GOST 22263-76 crushed stone and sand from porous rocks. technical conditions (with change n 1)

Where does that come from

How coarse sand is obtained:

• It is mined industrially from a quarry or river. Often with subsequent processing: washing, sieving, possibly additional crushing.
• Artificially - by crushing hard rocks, more often quartz. Sometimes it goes as a residue after metallurgical production.

How much effort has been expended on the extraction and / or production of sand depends on its cost. It's one thing to just dig clean coarse sand, another to process it for a long time, bringing it to GOST, and then take it to the other end of the country.

Sand extraction in a quarry

River sand is not quarry: there are differences

Coarse river sand is of better quality, cleaner than open-pit sand, there are initially fewer impurities in it. It is also smoother because it has undergone a kind of pretreatment with water. But it is less common - the current grinds the grains of sand, they become smaller over time. For these reasons, coarse river sand is more expensive. The latter can be considered a disadvantage, but there are others. For example, due to its weight (it is heavier), river sand settles faster in solutions. The problem is solved by thorough mixing.

Quarry sand is rougher, due to this it has better adhesion. In addition, it is more widespread, it does not have such high requirements as the river one. Although the latter is relative, any product must be of high quality. To be sure of quality, purchase sand from a trusted supplier with a good reputation.

And a little about coarse quartz sand

This is not to say that this type of sand is rarely used, just the scope of its application is specific.

Quartz sand is used:

• In the metallurgical industry (sandblasting machines work on it, it is used as filters).
• In various industries: glass, cement, tiles, bricks, etc.
• When building roads, arranging courts, surfaces covered with such sand get good performance characteristics.

But for each production, sand of different size is used. For sandblasting, consumables of different fractions are needed - from very large to subtle. And the top layer of the tennis court is preferable to cover with coarse sand.

Choice

When purchasing the material, it is important to correctly calculate the required amount of sand. For this:

• the given number is required * by 1.1-1.3. This is due to the fact that volumes change during transportation and storage;
• contact the manager to clarify the bulk density;
• carry out specific gravity calculations.

If possible, it is better to postpone the purchase. It is beneficial to do it when it is spring or summer outside.

Volumetric and specific gravity may be different

Therefore, at the stage of real estate construction, it is important to pay attention to all errors

The average volumetric weight in 1 cubic meter is 1.5-1.8 tons. These indicators are taken into account in accordance with a special GOST.

The specific gravity of alluvial quartz sand (the one that is mined from the bottom of the river) can be in the border from 2.74 to 2.80, these indicators are average, if there are no organic impurities there.

Sand has the ability to retain heat and accumulate energy. This number is considered to be a witness to the thermal performance of the sand. The ability to heat up depends on the chemical elements. They are also based on the structure and quantity of the material used, as well as its structure and physical characteristics.

Indicators of heat capacity are also necessary at the stage of concreting the walls.

Depending on the type, sand can have the following specific gravity:

• wet quartz-based - 2.9 kJ / kg.
• extracted from the bottom of the river - 0.8 kJ / kg.
• extracted by mining - 0.84 kJ / kg.
• extracted from a part of the world's oceans - 0.88 kJ / kg.

CF for different types of sand

Soil of different properties has different absorption coefficients of water or other liquid (water permeability coefficient). The exact data are given in GOST 25584. The properties of the liquid are not taken into account - the main parameter for calculations is the size of the fractions of sand and inclusions in it.
KF-00M device

The permeability coefficient of the fluid for quarry sand is 0.5-7 m / day, since there are many foreign inclusions in this building material - clay, dust, etc. All these unnecessary components retain liquid, therefore, when preparing mixtures and mortars based on cement, this sand is used very rarely.

After the quarry sand has been cleaned with water, the CV increases and the quality of the sand becomes better. KF in open pit reclaimed sand reaches 5-20 m3 / day, and the size of the average sand fractions remains at the level of 1.5 mm. Such washed quarry sand is already allowed to be used in the preparation of concrete and cement-sand mixtures.

Fine sand with a throughput of 1-10 m3 / day is widely used in the production of dry building mixtures - plastering, masonry, etc. In the presence of any foreign impurities in fine-grained sand, its CF decreases significantly.

