Specific weight of crushed stone. Specific weight of building rubble

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. Its other performance characteristics (strength, frost resistance, specific gravity, flakiness) are affected by raw materials and the method of manufacture, they must be taken into account when purchasing and mixing the solution. special attention requires bulk density - the ratio of mass to the occupied volume, the accuracy of the proportions and properties of the prepared concrete depends on this indicator.

Significance and influence of characteristics

It is quite difficult to correctly take into account the volume of voids between the grains of crushed stone, the weight of 1 m3 of crushed stone or gravel in its 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 the 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.

Knowing the exact weight 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, cement consumption is reduced and the performance of the mortar is increased. As a result, 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 indicates when selling. To determine it on your 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 is used in the selection of the proportions of the remaining components. It is impossible to find porosity and real density at home; if necessary, they are taken into account based on reference data or results laboratory tests manufacturer.

How much does a cube of crushed stone of a fraction 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 ones. rocks. Average weight crushed granite is 1.37 tons per 1 m3, limestone - 1.3. More clearly, the relationship between the basis and bulk density is reflected in the table:

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

An important factor is flakiness, 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 result, the bulk density of the material. The difference between the weight of 1 m3 of cube-shaped and needle-shaped crushed stone 5-20 mm reaches 20%, this affects its subsidence and sorbing properties. The first variety 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 falling asleep in mortars requires more cement, otherwise the adhesion quality of the filler will be poor.

The exact value of density and bulk mass must be indicated by the manufacturer in the attached documentation. But it can change during transportation or storage in unsuitable conditions (with a set of humidity). 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 cubic ones) and roughness, on average, any gravel fr. 5-20 mm will increase its weight by 10-15% with a long stay in a room with high humidity(not to mention storage under open sky and getting wet in the rain).

In order to avoid errors in the selection of proportions, the bulk density of building rubble is rechecked in a dry state.

Crushed stone is a very popular building material used at various stages construction works. Crushed stone is of primary and secondary origin. So, fine crushed stone obtained from inorganic raw materials is of natural origin. It is obtained during the explosion, after which the stone blocks are crushed using special equipment. But slag waste from metallurgical production, fragments of asphalt, bricks are crushed stone of secondary origin.

As you know, in the process of grinding natural granite or stone, particles are obtained different sizes. Further, depending on the size of the obtained parts of crushed stone, it is divided into fractions. Considering that voids are formed between the elements of crushed stone in a bulk natural state, the size of which depends on the size of the parts themselves, the concept of “volumetric weight” has appeared in construction, which is used when calculating the amount of material transported in the body truck.

The volumetric weight of crushed stone is the mass of a unit volume (1 m3) of raw materials without compaction, measured in t/m3; kg/m3; g/cm3. Often this concept are replaced by other expressions that, in fact, have the same meaning: specific gravity, bulk density or bulk specific gravity. The value of these concepts depends on such factors: the size of individual particles, the type of source material, humidity, flakiness.

We will omit the first parameter for now and talk about its effect on volumetric weight a little later. On the this moment we are interested in the breed from which the material was obtained. It is she who is the determining factor, because different types stones have a different degree of water absorption, as a result of which the volumetric mass of crushed stone in the raw material will be greater.

In addition, consider another indicator that characterizes crushed stone, namely flakiness. This physical parameter, which expresses the magnitude of the plane of crushed stone particles, which are divided into elements of needle and plate shape. The flakiness parameter is determined by the percentage of and angular stones to the total amount of material. According to the parameters of flakiness, crushed stone is divided into: cuboid (up to 10%); improved (10-15%); regular (15-25%); regular (25-35%); regular (35-50%).

Particles of the 5th, the last group of flakiness, are classified as low-grade materials. It is used to fall asleep pits, including during road works, and also used for railway embankments.

Types of raw materials, depending on the origin:

Based on the materials from which crushed stone was made, it is divided into:

Granite (obtained by the explosion of rock and its subsequent crushing).
Dolomite or limestone (mined from deposits of sedimentary rocks; this type is characterized by increased water absorption)
Gravel (obtained by grinding stone rocks. This type must be distinguished from gravel, which has a rounded shape).
Secondary (obtained from slag waste from metallurgical production; pieces of building bricks; crushed concrete residues; old asphalt).

