How to make concrete proportions with crushed stone. How to make concrete with your own hands: choose instructions on how to make concrete correctly. The main components in concrete

  • Date: 20-11-2014
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Concrete is a unique and multifunctional material. It is successfully used at almost all stages of construction; finishing materials and paving slabs are made from it. The strength and durability of any structure depends on its quality. How to make strong concrete that can last for many decades?

The technological process for preparing durable concrete seems straightforward, but at the same time the number of complaints about cracking, for example, in the foundation, is growing.

What do you need to know and take into account so that concrete for any purpose lives up to expectations?

Basic Concepts

Classically, concrete means a mixture of the following components:

  1. Cement is the connecting link that turns the components into a monolith.
  2. Sand is the basis of strength and filler of small voids.
  3. Aggregate - this can be gravel, crushed stone and some other materials. It is the stone component that provides the unique strength of the material.
  4. Special additives - all kinds of plasticizers, etc. With the help of these chemical compounds, concrete is given the desired consistency and its quality is improved.
  5. Water.

The main indicator of concrete quality is compressive strength. This characteristic reflects the ability of the solution to withstand mechanical stress, which is inevitable. This indicator is measured in MPa (megapascals) and reflects the level of load that concrete can withstand without deformation and changes in properties. The strength of concrete depends on the quality and type of cement used for preparation, the fraction of sand and aggregate, and compliance with the technological process. Concrete is marked depending on its strength from B 3.5 to B 80, where the number is an indicator of the pressure that this composition can withstand in 95% of cases.

The simplest concrete, often used for laying a foundation base, is a simple mixture of cement and coarse sand. Depending on the use of auxiliary components, the strength of the composition increases, and hence the durability and reliability of the structure.

But before choosing a recipe that will make concrete strong, it is important to understand all the components. The effectiveness of the work will depend on their quality.

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Cement is the basis

Cement is the main and most important ingredient of the composition called concrete. It provides linking of additional components.

The ideal option for preparing durable concrete is Portland cement. Due to the high content of calcium silicates, it provides ideal adhesion (cohesion) of materials. An additional advantage of this material is that it can work at lower temperatures, but this advantage should not be abused. Preparing the mixture and pouring it at temperatures below +16ْ°C will negatively affect the quality. If there is a need to carry out work in a cold climate, it is imperative to use special plasticizers. Portland slag cement is suitable for work in the warm summer.

When purchasing cement, the main reference point is the brand. It is indicated on the bag, and the cost will depend on it. Usually it looks like this: M 500-D 10 (numbers may vary). The first indicator is the same strength, the optimal grade is M 500, you can also use M 400, but this will affect the quality, the concrete will be less durable. The second indicator is the content of impurities, the value D 10 indicates that the cement contains 10% of foreign elements. In order for concrete to be sufficiently light and strong, you should choose a material with an index of up to D 20.

In addition to a thorough approach to choosing a cement brand, a visual assessment is also necessary. High-quality material must be dry, homogeneous and free-flowing. Even slight dampness will negatively affect the strength of the structure.

The need for concrete must be assessed immediately before starting work, maximum 2 weeks in advance. In this case, it is better to purchase the missing bag than to leave the excess; during storage, they will absorb moisture from the environment and become low-quality ballast. When purchasing, you need to carefully check the integrity of the packaging and the presence of appropriate markings.

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Can't do without sand

It is possible to do without this component of concrete in extremely rare cases. In the rest, it is sand that will provide sufficient density and high-quality filling of voids. What should the sand be like in order to?

  1. Clean. This is one of the most important characteristics. Foreign impurities, especially of plant origin, will decompose in the thickness of concrete, reducing its strength. If the sand was purchased clogged, it must be sifted. Even if it takes time, it will significantly increase the strength of the future structure.
  2. Homogeneous. Sand with a fraction of 1.5 to 5 mm is suitable for construction. But at the same time, you need to try to ensure that the run-up is no more than 1.5-2 mm. The more homogeneous the sand, the stronger the structure.

