Initially, in the 19th century, city streets were paved with stones (cobblestones). Starting from the mid-19th century, in France, Switzerland and the USA and a number of other countries, road surfaces began to be made from bitumen-mineral mixtures. In 1876, cast asphalt prepared using petroleum bitumen was used for the first time in the United States. Asphalt concrete was first used to cover the sidewalks of the Royal Bridge in Paris in the 30s of the 19th century. In the early 1930s in France, in the department of Ain, the sidewalks on the Moran Bridge over the Rhone River in Lyon were covered with asphalt. The rapidly developing road network required new types of road surfaces that could be constructed as quickly as subgrades. Thus, in 1892 in the USA, the first road structure made of concrete 3 m wide was built using the industrial method, and 12 years later, using a tarmacrator with the free flow of hot bitumen, 29 km of road were built. Asphalt turned out to be the most suitable material for road surfaces. Firstly, it becomes smoother, which means less noisy and has the necessary roughness. Secondly, you can immediately open traffic on laid asphalt concrete and not wait for it to harden, unlike cement concrete, which gains the necessary strength only on the 28th day. Thirdly, asphalt concrete pavement is easy to repair, wash, clean, and any markings adhere well to it.
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Sand is a sedimentary rock, as well as an artificial material consisting of rock grains. Very often it consists of almost pure quartz mineral (the substance is silicon dioxide). The word "sand" is often used in the plural ("sands"), but the plural form has other meanings. The Russian surname Peskov is derived from the word “sand”.Natural sand
Natural sand is a loose mixture of grains with a particle size of 0.10-5 mm, formed as a result of the destruction of hard rocks. Natural sands, depending on their genesis, can be alluvial, deluvial, marine, lacustrine, or aeolian. Sands resulting from the activity of reservoirs and watercourses have a more rounded, rounded shape.Heavy artificial sand
Heavy artificial sand is a loose mixture of grains obtained by crushing hard and dense rocks. The shape of the grains of crushed sand is acute-angled, and the surface is rough.Types of sand:
In trade, sand is classified according to its place of origin and processing:river sand
River sand is construction sand extracted from river beds, characterized by a high degree of purification and the absence of foreign inclusions, clay impurities and pebbles.Quarry washed sand
Quarry washed sand is sand that has been extracted from a quarry by washing with large quantities of water, causing clay and dust particles to be washed out of it.Quarry mountain sand
Quarry mountain sand is a natural material mined in open pits. This sand has a fairly high content of clay, dust and other impurities. Although quarry mountain sand, mined at some deposits, is distinguished by high technical characteristics, which brings its consumer properties closer to such a type as quarry washed construction sand.Quarry seeded sand
Quarry sifted sand is sifted sand extracted from a quarry, cleared of stones and large fractions. Quarry seeded sand is widely used in the production of mortar for masonry, plastering and foundation work.Construction sand
According to GOST 8736-93, construction sand is an inorganic bulk material with a grain size of up to 5 mm, formed as a result of the natural destruction of rocks and obtained during the development of sand and sand-gravel deposits without or using special processing equipment.Application
Widely used in building materials, for the reclamation of construction sites, for sandblasting, in the construction of roads, embankments, in residential construction for backfilling, in the improvement of courtyard areas, in the production of mortar for masonry, plastering and foundation work, used for concrete production , in road construction. In the production of reinforced concrete products, high-strength concrete, as well as in the production of paving slabs, curbs, well rings, coarse sand (Mk 2.2-2.5) is used. Fine construction sand is used to prepare covering mortars. Construction river sand is quite widely used in various decorative (mixed with various dyes to obtain special structural coatings) and finishing works of the finished premises. It also acts as a component of asphalt concrete mixtures that are used in the construction and laying of roads (including for the construction of airfields). Quartz sand is used for the manufacture of welding materials for special and general purposes.Radioactivity of sand
Almost all sands belong to the 1st class in terms of radioactivity (the specific effective activity of natural radionuclides in them does not exceed 370 Bq/kg, the only exceptions can be crushed sands), that is, they are radiation safe and suitable for all types of construction without restrictions.Sand is a bulk material of inorganic origin, so it does not interact chemically with the components of mortars. Sand contains rock particles that, as a result of natural phenomena, have acquired a rounded or pointed shape; the diameter of the grains is 0.05–5.0 mm. According to non-specialists, the choice of this material does not depend on the specific intended purpose. But this is a mistake - for certain jobs, bulk substances with the appropriate chemical and physical characteristics are purchased. Let's consider the classification characteristics of this material - natural and artificial.
