Proportions of concrete mixture components for the foundation. Concrete with your own hands: how to correctly calculate the proportions for its production The ratio of the components of concrete for the foundation

Composition: water, cement, sand and gravel/crushed stone. Proportions: if you count 10 kilograms, then cement - 10 kg, sand - 30 kg, gravel or crushed stone - 40-50 kg. To make concrete grade M300 or M400, you need half as much water as the weight of the other components. Example: in this case, you get 80-90 kg of dry mixture (cement (M500/M600) + sand + gravel/crushed stone), which means 40-45 liters of water are needed. If the solution is too thick, dilute with water. It's best to stick to a consistency that allows the concrete to be mixed with a shovel, but still requires some effort (and so that the solution doesn't flow off the shovel too quickly or easily).

Damp sand also contains moisture. Either dry it or subtract a few liters of water. Also check the sand for cleanliness. The cleaner it is, the better the adhesion in solution.

Use crushed stone or gravel of a small fraction (1-2 cm, no more).

Do not buy cement long before construction. It quickly absorbs moisture and deteriorates. It is better 1-2 weeks before preparing the concrete mixture.

It is advisable to pour any foundation in the warm season. In cold weather, you have to heat the water and solution so that it does not start to set earlier. Otherwise, it will lose a lot of strength, because it will not be firmly connected to the reinforcement and will not be compacted.

How to prepare concrete for a strip foundation

It is better to count each line (ribbon) of the foundation separately, and then add everything up. The length of the tape is multiplied by the height, then by the width. Let’s say one foundation strip has the following dimensions: length – 10 m, height – 1 m, width – 0.5 m. This turns out to be 5 m 3 of concrete per strip.

If you count each tape along its full length (from corner to corner), it turns out that the volume of each corner is counted twice. This is necessary, since it is better to make more concrete than required. The foundation pit is never perfectly smooth.

It is advisable to pour concrete into the formwork in layers. For example, if the height of the foundation is 1 m, then you can concrete it in 4 layers of 25 cm each. When pouring each layer, it is advisable to compact it with a vibrator or at least tapping it with a hammer/shovel. After pouring each layer, you need to release the air from it by sticking reinforcement every 1-3 m (not very quickly). Also, each layer of concrete must be leveled with a board. For clarity, the height of each layer can be marked in the formwork.

The calculation, preparation and pouring of concrete into the grillage is carried out in the same way.

How to prepare concrete for a slab foundation

Dimensions: length and width 10 meters each, height 25 centimeters. 10 times 10 times 0.25. Total: 25 cubic meters of concrete for a slab monolithic foundation.
The slab foundation must be compacted on every square meter of area. Since this type of foundation is a solid area, all the concrete must be poured at once. After filling, it is better to do the leveling starting from the smaller side of the perimeter and move in a snake towards the opposite side. For leveling, you need a wide board with a handle for convenience. Be sure to release air in many places.

How to prepare concrete for a columnar foundation

Concrete for a columnar foundation is calculated using the volume formula, poured all at once and compacted, followed by puncturing the mixture to release air.

Preparation of concrete for pile-rammed foundation

Compared to columnar foundations, only the calculation formula for cylindrical columns of cast-in-place piles changes. You need to multiply the height by the radius squared and by the number “Pi” (3.14). Calculation example: multiply the height of 1 m by 0.0625 (radius 0.25 m2) and multiply by 3.14. It turns out 0.19, rounded to 0.2 cubic meters. This is a calculation for one pile column.

After pouring any foundation, you need to cover it with a protective film from precipitation. On the day of pouring, pour plenty of water over the foundation at night, otherwise in the morning it may develop small cracks, because the top layer dries out quickly. For the first week, moisten the foundation every few hours. From the second week you can do it once a day.

Concrete is one of the most commonly used building materials. Only a properly prepared mixture provides good strength indicators and is able to cope with its initial tasks.

