Density of fine sand t m3. Sand density. Sand and gravel
The average density of sand is an important indicator on which operational properties substances and future parameters of the concrete building mixture, the strength and stability of buildings, as well as the possible consumption of raw materials. It shows how much sand is contained in one unit of volume, which is taken as cubic meter(1 m3).
The amount of a substance that fits in 1 m3 strongly depends on the type of sand - for example, fine building sand is more dense than medium-sized sand, since in the first case the gaps between the individual particles of the building material are much smaller, and a large mass fits into one cubic meter.
This parameter is closely related to such material indicators as voidness and moisture, the degree of compaction and porosity. The features and correctness of the measurement of parameters can also introduce a certain error into the final result. There is the following relationship between these factors: the greater the void between the particles and the moisture content of the substance, the smaller the bulk characteristic and the less pure sand fits in a cubic meter. This rule identical for humidity, but with the opposite sign - due to the adhesion of fractions, the wet building material is compacted.
Also, the density depends on the structure of the grains, with a decrease in the size of which grows this characteristic, and also on the content of clay and other impurities. For the above reasons, the density of river sand is usually higher (average coefficient 1.5) than that of purified sand (for construction, the ratio is 1.4).
What varieties are found?
Density in kg / m3 is an ambiguous characteristic that has two main varieties that differ in definition, some features and methods of measurement:
- True. It is the ratio of body weight (in this case dry sand) to its volume and is measured in kg/m3. This does not take into account free voids between individual particles, that is, we are talking about the density of the material in a compressed state. True density (like any other substance) is a constant value.
- Bulk density. An indicator that takes into account not only the volume of the substance itself, as in the previous case, but also all the existing gaps between the particles. Bulk is always less than the true and average density, measured in kg / m3.
There is also an average value, which has already been mentioned above.
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As mentioned earlier, the density varies greatly depending on the properties of the raw material. Help trace given fact called the following table:
Thus, one cubic meter of dry sand will have a mass of 1200 to 1700 kilograms, and a cube of wet sand will have a mass of 1920.
The table does not reflect all types - a more extended list with the coefficients necessary to calculate the density of raw materials can be found in reference sources.
In order to measure the density, the following methods are used on site:
- Apply conversion factors that differ for each type of material. This method is not entirely accurate, since the measurement error can reach 5%. At large quantities raw materials loss is not one cubic meter!
- Weighing bulk raw materials (for example, river) together with a vessel completely filled with it, after which the calculation is made by dividing the mass of sand by the volume of the vessel.
Definition bulk density plays an important role in construction, since the number of cubes of raw materials necessary for the work largely depends on its value. This is especially important in cases where every cubic meter counts.
Almost no construction is complete without the use of sand. This is, in essence, versatile material, extracted from various deposits and, accordingly, having different characteristics(density, humidity, etc.) and names: dune, river, sea, quarry.
Below we will talk about the last type of sand from the above list.
What is quarry sand?
This is one of the most common types sand used in various fields– construction, road works, landscaping and other areas.
It is extracted from the bowels of the earth by developing quarries, the location of which determines the structure, composition and fraction of the material.
In this case, the building material does not shrink, and the finished one is characterized by mobility and elasticity.
Kinds
According to the processing method to which the product is subjected after mining, sand is also divided into several types.
Alluvial - mined from flooded deposits using hydromechanical equipment for this. This processing method allows you to remove third-party impurities and components from the sand and, as a result, obtain a pure high-quality product.
It is used for the production of mortar and bricks, as well as in the arrangement of roads and in the manufacture of reinforced concrete products.
Seeded - the material is sifted through special equipment equipped with a system of sieves and cells. During the cleaning process, clay particles, dust and small stones are separated from the sand. As a result, the material is freed from foreign impurities and large fractions.
Can be used for cooking mortars and mixtures.
Ground sand is an unrefined product containing foreign components (up to 40%). The material has a low cost and is more suitable for rough procedures - alignment land plots and filling trenches.
Density
There are several types of material under consideration.
But the most useful are two types:
- true;
- bulk.
The true density of a material is the density of the grains of sand themselves.
When determining the true density, the amount of air between the grains, which can be 35-40% of the total volume, as well as the density of dust particles and clay components, is not taken into account.
It follows that the true density is always greater (1.5-1.9 times) than the bulk density. According to technical requirements specified in GOST 8736-2014, this parameter should be 2-2.8 g/cm3.
