Concrete for blind area: main classes, brands and cooking

Any foundation for a structure needs protection against erosion, therefore an additional barrier is created around it from a mixture based on cement, gravel and sand. It can not only prolong the durability of the structure, but also improve the aesthetic characteristics. In the process, the device will have to find out which concrete is needed for the blind area, which also functions as a walkway.

About the material used

Hardened mixture is an artificial stone, which is widely distributed in the construction industry. Modern binder-based material has been used since 1844. Over time, its composition began to appear special additives that improve performance.

Applicable Classes

The basic indicator characterizing the composition is the compressive strength, which allows us to assign the prepared mixture to a specific category. When carrying out work, it is necessary to select the class of concrete for a blind area, so that its strength characteristics fit the specific operating conditions.

Directly in SNiP 2.03.01-84, the designation of categories is used by the Latin letter “B”, next to which stands a figure reflecting the pressure carried in MPa. However, the composition class is a numerical characteristic with a guaranteed security of 0.95. Thus, in 5 cases out of 100 the condition may not be fulfilled.

Note! Knowing the class of suitable composition, it is easy to understand what brand of concrete is needed for the blind area. The table reflects the correspondences with the coefficient of variation of the strength characteristics of a concrete mix 13.5%.

More about brands

Simultaneously with the classes, the strength of the mixture can be set differently. The letter "M" of the Latin alphabet with a number indicates the maximum value for compression in kgf / cm ?.

The grade of concrete for the blind area must not be lower than the M200, otherwise damage to the created platform may occur.

• M200 - the main purpose of the composition is to create structures with a small load on the surface.
• M250 – смесь может использоваться для сооружений, которые подвергаются воздействиям средней степени.
• M300 – самая распространенная марка бетона для отмостки, так как позволяет выдерживать довольно ощутимые нагрузки.
• M350 – подобный раствор для устройства защитного барьера вокруг здания используется редко.

Attention! The price of the composition increases with increasing brand, so in order to save, it is recommended to select it as accurately as possible, taking into account possible loads on the surface.

Core Component Requirements

All materials included in the concrete for the pavement must meet certain conditions, otherwise it will not be possible to achieve high-quality mixture.

In this regard, the service life of the structure can be significantly reduced.

• The base ingredient is cement, which binds the components together. The main task is to choose the right brand of binder. The presence of impurities must also be taken into account.
• For the preparation of the mixture is recommended to use sand, a fraction of which ranges from 1.5 to 5 mm. The presence of impurities in the form of construction debris and plant residues may adversely affect the strength characteristics of the solution.
• The best aggregate is crushed rock material, which provides high-quality adhesion with other components. Suitable gravel sizes range from 8 to 35 mm.
• The solvent used is ordinary water, but it should not contain alkaline and acidic inclusions.

Addition! Some experts add slaked lime to the mix to make it easier to lay. With this option, the alignment of the surface is facilitated.

Solution preparation process

В процессе работ чаще всего применяется состав M300, относящийся к классу B22,5. Поэтому стоит рассмотреть именного его приготовление. Далее приводится инструкция для получения смеси без бетономешалки.

It shows the basic proportions of concrete for the blind area.

1. 2 buckets of sand are poured into the prepared container so that a small slide is obtained..
2. A bucket of cement M400 is added, after which the two components are thoroughly mixed in dry form..
3. Gradually water is poured into the composition., the amount of which is usually 0.5 mass of the binder.
4. After mixing, 4 buckets of gravel aggregate are introduced into the liquid mixture..

Note! Carrying out the mixing of the concrete composition with your own hands, you can not add too much water, otherwise the porosity will be very high, and this will lead to a decrease in strength properties.

Additional recommendations

• If, after solidification of the mixture, it is necessary to separate a fragment of the blind area, then the reinforced concrete is cut with diamond circles.
• Fill the finished composition should be carried out within a day, until he grabbed, otherwise notches are made.
• To insert pipes or other elements in the frozen concrete mortar, diamond drilling of holes in concrete is performed.
• If the blind area is made in the cold season, it is mandatory to warm the solution.

As a conclusion

Preparation of concrete composition should be carried out taking into account the provisions of SNiP 5.01.23-83 and GOST 7473-94. The documents presented reflect the general rules that take into account the density and ratio of materials. More detailed information on this topic is presented in the video in this article.