The composition of the foundation is not only the presence of all the required elements, but also the selection of appropriate concrete for pouring. Its proportions and calculation of the volume for the foundation will vary greatly for each foundation for the house.
For the foundation, you should take cement of a grade not lower than M200.
Today, various types of foundations are used, among them it is necessary to highlight the designs of slab, pile, and strip foundations. Sometimes combined options are used.
What should be the composition of the strip foundation?
The most commonly used construction is a strip foundation, which is simple and economical. This design consists of a shallow concrete strip, which is installed around the perimeter and under the load-bearing walls of the house.
In some cases, ready-made concrete blocks and bricks can be used for it. In this case, the duration of work does not depend on the curing time; only the time for drying of the masonry mortar is taken into account. But for its preparation it is also required.
Pie for the strip base of the house includes:
- sand and gravel cushion at the bottom of the trench;
- removable formwork from a regular edged board (removed after the concrete has hardened);
- concrete strip running along the perimeter and under the load-bearing walls;
- waterproofing the upper part of the strip foundation.
In production, such a foundation is considered one of the simplest; it can be erected on almost any type of soil.
To calculate the material, you only need to know the belt parameters such as height, width and total length. In some cases, the foundation is reinforced before pouring with metal reinforcing bars, which increases its strength and load-bearing capacity.
Return to contents
What does a pile foundation include?
A pile foundation for a house consists of a foundation in the form of special support pillars. This option is used when building on difficult soils, on slopes, on swampy or sandy soils. In this case, the house exerts uniform loads on the ground due to the features of this design.
To prepare such a base you don’t need much; the design cake consists of the following elements:
- sand and gravel cushion at the bottom of the well;
- support pillars, which are filled with concrete after installation;
- for grillages, a special belt is used, which is used as a base for the house.
There is a type of pile foundation, which is a combination of strip and support (walls are erected between the pillars to a small height). It doesn't take much time to prepare.
Return to contents
Slab foundation and its composition
The slab type of foundation for a house is a foundation that is a monolithic, reinforced slab made of concrete. The recipe for such a base is simple, but very reliable. Pie slab base includes:
- base made of sand and gravel;
- slab (can be of several types: regular solid, lattice);
- waterproofing on the top.
The slab itself is reinforced using special metal reinforcement. may include reinforcing polymer additives that increase strength and resistance to various loads. But there are also disadvantages here. Laying a foundation requires a lot of materials. In addition, when building a slab base, it is impossible to build an underground garage or a spacious basement.
Return to contents
Concrete for foundation: application features
To construct the foundation, concrete of various grades is used in a variety of proportions. Everything here depends on the type of foundation itself and the requirements placed on it. One of the most important issues is the proportions of ingredients. When choosing what the concrete composition will be for the construction of a monolithic slab, pile (columnar), strip foundation, the following features must be taken into account:
- must exactly correspond to the expected loads and construction conditions. In this case, the structure will be strong and very reliable.
- The foundation for a house can be of various designs (slab, pile or strip). To arrange it, blocks, support pillars or a liquid mixture for pouring can be used. But in any case, it is recommended to use only factory-made concrete mixtures that are of high quality. It is not recommended to make slabs or pillars from dry mixture at home.
- The composition of concrete includes: cement of the selected brand, fillers (gravel or crushed stone, sand, granite sand), water. Plasticizers and special reinforcing additives are often used. The proportions of such a mixture depend on what cement will be used and what brand of concrete should be obtained in the end.
- For the foundation it is necessary to take cement, the grade of which is no less than M200.
- The strength of the concrete mixture for the foundation largely depends not only on the correct proportion, but also on the quality of the fillers. It is recommended to use different-grained materials that will evenly fill all voids.
- After preparation, concrete can only be used for two hours, after which it begins to dry and lose its quality.
- Water plays a big role in preparing concrete. The mixture should not be too thin or too thick; its consistency should resemble thick sour cream.
Return to contents
Composition of concrete mixtures for foundations
The composition of concrete, as already mentioned, includes components such as gravel, sand and water. The base takes on the loads from the structure, so it is very important to take into account all factors when calculating the mixture. The proportions will differ depending on what brand of concrete will be used. For example, to build a house, you need to use concrete grades from M200, but for ordinary garden paths M100 is also perfect.
Let's consider the proportions and volumetric composition of concrete for various grades:
- M200, mass composition - cement 1 kg, sand 2.8 kg, crushed stone 4.8 kg, volumetric composition for every 10 liters of concrete (sand/crushed stone) - 25:42, amount of concrete for every 10 liters of cement - 54 liters.