Optimal proportions of concrete

During the manufacturing process of concrete, the composition, or rather the proportions of the main components, is determined by its original purpose. Some brands of concrete cannot be used in the construction of foundations due to their weak strength.

The general proportions for high-quality concrete look like this:

10 kg of cement;
30 kg of sand;
40-50 kg of gravel or crushed stone to choose from.

To recreate concrete mixtures, for example, grade M300 or M400, the total weight of all components must be twice the weight of the water used. Thus, in standard proportions, 80-90 kg of dry mixture is used, which will require 40-45 liters of clean water.

If, when making concrete with your own hands, the solution turns out to be too dense, you should add a little liquid to achieve the right look. It is extremely important that the solution has a high viscosity, otherwise the mixture can be considered spoiled.

The resulting mixture, in consistency, should be easy to mix with a shovel, but also require some effort. (see photo above)

It is worth noting that wet sand contains a certain amount of liquid. In order not to spoil the cement mortar, you should first dry the sand or subtract a few liters of water. Also, you should not leave sand in buckets for a long time so that it does not become saturated with moisture from the air.

Popular brands of concrete for foundations

Each individual type of foundation has its own brand. This marking, in turn, determines the strength of the mortar, which is extremely important in construction work. The most commonly used and suitable for foundations are M200 and M300 solutions.

It is important to note that it is often impossible to calculate the exact proportions of the mixture down to units. This is due to many different factors, for example, due to monthly storage, the dry mixture can lose up to 10% of its original strength, in 3 months up to 20%, and in six months up to 30%. Such structural changes occur due to moisture in the air, which gradually mixes with the mixture, making it less suitable for use.

The greatest savings can be achieved by using low-grade cement, but the resulting concrete should only be used for small structures.

Each type of concrete requires a unique ratio of components, taking into account the brand of cement. In this case, the amount of liquid, in most cases, is calculated in accordance with half the mass of the dry mixture in kg.

To produce M200 concrete mortar using M400 cement, you need to follow the following proportions:

1 part cement;
2.8 parts sand;
4.8 parts crushed stone or gravel.

When using M500 cement, concrete has the following proportions:

1 part cement;
3.5 parts sand;
5.6 parts crushed stone or gravel.

The amount of liquid used directly depends on the required consistency. Most often, when creating such concrete, less than 50% liquid is required. M200 concrete mortar is used in the construction of small buildings, for example, one-story country houses.

M300 concrete mortar is most often used to create a foundation. When making it using M400 cement, you need to adhere to the following proportions:

1 part cement;
1.9 part sand;
3.7 parts gravel or crushed stone.

For M300 mortar with M500 cement you need to use:

1 part cement;
2.4 parts sand;
4.3 parts crushed stone or gravel.

It is best to take the minimum amount of liquid for this solution, since the strength of the future foundation directly depends on the viscosity of the mixture. Concrete M300 is recommended for use in the construction of foundations for massive buildings. For example, such a mixture is often used in the construction of country cottages and some city buildings.

Proportions for a concrete mixer

The use of a concrete mixer during the construction process is only reasonable if you need to cover an area exceeding 100 m2. Otherwise, it is best to use a bucket or some suitable container and knead by hand.

The production of concrete must be carried out taking into account the approximate hardening time of the foundation, in order to have time to use the entire mixture before it dries completely. At the same time, on average, laying 1.5-2 m 3 of concrete needs to be completed in 2-3 hours.

When creating concrete in a concrete mixer, you must adhere to the following proportions: 1 part cement, 3 parts sand and 5 parts gravel or crushed stone. For example, for a 180 liter concrete mixer you need:

2 buckets of cement;
6 buckets of sand;
10 buckets of gravel.

Water is added depending on the volume of the dry mixture. Thus, a 180-liter concrete mixer will require approximately 90 liters of clean liquid.

