How to choose and prepare concrete for the foundation

Monolithic bases began to enjoy high popularity in individual construction, due to their seamless structure. When preparing concrete for the foundation with your own hands, it is necessary to take into account several factors at once, so that the construction lasts as long as possible.

With regard to the economic side of the issue, immediately before the work must be carried out accurate calculations.

You do not know how to make a choice?

Before you create a concrete foundation, you should understand what kind of structure it will be used for. First of all, the manufacturing material should be chosen, since the mass of modern products for construction can vary greatly. For example, for brick structures will require a more massive base than in the case of wooden structures.

Component Requirements

Technical conditions for heavy compounds, which are used for the construction of reliable foundations, are reflected in the paragraphs of GOST 26633-91, therefore, it is recommended that you first familiarize yourself with them.

The following are the most important points regarding the basic components of a concrete mortar.

• В качестве вяжущих веществ должны применяться портландцементы M400-600, шлакопортландцементы или сульфатостойкие аналоги M300-500. Выбор марки осуществляется в зависимости от назначения конструкции, класса приготавливаемого состава, а также требований водонепроницаемости и морозостойкости.
• Fine aggregate often acts natural sand. It is selected taking into account the grain composition, radiation-hygienic characteristics, as well as the content of clay and dust particles. The average density of particles should vary between 2000-2800 g / m3.
• Large aggregate is gravel, crushed stone from dense rocks or ferrous metallurgy waste. The permissible content of weak grains in the solution is given in the table.

Note! When concrete is prepared on the foundation, the correct ratio of water and binder is of particular importance. To determine the amount of fluid mass of cement divided by two.

Mix classes used

В ходе заливки оснований для жилых индивидуальных объектов применяются тяжелые составы, которые отличаются высокими прочностными характеристиками. Однако чаще всего используется диапазон классов от B15 до Sell ​​0. Далее приводится их сфера применения и соотношение с марками растворов, близкими по параметрам.

Note! After reviewing the tabular data, you can easily select the class of concrete for the foundation. However, along with this, it is necessary to take into account the indicators of frost resistance and water resistance.

Calculate the numbers

Непосредственно перед закладкой основания производятся определенные расчеты, позволяющие определить количество используемых материалов. Для наглядного примера рассматриваются вычисления для ленточной полосы размером 5×6 м: высота – 70 см, толщина – 45 см.

Scope of construction

To find out the cubature of the base, it is necessary to divide it into separate parallelepipeds, and then make calculations for each of them. The results should be added.

As a result, it will be possible to find out how much concrete is needed on the foundation.

1. The first thing is the volume of two long sides.. Для этого находится произведение длины, ширины и высоты: 6×0,7×0,45×2=3,78 м3.
2. Then the cubic capacity of short bars is determined.. При этом удвоенная толщина основания вычитается: (5-0,9)x0,45×0,7×2=2,583?2,58 м3.
3. Now it remains only to add the results that were obtained in the previous paragraphs: 3.78 + 2.58 = 6.36 m3.

Attention! Considering how much a cube of concrete costs for a foundation, it is desirable to carry out all calculations as accurately as possible. Otherwise, the total cost of the design may increase significantly.

Amount of materials

Before finding out the consumption of the materials used, it is necessary to determine the brand of the building mixture, since the proportions can vary significantly depending on the specific situation. In our case, concrete M200 is used for the foundation for a small structure, so all calculations are given for it.

The ratio of cement, sand and gravel when using the M400 binder is as follows: 1-2.8-4.8.

1. First, all the shares presented above are added together so that it is possible to determine the amount of each material separately: 1 + 2.8 + 4.8 = 8.6.
2. Now you can find out how much cement per cubic basement concrete will be needed, as well as the content of other components: 1 / 8.6? 0.12 m3 of cement, 2.8 / 8.6? 0.33 m3 of sand, 4.8 / 8 , 6? 0,56 m gravel.
3. На последнем этапе объем каждого материала умножается на кубатуру конструкции: 0,12×6,36=0,76 м3 вяжущего вещества, 0,33×6,36?2,1 м3 мелкого заполнителя, 0,56×6,36?3,56 м3 крупного заполнителя.

Addition! Based on the above calculations, you can easily determine how much 1 cubic meter of concrete is for the foundation, because the number of materials used is already known.

Concrete in a few "steps": the cooking process

In the manufacture of building composition manually, you need an airtight container made of wood or metal and a shovel for loading components and their subsequent mixing. Along with this, it is necessary to prepare some measuring container, for example, a bucket.

First, a certain amount of binder is poured into the mixing container, after which fine aggregate is added - natural or artificial sand. The two components are thoroughly mixed in dry form. It should get a monotonous composition.

The dry mixture is diluted with clean water without impurities. Its amount depends on the mass of added cement. In most cases, the ratio of 0.5 kg to the total weight of the binder is maintained, but the proportions can be slightly changed, if circumstances so require.

After pre-filling with water, coarse aggregate (gravel or crushed stone) is introduced into the solution to the extent that it suggests concrete for the foundation of one or another class. Insufficient mixing can cause a decrease in the strength properties of the composition.

After the solution is prepared, its mobility can be determined by applying a special cone-shaped tube pattern. This item is placed on a flat platform, which was filled with fresh concrete.

After a short period of time, the cone is removed, and its immersion level is measured by a tape measure. The results are presented in the table.

A small amount of water somewhat complicates the laying of the solution in the formwork, as it increases the rigidity. However, the strength characteristics of such a composition increase significantly. Therefore, in the preparation process, you will have to choose between technological capabilities and qualitative characteristics.

Finally

When the concrete slab for the foundation is made, it is necessary to select the class of building mixture correctly and carry out its preparation. Therefore, to help individual developers, this instruction was given (learn here how to make concrete for the foundation).

For more information, see the video in this article.