Crushed stone fr. 5-20 is in demand in private and industrial construction, this size of fractions is optimal for the preparation of concrete and reinforced concrete, pouring screeds and foundations, backfilling roads. For its other performance characteristics (strength, frost resistance, specific gravity, flakiness) are influenced by the raw materials and the manufacturing method, they must be taken into account when purchasing and mixing the solution. Bulk density requires special attention - the ratio of mass to occupied volume, the accuracy of proportions and properties of the prepared concrete depends on this indicator.

Significance and influence of characteristics

It is rather difficult to correctly take into account the volume of voids between grains of crushed stone, the weight of 1 m3 of crushed stone or gravel in a natural and dry state is several times less than its average density. The reason is obvious - when grinding, the resulting fractions have different shape and do not adhere well to each other, part of the material replaces air. For comparison: a solid piece of granite has a density of at least 2600 kg / m3, crushed stone weighs no more than 1470 kg with an equal occupied volume.

Knowledge exact weight it is necessary when calculating the capacity of storage rooms and the carrying capacity of transport, it must be taken into account in the process of preparing concrete. When using crushed stone 5-20 with a high value of the bulk density, cement consumption is reduced and the performance of the mortar is increased. As a consequence, this value is taken into account along with the strength grade.

Accurate measurements of this indicator are carried out in the laboratory using special barrels, weighed before and after filling. It is his manufacturer that indicates when selling. To determine it on our own (in the absence of a certificate), a container is selected, the volume of which is easy to calculate and the mass of crushed stone is 5-20 (tare weight is taken away). The desired value is obtained by dividing and used in the selection of the proportions of the remaining components. It is impossible to find porosity and real density at home; if it is necessary to take them into account, they are based on the reference data or the results of laboratory tests of the manufacturer.

How much does a cube of crushed stone of 5-20 different types weigh?

The mass of crushed materials depends primarily on the type of raw material. With an equal size of fractions, 1 m3 of soft tuff weighs almost half as much as hard and high-strength rocks... The average weight of crushed granite is 1.37 tons per 1 m3, limestone - 1.3. The relationship between the base and the bulk density is shown more clearly in the table:

For each variety, there is an optimal field of application: limestone within 5-20 mm refers to fine grinding and is used in the manufacture of lime, piece small-sized concrete products, mixing facing mixtures. Granite with such a grain is almost universal; according to its characteristics, it is suitable for all types of concrete, including industrial ones. The given range will be relevant when using crushed stone in a dry state, with an equal size of fractions, it can vary depending on the place of extraction and shape.

Flakiness is an important factor, it is it that determines the boundaries of the range indicated in the table. This characteristic directly affects the volume of air between fractions, and, as a consequence, the bulk density of the material. The difference between the weight of 1 m3 of crushed stone of cube-shaped and needle-shaped forms 5-20 mm reaches 20%, this affects its subsidence and sorbing properties. The first type is used in the manufacture of heavy grades of concrete and the pouring of structures that experience significant weight and mechanical loads. The second is classified as low-grade, with an equal size of fractions, crushed stone with a high content of grains irregular shape when filling in mortars requires more cement, otherwise the bond quality of the filler will be poor.

The exact value of density and bulk density must be indicated by the manufacturer in the attached documentation. But it can change during transportation or storage in unsuitable conditions (when moisture is collected). The percentage of water absorption for each breed is different, it is directly related to porosity, flakiness (acicular and irregular grains accumulate more moisture than cuboid) and roughness, on average, any crushed stone fr. 5-20 mm will increase its weight by 10-15% during prolonged stay in a room with high humidity (not to mention storage outdoors and getting wet in the rain).

To avoid errors in the selection of proportions, the bulk density construction rubble recheck dry.

Crushed stones are stones obtained by artificial crushing coarse gravel, pebbles, boulders, rocks, blast furnace slag and asbestos production waste, pumice, waste from the extraction of ferrous and non-ferrous metals. Secondary is obtained by processing construction waste - concrete, bricks, asphalt.

With a rough surface, it provides excellent adhesion to cement-sand mortar and is irreplaceable in the construction of foundations, railway embankments, in road construction. The density of crushed stone (one of the main parameters on which the strength directly depends) is the ratio of mass to the volume that it occupies, measured in kg or tons per m3.