Varieties of natural sand
Bulk material of natural origin is the result of the natural destruction of rocks. Depending on the location, this material is divided into quarry (mountain, ravine), river and sea.
- The most widespread type is the open-pit mine. Its disadvantage is the presence of impurities in the form of pebbles and dust particles. The grains are small - from 0.6 to 3.2 mm, color - yellow or brown. Unrefined, this material can be used as a cushion for foundation structures or for trenches. For mortars, bulk material is used, cleared of impurities by one of two possible options - washing or sifting. Alluvial sand is sand that is extracted using a significant amount of water and special equipment - a decanter. In it, the mass settles and impurities are subsequently removed along with water. This material is fine-grained, the particle diameter is on average 0.6 mm. The second category of processed material is seeded. In this case, impurities are removed by mechanical sifting of the mass. Purified quarry sands - inexpensive and easy to use - are used at all stages of the construction process where the presence of bulk sand is required.
- The place where river sand is extracted is the river bottom. This material does not need to be cleaned, the particles are small - 1.5–2.2 mm, oval in shape, color - yellow or gray. Its valuable quality is the absence of clay inclusions that reduce the effectiveness of mortars and mixtures. The downside is the high cost, so the river variety is often replaced with a cheaper quarry analogue.
Attention! When making concrete mixtures, river-type sand settles quickly, which requires constant mixing of the concrete.
- Sea sand is a non-metallic mineral extracted using hydraulic projectiles. This is a pure material, practically free of harmful impurities. It can be used in almost all areas - from the production of concrete mixtures to the creation of dry ready-made fine compositions and use in sandblasting units. The extraction of this mineral is quite difficult, so its mass production is impossible.
- A rather rare, one might say exotic, variety of this fossil is black sand. The reason for its formation is geological processes that wash away light components from dark-colored heavy minerals - hematites, ilmenites, magnetites. Such a fossil has no industrial significance not only because of its low prevalence, but also due to its high radioactivity.
Artificial sands - varieties and their characteristics
The uneven location of natural sand extraction sites has become the reason for the development of the production of artificial analogues, which are classified depending on the feedstock, crushed to the required fraction: 
- Crushed. It is obtained from marble, diabase, basalt, and metallurgical slag. Designed for acid-resistant or decorative mixtures.
- To produce porous sand, tuff, pumice, volcanic slag and even wood waste are used as raw materials.
- Expanded clay fine aggregates for lightweight concrete are made by grinding expanded clay raw materials. This product can be used as a thermal insulation material.
- Agloporite. The source is clay-containing raw materials, slag or ash formed during clay firing.
- Perlite sands are made by heat treatment of crushed glasses of volcanic origin, which are called obsidians or perlites. The color of the resulting product is white or light gray. Used in the production of insulating products.
- “White sands” - quartz - received this name due to their characteristic “milky” shade. Although more often you can find a product made from yellowish quartz, which contains a certain amount of clay impurities. This high-quality material is popular not only in construction (for decorative and finishing works), but also in water treatment systems and glass and porcelain production.
Definition! The concept of “construction sand” does not mean a separate type of this material, but a group of natural and artificial bulk substances, adapted according to their functional characteristics for use in construction.
Grades and fractions of sand
One of the important characteristics of this material, which determines the scope of its application, is strength, the value of which is indicated by the brand:
- for grade 800, the starting material is igneous rocks;
- 400 – metamorphic rocks;
- 300 – sedimentary rocks.
An equally important factor determining the ability of a material to be used to perform a specific task is the grain size. The following varieties are found:
- Dusty. The structure is very fine, particle size is up to 0.14 mm. This abrasive is divided into three more types - low-moisture, wet, and water-saturated.