As you know, different types of particles have different densities. The weight of 1 m3 of fine dry crushed stone without voids is the true density of the substance, but in practice it is customary to use a different value - volumetric bulk density (specific), that is, the weight of crushed stone, which is necessary to calculate the amount of concrete and the final mass of the concrete mixture. As a rule, due to the presence of air between the particles of crushed stone, the specific gravity is less than the true density. If there is no need for high calculation accuracy when calculating the finished concrete mix, the average value is usually used. For example, the volumetric weight of crushed granite is approximately 1.5 tons (in 1 m3). To make an accurate calculation, taking into account the fraction, a special table is used. Note that for different type and crushed stone size bulk density is also different. How the specific gravity varies by fractions is described in more detail in the table below.

table

Type of raw material	Fraction, mm	Bulk specific gravity, t/m3
granite	0-5 (dropout)	1,41
	5-10	1,38
	5-20	1,35
	5-25	1,38
	20-40	1,35
	25-60	1,37
	40-70	1,35
Dolomite	10-20	1,25
	20-40	1,28
	40-70	1,33
gravel	0-5	1,60
	5-20	1,43
	40-100	1,65
	over 160	1,73
Secondary (slag)		1,2-3,0
Secondary (slag)		800

It should be noted that in construction the size of the fraction is very important when performing calculations of consumables. Also, this indicator is important when performing calculations in cargo transportation. The table shows that the higher the bulk density in the natural state, the smaller size particles. So, by weight, 1 m3 of crushed granite corresponds to 2.6 tons. During transportation, it is poured into the body of a truck or wagon, where the crushed stone is in its natural state, forming voids between the particles. At the same time, the higher the fraction of the material, the more air is between the pebbles. Dolomite particles are heavier, so the true density of 1 m3 varies from 2.7 to 2.9 tons. Specific gravity calculated in laboratory conditions on special equipment. After that, the mass of 1 m3 of crushed stone is calculated. The data is entered into a table, with the help of which, knowing the type of material and its fraction, you can easily convert weight into volume and vice versa.

Crushed stone is a product of crushing rocks of various densities. Belongs to the category of bulk materials. To calculate the number of kilograms in one cubic meter, you need to take into account its type and technical characteristics.

How many kg of crushed stone in a cube

By origin, gravel happens, and. All components are different:

density, on which the strength of raw materials depends;
volumetric weight, which is equal to the volume of unground rock.
bulk density, as the ratio of total weight to volume in its natural form;
fraction size affecting tonnage;
the shape of the granules - flakiness;
the degree of moisture absorption, depending on the type and size of the grains.

Granite is the leader in terms of strength and density - up to t2600 kg/m3. The bulk volume of gravel and granite is almost the same - up to 1300-1400 kg / m3. Limestone has the lowest rates.

All specifications are specified by the manufacturer. Knowing them, you can calculate how much rubble in 1m3. For this you need:

density x fullness x water absorption coefficient.

For example, a cube of granite crushed stone with a density of 2600 kg / m3, a fraction of 5-20 mm, a fullness of 57%, a moisture absorption of 1.1 weighs 1347 kg.

The table will help you understand:

How many cubes of rubble in a cube of concrete

Concrete consists of several components - water and plasticizers. Gravel or granite crushed stone, sand or sand, small and are used as fillers. The mixture is classified by brand, for the manufacture of which certain proportions of all components are taken. For example, for one M100 cube, 200 kg of cement will be required. In order not to count how much crushed stone is needed manually, there are special tables with proportions for the product in demand.

If there are no such tables at hand, in order to calculate the amount of crushed stone, they proceed from the average consumption. To make one cubic meter mixtures take 0.7 m3 of gravel. A cube of granite weighs about 1400 kg. So you need to take at least 1 ton of rubble.

To prepare the solution, you can use a simplified scheme:

per part of cement - 0.5 parts of water, 4 parts of crushed stone, 2 parts of sand.