The density of construction crushed stone depends on what kind of rock it is made from. For example, 1 m3 of granite weighs 2,600 kg, and dense limestone - 2,700-2,900 kg / m3 (depending on the amount of impurities of quartz, dolomite and other minerals).

There is air between the individual stones (grains). Because of this, 1 m3 with voids cannot weigh as much as the same volume of uncrushed rock. Therefore, there is such an indicator as density bulk crushed stone- the ratio of its total mass to the volume that it occupies (in a natural, unconsolidated form). The smaller the fraction, the higher it is.

This indicator is taken into account:

• in the process of mixing concrete mortar, since the larger it is, the less cement is required and more money can be saved;
• during transportation - to calculate the carrying capacity and the need for transport, depending on the dimensions of its body;
• during storage and warehousing - in order to determine the size of the storage.

To determine this indicator, there are special containers with a volume of up to 50 liters of a certain shape, which are weighed before and after filling from a height of 1 m and leveling with its top. The difference between these results is divided by the volume of the vessel and the bulk density of crushed stone is obtained, kg m3. Measurements are made in special laboratories and are reflected in the quality certificates of the given batch.

You can make yourself necessary calculations, if you take, a construction trough for mixing the solution. Multiply the height by the length and width of the container, and find out its volume. After weighing the empty trough and the filled trough flush with the edges, calculate the difference - this is the mass. By dividing the second number by the first, you get the desired indicator.

There is also the concept of true density, determined in laboratory conditions by measuring the mass of a unit volume of crushed and dried material. This eliminates the presence of air-filled voids. Used when calculating porosity. For example, bulk and true density crushed stone 5-20 are 1 320 and 2 590 kg / m 3, respectively.

Indicator for various types

• granite - 1320-1690 (bulk density of crushed granite fractions 20-40 - 1370-1400, 40-70 - 1380-1400, 70-250 - 1400);
• gabbro-diabase - 1440-1580 (depending on the fraction);
• limestone - 1250-1330 (fraction 10-20 - 1250, 20-40 - 1280, 40-70 - 1330);
• gravel - 1350-1450 (fraction 0-5 - 1600, 5-20 - 1430, 40-100 - 1650, more than 160 - 1730);
• slag - 800;
• expanded clay - 210-450 (fractions 20-40 - 210-340, 10-20 - 220-440, 5-10 - 270-450);
• secondary - 1 200-3000 (from crushed concrete - 1 170-1 310).

Crushed stone grades and their density

Grades 800-1200 are considered strong, 1400-1600 - high-strength.

Crushed stone is an essential building material that is used in the construction of foundations and roads. Thanks to large fragments of boulders, coarse gravel and the rest of the rocks, it is given to create cement mortar which has a high adhesion density. The most important parameter of this product is density. It shows the ratio of weight to volume. Thanks to this indicator, there is a predominant effect on the other qualities.

Currently, the types of density are distinguished: bulk and true. Each fraction of this material is characterized by its own indicators of the presented characteristics. The granules have air interlayers, as a result of which its embankment is different than 1 m3 of uncrushed rock.

What is the difference between crushed stone and gravel can be found in this

The smaller the granules are, the more they will be specific gravity ... Based on this, the bulk density will also be high. This criterion depends on how many hard and durable mineral seals are in it.

What volume weight crushed stone by fractions in the table can be found in this

To determine the bulk density, it is necessary to use an empty container, the volume of which will leave 50 liters. First, send the container to the scales. The required indicator can be calculated using the presented formula:

P = (m2 - m1): V,

in which P is the density of the material, m2 is the weight of the container with crushed stone, m1 is the mass of the empty container, V is its volume.

It is necessary to carry out such experiments in special laboratories. There, special shapes and dimensions are involved in the process, which are regulated by GOST 9758-86. However, calculate the bulk density of crushed stone. In this case, you will need a trough in which you will mix the solution. First measure the weight of the empty container. Now place the rubble in the container and send it back to the scales. The calculation should be carried out according to the above formula. But the formula has one more parameter - the volume of the container. To calculate the volume of a container, you need to take the length, width and height and multiply everything.

