Composition of concrete for the foundation: proportions per 1m3. Concrete for foundation: composition

The most demanded material in construction is concrete. Without it you can neither build a house nor build a path. Concrete - a very strong durable material, and if it strengthen reinforcement, then strength and service life increase at times.

The foundation of any structure is the foundation, which bears not only the weight of the entire building, but also wind and snow loads. The harder it is, the higher and bigger the building can be.

There are several types of foundations: monolithic reinforced concrete, pile, prefabricated reinforced concrete.

Composition of concrete mixture

In individual construction, one of the most popular types of foundation is tape monolithic. It is simple in execution, allows you to do without special equipment and mix concrete for the foundation yourself. Proportion - the composition of the components in the mixture and their ratio. Its violation will lead to spoilage of the material. Instead of a strong and durable concrete, you can get a weak design, subject to rapid destruction.

A special role is played by the composition of concrete for the foundation. The proportions of the constituent components for the mixture must be kept very accurately.

To get quality concrete, it is necessary and fillers to use good. The composition of the mixture includes sand, cement, gravel or crushed stone and water.

Sand

It can be natural or artificial. The particle size varies from 1.2 to 3.5 mm. Sand should not contain any impurities such as clay, silt and others, so to achieve purity of the material, it must be sifted and washed. When working in winter conditions, sand should be heated. Add a frozen filler to the concrete inadmissible.

Gravel or crushed stone

These inert materials are the main constituent of the concrete mix. Their quantity in concrete should be about 80%. The fraction size is used from 5 to 70 mm (depending on the work performed). These fillers are also washed from foreign impurities.

Cement

This is the main component that is part of the concrete for the foundation, its proportions in the mixture must be maintained with special care. On this depends the quality, strength, as well as the brand of concrete. Usually Portland cement M300 or M400 is used for foundations, which is characterized by frost resistance and a fast set of strength. A higher brand is more expensive and is used in small responsible structures.

To get high-quality concrete for the foundation, the proportion, the composition of the components included in the mixture is maintained exactly.

Shelf life of cement is small. When buying, you need to look at the production date of the material. It is better to take cement, made no later than 1-2 months ago. With improper storage, it has the ability to collect moisture and quickly grasp. But in a dry room it is not recommended to store it for a long time. The longer the cement lies, the lower its brand becomes, and, accordingly, there will be more consumption and lower strength.

So, storage of material within 6 months will reduce the brand by 25%, for the year - by 40%, and for two years the brand will decrease by half. That is, the M400 will produce the M200, which is only fit for the paths in the garden.

Water

This is the main binder component that is part of the concrete for the foundation. The proportions of water and other fillers are calculated taking into account the density of the concrete. For hard concrete, it should be less, and for a plastic one - more.

The interaction of water and cement triggers a chemical reaction to solidify concrete. This is a very important process, the structural strength directly depends on it. A significant role is played by water quality, no impurities such as oil, fat, acids, sulfates are permissible here. All this will break the process of setting concrete. Do not use marsh or waste water. In work it is better to take a drink.

What and how much do you need

In individual construction, the proportions of concrete for the foundation have long been determined. The optimum composition of the mixture is one part of cement, three parts of sand and four parts of rubble (1/3/4). Water is poured individually. If the formwork is heavily reinforced, then for better penetration into the carcass the concrete becomes more plastic, if not, then it can be made rigid, this will harden more quickly, its strength will be higher.

It is necessary to immediately decide for what purposes the production of concrete is required. If it is a path in the garden, then for them enough concrete M100, then the cement needs only 1/11 part. If it is a foundation or other responsible structures, the cement in the mixture should be ¼ of the total mass.

When it is necessary to issue a certain amount and composition of concrete for the foundation, the proportions for 1m3 are taken as follows:

• The sand is 0.395 m3.
• Gravel - 0.87 m3.
• Cement - 0,193 m3.
• Water - 0,179 m3.

