The proportion of concrete: numbers and factors, their

What affects the density (it is - specific gravity) of concrete? What does it depend on? What, for example, is the specific gravity of concrete M200? What are the density values ​​characteristic of cellular and lightweight concrete? Let's figure it out.

Why do you need it

And in fact - why this information?

There are several reasons for curiosity.

• The calculation of the foundation for a monolithic or frame-monolithic structure is tied to the bearing capacity of the soil and the total mass of the structure. Knowing the total volume of the frame, walls and floors, their weight can be calculated only with a known density.
• When assessing the load on the bearing reinforced concrete structures have to take into account their own weight.
• Finally, when transporting reinforced concrete structures (wall panels, floor slabs, beams, etc.), it is advisable to at least roughly estimate their mass in order to choose the appropriate type of transport and loading equipment.

Specify: for standard products, the calculation is usually not required. Information about the dimensions and weight of the structure is provided by the seller.

Factors

What factors determine the specific density of concrete?

1. First of all - the type and amount of aggregate. It is obvious that the proportion of 1 m3 of concrete with crushed granite and quartz sand will be greater than that of claydite-concrete or a mixture of perlite sand. What are concrete types of aggregate?

1. For cellular concrete, an equally important factor is the degree of porosity, the number of pores in the volume of material.

1. Finally, the class (strength mark) also has a certain effect on the density. Quite predictably - because the class of concrete is determined by the ratio of its components, which differ in physical characteristics.

Numbers

In order to calculate the mass of the structure with your own hands, it is necessary to calculate its volume and multiply it by the density. The instruction is simple; however, it implies that density is known to us.

Above were given the boundaries of values ​​for concrete of different types. Let's specify them for each case, using several independent sources of information.

Filler Types

In SNiP 2.03.01-84, dedicated to concrete and reinforced concrete structures, along with a large list of other reference values, the specific weight of concrete for different aggregates is given.

The list in the document, however, does not contain references to some fairly common types of filling.

We hurry to fill the gap:

• Pumice - 800 - 1600 kg / m3.
• Volcanic slag - 800 - 1600 kg / m3.
• Shungizite - 1000 - 1400 kg / m3.
• Perlite - 600 - 1200 kg / m3.
• Granulated blast furnace slag - 1200 - 1800 kg / m3.
• Fuel (boiler) slag - 1000-1800 kg / m3.
• Ash gravel - 1000 - 1400 kg / m3.
• Vermiculite - 300 - 800 kg / m3.

Please note: the variation in the parameters is associated with both the different percentage ratio of the binder with the aggregate and the non-constant physical characteristics of the materials themselves. For example, the density of vermiculite, swelling when heated, depends on the degree of its heat treatment.

Strength mark

As already mentioned, the strength mark is related to density, and nonlinearly. It increases with increasing binder content; up to a certain limit, an increase in the mark contributes to the compaction of the material and an increase in the specific gravity.

However, cement stone is lighter than rock minerals; that is why, after the brand M350, a further increase in compressive strength leads to a drop in the density of concrete.

Cellular concrete

How to find out the density of foam or aerated concrete?

The main factor determining it (and at the same time the thermal insulation properties and strength of the material) is the degree of porisation. The type of mineral filler has virtually no effect on specific gravity.

Captain Evidence suggests: the brand of cellular concrete in density corresponds to the weight of a cubic meter of material in kilograms. So, D600 aerated concrete has a density of 600 kg / m3.

Universal method

How to find out the density of any material with unknown composition and other characteristics?

1. Weigh the construction fragment.
2. We immerse it in water (for example, in a full bucket with a basin inserted under it).
3. In any way (even liter cans), we measure the volume of the displaced fluid.

1. We recalculate the volume in cubic meters (1000 liters in one cubic meter).
2. We divide the mass of the fragment in kilograms by its volume in cubic meters. The result will be the actual density of the material.

Conclusion

We hope that the materials and reference data offered to the reader will be useful. The video in this article, as usual, contains additional thematic information. Successes!