One of the main factors ensuring the quality of building structures is compliance with the correct proportions of concrete components for the foundation, as well as the technology for its preparation. The technical characteristics of the material such as strength, moisture and frost resistance and thermal conductivity depend on this. The ingredients themselves also have quality requirements. Fulfillment of these conditions is the key to reliable and durable operation of the structures being built. Therefore, knowledge of the main indicators and sequence of processes is important for contractors and customers of work, as well as for those who plan to lay the foundation for a house or fence on their own.

Depending on the type of foundation, characteristics of the structure and construction conditions, the composition may differ. In any case, it includes ingredients such as filler, binder, sealer and additives to impart special properties to the solution. Sand, screenings, gravel, and crushed stone are used as filler, creating the bulk of the foundation. To avoid the formation of voids, a combination of material of different fractions is used: smaller particles fill the gaps between large elements.

Cement is the substance that binds the filler into a single monolithic structure. The operational reliability of the entire structure depends on its quality. Based on the specific construction conditions, various brands and types of cement are used to mix concrete of the required composition. Ordinary Portland cement M400 or M500 is suitable for preparing popular grades of concrete M200, M300, which are used for pouring most types of foundations. The material provides the required load-bearing capacity in compliance with the requirements of standards for moisture and frost resistance.

During construction under special conditions, the composition of concrete for the foundation includes fast-hardening types of cement. Features of working with them include continuous pouring technology. To avoid premature setting, laying is carried out directly from the concrete mixer into the formwork. In addition to these varieties, there are also pozzolanic and Portland slag cement. They have lower strength characteristics, but are more resistant to moisture.

Drinking or industrial water acts as a sealer. In the case of preparing a solution for pouring a foundation during a period of the year with negative temperatures, its composition is supplemented with frost-resistant additives. If necessary, heating of the concrete mixture with electricity or other measures is provided in accordance with the work project. All materials used must be of quality confirmed by certificates of compliance with regulatory requirements.

Component ratio

Most often, concrete grades M100-M450 are used in construction. The numerical indicator in this case indicates the maximum permissible load, measured in kilograms per square centimeter. You can achieve certain characteristics by adjusting the proportions of the concrete mixture solution, as well as the grade of cement. The higher this parameter, the stronger it will be.

To prepare M100 concrete (“lean concrete”), which is used, for example, to create an artificial base for foundations, the following ratios of ingredients are used: 1: 4.6: 7.0 (M400 cement: sand: crushed stone) or 1: 5, 8:8.1 (for Portland cement grade M500). At home, the mixing measure is usually a bucket. Therefore, to a 10-liter container of cement add 4-5 of the same parts of sand and 6-8 buckets of crushed stone.

The proportions of concrete for the foundation are different, since the requirements for its strength are higher. To do this, the proportion of cement in the solution is increased. So, for the preparation of M450, the proportions are 1: 1.1: 2.5 (M400 cement: sand: crushed stone) or 1: 1.4: 1.9 (for the M500 brand of Portland cement). That is, about one and a half volumes of sand and two crushed stones are taken per bucket of binder. The water ratio is usually approximately 70% of the amount of cement. It may fluctuate to some extent as it depends on the moisture content of the sand used.

What composition of concrete is used in each specific case is determined by calculations in the design documentation. Considering the high cost of the main components and additives, it is not economically feasible to overestimate the strength for significant volumes of work. But you should not risk the quality of the foundation by ignoring the advice of experts.

Mixing methods

Today there are a sufficient number of organizations that supply ready-mixed concrete. As a rule, their products undergo quality control in a laboratory, and the likelihood of purchasing a defective product is low. The proportions of concrete for foundations and other building structures are determined by regulations, and mixing is carried out using stationary equipment in a factory environment. The only downside in this case is the price of the product. Therefore, for small amounts of work, you can mix the solution yourself. This is done in the following ways:

in a concrete mixer;
shovel in a trough;
on the floor or on the floor covered with polyethylene.