It is preferable to use river sand, as it is often already clean. The ravine often contains loamy impurities and silty inclusions. In some cases, it is possible to thoroughly wash and then allow the sand to settle, but this is labor-intensive, especially at home.

In some regions far from large rivers, you can find so-called stone or rock sand. It is a rock crushed to the required fraction. When using such a material, you need to take into account that it is much heavier than ordinary sand, which means that its use will not allow you to obtain lightweight concrete, which is especially important when installing interfloor floors.

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What should a quality filler be like?

Almost any stone of suitable size can act as a concrete filler. But here there are several requirements that will help improve the quality of concrete.

  1. The filler must be clean. As with sand, you need to make sure in advance that there are no impurities. If necessary, resort to sifting.
  2. Regardless of the type of filler, all elements must have a rough surface; it is this that ensures high adhesion. For this reason, you should avoid using pebbles.
  3. The optimal fraction is from 8 to 35 mm, the rule of uniformity is maintained. But in the case of self-filling, it is better to use gravel of different fractions, for example, fine and medium. In this case, it will provide better compaction even without the use of professional tampers.
  4. In order to obtain a lightweight but very durable casting material after hardening, it is recommended to use expanded clay.

Aggregates are usually quite heavy, so they must be stored in close proximity to where the concrete is mixed. In addition, you need to take into account that gravel can become dirty during storage, which means it is better to organize the embankment on a solid base or on a tarpaulin. When storing material on the ground, the bottom layer becomes waste or requires washing and drying.

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What about water and other components?

In order for concrete to be durable and last for many years, you need to use tap water that is at least conditionally drinkable. It is strictly not recommended to use water from natural reservoirs; it contains acidic and alkaline impurities that will not allow you to make strong and lightweight concrete.

In addition, various components are often added to the solution, changing the properties towards improvement.

  1. Plasticizers. These are special compositions that allow you to change the properties of concrete. With their help, you can reduce the need for water, adjust fluidity and plasticity.
  2. Lime. It is usually added to simplify working with concrete, which is especially important for delicate manipulations. This is an optional component and use is at the discretion of the artist.
  3. Corrective components. With their help, you can make concrete resistant to low temperatures and other aggressive conditions. Moreover, if work is carried out outside the permissible temperature limits, the use of such means becomes mandatory.
  4. Reinforcing additives. As a rule, PVC sheeting is used; it is soft and not very strong, but when placed between layers of screed, it successfully protects concrete from tearing and cracking. With its help you can make a fairly strong, but at the same time lightweight layer.

Thus, all kinds of additives make it possible to improve concrete and make it more resistant to external factors.

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Correct ratio of components

So, the high-quality components of the future durable concrete have been selected and purchased, but that’s not all. Their ratio is no less important; in addition, the proportions vary depending on the type of work.

For pouring, coarse crushed stone and sufficiently liquid concrete with good fluidity are required. This will fill all the voids. But before pouring, it is recommended to install a substrate of low grade cement; the consistency of the material should resemble moist soil.

The most common proportion is 1:3:6, respectively, cement, sand, aggregate and up to 1 part water, depending on the need and type of structure. But this relationship is not universal, since the density of materials can change under the influence of many factors. It would be most reasonable to calculate the indicators, armed with technical reference books. If weight is chosen as the main measurement, it is necessary to dry the sand and aggregate so that the liquid does not disturb the calculation.

This rule holds true for any determination of the ratio of components. It is necessary to use the same dishes and make adjustments if necessary. Otherwise, the error will definitely make itself known, but at a time when it will no longer be possible to correct it.

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Mixing ingredients

The process of mixing the components is no less important. Inhomogeneous concrete not only causes difficulties during pouring, but also changes the ratio of components due to their sticking to the tool.

The ideal option is to use a concrete mixer; this device is designed to make perfect concrete. The unit can be purchased or rented; today many construction companies offer this service. The concrete mixer must be installed at a minimum distance so that the concrete does not have time to harden during transportation - this is contrary to the technological process.