- Fine – grain size 1.5–2.0 mm.
- Medium size – 2.0–2.5 mm.
- Large – 2.5–3.0 mm.
- Increased coarseness – 3.0–3.5 mm.
- Very large – from 3.5 mm.
A value such as the filtration coefficient shows the speed of water passing through sand under the conditions defined by GOST 25584. It depends on the porosity of the material.
Definition! For materials of natural origin, the bulk density is 1300–1500 kg/m3. As humidity increases, this figure increases.
To determine the quality of a bulk substance, indicators such as radioactivity class and the percentage of impurities - dusty, silty and clayey - are also used. In very fine and fine sands, the permissible limit for the content of such impurities is 5%, in other types - 3%.
What questions do we often receive from our clients?
What is the main difference between sand and clay
The different mineral and chemical composition of these two materials determine their three main differences, the essence of which is reflected in the table:
| Characteristic | Sand | Clay |
| Waterproof | In nature, it is often found dry because it allows water to pass through perfectly. This quality allows the material to be used to create filter units. | Absorbs water to a certain extent with an increase in volume, which is restored after drying. This material is not capable of passing water both in dry and in water-saturated states. |
| Plastic | It exhibits some ability to stick together when wet, but stable forms cannot be made from it. | Raw clay is characterized by high viscosity and plasticity, so it can be used to create artistic forms, construction products, and household items. |
| Flowability | Dry material does not have the ability to stick together, so it is characterized by high flowability. Such a bulk substance passes through any openings at the same speed. This property is used in the manufacture of hourglasses. | Clay consists of tightly adhered particles, so it does not flow. To separate the clay grains from each other, the lump must be crushed mechanically. |
What is the difference between sand and sandstone?
The grains of sand that make up sandstone, a sedimentary rock, are tightly bound together by clay, carbonate or other materials. Based on the time of appearance, bonding substances are divided into syngenetic - which appeared in the rock at the same time as sand grains, and epigenetic - which filled the voids between the grains after a certain period. Sandstones can be monomineral, consisting of grains of one mineral, or polymictic, consisting of several initial components.
What kind of sand is needed for the foundation?
The foundation is the basis of the structure, and it must be strong and reliable. The best option for this type of work is medium-fraction alluvium material. It combines an affordable price and the required level of quality. The same variety is used for making screeds.
Which sand is best to use for masonry
What kind of sand is needed for sandblasting
Some craftsmen, trying to save money, use ordinary quarry material for this purpose. Such an abrasive can cause irreparable harm not only to the product being processed, but also to the device itself. The most common option in this case is quartz sand.
Attention! When working with quartz abrasive, it is imperative to follow safety rules, since it generates a large amount of dust that can cause silicosis.
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Sand, the formula of which is as follows: SiO2, is a sedimentary rock and an artificial material containing rock elements. Quite often it consists of pure mineral and quartz, which is silicon dioxide.
Today, sand is widely used in many areas of human activity. This primarily includes private and industrial construction. Sand becomes part of various mortars for forming foundations and plastering surfaces.
Description of sand
Natural sand is a loose mixture of grains, the fraction of which varies from 0.16 to 5 mm. The material is formed by the destruction of hard rocks. Depending on how the accumulation occurred, sand can be:
- deluvial;
- alluvial;
- lake;
- sea;
- aeolian.
As a result of the activity of watercourses and reservoirs, sands appear that have a rounded and rounded shape.
Main characteristics of construction sand
Sand, the formula of which was mentioned above, is a bulk non-metallic material that can be used in almost any construction work. The bulk of such sands consists not only of quartz, but also of feldspars. Silicates are also present as impurities.
Sands are quite common on the surface of the earth, both in the seas and on land. Porosity in a loose state is approximately 47%, while in a dense state it reaches 37%. Density is estimated by the porosity coefficient. For fine sands this value is 0.75.
Sand, the formula of which can be useful to professionals, has open porosity, which ensures the quality of water permeability. If the sand is packed tightly, it is able to absorb loads and distribute stress under the foundations. The deformation modulus of fine sands varies from 30 to 50 MPa.