- M250, mass composition - cement 1 kg, sand 2.1 kg, crushed stone 3.9 kg, volumetric composition for every 10 liters of solution (sand/crushed stone) - 19:34, amount of concrete for every 10 liters of cement - 43 liters.
- M400, mass composition - cement 1 kg, sand 1.1 kg, crushed stone 2.5 kg, volumetric composition for every 10 liters of solution (sand/crushed stone) - 11:24, amount of concrete for every 10 liters of cement - 31 liters.
- M450, mass composition - cement 1 kg, sand 2.8 kg, crushed stone 4.8 kg, volumetric composition for every 10 liters of solution (sand/crushed stone) - 10:22, amount of concrete for every 10 liters of cement - 29 liters.
The higher the grade of concrete for the mixture, the greater the amount of cement will be contained in the composition. Therefore, it is important to correctly determine which brand is needed in order to. The optimal ones are M300 and M400, which are quite enough to build a foundation even for a massive country house.
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.
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.
The calculation of the proportion of concrete for the foundation is carried out taking into account the technical parameters of the component parts. The technology for preparing a concrete mixture depends on its purpose, volume, quantity and physical condition of the components. It can be prepared manually or using specialized equipment and concrete mixing equipment.
Solution components
Cement is a powdery binder that can harden in water and in open air. In combination with coarse and fine aggregate, it ensures the strength and reliability of the structure being built.
Cement is obtained by grinding a mixture of clinker, gypsum and special additives in specified proportions. In turn, clinker is a product from the firing of limestone with clay and other components on which the properties and name of cement depend. Depending on the feedstock, the following types of hydraulic binders are distinguished:
- Portland cement:
- Portland slag cement;
- pozzolanic;
- lime;
- plugging;
- sulfate-resistant and others.
When forming a cement-sand mixture (CSM) in order to obtain concrete of a given strength, it is necessary to take into account the strength grade of Portland cement. The following table shows the strength indicators of the material according to the old and new systems:
In addition, when choosing a material for preparing concrete with the required characteristics, other properties of cement are taken into account:
- The fineness of grinding directly affects the strength properties of the concrete mixture, especially at the beginning of hardening.
- Density affects the water-cement ratio, and therefore water consumption. To reduce it, while still achieving good workability of the mixture, plasticizing additives are used.
- Frost resistance is especially important when building in winter or in areas with year-round low outside temperatures.
- Crack resistance. This indicator is influenced by such a concept as the uniformity of volume expansion during hardening.
Depending on the components from which cement is made, the above qualities vary within fairly wide limits.
The concrete mixture, which, in addition to cement, includes sand, as well as crushed stone or gravel, is formed depending on the purpose of the composition. What proportions of cement, sand and crushed stone should be contained in it are determined in accordance with the recommendations of GOST 27006 - 86 (1989) “Concrete. Rules for the selection of compositions" and GOST 7473 - 94 "Concrete mixtures. Technical conditions".
For the concrete mixture, sand with a grain size of 1.2-3.5 mm is used. When choosing this component, pay attention to the purity of the material. In order for the prepared cement-sand mixture to be of high quality, the presence of silt and clay particles in the sand should not exceed 5%.
You can check the suitability of sand for use using water. To do this, you need to pour a small amount of the test component into a container, add water and shake the composition. If the liquid is cloudy and contains suspended clay particles, then the sand is not suitable for preparing concrete.
The concrete mixture used to pour the foundation includes crushed stone or gravel of medium fraction. The use of large grains will lead to loss of strength of the foundation for the construction of the building.
The production of high-quality concrete is possible using warm and clean water, without minor impurities (oils, paints).
When preparing a cement-sand mixture, you need to take into account that there are no absolutely pure components. In practice, it can be difficult to accurately calculate the proportion of sand and cement for the foundation, especially when pouring the foundation for individual construction.
Additionally, you need to take into account the fact that over time, foundation cement loses some of its properties. Over six months of storage, the material reduces its binding properties by a third. Accordingly, the grade characterizing the compressive strength is reduced.
Classification of concrete
Based on the purpose of the structural material and its specific gravity, the following types of concrete are distinguished:
- especially heavy;
- heavy;
- easy;
- especially light.
The composition with the highest density is used in the construction of nuclear and power plants, with a specific gravity in the range of 500-1800 kg/m³ - for the manufacture of panels and wall blocks. Particularly lightweight (less than 500 kg/m³) is intended for thermal insulation of house facades.
Heavy concrete (1800-2500 kg/m³) is used for the manufacture of prefabricated, monolithic reinforced concrete structures and foundations. Special impurities that are added to improve its technical characteristics increase strength, resistance to overheating, temperature changes, reinforcement corrosion, and moisture.