You can make high-quality concrete the old fashioned way, by mixing it in an old trough. But in this case, you will have to put in a lot of effort to make the mixture homogeneous.

There are two methods for preparing the solution:

  1. Dry. When using it, all dry components are pre-mixed, and only after that water and plasticizers are added. The danger of this method is that it is extremely difficult to ensure high-quality and fast enough access of liquid to the lower layers, and this can upset the proportion. When mixed for a long time, the cement will begin to set, which will affect the strength of the concrete.
  2. Wet. All dry ingredients are gradually added to the measured water. This method is not without its drawbacks, but it is still preferable, especially when preparing a small volume of solution.

Concrete is a unique material due to its properties. It is used not only for construction work, but also for the construction of all kinds of structures and buildings. Many piece goods are also made from it, for example, such as: vases, balusters and even tabletops for the living room, paths in the garden. Modern methods of producing concrete and its further processing help it to be on par with materials such as marble or granite. Although this material is not very aesthetic, unlike the latter, everyone has long known what it is made of.

If you decide not to buy concrete, then you need to find out how you can make this material yourself, so that it can meet the required qualities and have excellent strength and a long service life. Although the procedure for making concrete is the simplest, it is necessary to take into account a number of some nuances and features that will determine its further quality and suitable properties. Depending on the main purposes for which this material is manufactured, its scope of application, as well as the recipe, will be changed.

What qualities does concrete have?

And if you want to learn about how to make concrete with your own hands, then you must take into account the proportions. But before we talk about the manufacturing process of this building material, it is necessary to find out what concrete is and what basic qualities it has.

Basically, concrete consists of a mixture of special filler and cement. Based on this, the most important ingredients of concrete are: sand, cement and filler. Moreover, the filler can be: pebbles, crushed stone, gravel and other solid materials. Modern manufacturing technology for this composition involves the use of some additives, such as plasticizers. Their main goal is to give concrete additional unique properties.

The most important properties of concrete should be compression and strength. The latter property is usually expressed in mega pascals (MPa). They determine the class of concrete, as well as the pressure. Depending on the strength, concrete is divided into appropriate grades. In the CIS countries, according to the approved GOST, the classes have the following designation:

B7.5-B80. Their main difference depends on the type of cement that is used in the preparation of concrete.

(M300-M-600), as well as all kinds of fractions, sand, and crushed stone. The numbers in the class name usually indicate the pressure in MPa that the concrete will withstand in 96% of cases.

The simplest version of concrete is a simple mixture of coarse sand and cement mortar. This type of concrete is mostly used as a foundation or substrate. Such concrete can be made at the bottom of the formwork when laying out the foundation. In this case, during preparation, you need to add a small amount of water to the mixture to be able to acquire its density. Strength in this case will be absent, but this material will have protection for the foundation.

To produce more durable concrete, it is necessary to use all kinds of crushed stone as the main fillers, having a fraction from 2-3 mm to 35-40 mm. The quality of such material will depend on the components used and composition.

Based on this, we can draw the following conclusion - before you begin to understand the methods of preparing concrete and its proportions, in order to be able to make a concrete solution correctly, you need to very carefully study each of its ingredients separately.

Requirements for concrete components

Cement.

Cement is one of the most important and unique components, which ensures the binding of all ingredients into a single whole. Portland cement is considered more suitable for making concrete. It is characterized by a high content of calcium silicates (up to 79-80%). This in turn will provide better adhesion and excellent bonding of all materials. But still, depending on the task, any other types of cement can be used.

A more suitable grade of cement for frequent use is 500. You can also use the standard grade M 400. But this may affect the service life of the foundation. Portland cement is excellent for working at low temperatures. But still, you should remember that you cannot work with concrete at temperatures below 15 degrees. But if there is a good reason for using concrete at a very low temperature, then you will definitely need to use special additives and various plasticizers. We'll talk about this later.

