with the requirements of GOST 8736-93.

The characteristics of building sands also include:

class of radioactivity;
the amount of dust, clay and silt impurities present.

To ensure the quality of the material and the possibility of its subsequent use as a binder in mortars, there are quite stringent requirements regarding the amount of impurities contained in it.

In particular, in the total mass of medium, coarse, as well as sand of increased size, the presence of no more than 3% of dust, clay and silt impurities is allowed. For fine and very fine sands, this figure is 5%.

artificial origin

Unlike natural varieties, artificial sands are produced using specialized equipment by mechanical action on rocks. In turn, artificial sands are divided into subspecies of sedimentary and volcanic origin.

These include:

thermosite or porous sands from slag melts obtained from materials with a porous structure, for example, slag pumice. They are considered one of the most economical types, since the basis for their production is industrial waste.
perlite sands. They are produced by heat treatment from crushed glass of volcanic origin, called perlite and obsidian. They are white or light gray in color and have a minimum bulk density of 75-250 kg/m?. Used in the manufacture of insulation elements.
quartz. Sands of this type are also commonly called "white" because of the characteristic, white-milky shade. However, the more common varieties of quartz sands are yellowish quartzes, which contain a certain amount of clay impurities. Due to its versatility and high quality, this type of sand is widely used in various industries, including water treatment systems, glass, porcelain, etc.
expanded clay. P obtained by crushing expanded clay gravel, mainly in roller crushers, followed by roastingin a fluidized bed orin a rotary kiln.
marble. It is one of the rarest species. It is used for the manufacture of ceramic tiles, mosaics, and tiles.

The main advantage of artificial sand compared to its natural counterpart is the minimum amount of impurities and the uniformity of the composition, due to which a higher quality of the final product produced on its basis is achieved.

If you evaluate this material using the traditional five-point scale, its cost, practicality and appearance can be assigned solid "five". Only the environmental friendliness of this species is doubtful, since the radioactivity index of sands of artificial origin is much higher than natural.

Varieties of building sand

natural views

According to the method of extraction and origin, natural building sands are usually divided into several main groups. These include:

river sand. This variety is considered the most "clean" and is used in the manufacture of many mortars. The main advantage of this type can be called its homogeneous structure and small particle sizes, averaging from 1.5 to 2.2 mm. At the same time, individual grains of sand, due to “grinding” with water for a long time, have a “correct”, oval shape. However, along with this, river sand is considered one of the most expensive varieties of this building material, which is why, in order to save money, it is often replaced by cheaper sand of quarry origin.
nautical. Sand of this type also has a minimum amount of contamination caused by the accumulation of salts present in sea water, most of which is removed during the two-stage cleaning system. Possessing a sufficiently high quality, sea sand, including for cleaning industrial equipment using sandblasters, creating screeds, etc.
ravine or mountain. These species are characterized by the presence of clay, which somewhat reduces the strength of the solutions, therefore they are used less often.
career. It also has a fairly large volume of clay and dust, but is one of the commonly used types due to its low cost. For example, quarry-type sand is widely used in the implementation of "zero cycle" works, as well as in housing and road construction, for preparing construction sites and backfilling.

Characteristics of river ordinary sand

Specifications	Indicators
Density of dry river sand	1.5kg/m3
Density of river sand in a state of natural moisture	1.45 g/cm3
Humidity of river sand	4,00%
The content of dust, clay and silt particles in river sand	0.7% by weight
Specific gravity of river sand	2.65 g/cm3
The presence of lumps of clay in river sand, loam and other clogging impurities	0,05%
Gravel particles in river sand more than 10 mm in ballast	0%
River sand size modulus	1,68

In addition to this gradation, sand of quarry origin is divided into the following subgroups:

Alluvial (washed)

It is mined in quarries using a special technology using a large amount of water and a device called a decanter, in which the sand mass is settled and the waste liquid is removed from the sediment. Thus, it is cleaned from clay and dust particles present in the bulk of the material. Sand of this type is characterized by the presence of very fine fractions, with an average size of about 0.6 mm. It is used in the manufacture of mortars and concretes, in road construction, etc.

Seeded

This species is also mined in quarries and, once it reaches the surface, it is subjected to a mechanical treatment that removes foreign matter present in it, such as dust particles and clay.

The main advantage of sand can be called its versatility, which allows the use of this building material in all areas of construction production: from the zero cycle to the finishing of the structures under construction.

Using the five-point scale already mentioned above to evaluate this material, you can give it "five" for low cost, practicality and ease of use, as well as for availability and excellent environmental performance.

And artificial material, which has a fraction of rocks. Quite often, it is made up of the mineral quartz, which is a substance called silica. If we are talking about natural sand, then it is a loose mixture, the grain fraction of which reaches 5 mm.

