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Consumption of materials per 1 m3 of concrete: optimal proportion, features of calculation and recommendations

At a construction site of any level, from a skyscraper to a summer cottage, you can not do without concrete. This material is used for pouring foundations, erecting walls in monolithic construction, installing ceilings and screeds, laying bricks and other artificial stone. The preparation of concrete in the correct proportion not only ensures the durability and strength of the structures, but also avoids unnecessary costs for materials.

Composition of concrete

In the simplest case, concrete consists of three components:

  • Binder.
  • Aggregate.
  • Water.

Consumption of materials per 1 m3 of concrete is determined by the properties of these materials. As a binder in the production of the mixture used cements M100-M600 in strength. When mixed with water, a viscous mass is formed, upon solidification of which an artificial stone is formed. As a filler, sand or various types of rubble are used. This increases the strength of the frozen solution, since the strength of the rubble is higher than the strength of the cement. In addition, the use of aggregate reduces the shrinkage of the cement mixture.

In addition to the main constituents, various additives are added to the concrete to give the solution additional properties: frost resistance, water resistance, color, etc.

The required consumption of materials per 1m3 of concrete - crushed stone, cement, sand - is determined based on the requirements for the characteristics of the mixture.

Basic characteristics of concrete

The most important characteristic of concrete is its compressive strength. Depending on it, a strength class is established. Denoted by the English letter "B" and numbers corresponding to the strength of the sample in MPa. Concrete grades from В3,5 to В80 are produced, in civil engineering the most suitable solutions are В15 - В30. In addition to classes, a stamp may be used to indicate strength. Denoted by the Latin letter "M" and the number corresponding to the strength in kg / cm square. Classes and brands are quite accurately correlated, for example, solution M200 corresponds to class B15, and M300 to class B22.5.

Consumption of materials per 1 m3 of concrete can vary significantly depending on the required grade or grade of solution.

It should be noted that the actual class of concrete is determined only in laboratory conditions on day 28. Therefore, if it is necessary to know exactly the brand of the mixture, several samples, cubes or cylinders 100 mm high, should be poured at the stage of its preparation. It is possible to determine the strength of concrete by the instrument method or the Kashkarov hammer, but these methods are less precise.

Select the required class of concrete

The required brand of concrete should be indicated in the design documentation for the construction site. In case the construction is carried out independently, it is necessary to determine the brand of the mixture, since this will have a decisive effect on the strength and cost of the erected building or structure.

Appointment of concretes of the most common brands is given below.

  • M100 - it is used for the device of the concrete, installation of parebrikov, small architectural forms;
  • M150 - is used for the installation of tracks, fixing the supports of fences;
  • M200 - for the erection of walls, fenders;
  • M250 - production of monolithic foundations, grillage, foundation slabs, low-loaded slabs, ladders, retaining walls ;
  • M300 - for any loaded structures: walls, ceilings, foundations;
  • M350 - bearing walls, columns, ceilings, beams, monolithic foundations.

Sand parameters

To prepare the solution used sand of various origins: quarry or river. The second is more preferable, since it has a larger granule size and does not contain impurities. The quarry sand may differ in its granulometric composition. It is preferable to use sand with medium and coarse granule size. Since quarry sand may have clay or other impurities in its composition, it is recommended to sift it.

It is very important to pay attention to the humidity of the sand. Depending on this, the amount of water added to the mixture should be adjusted. Taking into account the humidity and granulometric composition, the density of bulk sand can vary from 1.3 to 1.9 t / m3 cube, this should be taken into account when calculating the consumption of materials per 1 m3 of concrete.

Choice of rubble

Crushed stone in the concrete mix increases the strength of concrete and reduces its shrinkage when it solidifies. When choosing rubble, its faction and origin are most important.

In construction, gravel is used in fractions:

  • From 5 to 20 mm;
  • From 20 to 40 mm;
  • From 40 to 70 mm.