The main indicator of strength is reflected by the grade or class of concrete.
Preparing the mixture
Concrete is used in almost all areas of construction, when performing repair, construction or restoration work.
You can prepare the mixture for the foundation yourself by combining the components in a concrete mixer, bathtub, or box. When producing artificial material, it is important to follow the technology and proportions of concrete for the foundation.
Industrial production differs from artisanal production in large volumes, and therefore requires the use of special technical equipment. Mechanical preparation of concrete mixture for foundations by specialized enterprises makes it possible to improve properties and quality through additives.
When forming the foundation for building a house, you can use the services of a company that can prepare a concrete mixture using special equipment on the way to the customer.
To make a composition for the foundation with your own hands, you need to correctly determine the quantitative composition of the components. To obtain concrete grade 300 or 400, sand and cement are taken in proportions of 3:1, i.e. for 10 kg of cement you need to take 30 kg of sand, gravel (crushed stone) - 40-50 kg.
In this example, cement, sand, crushed stone weigh 80-90 kg, so 40-45 liters of water will be required to connect the components. You can mix the mixture using a mobile concrete mixer, a shovel or a construction mixer.
Preparation of concrete from a cement-gravel mixture requires adherence to technology. If the solution turns out to be dense, then it must be diluted with water to such a consistency that it can be stirred with a shovel without much effort. The amount of water is affected by the moisture content of the aggregates, so you should not add it all at once. It is better to do this in portions with constant stirring.
It is better to choose the warm season for concreting. At low temperatures, to improve the quality of concrete, you need to heat up the water, otherwise it may lose strength. And also use antifreeze additives.
Types of foundations
The foundation for the construction of buildings is formed taking into account the load, types of soil, and structure. Depending on the type of foundation and its volume, the need for materials is calculated.
- The strip base is a closed loop made of reinforced concrete, placed under the load-bearing and internal walls of the building. How to make a solution for a strip foundation? To calculate the need for materials, you should determine the volume of each section and add them up. The mixture must be poured continuously, with layer-by-layer compaction and compliance with the protective layer of the reinforcement.
- The columnar type of base is used for lightweight structures located on dense soils. In practice, a combination of both types of foundation is often used.
- The slab type of foundation is practiced on weak, heaving soils. Made from reinforced concrete. Filling should be done in one go to prevent delamination of the finished structure. The concrete mixture is distributed evenly with mandatory compaction with vibrators or bayonet.
- Pile-rammed foundations. The volume of concrete is calculated using a geometric formula: the cross-sectional area of the well must be multiplied by the depth of the pile and the number of rods.
After pouring the concrete mixture into any type of base, it requires moisture, otherwise the structure may crack due to the rapid drying of the top layer. The first week should be regularly watered and covered with film or tarpaulin.
Do-it-yourself concrete for the foundation
You can use the materials separately or a ready-made sand-gravel mixture (proportions in buckets: 1 volume of cement per 5 volumes of mixture).
The components per 1m3 of concrete must be mixed in the following ratio:
- cement - 300-350 kg;
- crushed stone - 1200 kg;
- sand - 600-700 kg;
- water - 150-180 l.
Calculation of the amount of cement and sand, crushed stone and water should take into account the properties of the materials, their qualitative composition, strength, and the presence of foreign impurities (the sand may contain clay particles).
To properly make a cement mortar for pouring the base, pour dry components into a concrete mixer and mix for 2-3 minutes. Then, without stopping stirring, add water in portions. It is better to first dissolve the necessary additives in water. The mixing process should not be long, 5 minutes is enough.
Methods for calculating materials
The concrete recipe for the foundation includes the following components: cement, sand, gravel or crushed stone as aggregates,. Each component is responsible for quality. In order for the final result to meet regulatory requirements, you need to correctly perform the calculation and determine the required number of components, observing the proportions.
Calculation of components and preparation of concrete for the foundation in buckets is relevant for small volumes of construction work, where 1-4 m 3 of solution is required. The basis for this calculation is usually the volumetric value of cement.
What should be the ratio of sand and cement for pouring a foundation?
Each component of the concrete mixture differs in volumetric weight, so in practice the following proportions are used: for 2 buckets of cement, take 5 buckets of sand and 9 of crushed stone or gravel.
A preliminary calculation of ingredients can be done using an online calculator in liters or kilograms. Emergency calculations are carried out taking into account the requirements for concrete and the characteristics of the main materials.
For example, to obtain 1 m³ with a 180 liter concrete mixer, sand and crushed stone you will need:
- water - 215 l;
- cement - 233 l;
- crushed stone - 818 l;
- sand - 389 l.