A very high CV in coarse sand is a material of practically maximum water permeability, since there is always air between the coarse grains, through which water or any other liquid can flow freely.
Different fractions of sand

CF is used to determine the parameters of the sand. High water permeability determines the purity of the sand and the degree of suitability for use in construction, since the quality of the sand directly affects the reliability indicators and the duration of operation of construction projects.

CF calculation

Given the constant demand for sand for the organization of any construction work - both in industrial and in individual construction and repair - the characteristics of this building material should be such as to provide the highest possible quality, strength, filtration (CF) and other parameters.
Approximate values ​​of KF of sand

CF is determined using the following set of tools:

1. KF-00M device, which consists of the following components:
   1. A filtration tube (tube) with a height of more than 100 mm and a diameter of 5.65 cm. The tube has a bottom with perforations for the passage of liquid.
   2. Steel mesh sleeve for liquid filtration.
   3. Glass tank.
2. Electronic balance.
3. Chronometer or stopwatch.

More details about the experiment on measuring the CF of sand:

Dry sand, which must be examined, is poured into the test tube of the KF-00M device, and a mesh with holes is attached to the bottom of the test tube. The device is placed on a horizontal surface, the sand in the test tube should be tamped tightly. To do this, it is covered with small portions, and each portion is rammed separately. Make three or more servings in total.
Apparatus for determining water absorption in the laboratory

The distance from the top edge of the tube to the beginning of the sand level must be measured, and if it is more than 100 mm, the sand is tamped additionally. To investigate the CF unit, begin by pouring water into a test tube so that it is 0.5 cm above zero.As soon as the liquid begins to drain through the perforated bottom, the time is measured with a chronometer to the 50 mm mark - the water should sink to it. Add liquid to the test tube with water four times, 5 mm each. The result of the measurements will be the arithmetic average of all measurements taken.

At the end of the research, the difference between the density index of dry pit sand and its limiting density should not be more than 0.02 g / cm3. For laying the roadbed, they take river, sea or quarry washed sand, since these sands have improved quality parameters, and the washed building material also has better cleaning. Due to the quality of washing, asphalt based on such sand will be stronger, and the duration of its operation will be longer. Sand extracted from the bottom of the sea is not used as often in construction and repair work as river sand, because its cost is higher. Sand with clay admixtures in construction is used much less often than other bulk materials, but if it is cleaned (washed and dried), then the scope of its use can not be limited due to the small CF.

Extraction of sea sand

Dirty sand mined in a quarry has a low filtration coefficient according to GOST - no more than 0.5-0.7 m / day. When it is washed, clay and other impurities are washed out, and large foreign grains (stone, granite or crushed stone) remain. To obtain a higher quality of such sand, it must not only be dried, but also sieved, after which it can be safely used to obtain high-quality solutions or mixtures. The CF for such sands turns out to be high - ≤ 20 m3 / day, since all extraneous fractions and impurities are removed from it by washing and sieving.

Table: soil filtration coefficient according to GOST

 
Extraction of sea sand

Types of construction sand

The classical definition says that sand is a mixture of mineral particles (quartz, mica, limestone) formed as a result of natural or artificial destruction of rocks.

According to GOST 8736-93, the most important properties of sand are laid out “on the shelves”. According to this standard, sand is divided into two classes:

• Class I - very coarse, followed by sand of increased coarseness, coarse, medium and fine;
• Class II - very large, increased size, large, medium, small, very small, thin and very thin.

The main difference between these classes is that lower quality sand (second class) includes three additional fractions. Fine dusty particles are an undesirable component of mortars. They impair the bond between the coarse sand grains that the cement binds.

Further, GOST contains a table in which building sand is divided into groups according to the size modulus (mm).

In real production, there is no such fine gradation.

Here, the mined sand is conventionally divided into three fractions:

• 0.5-1 mm - small;
• 1.5-2 mm - medium;
• 2.5-3.5 mm - large.

Sands with a fineness module of 2-2.5 mm are used for the production of concrete and reinforced concrete structures. Loose material 1.5-2 mm in size is used for the manufacture of bricks. The finest sand is used for the preparation of dry building mixtures.

Having taken into account the GOST classification, let's move on to the practical aspects of the origin and use of building sand.

By the type of prey, they are distinguished:

• Career;
• River;
• Nautical;
• Quartz (artificial) sand.