Specific gravity of crushed stone. Specific gravity of building crushed stone

When performing many types of repair or construction work the use of crushed stone is required. To be able to use it for specific purposes, crushed stone is produced in different fractions. Small size material is used in decorative purposes, a large fraction is needed when constructing important heavy objects.

The average fractional size is 20-40. Crushed granite of this size is the most in demand. For its production, quartz diorite or granite is used.

Material composition

Granite is considered the hardest rock found on our planet. Due to their special strength, materials made from granite, including crushed stone, are used where objects under construction will be subject to heavy loads during operation. And since granite rock is widespread in almost all countries, the cost of materials made from it remains affordable and popular.

The color of the materials depends on what minerals granite contains, but it usually ranges from red to gray. If small amounts of dark-colored minerals are ingested, the material may have a mottled appearance.

Material advantages

Fraction 20-40 - crushed granite stone, which is considered the best filler for the construction industry. Thanks to its use, you can easily fill out necessary forms, saving, and quite significantly, expensive concrete mixtures. Since granite grains have a rough, crushed shape, excellent grip components, which ensures excellent adhesion of the material.

When compared with fractions of other sizes, it is the medium grains that are produced at the lowest labor costs, which guarantees the most affordable cost of the material.

Properties

Performance indicators depend on the following properties:

1. Fraction 20-40 is granite crushed stone, which has the highest wear resistance and compression.
2. The material is able to withstand an infinite number of freezing/thawing without collapsing.
3. The presence of low flakiness. There are few grains in the total mass, which have needle-like and flat shapes, so crushed stone is easily compacted in bulk structures and mortars.
4. The density of granite crushed stone 20-40 depends on the rock from which it was made. For example, a cube of granite material weighs about 1370-1400 kg, limestone - 1280, gabbro-diabase - 1440 kg.
5. Slight porosity. The almost complete absence of pores contributes to high throughput and low moisture absorption coefficient.
6. Low radioactivity. This quality is very important because it allows the material to be used in the construction of residential, commercial, public and industrial buildings. This number also includes kindergartens, schools, and hospitals.

Compliance with GOST

For crushed granite 20-40 GOST number 8267-93 determines the following indicators:

• 5-23% flakiness;
• the composition should not contain more than 0.5% of grain 5 mm and more than 10% of fractions whose size is less than 20 mm.
• clay dust should not exceed 0.3%;
• 1000-1400 mark strength;
• weight of 1 m3 of granite crushed stone 20-40 - 1.35 tons;
• presence of lumps of clay - maximum 0.25%;
• the presence of particles of weak rocks - no more than 5%;
• volumetric mass size is about 2.7 g/cm 3 ;
• wear resistance - indicator I1.
• percentage of water absorption - maximum 0.4%.

In addition, the material must have the following properties:

1. The frost resistance index is F300.
2. The level of radioactivity should not exceed 370 bq/kg.

When determining product quality, assessment occurs based on these and other characteristics of crushed stone.

Scope of application

Crushed granite has chemical and physical properties that provide the material with excellent performance characteristics. The scope of its application is determined by the grain size.

Fraction 20-40 - crushed granite stone, which is used:

1. In concrete solutions.
2. During the construction of reinforced concrete structures.
3. During the laying of foundations.
4. As a bulk mass for the base of an asphalt road.
5. To strengthen or level roads.
6. When arranging parking lots for cars.
7. For the production of temporary sites where construction equipment will be placed.
8. During the construction of tracks for tram transport.
9. To harden the surface under railway routes.

Purchase Features

This is not about the acquisition process itself, but about the choice of material. The most important thing is that the material meets all the declared characteristics, and this is only possible when it meets the requirements of GOST. But are the characteristics described in this state document really important? What happens if the crushed stone does not meet the above GOST requirements?

As practice confirms, any changes will lead to a deterioration in quality. For example, if there are more flat grains in the total mass than prescribed, the concrete obtained using them will be of lower quality, and the amount of concrete mixture will need to be increased, which leads to an increase in monetary costs.

If crushed granite stone 20-40 weighs less (or more) than necessary, it means that it contains grains of other fractions. So, the greater the weight, the greater the number of small grains in the total mass and vice versa: large particles take up more space, so such crushed stone will weigh less.