Depending on the raw material, crushed stone is classified into:

  • Limestone, based on sedimentary rocks.
  • Gravel of rolled up debris of rocks.
  • Granite, obtained by crushing granite and granite-gneiss rocks.

Granite crushed stone has the best parameters for strength, so if concrete is prepared for responsible structures - foundations, columns, floors, it is better to use it. We must not forget that the rubble used should not contain impurities, especially clays.

Water-cement ratio

In the production of concrete, the primary importance is the ratio of cement and water. Water is necessary for the chemical reaction of cement hydration, leading to the formation of cement stone. This ratio determines the class of the concrete mixture to a decisive degree. It is important to consider the cement brand. The lower the water-cement ratio, the stronger the concrete. The minimum ratio necessary for cementing cement is 0.2. In practice, concretes with a water-to-cement ratio of 0.3 to 0.5 are used. Mixtures with a large water-cement ratio are practically not used.

Determination of the proportions of the concrete mixture

As a rule, for the preparation of concrete, Cement M400 and M500 are used. In practice, the following table is used to determine cement consumption per 1m3 of concrete.

Concrete grade Cement consumption of M500 grade, kg / m3
M100 180
M150 210
M200 250
M250 310
M300 360
M400 410
M500 455

These data are given for conditions with normal temperature and humidity, as well as for cement, the parameters of which correspond to those indicated on the package. In real life, a surplus of cement 10-15% should be envisaged.

Then, according to the known amount of cement, the consumption of materials per 1m3 of concrete is calculated, the optimum proportion of cement to sand and gravel is given in the table.

Concrete Proportion of cement, sand and gravel
Brand M400 Brand M500
M100 T1: P3.9: N5.9 P1: P5,1: Щ6,9
M150 Ц1: П3.0: Щ4.9 Ц1: П4,0: Щ5,7
M200 T1: P2.3: N4.0 Ц1: П3,0: Щ4,7
M250 P1: P1.7: S3.3 T1: P2,3: N3.3,8
M300 T1: A1.5: N3.1 T1: P2,0: N3.5
M400 P1: P1.1: S2.4 N1: N1,3: N2,6
M450 T1: P 1.0: N2.0 C1: П1,2: Щ2,3

For example, the consumption of materials per 1 m3 of M200 concrete will be: cement of the M500 grade - 240 kg, sand - 576 kg, crushed stone - 984 kg, water - 120 liters.

Production of concrete

For large volumes of concrete work, it is advisable to buy ready-mixed concrete at a nearby factory with a mixer delivery. In the conditions of industrial production, the norms of consumption of materials per 1 m3 of concrete are kept quite strictly. If this is not possible, you can prepare the necessary amount of the mixture and at home. It is important to properly assess their capabilities - concreting of a separate structure must be done in one run.

Before mixing the mixture, determine the consumption of materials per 1m3 of concrete. Calculation of the consumption rate of components is not necessary, it is enough to use the table below.

Brand of produced raskor Composition of the mixture, kg
Cement M400 Crushed stone Sand Water, l
M75 173 1085 946 210
M100 212 1082 871 213
M150 237 1075 856 215
M200 290 1069 794 215
M250 336 1061 751 220
M300 385 1050 706 225

The mixture is prepared in a concrete mixer of the appropriate volume, laying in it the measured portions of dry cement, sifted sand and gravel. It is recommended to add water in portions last.

Additives

In addition to the main components, additives for various purposes are added to the concrete:

  • Modifiers . Designed to increase the strength and increase the frost resistance of concrete.
  • Plasticizers . Increase the mobility and water resistance of the mixture.
  • Mobility regulators. Allow to extend the setting time, keep mobility during transportation.
  • Antifreeze additives. Provide a normal setting of the solution at negative temperatures, down to minus 20 degrees.
  • Accelerators of grasping. Increase the setting speed ensuring the fastest strength set in the first day.

When using additives, the consumption of materials per 1 m3 of concrete should be determined taking into account the manufacturer's recommendations. Violation of the instructions for use can have quite the opposite effect.

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