Density determination
Possible ways, their essence, necessary fixtures and tools for measuring procedures are designated in GOST 8735-88. The same standard specifies the stages of test actions and methods for processing the received data.
The bulk density of the material is determined by weighing it in special cylindrical metal containers.
For this, vessels with a volume of 1 dm3 and 10 dm3 are used. A small container is used for weighing dry and sifted sand, a larger one is used for unsifted material of natural moisture.
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Empty and filled vessels are weighed, after which the bulk density is calculated using the formula. To perform calculation procedures in everyday life, a ten-liter bucket is used, where sand is poured “with top” from a small height (about 10 cm).
After that, the “hill” is removed, comparing the material with the edge of the bucket, the sand remaining in it is weighed and the net weight in kilograms is found out, without capacity. The resulting figure is divided by 0.01 m3, thanks to which it is possible to calculate the bulk density of sand or the weight of 1 m3 of product in tons.
The true density of sand grains is determined in the laboratory by one of two methods:
- pincometric method - using a pincometer (special glass container);
- accelerated method, in which the Le Chalier device is used - glass vessel with a funnel-shaped top and a scale on the neck.
For more information about determining the density of pitch, see the video:
Characteristics
In addition to density, there are other characteristics, by which the properties of sand can be evaluated:
- the presence of foreign impurities. They should be as small as possible in the material. Thus, the allowable content of organic components is 3%, and sulfur and sulfides - up to 1%;
- humidity. It depends on the mass of sand. The wetter the material, the greater the weight, and vice versa. According to the standards, this parameter should not exceed 7%;
- the level of radioactivity (depending on the deposits). Material with a high degree of radioactivity cannot be used in residential construction;
- coefficient . This refers to the ability of the material to pass water. In quarry sand, this figure is 0.5-0.7 meters per day.
- coefficient ;
Conclusion
Summing up, we can say that quarry sand is a product that can be used in the most various fields: agricultural industry, road construction and building construction, for the preparation of solutions and decoration of suburban areas.
At the same time, the material has an acceptable price, which is also the reason why it is worth giving preference to it.
Density is represented by a physical quantity characterized by a certain amount of a substance, expressed in grams or kilograms, per unit volume. This indicator, characteristic of bulk substances, including sand, cannot be unambiguously determined. This is due to the fact that the volume in which the same amount can fit can be different. The indicator is influenced by several factors, among them:
- degree of tamping;
- humidity percentage;
- fraction structure;
- porosity;
- all kinds of inclusions.
Density Level Determination
The density of sand acts as the main parameter, the level of which determines the scope of its application and the final strength of buildings and structures. The described characteristic is required to calculate the consumption of sand when it is necessary to obtain a certain volume of building mixture.
In addition, in some cases it becomes necessary to convert the mass of sand into volume or vice versa. If it is necessary to determine the mass of 1 m 3 of sand or calculate the volume of a ton of the mentioned material, then the following steps must be taken.
The density of sand or any other material can be determined by dividing the mass (M) by the volume (V) that was occupied by it. So, ρ=M/V. The mass of material that occupies a certain volume can be determined using the following formula: M=ρ*V. But the volume can be calculated if the exponent ρ and mass are known. So, the volume is determined by the formula: V \u003d M / ρ.
In the preparation of mortars, mixtures and in the construction of structures based on concrete, sand should be used in a given proportion in relation to the rest of the components. In order to correctly determine the proportion of sand in these mixtures or structures, it will be necessary to know exactly what its density index is.
If you make calculations with an error, then the amount of sand in the total volume will be insufficient or excessive. If you make up for the lack of sand, then most likely you will have to do this at the expense of more expensive components, which will lead to an unjustified rise in the cost of the entire mixture. Whereas if the amount of sand turned out to be greater in the volume of the mixture, this will cause a decrease in the quality of the products or solution. Due to this, frost resistance, abrasion resistance and water resistance will suffer, as a result, the master will receive products or designs whose characteristics will differ from those provided by the standard.
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Types of indicator ρ
Sand is characterized by some types of density, among them: true, bulk and average.