When carrying out work in hot weather, it is better to use Portland slag cement. In the Russian marking of cement, in addition to indicating its strength (MPa), there is also the designation D. After this letter, as a rule, a number is written that indicates the amount of impurities in this cement. Thus, for the production of concrete of excellent quality, cement grade M500-DO or M500-D20 is best suited. (with impurities from 0 to 20 percent).

The cement must be dry. You should not buy very damp cement with lumps. Also, there is no need to save too much on its purchase and buy unmarked or stale material. And all because concrete will be used for the construction of the main elements of a residential building. And the quality of construction will depend on its appearance. Remember that your safety depends on this fact. In poor conditions, cement begins to absorb large amounts of moisture from the air. Thus, its basic qualities are lost.

It is better to buy the volume of cement you need in advance (2-3 weeks before its use). When purchasing, be sure to carefully check the presence of markings and the integrity of the packaging itself.

Sand.

Regardless of what kind of aggregate you use (gravel or crushed stone), you will also need sand. Only in some cases, you can do without it, when it is possible to compact the coarse aggregate in such a way that all the gaps between the components are small. The sand that is more suitable for making concrete must contain a fraction from 1.7 to 5 mm. But it is best when this material has a uniform size (no more than 1-2 mm). The sand should not contain various third-party impurities. Various plant residues or any inclusions that are likely to decay over time will negatively affect the durable properties of concrete. But if the sand is not very clean, it is easier to sift it through a special sieve with small cells. The same can be done with crushed stone. When making concrete, it is best to use river sand. Of course, this material will differ in cost from gully material, but it will have the required grain size, and it will not contain silt inclusions or clay. The most important thing is to ensure excellent adhesion of the cement mortar, which has large aggregates, which will determine the strength of the concrete itself. It follows that it is better not to use sand containing loam or grains smaller than 1 mm in the manufacture of concrete, since it will be very difficult to remove them. To do this, it is necessary to carry out the procedure of settling the sand and washing it, which is difficult to do even in industrial conditions. For those places near which stone quarries are located, artificial heavy sand can be used. It can be obtained by crushing rocks. It is distinguished by its density and greater mass. If you perform excellent washing and filter out the particles by size, then this material will have better properties than river sand. You just need to take into account the fact that during its manufacture and further use, the concrete will be much heavier. This is an important fact if it is used in the manufacture of screeds over multi-storey floors. A weight barrier to the use of heavy sand can be a high background radiation.

Aggregate. Gravel, crushed stone.

The main and main strength of concrete is provided by crushed stone and gravel. River or sea pebbles will not be suitable in this case, since the surface of this natural material is polished with water, and thus will not be able to provide the necessary adhesion to the solution. The best material to use as a filler is the one obtained from crushed rock. Very often, expanded clay or some similar material is used, which is quite durable, but at the same time light. Below, in our article, we will take a closer look at the principle by which you can select the right material for the manufacture of concrete, ensuring its reliability and strength.

In order to make concrete with your own hands, it is important to consider its composition and proportions. Now we are talking about important materials that are used to make concrete composition. In this part of the article we are talking about an important component of concrete - gravel and crushed stone.

The size of crushed stone or gravel can range from 9 to 35 mm. And large pieces are used to a greater extent in production, but very rarely. It is best that the filler contains a small amount of dust or various clay impurities on the surface. All debris should be removed before the gravel is added to the solution. The greater the roughness on the particle faces, the better. Excellent and reliable grip will depend on this fact. In order to be able to prepare concrete with your own hands, it is best to use a filler that contains particles of various sizes, or mix coarse gravel with medium gravel. Since you do not have professional equipment to compact the concrete, this will ensure that the aggregate particles used will adhere better to each other and will not allow large voids to appear. Otherwise, they will begin to fill with mortar, and this will directly affect the strength of the concrete itself.

It is best to store crushed stone and gravel in bulk. And this material should be stored close to the place of its use. To avoid contamination of these materials, it is best to store the mounds on a dry tarpaulin or area with a solid base. In a simpler version, when all materials are scattered directly onto the ground, when making concrete, there is no need to use a bottom layer that was in contact with it.