Under the given conditions, the calculator will calculate the need for materials for 1 batch and the number of loads.
When it is necessary to adjust the consumption of raw materials, taking into account the operating conditions of the structure being built, the type of mixture, the use of a plasticizer, the value of the coefficient of separation of concrete particles, it is necessary to use a correction table.
In this article we will look at you: what concrete is, what it consists of, what the grade of concrete is, in what proportions the components are present in it and how to make concrete for different types of foundations.
We think most of you already know what concrete is. Let us remember that this is a solution for the construction of strong stone structures in construction. It is used to create foundations, floors, supports and pillars, dams and dams, roads and blind areas around buildings. In short, the scope of application of concrete is very wide. We will look at a special case, namely concrete for the foundation.
For constructing the foundations of buildings, outbuildings, fences, etc. concrete is used consisting of:
- Cement is the main component of concrete for foundations. It is the main binding filler in concrete.
- Sand – concrete for the foundation must contain clean, medium-sized quarry or river sand. No impurities such as clay are allowed in it.
- Crushed stone – granite or gravel crushed stone with a fraction of 5-20 mm is required for the foundation.
- Water must be clean.
- Plasticizer – various plasticizers for concrete have recently been widely used. If you want to make high-quality concrete for the foundation, be sure to use a plasticizer suitable for your needs. It will make it much easier for you to mix and use concrete, clean tools, increase the time you work with concrete, and add strength and ductility to it. There are also special additives for working in cold weather that add waterproofing properties to foundation concrete and others.
The composition and proportions of concrete for the foundation determine its grade. What it is? Read more about it.
Brand of concrete for the foundation
Let us immediately decide that the grade of concrete M100 – M350 is suitable for building a foundation. Now let's see what it depends on and what it is.
Everything is quite simple: the letter M denotes the grade of concrete and shows the tensile strength in numbers. Those. how many kilograms per square centimeter will concrete of this brand withstand the load. Grade M200, the most common for the construction of foundations for private houses, means that the concrete will withstand a load of 200 kg per cm2.
In addition to the concrete grade, the concept of concrete class is often used. It is designated by the letter “B”. Concrete of class B7.5 - B25 is suitable for the foundation. Below see the table of correspondence between class and grade of concrete.
So, what brand or class of concrete is suitable for a certain type of foundation?
What kind of concrete is needed for the foundation?
Depending on what kind of building you want to build a foundation for, you need to choose the right brand of concrete. The more important and heavier the structure, the stronger the concrete for the foundation should be and the higher the grade or class of concrete should be.
To build the foundation of light outbuildings, such as a gazebo, greenhouse, chicken coop, concrete M100-M150 is suitable.
For a bathhouse, garage, etc. you can use concrete M150-M200.
For the foundation of a private house, use concrete grade M200 and higher.
All the figures given are very approximate. And if you do not have a design for the structure being built, and you doubt the sufficient strength of the future foundation, take concrete of a higher class. Also keep in mind that self-prepared concrete for the foundation may differ in brand from the factory one. And as a rule, to a lesser extent.
So, you have decided on the brand of concrete for your foundation. It's time to find out what proportions of concrete for the foundation must be observed for this.
It is no secret that most “home builders” use standard formulas with the proportions of components to prepare concrete for the foundation.
Basically, they use two types:
- For “ordinary” concrete - 1 part cement, 3 parts sand, 5 parts crushed stone. Water is added to a minimum, but to a plastic consistency.
- For “strong” concrete – 1 part cement, 2 parts sand, 4 crushed stone.
In principle, such formulas have the right to life, because they are suitable for most foundations in private buildings. If you want to build your foundation correctly, use a table that will tell you the proportions of concrete for the foundation.
The table shows not only the proportions of concrete for the foundation in kilograms, but also the proportions in parts. Since many builders use it to measure the required proportions, for example, in buckets or shovels. If it is more convenient for you to use this method of dosing components, then in the table you will find the proportions of concrete for the foundation in buckets. Because “parts” can be replaced by any measure of volume. Be it buckets, shovels, scoops and even hands.
Do not forget that the proportions of concrete for the foundation in kilograms and buckets are not the same thing. Because cement, sand, crushed stone and water have different specific gravity. A 10 liter bucket will weigh 10 kg with water, about 12 kg with cement, 14 kg with sand and 15 kg with crushed stone. But these figures are conditional, because cement can be either loose or compacted. The sand is wet, and the crushed stone is large or small.
Advice! To make it easier to calculate the composition of concrete, use one of our free online calculations.
And finally, watch the video, which clearly explains how to make it and all the proportions of concrete for the foundation. Good luck with the build!
Proper concrete according to standards. Video.