The indicator of bulk density in the construction industry is very difficult to overestimate. It must be known exactly and must be taken into account when preparing the solution. If it is high, then the amount of cement used is reduced. Also, you will be able to save money on transportation and storage of bulk materials.

The bulk density value is many times different from the true one. To determine it, it is necessary to use laboratory equipment. First, you need to grind the crushed stone, dry it and get rid of the existing voids. After such events, you must weigh the dried material. There is a specific bulk density for different fractions.

And other technical data are indicated in this article.

Table 1 - For crushed stone of various fractions

Granite

Today it is considered the most demanded. Its density can reach such a value of 1300-1700 kg / m3. Crushed granite is classified by fractions. There are such groups of material:

Other types

In addition to crushed granite, which today has gained wide popularity, limestone, slag and gravel material. Each of the options presented has its own quality characteristics and bulk density.

Limestone crushed stone is considered a unique bulk material. It is characterized by high strength, frost resistance, and environmental friendliness. For fractions 5-40 mm, the following characteristics are characteristic:

• bulk density - 1300 kg / m³;
• flakiness - no more than 12%;
• the presence of dust - up to 2%;
• the presence of weak breeds - up to 9%;
• strength grade - M600-M800;
• porosity - not higher than 7.3%;
• humidity level - no more than 4%;
• water absorption - 2.5%;
• frost resistance - F-150.

The next type of crushed stone is gravel. It is used as a filler for making blocks of concrete and reinforced concrete, for the construction of monolithic structures, floor slabs. It has the following characteristics:

• bulk bulk weight - 1400 kg / m3,
• strength grade - 1200,
• frost resistance - F-350.

For crushed slag average density can reach 800 kg / m3. Appropriate markings are characteristic of durability. The most durable are the M800-M1200, and the high-strength M1400-M1600. For secondary crushed stone, the density will reach 1200-3000 kg / m3.

Crushed stone is an important material in construction, which has a wide range of applications. An important quality parameter of this product is its bulk density. But for each type of crushed stone, this indicator is different. It is determined by a laboratory method, but it is completely easy to do it at home. It is precisely determined, then you will be able to avoid subsequent shrinkage, and therefore, extend the service life of the structure being erected.

The KULSYSTEMS LLC company sells crushed stone granite fractions 5-20, 20-40 and 40-70mm

General information

Granite crushed stone - granite (derived from the Italian Granito - granular; in ancient Russia it was called "wild stone") is a solid rock with a granular structure. The formation of granites took place throughout the history of the Earth, and now it is the most common rock.

Granite rock is magma thrown to the surface of the earth and solidified, consisting of well-formed crystals feldspar, quartz, mica, etc. And it has a color of red, pink or gray, set off from the predominance of spar and mica in it. Lumps are usually obtained by blasting a monolithic rock, then they are crushed in a machine, and the resulting crushed stone is sieved into fractions. This is the last stage of crushed stone production. Crushed stone is assessed by the quality of its fractions. The smaller the fraction of crushed stone, the more expensive it is, because more work was spent on crushing it. The main fractions of crushed granite are: 5-15, 5-20, 5-40, 20-40, 40-70mm.

Crushed stone indicators. The most important indicators of granite crushed stone are:

• compressive strength grade
• flakiness (content of needle-shaped particles in granite)
• density
• fraction.

Crushed stone groups. Depending on the brand, crushed stone is divided into the following groups:

• high-strength crushed stone - М1200-1400
• durable crushed stone - М800-1200
• crushed stone of medium strength - M600-800
• low strength crushed stone - М300-600
• crushed stone of very weak strength - M200.

In most types of construction, granite crushed stone is optimal building material since its main properties are strength, frost resistance, density, water absorption and water saturation. For example, modern GOSTs are prohibited from using in the construction of roads and road surfaces any rubble, except for granite.

Crushed stone characteristics:

Frost resistance of crushed stone is characterized by the number of freezing and thawing cycles. It is allowed to evaluate the frost resistance of crushed stone by the number of saturation cycles in a solution of sodium sulfate and drying. According to frost resistance, crushed stone is subdivided into grades: F15; F25; F50; F100; F150; F200; F300; F400.