Water.

A very important point when making concrete is the choice of water. It must be clean and free from foreign impurities and alkaline inclusions. Also, river or lake water should not be used. You just need to follow the following rule: the water that is suitable for drinking will also be suitable for making concrete. If you follow this rule, your concrete will be able to serve faithfully for many years.

Additives: Lime.

Most craftsmen who add a certain amount of slaked lime to the concrete composition thereby increase the workability of the concrete. This can make the process of leveling the concrete screed much easier. But still, lime can negatively affect the good bond between cement and aggregate. This in turn will affect the strength. By the way, no one has extinguished lime on their own for quite a long time. You can use already prepared lime (slaked). It can be found on sale at any hardware store.

Plasticizers.

In order to give a concrete solution good fluidity, or vice versa, to ensure maximum viscosity, as a rule, various plasticizers are used, which are ways to change the properties of the solution in the desired direction. The use of plasticizers can significantly increase or decrease the amount of water required to make a solution.

To fill the foundation, it is not at all necessary to use plasticizers, but still, they will play a big role if the foundation has a rather complex shape, or the reinforcement is more dense. And more fluid concrete can reliably fill all existing voids, which in turn can speed up the process and improve the final result.

Plasticizers for concrete. Auxiliary elements.

In addition to all of the above, it is quite possible to use special additives to give progressive properties to concrete. For example, additives can be used to harden and set concrete at low temperatures or in the presence of high humidity. Appropriate additives are also used for the required purposes. The most important thing is to determine for yourself the need for their use, and also choose the right supplement in a specialized store. In this case, it is important to carefully study the instructions on the properties and use of these additives.

In the same case, if the conditions for using concrete will have boundary parameters in terms of humidity and temperature, then the use of plasticizers and various additives will be necessary.

Reinforcing substances.

In addition to concrete filler, specific additives for reinforcement are often used. For example, when using concrete to make a thin screed, polyvinyl chloride or polypropylene fiber is usually used. This material is very soft and rather fragile, but thanks to its use, situations can be avoided when concrete begins to crack in those areas where the floor slabs meet.

Selection of the ratio of all materials for the manufacture of concrete

For certain purposes, as a rule, different compositions of concrete will be required. Let’s say that to make a foundation for a residential building, you need to use stronger concrete, which will contain large crushed stone measuring from 25 to 35 mm, and a certain amount of mortar, which will be sufficient to strengthen the aggregate. In this case, it must be fluid, since it is necessary to compact the concrete more reliably and try to remove all formed air bubbles from it. But still, before you start pouring the main amount of concrete, you must first equip the substrate. As a rule, for this purpose, simpler to manufacture and not very durable concrete B 7.5 is used, which, in addition to cement mortar, includes coarse sand. Since the concrete solution is not made very liquid, and it is more like wet soil.

To make a foundation, you need a medium fraction of filler, as well as a liquid solution. This will help ensure easier distribution of the solution over the surface in a thinner layer. In addition, the medium and fine fraction of aggregate will be necessary in the manufacture of decorative elements, balusters, or some garden utensils.

The composition of concrete by components and their ratio must be carried out in accordance with GOST 7473-94 and SNiP 5.01.23-83. In this case, you must also take into account the density of each component and the average density of concrete. After making the necessary calculations of all the ratios of the ingredients, you can begin making concrete and pouring it.

More common concrete proportions are 1:3:6 parts cement, aggregate and sand, and 0.5-1 parts water. But still, very often adhering to this arrangement, as a rule, the result will be concrete that is not very good in quality. And this can be noticed only after a certain time. It is best to make a simple calculation and prevent trouble from occurring. After carrying out the necessary calculations, you need to wisely choose the method for measuring the components. You will only have weight and volume parameters on your hands, and unfortunately, they are incompatible with them. Material such as sand may be very wet or loose. It follows that one bucket with a volume of 10 liters will not have the same weight that can be calculated from the ratio of density to volume. If you analyze the moisture content of the same sand and gravel, then you should definitely dry them, rather than calculate the required number of servings of these ingredients.