Specific gravity of different types of sand
Sand, the formula of which is not so often required by builders, has a certain specific gravity, depending on the type of material. If we are talking about construction sand, then this value is 1.5 t/m3, while a cubic meter of dry, loose construction sand will weigh 1.44 tons. When compacted, this value increases to 1.68 t/m3.
When wet, construction sand weighs 1.92 t/m3, and when compacted wet, the specific gravity is 2.54 t/m3. The mass of sand will vary between river, quartz, sea and quarry varieties. The specific gravity of these sands will be as follows: 1.6; 1.6; 1.62; 1.5 t/m 3 respectively.
More about density
Considering the properties of sand, it should be noted that one of its important qualities is density. If we are talking about the quartz variety of material, then this characteristic is determined by two approaches. Thus, the density can be bulk and true. Bulk is determined by the mass-to-volume ratio method in a bulk state. This value means not only grains, but also air space. This value may vary depending on humidity.
Construction sand can also be characterized by true density; this value is constant and is determined by the ratio of the substance to the volume in a dense state. In this case, humidity does not matter. Density changes when the chemical composition or molecular structure changes.
The true density is greater than the bulk density. The hardness, crushability and abrasion of sand are indirect indicators of strength. To determine these parameters, tests are carried out on a rotating and abrading circle. In this case, the grains are clamped mechanically.
GOST and basic parameters of construction sand
Construction sand is divided into quarry sand and river sand. This material is manufactured in accordance with GOST 8736-93. Depending on the purpose, quality and standardized indicators that determine the content of clay and dust particles, the material can be divided into two classes, each of which has its own grain composition.
The chemical formula of sand was mentioned above, but it is not the only thing that professionals are interested in. Depending on the grain composition, the material can be classified by size. The first class includes coarse sand, which is obtained by crushing screenings. The second class of sand involves not only very, but also fine, medium, and thin material.
Sand, the GOST of which was in those mentioned above, can also be alluvial. This material is obtained by washing quarry sand. In this case, a large volume of liquid is used, which allows you to rid the material of clay and dust particles. Alluvial sand may involve the presence of small fractions, the size of which is 0.6 mm. This type of sand is used for plastering work where the presence of clay is undesirable.
Modulus of river sand fineness
The chemical formula of sand can help a specialist, but private craftsmen rarely pay attention to this. A more important parameter for them is the grain composition, which is determined by a set of sieves with cell sizes ranging from 0.16 to 5 mm. Dry sand passes through a sieve, which makes it possible to determine partial and total residues. The size of the total residues will determine the grain composition.
Construction sand is an inorganic sand that is formed by the natural destruction of rocks. Artificial heavy sand is a loose mixture, which is obtained by crushing rocks according to the type:
- limestones;
- granite;
- marble;
- slag.
The shape of the grains is acute, and the surface is rough. This material is used as a filler and when carrying out plastering work, when there is a need to achieve the effect of a noticeable texture of the covering layer.
Artificial sands can become part of any layer of plaster, the fractionation may be different, which depends on the solution and the requirements of the project.
Artificial sand is made from coal slag, and burnt coal is recycled. As a result, the material has a low sulfur content, which determines the quality of the coating layer. When carrying out decorative plaster using artificial sand, crushed stone, powder and crumbs of this rock can be used together with it to save money.
Conclusion
The cost of sand depends on its characteristics and is related to the distance of the quarry from the areas of consumption. The cheapest is natural quarry sand that has not undergone further processing. It contains lumps of clay and a high content of clayey silt particles. After processing is completed, the price of sand increases. Seeded sand can cost 2 times more than its predecessor.
Here you will get acquainted with minerals that are widespread in nature. One of the first places among them is occupied by such stone building materials as sand, clay, limestone and other rocks. It is these rocks that make up the thickness of the earth’s crust and in some places extend directly onto its surface.