With any method of preparing material for pouring the base, several important conditions must be observed. First, all components are poured into a container in dry form and mixed until a homogeneous mass is obtained. Then they begin to gradually pour water into the container, continuing the kneading process. It is believed that the optimal consistency of the solution should not easily slide off the shovel, but also not look too dry. When installing the foundation, the following must be considered:

1. in wet weather, sand has high humidity, so the number of added buckets of water is reduced;

2. First, it is better to fill in the minimum amount of water. If the mixture turns out to be too thick, you can always thin it further;

3. cement tends to deteriorate over time, so it should be purchased shortly before starting work on preparing the foundation;

4. must be stored in a dry place;

5. When storing Portland cement in the winter, you need to ensure that it does not gain moisture, freeze or set. Petrified material is not suitable for preparing the solution, since it will not be possible to achieve the required grade of concrete;

6. The sand must be cleaned and free of silty inclusions, as this reduces the strength properties. Before mixing it must be sifted through a sieve;

7. The mixture should be consumed within two hours. After this period, the material loses its properties and begins to set;

8. When pouring the foundation in winter, additives are added to the solution to increase its frost resistance. If necessary, additional heating is provided.

Cement is an element that binds foundation mortar into a complete conglomerate. It must be purchased right before construction starts. The problem lies in the extreme hygroscopicity of cement, which can absorb moisture even from the atmosphere, becoming almost stone.

In the case of long-term storage of packages with a binding component in warehouses or at home, when opening it, there is a chance to find not powder, but hard lumps. If they are small and crumble in your hand, then cement can be used for the job. Otherwise, the bag will have to be thrown away. To avoid such situations, when purchasing, carefully look at the production date, which is on the packaging. At home, cement should be kept for a short time in a place protected from moisture.

Characteristics of foundation mortar ingredients.

To achieve the required characteristics of concrete, the grade of cement matters. Often to make foundation mortar grades M300, M400 or M500 are used, where the number means compressive strength, measured in kg/cm 2. Online calculation of the composition of cement mortar.

Water- an element that turns cement into a durable stone material. The process of mixing it with a binder is mixing. It is important to use clean water without dirt or excess salts.

Optimally in foundation mortar add water in the amount required for the chemical reaction with cement. But then the composition turns out to be too rigid, and it is quite difficult to lay it.

When there is a lot of water, the concrete mixture will spread well. During drying, moisture will evaporate, forming pores in the foundation, reducing its strength.

During mixing, a chemical reaction occurs in which a hard stone is formed, which after a certain time shrinks and cracks. To relieve internal stress and reduce the price of concrete, aggregates of different sizes (sand, crushed stone or gravel) are added to the solution of water and cement.

Sand must meet the main conditions: purity (there should be no clay additives and organic elements), grains of a specific size (0.14 - 5 mm). Washed river sand is optimal for construction work. Sand from quarries contains clay impurities, which reduce the strength of the concrete mixture.

Crushed stone and gravel are coarse aggregates. They must meet the same conditions as sand: purity and grain size. Ideally, the size of the aggregate components should not exceed one-fourth the width of the foundation. It is important to use coarse aggregates with different grain sizes, this reduces the number of voids, reducing the consumption of binder material.

The brand of coarse aggregate must be taken into account. After all, the strength of ready-made concrete doubles, while crushed stone and gravel remain unchanged. Therefore, it is necessary that the grade of coarse aggregate be twice as high as that of concrete.

Proportions for making foundation mortar.

To achieve good quality foundation mortar and the reliability of the finished product, not only the choice of elements that satisfy the conditions, but also the correct proportions for preparing the solution are of great importance. In concrete produced in factories, the following ratio is observed: cement, sand, crushed stone and water - 1: 2: 4: 0.5, respectively. For private construction work, the ratio is determined by the planned grade of concrete mixture ( foundation mortar usually requires grades M 200-M 300) and the properties of its components.

When foundation mortar contains more cement, the concrete is too hard and difficult to lay. If there is more sand and crushed stone, the mixture does not set well. If there is excess water, the concrete will be porous. That is why it is necessary to strictly observe proportions.