With this ratio, for one cube of solution, approximately:

330 kg cement mixture;
180 liters of water;
600 kg of sand;
1250 kg of gravel.

This method is used when factory grade accuracy is not required.

How much crushed stone in KAMAZ

For the delivery of bulk materials, machines of various carrying capacities are used. To calculate the amount that will enter KAMAZ, you need to divide the carrying capacity by the density of crushed stone indicated in the manufacturer's specifications. For example, at a density of 1300 kg/m3, enters the machine:

7.7 tons - 5.9 cubic meters (7700: 1300);
15 tons - 11.5;

25 t - 19.

In addition, take into account the volume of the body, which will show the maximum allowable load. It is usually less than the received indicator. The higher the bulk density of the material, the less it will fit in the machine.

Thus, when choosing, the load capacity of the dump truck, the density of the crushed stone, its moisture content (since the weight depends on it), the fraction that affects the bulk density are taken into account.

If the rubble has already been brought to construction site, you can check its weight. To do this, before unloading, you need to measure the height, width, length of the car body and multiply the values. So we find out the volume of cargo in cubic meters. Taking into account the fact that a couple of cubes still fit from the sides, they can be added to the result. The found value will show whether the weight corresponds to the declared and paid.

Crushed stone is obtained by crushing rocks, followed by sieving. Such a crushed stone - important element construction. The quality of any produced concrete depends on the technical characteristics of the crushed stone used. Its main indicator is the specific gravity, which determines the ratio of the mass of raw materials to the volume filled by them.

This parameter is taken into account when calculating the amount of material used in construction. The bulk density is also determined - the mass in the natural uncompacted state. It is characterized both by the volume of individual crushed stone stones and the space between them and is used in calculating the composition of the concrete mix. The more air, the lower the density. Having a rough surface, crushed stone adheres very tightly to a solution of cement and sand, forming a monolithic composition. Thanks to this indicator, the stone small sizes is an excellent filler.

Specific gravity (SG) depends on density and fractions. The larger the stones, the stronger the solution will be. In the production of concrete, fractions are needed various forms and dimensions because the purpose building mixtures can be different: production reinforced concrete products and ceilings, arrangement of foundations for buildings and structures, three-dimensional structures. When mixing the mortar, you need to know that the higher the bulk density value, the less cement consumption will be.

In addition, the weight of crushed stone depends on storage conditions. Each rock has its own porosity and water absorption, therefore, if there are few pores in a stone, the less water it absorbs and, therefore, is less prone to subsidence. The HC value must be taken into account when transporting building material. Knowing the volume and specific gravity of crushed stone, you can calculate the amount of transport needed and its carrying capacity.

Characteristics and operational properties of crushed limestone

The highest quality and most expensive is crushed stone obtained from rocks that contain calcium carbonate, and various impurities reduce its hardness. Possessing high resistance to temperature changes and having sufficient strength and frost resistance, it is environmentally friendly. pure material. If the percentage of impurities included in the composition is relatively small, the color of the crushed stone will be reddish, yellow or brown.

The flakiness of crushed stone (the presence of lamellar and needle-shaped forms) is not more than 10-15%, which is a good indicator of its operational characteristics. This means that there are very few voids in the mixture, so the amount of binder used will be much less.

When determining the specific gravity of crushed limestone, you need to know that this is a bulk density of 1 m3. This parameter takes into account the density of hard grains and the air contained in the composition. GOST 8267-93 "Crushed stone and gravel from dense rocks for construction work" regulates the main characteristics of this type of crushed stone:

Limestone crushed stone is produced in three fractions:

Fraction 5-20 mm - fine grinding is used in the production of lime, small reinforced concrete structures, roadway with a slight throughput, building mixtures, building cladding;
20-40 mm - medium crushing, used more often than other fractions. Found application in the bay of the foundation, the manufacture of reinforced concrete products, roads with heavy traffic;
40-70 mm - a large fraction is used very rarely. Ballast bed and gravel pads are the main area of use.