Sand and gravel
Sand is a common and well-known rock. However, look closely at a handful of sand, compare river sand with sand taken from a ravine or pit, and you will see that they differ greatly from each other in color, grain size and impurities. Impurities are sometimes visible to the “naked” eye, as they say, but sometimes, on the contrary, they are difficult to distinguish even under a magnifying glass. Impurities greatly change the properties of sand and limit its use.
The mineral composition of sand is not always homogeneous. Its bulk consists of quartz grains. The presence of pinkish, grayish and other colored grains indicates the presence of another mineral in the sand - feldspar.
Now a little about impurities. The most common admixture to sand is clay particles, otherwise known as fine earth. Depending on the amount of clay, sands are divided into three groups: loose or loose, clayey and sandy loam. Quick sand is easy to distinguish from other sands we have noted: they do not generate dust when you stream sand from a handful, well dried in the sun or in an oven. When viewed under a magnifying glass, the grains of sand are transparent and almost not shrouded in dusty deposits (fine soil). For this reason, a teaspoon of such sand will not produce noticeable turbidity in a glass of water.
Clay sands are a little dusty when dry, but when wet they show some cohesion. Under a magnifying glass, an admixture of fine earth is clearly visible in them.
When dry, sandy loam generates a lot of dust; when wet, it slightly sticks to your fingers (you can even roll it into a ball).
If you look at sandy loam under a magnifying glass, you can see that the grains of sand are shrouded in fine earth.
Other impurities are also found in sand. You can find sand in which “golden grains” clearly burn. There are a lot of them. It even seems to you that they make up the bulk of the sand. But take a pinch of this “golden sand”, throw it into a glass of water, and you will see that real sand will quickly settle to the bottom, and heavy “gold”, contrary to the laws of physics, will float...
This is “cat gold” - small flakes of golden mica. Mica comes in a different color - light, silver-white (“silver sand”), and there is also mica in darker shades. Such sands are called mica sands. In the sand you can also find small rounded grains of bluish-green and dark green color; sometimes there are so many of them that the sand appears green. Such sands are called glauconite sands after the mineral glauconite (in Greek “glaukos” - bluish). Glauconite grains can be easily crushed with a fingernail into a green powder.
A harmful impurity for sand, especially when used as an additive to cement, is pyrite, otherwise known as iron or sulfur. The presence of pyrite is indicated by small golden grains and cubes, clearly visible in the total mass of sand. We will take a closer look at pyrite as a valuable ore for sulfur mining later.
The presence of lime in sand is also a harmful impurity. This impurity is easy to detect if you drop 10% hydrochloric acid or vinegar, since rocks containing lime boil when exposed to acid.
The accumulation of lime is also clearly visible in the form of individual white grains and pebbles, which also boil violently under the influence of acid. Iron compounds color the sand in yellowish-reddish tones. The admixture of organic substances gives the sand a dark color.
Based on grain size, sands are divided into the following groups:
- Fine-grained - very fine, powdery sand;
- Medium-grained - individual grains of sand are smaller than a pinhead;
- Coarse - grains of sand approximately the size of a pinhead;
- Coarse-grained - grains of sand smaller than a match head.
If you have a magnifying glass, you can do some interesting research. Examining various sands on a glass plate, you are convinced that the shape of the grains in some sands is round (river and sea sands), while in others it is angular (mountain sand).
For concrete and gray sand-lime brick, sand with angular grains is used. Thanks to this shape, the products retain greater strength. Sands used in foundry have a rounded grain shape. It creates porosity in the sand in which the casting is made. And the result is better heat and gas transfer.
Sands are widespread in nature, but they do not always meet certain technical requirements. Sand added to cement should contain no more than 2 percent of impurities, especially clayey and organic substances, and should not contain pyrite at all. For building bricks, you need sand without admixtures of limestone pieces, since after firing the brick, the limestone turns into quicklime; as it absorbs moisture from the air, the lime “quenches”, increases its volume and tears the brick. Clay sands are unsuitable for road construction - they generate dust. The iron content makes the sand unsuitable for the glass industry, as it produces brown and green glass.
(in French, gravel means coarse sand).