In private construction, the foundation is usually poured independently, without ordering kilotons of concrete in a mixer. Because imported concrete is much more expensive, given the small volumes. If, for example, you are pouring a strip foundation under a garage or a masonry fence, the cost of a mixer will not be justified in any way. Therefore, in such cases, they prepare concrete with their own shovel in a convenient, dear trough. If, of course, they know proportions and technologies...

Composition and materiality

Concrete is not a mortar for masonry, so the presence of aggregate must be taken into account. The composition will certainly include crushed stone or other crushed material, small broken red bricks, and gravel. The ratio of materials is taken depending on the purpose and the required grade of concrete. The more irregularities on the surface of the aggregate, the better its adhesion coefficient. Pellets (river gravel) are not suitable for making concrete!

It is better to take medium-grained sand, mined in quarries, and not washed along the banks of rivers. River sand, in addition to having a fine fraction, also contains a large percentage of clay particles, which is an aspect that worsens performance for high-quality concrete.

It is optimal to choose crushed stone or another type of filler in a fraction of 5-20 for pouring formwork or 20-40 for pouring a foundation “on the ground”.

Lightweight concrete (containing a minimum of gravel, granite or other heavy crushed stone) is not suitable for pouring a foundation. The same applies to masonry mortar prepared using technology without any aggregates at all.

The standard cement/sand/crushed stone ratio for concrete grade M200 and cement grade M400 is 1 / 2.8 / 4.8 (proportions are indicated by mass, not by volume). To prepare M250 concrete from the same brand of cement, you will need to mix the solution in proportions by weight of 1 / 2.1 / 3.9. To prepare M300 concrete, mix the components in the proportions 1 / 1.9 / 3.7.

Pay attention to the mixing method! This is not a masonry mortar, and mixing all the ingredients before adding water will be very problematic, unless you had the worthy nickname “excavator” as a child. Therefore, first mix the sand and cement, as for a regular mortar, and then gradually add water and crushed stone, ultimately achieving the required consistency. It should be noted that for pouring a strip foundation without formwork, a more liquid consistency is always prepared “in the ground” to the level of the top layer of soil.

So, you will need materials:

cement grade M400 or M500;

river or quarry sand;

aggregate;

additives, hardeners, additives, softeners and others - only with the subsequent use of the prepared concrete in non-standard conditions (high humidity, constant rain, air temperature less than +5℃, the need to quickly load a freshly poured foundation and other circumstances).

Prepare your tools:

electric or manual concrete mixer;

large container (trough) for manual stirring;

10-12 liter bucket for transporting components, water;

shovel;

The sieve is large enough to sift sand from weeds. “Handicraftsmen” often use a metal mesh from an old spring bed, set at an angle of 45° or higher.

It is worth noting that purchasing a concrete mixer for a one-time use is also unprofitable, as in the case of ordering a mixer with ready-made concrete for small volumes of construction. The foundation for an ordinary garage will be much cheaper to prepare in the “old-fashioned” way, stirring the ingredients in a trough. It won't take much longer. Tested by time and billions of private developers.

Construction technologies used in everyday life involve the formation of concrete mortar directly on the construction site. Making concrete for the foundation with your own hands does not seem to be a particularly difficult task.

Most often, household construction work is carried out using self-made concrete solutions. The formation of a concrete mixture of proper quality requires the presence of the following components: aggregate, cement, lime, additives, water.

concrete aggregate

The production of mortar for construction purposes most often involves the use of sand or fine crushed stone. It is also possible to use coarse crushed stone or gravel. Preparation of mortar for plastering or masonry work is done using fine sand. Plaster with a special, non-smooth texture can be made from coarser sand.

As a rule, the sand offered by manufacturers is of river or ravine origin. The first is considered medium-grained. Its cost is high, but the quality matches. The second type of sand can be fine-grained, but the presence of impurities and clay particles in its composition makes it not the best choice for making good concrete, but mortars can be made with such material.

The production of high-quality lightweight concrete mortar involves using exclusively sand as a filler. Gravel and crushed stone are used to make stronger concrete.