Classification by destruction of rocks

This material is formed during the destruction of rock hard rocks. Depending on the accumulation conditions, sands can be:

alluvial;
maritime;
deluvial;
eolian;
lake.

When the material arises in the process of the activity of reservoirs and watercourses, then its elements will have a rounded rounded shape.

The main types of sand and features of their extraction

Today, almost all types of sand are used by man in various fields of activity and industry. River sand is a building mix that is extracted from the river bed. This material has a rather high degree of purification, which is why there are no small stones, clay content impurities and foreign inclusions in the structure.

Quarry sand is extracted by washing with water in a huge volume, as a result, it is possible to get rid of dust-like particles of clay. Considering the types of sand, you can find quarry sand, which is cleaned during the extraction process from large fractions of stones. This material is quite widespread in the manufacture of mortars that are used for laying foundations and plastering. You can find quarry seeded sand in asphalt concrete mixtures.

Construction sand must comply with GOST 8736-2014, according to which the material is a free-flowing inorganic mixture of coarse grains, the size of which reaches 5 mm. equal to 1300 kg / m 3. Building sand is formed during the natural destruction of rocks, it is mined by the methods of developing sand-gravel and sand deposits without and using enrichment equipment.

The main types of sand also include artificial heavy sand, which has the form of a loose mixture obtained by mechanical crushing of rocks, among the latter should be highlighted:

slags;
granites;
limestone;
marble;
pumice;

Features of artificial sand

They may have different origins and densities. If we compare the grains of this sand with grains of natural origin, then the former are distinguished by an acute-angled shape and a rough surface. Artificial sands are commonly used as aggregates in the preparation of plasters and decorative mortars. As a result, it is possible to achieve a tangible texture of the top layer on the outer surfaces.

This material can become part of any layer of plaster, because the fractionation of the grains can be different, depending on the type of mortar. Usually the grain size is assumed to be equal to the size of natural sands. In the manufacture of artificial sand, burnt coal, rocks, as well as unburned particles, in which the sulfur content is low, are taken for processing.

The characteristics of the material will depend on the quality of the coating layer. In the manufacture of decorative plaster from such sand, crushed stone, powder of this rock or crumb can be additionally added to save money, it even benefits from this quality of the texture.

Application and characteristics of sea sand

Sea sand can be used in the production of building mixtures, the manufacture of aggregates, the implementation of plastering work, laying road bases, the construction of fences and barriers, as a filler for building grouts and dyes. The production of such sand is regulated by GOST 8736-93.

Fractions can vary from 2.5 to 3.5 Mk, which determines the fineness modulus. The grain density is equal to the limit from 2 to 2.8 g/cm 3 . In sea sand, foreign impurities should be completely absent, but in some fractions one can find a small content of clay and dust particles. Sea sand is characterized by the labor intensity of production, which makes its cost higher than quarry sand.

Characteristics and price of quarry sand

The main feature of quarry sand is the absence of impurities and frequency. Alluvial quarry material has the following characteristics: a fraction in the range from 1.5 to 5 mm, a density of 1.60 g/cm 3 , and a low content of clay, dust and other impurities. The latter in the composition should not be more than 0.03%.

Quarry sand, the price of which per cubic meter will be 2200 rubles, is used not only in construction, but also in decoration, as well as in the national economy. Especially profitable is the use of such sand in the production of concrete and bricks, as well as in road and housing construction.

Quarry sand, the price for which will be 2300 rubles, can be presented in the form of a material with a fraction ranging from 2.5 to 2.7 mm. In the production of high-strength concrete and reinforced concrete structures, an alluvial quarry fraction is usually used. Quarry material goes to masonry and paving slabs.

Technical characteristics of river alluvial sand and features of its production

Alluvial river sand has a density of 1.5 kg / m 3. If we are talking about density in a state of natural humidity, then this figure will be reduced to 1.45. The composition may contain dust particles, silt and clay elements, but not more than 0.7% by weight. The moisture content of the material is 4%, while the specific gravity is 2.6 g/cm 3 . These types of sand are mined using a dredger, which is fixed on a barge. Such equipment is supplemented with hydromechanical installations, powerful pumps, networks and tanks for dividing the material by composition. The extraction of sand from the beds of dried up rivers is like the extraction of quarry sand.

Conclusion

Almost all varieties of sand can be attributed to the first class in terms of radioactivity. The only exceptions are crushed sands. If we talk about other varieties, then they are radiation safe and can be used in all construction work without restrictions.

The use of sand is quite common today. For example, its quartz variety is used for the manufacture of welding consumables for general and special purposes. As for the construction variety, it is used to obtain structural coatings by mixing with dyes. Sands are also used during finishing work, as well as in the repair of premises. The material also acts as a component that is used in laying roads and in construction.

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