With a grain size from 2 millimeters to 1 centimeter, the rock is called gravel if the grains are rounded; if the grains are angular, the rock is called gruss, or crushed stone.
Gravel is a very valuable material for concrete production; necessary for the construction of railways and highways.
Significant accumulations of gravel occur among glacial sediments, as well as ancient and modern river sediments.
And an artificial material that contains fractions of rocks. Quite often it consists of the mineral quartz, which is a substance called silicon dioxide. If we are talking about natural sand, then it is a loose mixture, the grain fraction of which reaches 5 mm.
Classification by rock destruction
This material is formed during the destruction of hard rocks. Depending on the accumulation conditions, sands can be:
- alluvial;
- sea;
- deluvial;
- aeolian;
- lake
When a material arises during the activity of reservoirs and watercourses, its elements will have a rounded round shape.
Main types of sand and features of their extraction
Today, almost all types of sand are used by humans in various fields of activity and industry. River sand is a building mixture that is extracted from river beds. This material has a fairly high degree of purification, which is why the structure does not contain small stones, clay impurities and foreign inclusions.
Quarry sand is extracted by washing with water in a huge volume, as a result it is possible to get rid of dusty clay particles. Considering the types of sand, you can find quarry sand, which is cleared of large fractions of stones during the mining process. This material is quite widespread in the production of mortars that are used for laying foundations and carrying out plastering work. You can also find quarry seeded sand in asphalt concrete mixtures.
Construction sand must comply with GOST 8736-2014, according to which the material is a loose inorganic mixture of coarse grains, the size of which reaches 5 mm. equal to 1300 kg/m3. Construction sand is formed during the natural destruction of rocks; it is mined by methods of developing sand-gravel and sand deposits without and with the use of processing 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 we should highlight:
- slags;
- granites;
- limestone;
- marble;
- pumice;
Features of artificial sand
They can have different origins and densities. If we compare the grains of this sand with grains of natural origin, the former are distinguished by their acute angular shape and rough surface. Artificial sands are commonly used as fillers in the preparation of plasters and decorative mortars. As a result, it is possible to achieve a noticeable texture of the top layer on the outer surfaces.
This material can become part of any layer of plaster, because the fractionation of grains can be different, which depends on the type of solution. Typically, the grain size is assumed to be equal to the size of natural sand. When making artificial sand, burnt coal, rocks, and unburned particles with a low sulfur content are processed.
The characteristics of the material will depend on the quality of the covering layer. When making decorative plaster from such sand, in order to save money, crushed stone, powder of this rock or crumbs can be additionally added; the quality of the texture even benefits from this quality.
Applications and characteristics of sea sand
Sea sand can be used in the production of building mixtures, the manufacture of aggregates, plastering work, laying road bases, building fences and fences, as a filler for construction 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 particle size modulus. The grain density is equal to the limit from 2 to 2.8 g/cm 3 . Sea sand should be completely free of foreign impurities, but in some fractions you can find a low content of clay and dust particles. Sea sand is characterized by labor-intensive production, which makes its cost higher than quarry
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: fraction ranging from 1.5 to 5 mm, density equal to 1.60 g/cm 3, as well as low content of clay, dust and other impurities. The latter should not contain more than 0.03%.
Quarry sand, the price of which per cubic meter is 2,200 rubles, is used not only in construction, but also in decoration, as well as in the national economy. The use of such sand is especially cost-effective in the production of concrete and bricks, as well as in road and housing construction.
Quarry sand, the price of 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, alluvial quarry fractions are usually used. The quarry material is used for masonry and the production of paving slabs.
Technical characteristics of river alluvial sand and features of its extraction
Alluvial river sand has a density of 1.5 kg/m3. 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 extracted using a dredger that is fixed to a barge. Such equipment is complemented by hydromechanical installations, powerful pumps, networks and tanks for dividing the material by composition. The extraction of sand from dry river beds is similar to the extraction of quarry sand.
Conclusion
Almost all types of sand can be classified as class 1 in radioactivity. The only exception is crushed sand. 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 materials 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 when carrying out finishing work, as well as when renovating premises. The material is also a component that is used in road laying and construction.