The best option is considered to be a combination of a mixture of crushed stone of different fractions; this composition contributes to the formation of a minimum number of voids. All kinds of contaminants such as soil, glass, peat and plants are not allowed in the solution.

Cement - characteristics

This is the generally accepted name for substances of powdery texture, made on the basis of clay and calcareous rocks using various additives to them.

The most commonly used is Portland cement. This type of material contains a large amount of calcium silicates. There are two types of this substance:

Type 1 – additive content does not exceed 5%;
Type 2 – additives reach 35% of the composition.

Domestic cement is marked with the letter D to indicate the presence and quantity of additives in its composition. For example, the inscription on the packaging of PC 300-D20 informs the buyer about the presence of 20% additives in the composition of this product.

When purchasing cement, you should check for proper labeling on the packaging, and also check that there is no moisture in the packaging itself.

As a rule, this can be understood by appearance or simply felt with your hands. Stale cement is not the best purchase for construction repairs or work.

Lime - what is it for?

Lime can improve the properties of the mortar and ensure its high-quality installation. Previously, it was necessary to “extinguish” it before adding it to the solution. Now slaked lime (fluff) is available for sale, packaged in bags. You can use either a dry mixture or water-based lime dough. Lime is added to make plaster or masonry mortars.

When working with lime mortars, you must follow safety precautions:

Wear protective gloves and avoid getting lime on your skin or eyes. This composition has strong corrosive properties. In case of contact, rinse with water.

Additives - nuances of use

To improve or improve the properties of a cement mortar, its composition includes additional additives.

Plasticizers. Allows you to improve the flow properties of concrete. The use of such substances makes it possible to create concrete structures of various shapes and generally improves the laying properties of concrete.
Superplasticizers or thinning additives help reduce the water content of the solution. Also, such elements make the concrete structure frost-resistant and waterproof;
additives that promote rapid hardening;
additives that allow you to work with concrete at temperatures from -10 to +35 degrees;
Aerating or air-entraining components. Serve to increase resistance to frost and reduce the moisture content in the finished product;

You can buy additives at a hardware store, checking for dosage information on the packaging. They are sold in ready-made liquid form; adding them to the solution should not exceed 2% of the total mass.

In some cases, supplements can be made independently. For example, it is common to make plasticizers from soap or soap solutions.

Compliance with the dosage when using such substances is of key importance; violation of the proportion can lead to a decrease in the quality of the solution.

And, of course, water for the concrete mixture

The choice of water for preparing a concrete mixture must be carried out in accordance with GOST. Water requirements include the absence of impurities, sugars, oils or acids.

It is recommended not to use water from questionable sources, such as a lake or river, but to take liquid that is suitable for drinking. If you still plan to use water from a reservoir, then it is better to check its suitability in a special laboratory.

Proportions and composition of the solution

Parameters such as the composition of the concrete mixture and the proportions of the components used depend on the purpose of the solution. When making concrete for the foundation with your own hands, it is better to take high-density concrete, which has sufficient strength.

The manufacture of elements such as the base for a fence can be made from lighter grade concrete. It is better if the concrete for making the mixture yourself corresponds to grades M300 or M400.
The proportions of the components required to make a high-quality mortar are: 1 part cement, 3 parts sand and 5 parts crushed stone. The weight of added water should be half the weight of the dry mixture
Components can be added during the mixing process. If the solution is too thick, you can add water.
Using wet sand requires less liquid to be added.
The consistency of the solution should be such that mixing it with a shovel does not require excessive effort.
Work with concrete carried out in subzero temperatures must be carried out with heating of the material and water. If this condition is not met, then premature hardening of the mixture is possible and, as a result, a violation of the construction technology.
It is better to mix the components in a purchased concrete mixer, but it is also possible to use homemade devices.

Following recommendations for the production of concrete helps to improve the quality of work performed. The correct choice of material brand, components and additives will allow you to create a solution that is optimal for each specific task.

It is mandatory to observe safety precautions during work, as well as to use high-quality tools and devices.