Therefore, in order not to purchase a material that will not have the required characteristics, when purchasing, you must make sure that you have a certificate, a sanitary-epidemiological report, hygienic characteristics of the product and its passport.

When choosing building materials It is very important to avoid both extremes - large balances in warehouses and, naturally, shortages of material at the most crucial moment. At the same time, very often the calculation of the required quantity can be very approximate, based on average data.

So, for example, knowing how much crushed stone in a cube of concrete is needed for its production, you need to order a certain number of tons of this material. But crushed stone is sold in cubic meters and you are faced with the task of determining how many tons of crushed stone are in 1 m3 of purchased material.

A rough estimate can be made based on the tables. Table 1 shows the bulk density of granite crushed stone of various fractions.

Table 1

Table 2 shows the density of limestone crushed stone of various fractions.

table 2

These are averaged data, but the weight of 1 m3 of crushed stone can be more accurately determined taking into account its properties.

Characteristics of crushed stone affecting its bulk density

The technology for the production of crushed stone, which is the crushing of rocks, causes its heterogeneous structure. The main factors determining the specific gravity of crushed stone are:

• source rock (granite, limestone)
• water absorption;
• flakiness;
• crushed stone fraction;

The breed factor is easy to track using the tables above. Thus, limestone crushed stone of fraction 20 40 has a density of 1.31 t/m3, and granite crushed stone of the same fraction has a density of 1.37 t/m3. The flakiness of the crushed stone also plays an important role. The needle and plate shapes imply a larger number of voids and, accordingly, lower density. The cuboid shape indicates higher density. The scope of its application also depends on the density of the material. Hollow crushed stone is suitable for creating a cushion, while material with a flakiness of less than 15% is advisable to use for dense backfill.

Water absorption (the amount of moisture absorbed by a material) directly affects mass. Depending on the porosity, the error can reach 10%, introducing errors into the measurements. And the last factor is the fraction of the material. The smaller the grain size, the higher the specific gravity of crushed stone.

Determine how many tons of crushed stone are in a cube of concrete

It is possible to determine exactly how much crushed stone in a cube of concrete only if you have documentation for the material containing accurate information. The recalculation process itself consists of multiplying the density of the material (granite, limestone) by the fill level. So, with crushed stone filling of 56% and granite density of 2600 kg/cub.m. we get:

2600*0.56=1456 kg/cu.m. m. or 1.45 tons per cubic meter.

There is no problem with reverse calculation when it is necessary to determine how many cubes are in a ton of crushed stone. In the above case, 1/1.45 = 0.68 m3.

As mentioned above, the bulk density of crushed stone indicated in the tables represents an average value. Therefore, having previously determined from the table how many tons of crushed stone are in 1 m3, use the following tips:

• Do not rush to order the exact amount of material. Flakiness, fractionation and water absorption can change the weight by 5-10%. Crushed stone is purchased, as a rule, with a reserve of 10 - 20% of the required quantity.
• If the demand for material is large, it is best to order in two or more stages. This will allow you to minimize leftovers and accurately calculate the required amount depending on practical consumption indicators.
• When ordering and transporting by road, you should proceed from the fact that on average a MAZ dump truck can fit 6 m3 of crushed stone, and a KamAZ dump truck can fit 12 m3 of this bulk material.

In general, wholesale purchases of building materials, including crushed stone, are more profitable and safer to make from large suppliers, ideally from manufacturers of this material. This way you can be confident in the quality, the possibility of regular delivery in the volumes you require and, most importantly, the availability of certificates and accompanying documentation.

Specific gravity 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 fraction is the most in demand in the construction market, as it is used as widely as possible and there are several reasons why you need to know how many cubes of crushed stone are 20-40 per ton.

Determining the amount of material for your construction purposes

Firstly, knowing how much a cube of crushed stone of fraction 20-40 weighs, you can calculate the tonnage of material delivered by the supplier. Construction companies sell crushed stone based on its cost per 1 ton (per 1 cubic meter). Therefore, for the calculation it is enough to find out 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 20-40 tons of crushed stone per cube, it is easiest to calculate how much special equipment, taking into account its carrying capacity, will be required to transport this material, as well as how much space it will take up 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 manufacturing concrete mixtures, where two are especially important specifications crushed stone - its density and flakiness. They can be determined based on the volumetric weight of the material.

