There is an established opinion that choosing sand is quite easy: I ordered construction sand - here you have both a raw material component for concrete and backfill for a path. But this opinion is wrong. Since there are several varieties of sand, which have their own distinctive characteristics, and are used to perform certain jobs.
Classification
So, according to the place of origin, sand is usually classified into the following types:
river sand
River sand is mined from the bottom of rivers. It is characterized by natural purity and good water-permeability qualities. The size of sand grains in river sand ranges from 0.3 to 0.5 mm.
This type is used for the preparation of concrete solutions, cement screeds, treatment filters, and drainage structures. It is worth noting that when preparing a concrete mixture, this type of sand quickly settles, so the solution must be constantly stirred. The cost of river sand ranges from 600 to 800 rubles per 1 m 3.
Quarry sand
Quite logically, quarry sand is mined using the open-pit method and includes impurities in its composition: dust particles, stones. Sand grains of quarry sand are much smaller than those of river sand, their sizes range from 0.6 to 3.2 mm.
In its original unprocessed form, the building material can be used to construct trenches or as a foundation foundation. Typically, leading manufacturers wash and screen quarry sand. In this case, it can be used when performing plastering and finishing work, to create an asphalt concrete mixture, and to form a screed.
Sea sand
This non-metallic mineral is extracted from the seabed using hydraulic projectiles. There are practically no foreign impurities in it, and salt is involved in purification.
This type of sand is considered the most popular. It is used everywhere, from the creation of concrete structures to the formation of finely dispersed dry mixtures. But, despite the unique characteristics of this building material, there is a shortage of it, since it cannot be mass produced.
Sometimes construction sand is considered a separate type. But, as a rule, it means both river and quarry sand. River sand can be of two colors - yellow and gray, and quarry sand - brown and yellow.
But it turns out that in nature there is also black sand, which shines like metal. It can be found in different parts of the world. This type of sand is formed as a result of geological processes.
This mineral consists of dark-colored heavy minerals and is formed by washing away the light components. The main minerals are magnetite, ilmenite, hematite.
Such sands are characterized by high radioactivity - 50-300 microroentgens per hour, but sometimes this parameter can reach a thousand microroentgens per hour. Due to its high radioactivity, this mineral is not used in construction and economic activities.
Artificial sand
It is worth noting that the above types of sand are natural, as they were formed by the natural destruction of rocks. But there is also on the market artificial sand, created by crushing marble, limestone, granite.
The most popular among artificial types of sand is quartz. It is made by grinding and dispersing the white quartz mineral to obtain a homogeneous fraction. It differs from natural types of sand in that it does not contain impurities and has a homogeneous composition. These advantages allow you to accurately calculate the parameters of a structure made on quartz sand.
It has found its application in the creation of decorative and finishing materials, as well as welding materials. It is also used in the production of concrete, but quite rarely.
Sand fineness modulus
In accordance with GOST 8736-93, construction sand is divided according to its fineness modulus. This is very important to remember, since the finer the building material, the more water is needed to wet it.
Non-metallic minerals with a particle size of 1.5-2 are widely used in the manufacture of bricks. The finest sand is used in the preparation of dry construction mixtures, and with a fineness module of 2-2.5 - for reinforced concrete structures and concrete production.
In conclusion, we repeat that for certain jobs and applications you need to choose a specific type of sand.