Indicators of frost resistance of crushed stone are determined by testing by freezing and thawing or saturation in a solution of sodium sulfate and drying.

In construction, crushed stone with a strength grade of at least F300 is mainly used.

Crushed stone strength characterize the ultimate strength of the original rock in compression, crushed stone crushed stone in compression (crushing) in the cylinder, and wear in the shelf drum. These indicators mimic resistance stone material under the influence of vehicles passing along the road and mechanical influences during the construction of road structures (laying and compaction with rollers).

In crushed stone, the content of grains of weak rocks is normalized with the ultimate strength of the original rock when compressed in a water-saturated state up to 20 MPa. According to GOST 8267-93, crushed stone of grades M1400, M1200, M1000 should not contain grains of weak rocks in an amount of more than 5%, crushed stone of grades M800, M600, M400 more than 10%, crushed stone of grades M300 and M200 more than 15% by weight.

The greatest demand is crushed granite strength M1200, rarely used high-strength granite crushed stone or basalt crushed stone with strength grade M1400-1600. It is mainly used in the production of heavy, high-strength concrete, in supporting bridge structures, foundations.

Flakiness of rubble. In crushed stone, the content of grains of lamellar (flaky - comes from the word "bream", that is, flat like a bream) and acicular forms is normalized. Lamellar and needle-shaped grains include those grains whose thickness or width is less than three times the length or more. According to the shape of the grains, crushed stone is divided into four groups (the content of grains of lamellar and acicular forms,% by weight):

• Group I "cuboid" up to 15%,
• II group "improved" from 15% to 25%,
• III group "usual" from 25% to 35%,
• IV group "usual" from 35% to 50%.

It should be noted that "flakiness" is one of the most important characteristics of the quality of crushed stone. The less flakiness, the better the crushed stone is considered. The use of cuboid crushed stone gives the most dense compaction.

The presence of grains of lamellar and acicular forms in the crushed stone leads to an increase in intergranular voidness in the mixture. This, in turn, leads to an increase in the consumption of the binder component, and this entails additional material costs. In addition, cuboid grains are more durable than lamellar and needle-shaped grains. Consequently, the use of cube-shaped crushed stone in production is more economically feasible.

Crushed stone adhesion and grain size. One of the specific characteristics of crushed stone is adhesion. This parameter reflects the assessment of the quality of adhesion of bituminous binders to the surface of crushed stone. It should be noted that the quality of adhesion is influenced by the color of the crushed stone. The best indicators for adhesion are given by gray and dark gray crushed stone.

Grain composition each fraction must meet the requirements of GOST 8267-93 "Crushed stone and gravel from dense rocks for construction works". Based on the requirements of the specified GOST, it follows that in the fraction of crushed stone supplied for construction, for example 20-40mm, the number of grains smaller than 20mm should not exceed 10%, and grains larger than 1.25 * D (50mm) should not exceed 0.5%. These requirements are necessary for strict adherence to the grain composition of individual fractions. Compliance with these requirements is reflected in the sieving.

Content of dust and clay particles: In crushed stone, the content of dusty and clay particles (less than 0.05 mm in size) is normalized. In addition, lumps of clay are isolated with a particle size from 1.25 mm to the largest grain size of crushed stone of a given fraction with a mixture of fractions. For all types and grades of crushed stone in terms of strength, the content of clay in lumps in the total amount of dust and clay particles should not exceed 0.25% by weight. In crushed stone from igneous and metamorphic rocks, the content of dusty and clay particles by weight should not exceed 1%, in crushed stone from sedimentary rocks of grades from M600 to M1200 - 2%, and grades from M200 to M400 - 3%.

In terms of its qualities, crushed granite is superior to other types of crushed stone and artificial analogues. It has high strength, is a high-quality filler for concrete mix and also this material lends itself well to processing. The disadvantages of crushed granite include a high natural radioactive background.

Our company offers granite crushed stone with the following characteristics:

Crushed stone characteristics

Scope of crushed granite stone:

Due to its physical and technical properties crushed granite widely used in construction.