The main characteristics and properties of crushed granite

This gravel is very durable and often used construction material. It is obtained by crushing rocks. He is rated according to the quality of his fractions, the larger it is, the cheaper the gravel itself. An important characteristic is the specific gravity of crushed granite. To do preliminary calculations quantity required material for production, it is better to take the weight of gravel in a dry state, it is also called bulk mass. The average value of the weight of a cubic meter of crushed stone is 1.6 tons.

The presence of needle and flat particles reduces the compaction density, which leads to a decrease in hardness pavement and concrete structures. Therefore, the lower the flakiness, the higher the quality of the material, the less will be the consumption of cement or other binder component. In this type of gravel, it is 5-23%, depending on the size of the fraction.

Fraction 5-20 mm - the most popular type and high price. Used in the manufacture of industrial concrete, road surfaces and areas of industrial complexes.
20-40 mm - ideal for creating highways, erection of embankments for railway tracks, tram lines, in the production of reinforced concrete products, the construction of buildings and structures for various purposes.
Crushed stone with a fraction of 40-70 mm is a frequently used gravel with a low price. It is used as a semi-finished product for the production of crushed stone with a finer composition.

The table shows the HC data (t / m3) of the two main types of crushed stone by fractions:

Fraction size, mm	Limestone	granite
5-20	1.37	1.34 – 1.37
20-40	1.41	1.37 – 1.4
40-70	1.47	1.4 – 1.5

Dolomite crushed stone, as well as granite, has high strength, frost resistance and a low degree of moisture absorption. When calculating the specific gravity, it should be remembered that this characteristic refers to its volumetric mass or weight of 1 m3.

Due to its low radioactivity, it is used not only for pouring foundations and other external works, and for interior decoration buildings, lime production and landscape design. The various impurities contained in dolomite gravel give the gravel different colors, which is especially appreciated in facing works. It is resistant to temperature extremes, impact resistant and environmentally friendly. The density coefficient is lower than that of granite and its consumption during use is less. Rough edges and increased binding properties increase the adhesion of pebbles. Composition by dimensions in mm: 5-10; 10-20; 20-40; 40-70. The average fraction of dolomite has high performance, therefore, it is more often used for the production of asphalt and high-quality concrete.

The specific gravity of crushed stone 20-40 is one of the main characteristics of this bulk material, which allows you to correctly calculate the ratio of its weight to volume. This faction is the most sought after construction market, since it is used as widely as possible and there are several reasons why you need to know how many cubes of crushed stone 20-40 are in a ton.

Determining the amount of material for your construction purposes

Firstly, knowing how much a cube of crushed stone with a fraction of 20-40 weighs, you can calculate the tonnage of the material delivered by the supplier. Construction companies, carry out the sale of crushed stone, starting from its cost per 1 ton (per 1 cubic meter). Therefore, for the calculation it is enough to know the cubic capacity of the cargo compartment of the car. If the supplier has made a large underweight, it can be determined even by eye, looking into the body.

Secondly, having information about the number of tons in a cube of crushed stone 20-40, it is easiest to calculate how many special equipment, taking into account its carrying capacity, will be required to transport this material, as well as how much space it will take after unloading. This The best way rationalize your own costs.

Thirdly, the volumetric weight of crushed stone 20-40 is necessarily taken into account in some areas of operation of this non-metallic material. Particular emphasis should be placed on the production concrete mixtures, where two technical characteristics of crushed stone are especially important - its density and flakiness. It is possible to determine them based on the volumetric weight of the material.

About specific numbers

There are several types of crushed stone, with different technical specifications(gravel, limestone, secondary, granite, slag). But traditionally, granite rock is used to determine the weight of a cube of crushed stone 20-40, as the highest quality (in terms of technical properties).

The weight of 1 cube of crushed granite is 1.35 tons.

For the purchase of crushed stone in St. Petersburg and throughout Leningrad region you can always contact our specialists. We will help you accurately calculate the weight of 1 m3 of crushed stone fraction 20 40 and make all other necessary calculations to perform construction work, as well as carry out its prompt delivery of goods. You can also take out the material yourself.