This is the consumption of inert and binding materials for M200 concrete, if a higher brand is needed, the amount of cement is increased.

There is such a thing as water-cement ratio, on it depends the operational characteristics and quality of the mixture, and, accordingly, the whole structure.

If the water is added more than normal, the plasticity of the concrete will increase, it will be easier to fit into the formwork, but the mark will decrease, more time will be required for grasping.

Adding a smaller volume of water will lead to an increase in the rigidity of the concrete, making it more difficult to lay, and in heavily reinforced structures, voids can emerge, leading to a weakening of the entire monolithic tape. Therefore, it is necessary to vary the amount of water to yield a better mixture.

In short, in order to obtain a good composition of concrete for the foundation, the proportions of water and cement should be such that the mixture in the formwork is laid, rather than poured. The laid concrete must be tampered with, it is done either with a special electric vibrator or with improvised tools - shovel, reinforcement.

Production of concrete in a concrete mixer

For the convenience of concreting monolithic structures, there are a large number of types of mixers. They can be a capacity for a half-cubes, one cubic meter, one and a half cubic meters or more.

How to make concrete for a foundation? The proportions for one mix of a cube mixer are approximately the following:

• Sand - 650 kg (density - 1400 kg / m3);
• Crushed stone - 1300 kg (density - 1350 / m3);
• Cement - 300 - 350 kg (approximately 6-7 bags);
• Water - 180 kg.

The output is concrete M300 (the numbers indicate that a sample of 10x10 cm cube made of concrete of this brand can withstand a compression force of 300 kg / cm2).

At the enterprises for making concrete use a sand-gravel mixture, in which the ratio of gravel and sand is already maintained in the right proportions.

Since all fillers have almost the same bulk density, it is possible to measure the composition of concrete for the foundation with buckets. The proportions in the buckets will be: cement - 25, sand m 43, crushed stone - 90, water - 18.

25 buckets of cement - this is approximately 6-7 bags (calculation for 1 m3 of finished concrete). For a small concrete mixer, a bucket of binder is taken:

• Sand - two buckets;
• Crushed stone or gravel - four buckets;
• Water - half a bucket.

You can choose the proportions of aggregates so that the concrete of the same brand will turn out, but the cement content in it will be different.

Calculation of the required quantity and composition of concrete

In the construction drawings issued for work, the volume and weight of all materials used are indicated. In individual construction, if there is no project, the calculation is made independently. It is important to choose the right concrete for the foundation. How to calculate it so as not to miss?

First, you need to determine how much concrete you need for the whole volume of construction. It is necessary to measure the length of the entire foundation along the perimeter. Each side is counted separately. For example: the length of the tape - 10 meters linear, height - 1 m, width - 0.5 m. Multiply, it turns out that the filling of this side of the foundation requires 5 m3 of concrete. Also calculate the volume of the other parties. After summing up all the sums, we get, for example, 20 m3 of the mixture.

Example: for 20 m3 of finished concrete M300 it is necessary:

• Cement - 7000 kg;
• Sand - 13000 kg;
• Crushed stone or gravel - 26000 kg;
• Water - 3600 kg.

Some recommendations for laying concrete

Calculating the volume of concrete for foundation pouring, it is necessary to add 10-15 percent more to the received mass for unforeseen expenses, losses during transportation, stacking, etc. Fill concrete in the formwork with layers of 25-30 centimeters each, with obligatory tamping. The second and subsequent layers are recommended to vibrate or pierce with a shovel, reinforcement with the gripping of the previous one so that the stratification of the structure does not occur.

If the day did not manage to lay the concrete in the entire foundation, then from the previous layer with a metal brush it is necessary to remove the cement film. This is done for better subsequent adhesion of old and new concrete. Grout is recommended to do on a fresh surface, when the concrete lightly grabbed, but still completely not frozen. All the sludge obtained from the grouting of the film must be removed.