On fig. 1 is a table in which you can see the bulk density of sand in different states. If we consider this material, then it is represented by a solid rock of non-metallic origin. This explains the fact that it has an indicator approximately equal to 2500 kg / m 3. This indicator is the true density. If it is necessary to make calculations for use in practice, another indicator should be used - bulk. It characterizes building materials in an unpacked form and is calculated taking into account the volume of grains and the hollow space that remains between them. This leads to the fact that the level of bulk density in all cases is less than the true one. But when tamping a material that is in a loose state, it is possible to increase its level ρ. So, if the material is in the body of the car, then it has a natural, unpacked state and a bulk level is characteristic of it. If this value is known, then it is possible to determine the volume and mass of the material. This is important, because the cost of transporting building materials can be calculated not only by weight, but also per 1 m 3 of volume.
The density of sand, which is in bulk, is 1300-1500 kg/m 3 . The level of humidity of the external air can affect the volume of the material, this entails variations in the level of bulk density. If the humidity becomes greater, then this entails a decrease in the level ρ of the material. This is due to the adhesion of grains. The decrease in this level can last until the humidity reaches 10%. After that, moisture particles entail an increase in the volume of liquid in the building material, while the level ρ begins to rise. This feature of the change in the indicator under consideration should be taken into account if the dosage is by volume.
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Bulk level calculation ρ
In order to calculate the density of the grains in the bulk state, the material must be sieved in advance using a sieve with a mesh size of 5 mm. After that, it must be placed in a measuring vessel of 1 liter. At the same time, it must be freely filled from a height of 10 cm, forming a cone above the vessel, which must be cut off using a ruler. You need to know how much the vessel weighs in an empty and filled state. It is permissible to calculate the bulk level using the formula: ρн=(m2-m1)/V. In it, m1 and m2 are the masses of the vessel in an empty and filled state, while V is its volume. The table may not be needed, since all calculations can be done independently.
The level of the average index ρ is influenced by voids and humidity. There is a dependence: with fewer pores, this figure is higher. It can be assumed that ρ characterizes the fractional composition.
Its average level varies for certain types of sand. Dry material based on quartz in its natural state has a density index in the range of 1500-1550 kg/m 3 , while in the compacted state this level is 1600-1700 kg/m 3 . This indicates that the average density index is determined by the structure of the fractional composition.
If you need to produce concrete that will have the qualities of high strength and resistance to frost, then you should use a material that has an increased average density.
During construction, you can use the data of the tables, but you should be aware that in a loose state, the quartz material has ρ in the range of 1500 kg / m 3, but the level can reach 1700 kg / m 3.
In order to determine the bulk density, you can use not only the measurement method that was described above. By the way, an ordinary construction bucket can also be used as a vessel. These calculations will allow you to get the closest to the true result. If you use a bucket, then you can use a scoop to pour the material.
When calculating the volume, several important indicators are taken into account, one of them is the density of the sand. The operational properties of the prepared mixture for a particular building object and its main parameters are influenced by the bulk density of sand (average). In the price list of IdealTrade, prices are indicated in rubles per m3, therefore, knowing the average density of sand (kg / m3), one can estimate the costs of construction in general.
Factors affecting the formation of density
From one of physical characteristics sand, its degree of density, depends on what volume will occupy the same amount by weight. Sand density, kg/m3, depends on the following criteria:
- , i.e. - grain sizes: fine-grained sand fractions are denser, larger ones have a smaller size.
- and porosity of the material: this criterion shows the volume of voids in the bulk material. The reduction in friability is due to several factors, such as: dynamic effects and vibrations, moisture saturation, pressing, etc.
Sand density, kg/m3 is shown in the table:
- Moisture indicators - the bulk density of sand (kg per m3) is formed based on the conditions of humidity: with its growth to 10%, the volume increases in proportion to the decrease in density; with moisture saturation up to 20%, air is displaced by water and the weight of one cubic meter increases. The density of river sand, kg m3, judging by the data in the table, is higher than similar materials.
- Impurity content: the presence of particles of dust, clay, mica, crushed stone, gypsum, stone chips, etc. necessarily affect the characteristics and properties of the bulk material. Alluvial (cleaned with water) sand becomes much cleaner and a little more expensive.
Our advantages
In the company "IdealTrade" - a pro in the market of non-metallic materials - all resources comply with GOST standards, as we constantly monitor product quality.
Construction or repair work often produced using different sand-cement mortars prepared by yourself. The quality of any mixture depends on the condition of its components. If for cement all parameters are known, then with sand the situation is more complicated. The density of dry sand is an important parameter that largely determines the quality and consistency of the solution. The ability to calculate this value is as necessary for the builder as the ability to calculate the amount of materials.