About specific numbers

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

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

To purchase crushed stone in St. Petersburg and the entire Leningrad region, you can always contact our specialists. We will help you accurately calculate the weight of 1 m3 of crushed stone of fraction 20 40 and do all the other necessary calculations to carry out construction work, and also carry out prompt delivery of goods. You can also remove the material yourself.

Crushed stone is a material of natural origin, actively used in construction for filling roads, all kinds of sites, paving, and pouring various objects with concrete.

It is a bulk building material that is usually sold by weight. Regardless of the scale of the work being carried out, in order to ensure a sufficient amount of this material at the construction site, it is necessary to calculate in advance the volume of supplies, namely the amount of crushed stone in tons.

How to find out how many kilograms are in a cube of crushed stone?

To find out how much material is needed to fill an area of ​​a certain area, proceed according to the following algorithm:

1. decide on the thickness of the layer;
2. knowing the area of ​​the site and the height of the backfill, calculate the volume of the embankment in cubic meters;
3. Knowing how much crushed stone is in 1 m3, calculate the weight of the required batch.

But it's not that simple. The fact is that reliable calculations can be made only taking into account the characteristics of the material. Let's try to figure out what exactly can affect the weight of a cubic meter of rubble.

Factors affecting the specific gravity of crushed stone

Crushed stone is obtained from rocks by crushing them, so the properties various types rubble can vary significantly.

The most important characteristics that can affect the specific gravity of crushed stone are:

Type of rock used as the main material for the production of crushed stone;
place and conditions of production;
storage conditions;
the size of the fraction obtained as a result of crushing;
crushed stone form;
water absorption of the material of manufacture;
humidity.

Depending on the properties of the manufacturing material, the weight of a cubic meter can differ by hundreds of kilograms. Compare the weight of crushed stone from various materials can be done using the following data on the number of tons in one cubic meter (t/m3):

Granite – 1.32-1.39
natural – 1.35
color – 1.7
sandstone – 1.3
construction – 1.36
from natural stone – 1,24-1,53
concrete – 1.7
limestone – 1.26-1.32
dolomite – 1.3
gravel – 1.32-1.45
slag – 1.0-1.5
marble – 1.5
marble according to GOST 8267-93 - 2.65
quartzite – 1.55-1.75
brick – 1.25-1.275
tuff – 0.8
from light shell rock - 0.6-1.8
rubble – 1.4-1.6
from ceramic batt - 1.2-1.35
expanded clay – 0.25-0.6
aerated concrete – 0.4-0.6
chalk – 1.2

This is not the whole list of materials used for the production of crushed stone. Using similar tables given in reference books and on specialized websites, you can find out approximate data on how many kg of crushed stone are in a cube. But it should be understood that these data are very approximate. The value in each specific case may vary depending on the fraction, shape, porosity and moisture content of the material.

The size and shape of the rubble affect the filling of the volume. For example, cube-shaped crushed stone has a high degree of compaction, while lamellar and needle-shaped types of crushed stone form many voids, which means the weight of such material will be lower in comparison with other types.

Water absorption of crushed stone is a property of the manufacturing material, which depends on the number and size of pores. Depending on this, dry or wet material will have a different weight. The higher the water absorption value, the greater this difference will be.

The size of the fraction also makes its own adjustments to the calculations. A cubic meter of finer crushed stone will weigh more than similar material crushed into large pieces.

Principles for accurately calculating the weight of a batch of crushed stone

An exact answer to the question of how many m3 in a ton of crushed stone can only be found if you have information about the material specified in GOST for its manufacture or accompanying documentation for the batch.

When calculating the weight of a batch, data on the properties of crushed stone are used, such as
average density,
voidness of the fraction,
fullness,
bulk density.

The calculation procedure will be as follows:
1. knowing the emptiness of a particular fraction, they find fullness;
2. Multiplying the fullness by the average density to find the bulk density.
3. Knowing the bulk density, find the number of tons of crushed stone contained in a batch of a certain volume.
Let's try to calculate the weight of a batch of granite crushed stone with a volume of 5 cubic meters.