Granite crushed stone 5-20- one of the most demanded types. For such crushed stone, the price is the highest. It is used to make industrial concrete. In addition, crushed stone 5-20 can be ideal for construction and road surfaces in settlements, on the territory of construction sites. Crushed stone with fractions of a given size is widely used in the installation of all kinds of industrial facilities, to cover the zones of industrial complexes, etc.

Granite crushed stone 20-40 ideal for creating temporary and permanent roads in cities and other settlements. When erecting embankments on railways, it is simply impossible to do without crushed stone of this fraction, and the high frost resistance of granite makes it possible to reduce the frequency of filling to a minimum. In addition, granite crushed stone 20-40mm is actively used for the production of concrete, as a reinforcing material in foundations, in the construction of various residential and non-residential structures.

Granite crushed stone 40-70 has the most low price however, this does not diminish its relevance in industry and construction. In addition, 40-70mm crushed stone is often used as a semi-finished product, which is re-crushed and sorted into crushed stone with finer fractions.

Bulk density

The amount of crushed stone supplied is determined by volume or weight. Crushed stone is measured in wagons and cars.

Crushed stone, shipped in wagons or cars, is weighed on railway or truck scales. The amount of crushed stone from units of mass to units of volume is recalculated according to the value of the bulk density of crushed stone, determined at its moisture content during shipment.

The volume of crushed stone supplied in a car or car is determined by its measurement, the resulting volume is multiplied by the coefficient of compaction of crushed stone during transportation, which depends on the method of loading, distance of transportation, grain composition. The maximum permissible humidity and compaction coefficient, which should not exceed 1.10, are set in the supply contract.

Questions and answers:

Question: What is the usual radioactivity of rubble?
Answer: The radioactivity of crushed stone is the most important characteristic with which the discussion of the quality of construction crushed stone with the buyer usually begins. If the products must be suitable for all types of construction work without exception, which must be confirmed by appropriate certificates and sanitary and epidemiological conclusions, research by special laboratories, then this means that all supplied granite crushed stone and other types of high-strength crushed stone belong to the 1st class for radioactivity (less than 370Bq / kg). Crushed stone of II class in terms of radioactivity (more than 370Bq / kg) is suitable for road construction.

Question: How can I check the quality and quantity of the goods delivered to me?

Answer: Acceptance of goods by quantity and quality(in terms of appearance and pollution) occurs in the body of a vehicle, i.e. while the bulk cargo is in the back, you have the right to measure and inspect it appearance... If the material has already been unloaded, you have no right to make a claim (in accordance with GOST 8267-93). Therefore, we strongly recommend that you carefully consider the acceptance of the product, especially in terms of quantity. This has its own subtleties related to the compaction ratio.

TO compaction factor (Purchase.) – this is a standard number determined by GOST and taking into account how many times the bulk material has compacted (and, consequently, its apparent volume has also decreased) during transportation. The compaction factor is taken into account in measuring the volume of the supplied bulk material (soil, peat, sand, crushed stone, expanded clay, etc.). For example, a car with rubble arrives at your facility. You need to measure the volume of the body (LxWxH, where "H" equals the level of the material, not the height of the sides). The resulting volume must be multiplied by the compaction coefficient (according to GOST 9757-90 for crushed stone Purchase = 1.10).

If the bulk cargo is delivered with a so-called "slide" above the board, 2m 3 is always added to the resulting volume. This is the average of a given volume accepted by all suppliers of aggregates.

Question: What is the difference between crushed stone and gravel?

Answer: Crushed rock from rocks is an inorganic granular bulk material with grains larger than 5 mm, obtained by crushing rocks, gravel and boulders and subsequent screening of crushing products.

Gravel from rocks is an inorganic granular bulk material with grains larger than 5 mm, obtained by sieving natural gravel-sand mixtures... Gravel grains are round, crushed stone - angular. The fractions of crushed stone and gravel can be very different.

Question: How much does 1 cube of rubble weigh?

Answer: Average weight cubic meter crushed stone 1.4 tons. Weight depends on the material of crushed stone, granite is heavier, limestone is lighter. The fraction of crushed stone practically does not affect its weight.