Why is it necessary to determine the density of dry sand
Types of sand
Sand is a dry bulk material, which is a finely crushed rock. The size of the fraction ranges from 0.05 to 5 mm, which creates problems in the calculations. Compound building mixtures requires fairly accurate proportions, otherwise the strength of the materials will not meet the requirements of SNiP.
Determining the density of sand in practice is very difficult task. The gaps between individual sand grains are almost impossible to measure, since the shape of the sand grains obtained by various conditions crushing rocks, has a complex and irregular configuration. Between the corners and faces of individual particles there may be gaps that are much larger than the gaps between natural sand grains, whose shape is closer to spherical.
Dry sand of natural origin (river) has a denser structure, so the use of the same volume of material different origin or fraction size will give mixtures that differ from each other in their parameters. Therefore, it is very important to have the most correct knowledge of all parameters of the mixture components, the mass of the material, its density and other indicators.
The main types and parameters of sand
The complexity in the definition forced the introduction of the concept of bulk density of sand, which determines the amount of mass per unit volume. There are three types of density:
- True. This is an indicator of extremely compressed sand that does not have voids between grains.
- Bulk. Value in weighted and dry form.
- Average. This value takes into account the presence of moisture and the porous structure of the grain. The average density is higher than the bulk density, but less than the true one.
Humidity is one of the most important factors that constantly change the condition and bulk density. Sand is stored, as a rule, in the open air, as a result of which the degree of humidity begins to depend on weather conditions. The compositions of all mortars assume the presence of dry material, and the sand in the mixture has other than ideal parameters. The change in density forces the use of compaction factors that correct the value that dry sand has.
The most common options correction factors indicated in the table:
The average density of the sand is multiplied by the compaction factor, and the result is a value close to the real one. However, it is necessary to take into account the presence of an error (about 5%) arising from the impossibility of establishing the correction value for each specific case with absolute accuracy. A more accurate result is given by the weighing method, but under conditions construction site it is not available, so calculated indicators are most often used.
Sand Density Calculation
Self-calculation of indicators can be performed by weighing. To do this, you need a scale or a steelyard for 20–25 kg, a dry container (you can use a regular bucket). The procedure is as follows:
- An empty container (tare) is weighed, the result is recorded separately.
- The container is completely filled with sand. The best option- fall asleep with a slide, then carefully remove the excess with a flat bar and leave it flush with the edges.
- The full capacity is weighed.
- The tare weight is subtracted from the value obtained.
- The resulting value is divided by the volume of containers, the result is converted into standard units - kg / m 3.
More accurate indicators can be obtained by weighing several times, collecting material from different areas. It must be remembered that building sand stored in conditions that do not allow maintaining the same degree of humidity, so you should use it as soon as possible, or periodically re-measure and adjust the calculations.
Bulk density values for different types of sand
Sand mined in different places, has a different structure, composition and fraction size. In order to correctly calculate the number of components in different mixtures or concrete, it is necessary to take into account the value of the bulk density of sand of one kind or another.
| View | Mining method | Density of dry material (bulk) | |
| g/cm 3 | kg / m 3 | ||
| River | Mined from the bottom of the river | 1,5–1,52 | 1500–1520 |
| River with a grain size of 1.6–1.8 | 1,5 | 1500 | |
| River compacted | Washed, without clay fractions | 1,59 | 1590 |
| River alluvial | Extracted from the bottom of the river by alluvial method | 1,65 | 1650 |
| Career | From quarries, alluvial | 1,50 | 1500 |
| Quarry, fine-grained | Seeded, dry | 1,7–1,8 | 1700–1800 |
| Building | Corresponds to GOST 8736-93. Produced during the development of deposits | 1,68 | 1680 |
| Loose | 1,44 | 1440 | |
| Quartz | Obtained as a result of crushing white quartz | 1,4–1,9 | 1400–1900 |
| Nautical | Mined from the bottom of the sea | 1,62 | 1,62 |
| ravine | mined open way, may contain many impurities | 1,4 | 1400 |
| gravelly | With a mixture of gravel | 1,7–1,9 | 1700–1900 |
| pearlite | Obtained on the basis of expanded rocks | 0,075–0,4 | 75–400 |
| slag | Obtained as a result of crushing screening of metallurgical waste | 0,7–1,2 | 700–1200 |
The indicated values are valid for dry raw materials, therefore, when calculating, it will be necessary to take into account the real state and use compaction factors. If they are neglected, then there will be an excessive consumption, and the composition of the solution or concrete will be changed, which can reduce the strength of the pour or connection of building structures.