1. With a void fraction of 5-20 mm equal to 43%, the fullness will be 57%.

2. Then, with an average density of granite crushed stone of 2,600 t/m3, the bulk density can be found as follows:

2.600*0.57=1.482 kg/m3.

3. This means that for backfilling with a volume of 5 m3 you will need

1.482*5=7.410 tons of material.

If the bulk density is indicated in the accompanying documentation, it is even easier to find the weight of the batch. To do this, simply multiply the bulk density value by the volume in cubic meters.

Often, average bulk density values ​​are used in calculations. A certain error depends on the ability of the material to absorb moisture, compaction during transportation or storage, and the shape of the crushed stone. That is why in accurate calculations a correction factor of 1.1 or 1.2 is used, depending on the properties of the material and its storage conditions.

Accurate calculations are used for serious construction work and the use of large volumes of crushed stone. For private construction, the above-mentioned characteristics of the material, and especially the correction factors, are rarely taken into account. You can always clarify the bulk density and approximate weight of a cubic meter of crushed stone from specialists when placing an order for delivery of the material. How many kg are there in a cube of crushed stone?

Crushed stone of fraction 40-70 is one of the universal natural building materials that can be used independently and as a component in the production of, for example, concrete. Such crushed stone is mined in quarries and may have different nature and the corresponding name by origin: granite, limestone, gravel. There are significant differences between these types in technical, physical characteristics, cost.

Regardless of the type, this building material remains one of the most popular in construction and manufacturing. It is constantly and in large quantities used in the manufacture of concrete, reinforced concrete products, when carrying out various kinds of dumping (building roads, building foundations). The demand for crushed stone of fraction 40-70 serves as an indicator general condition economy: it increases when it rises and falls when it stagnates.

Physical characteristics and properties of crushed stone

The main thing that the consumer pays attention to when ordering crushed stone of fraction 40-70: technical characteristics, compaction coefficient, specific gravity, price. The characteristics include such indicators as strength (hardness), flakiness, abrasion, frost resistance and radioactivity. These technical characteristics of crushed stone fraction 40-70 are obtained in the laboratory by conducting appropriate research and measurements on special equipment.

Strength properties directly determine the grade of crushed stone, which corresponds to the magnitude of the breaking pressure. For granite crushed stones it is in the range 800-1600 kgf/cm2(corresponding grades of crushed stone from M800 to M1600). Crushed gravel of a lower grade - about M800. Crushed limestone is even less durable - grades from M600 to M800.

The price of crushed stone largely depends on the brand, so the required building material is selected based on strength requirements. Granite crushed stone is considered the most expensive, limestone is the cheapest, gravel is in the middle position. The price of crushed stone also depends on its fraction. When producing crushed stone of fraction 40-70, less labor is required, therefore its cost is lower in comparison with other types.

Volumetric characteristics of crushed stone

The compaction coefficient characterizes the property of any bulk material to decrease in volume during transportation and the shaking caused by it. These include crushed stone. For fraction 40-70 compaction factor averages 1,3 – that is, when transporting such crushed stone, its bulk volume can decrease by approximately 1.3 times. This indicator is important to take into account when loading dump truck bodies - if the load capacity allows, it is allowed to ship with a small slide.

Since bulk building materials are shipped in volumetric quantities, you need to know how much a cube of crushed stone of fraction 40-70 weighs. This is important so as not to overload the dump truck in weight (to avoid emergency situation). For this purpose, a quantitative characteristic such as specific gravity of crushed stone 40-70. This parameter shows how much mass of building material is in 1 cubic meter of volume. For granite crushed stone 40-70 it is approximately 1400-1500 kg/m3, for limestone - approximately 1470 kg/m3.

The density of crushed stone of fraction 40-70 should not be confused with specific gravity. Density is physical quantity showing the mass of a single piece of stone with a volume of 1 cubic meter. It is higher for a single piece than the specific gravity of crushed stone, since the entire volume is completely filled, and is 2600 kg/m3 for granite, 2700-2900 kg/m3 for limestone.