And in order to be able to determine looseness and calculate portions, it is necessary to weigh portions of each component to one volume. To do this, take a bucket or other container and fill it with sand, aggregate and cement without compacting it, and weigh the resulting portion.

Then, after carrying out simple calculations, you should convert the resulting calculations into the ratio of buckets.

How to mix concrete

Above we have described each component of concrete in detail. Now it’s worth talking about how to make concrete for the foundation with your own hands. Right now it’s worth indicating what proportions should be used in this case.

In order to replace concrete, it is necessary to use special concrete mixers. Only in this way can all the ingredients be mixed more efficiently and quickly and the resulting concrete be delivered to the desired location. You can also make concrete yourself. There are two popular options:

  • In the first option, you first need to mix all the ingredients dry, and only after that add water.
  • In the second option, cement, aggregate and sand are poured into measured and poured water.

By mixing the ingredients in dry form, it seems that all the materials are distributed more evenly, but still, when adding water and mixing yourself, there is no absolute guarantee that the entire volume can quickly get wet. The result of this work you will get the following: an unmixed dry composition will remain at the bottom. And this means violations of proportions.

If this composition is mixed for a long time and thoroughly, then a lot of time will pass, and the solution will again begin to harden and separate. And when all the necessary components are added to the water, the cement will be mixed for quite a long time and will not be able to adhere to the filler.

The second option is still slightly better than the first. Based on this, it is in this way that it is necessary to mix concrete in small quantities.

Now we were able to find out that manual kneading is not very good. The easiest way is to rent a concrete mixer or buy one. The concrete mixer should be located no further than 40-45 meters from the place where the concrete will be used. All components should also be located next to the concrete mixer.

Mixing concrete

  1. The volume of a standard concrete mixer is 200 liters of the prepared solution. For this figure, it is necessary to carry out all calculations for the number of each component.
  2. Then you need to start preparing the concrete by adding it to the concrete mixer.
  3. After which a certain amount of water is added to it. Approximately 10-15% can be added later. This in turn can facilitate mixing after adding all the materials.
  4. Next, cement should be laid. If you were left with a certain amount of water, then the cement can also be left in the same amount.
  5. Now sand is poured in. Mixing at this stage is necessary until all components are evenly distributed.
  6. After the cement mortar is prepared, the necessary additional components should be added to it. components (additives, plasticizers). The main aggregate (crushed stone, gravel) is poured last.
  7. If you need to add water, you should first mix it with cement, and pour the resulting cement lait into a concrete mixer. This procedure should take you approximately 10-15 minutes. If you stir longer, the cement in the solution will set.
  8. The solution is delivered using a wheelbarrow. If the entire mixed solution does not fit into the wheelbarrow, then its remains must be left in a running concrete mixer.

Pouring concrete

Now you need to properly pour and then distribute the concrete. The result will depend on this work, but to a lesser extent than on the two previous options. Concrete is a heterogeneous solution. This means that in order to be able to distribute it correctly, it needs to be compacted so that the filler can be more densely packed inside the solution itself. Also, you need to carefully ensure that there are no air bubbles left in the solution. For this purpose, vibration is usually used. The use of special vibrating units will help compact concrete more efficiently. For the construction of walls and foundations, a special unit is used, which is equipped with a vibrating hose. The latter is immersed in the solution, and then compacted.

To produce a thinner layer, such as a screed, surface tools with a long lath are used. Under the influence of fine vibration, the solution is mixed over the surface. The surface of the concrete, in this case, will be leveled and immediately compacted. When pouring concrete, you should use a sharp reinforcement rod and pierce it to the entire depth of the solution. This is how all the accumulated air in the solution will be released. Since the pouring occurs gradually, when piercing a new portion of concrete, it is necessary to deepen the rod 10 cm into the previous layer for better bonding. The very last step is to level the top layer. This process can be carried out in several stages, depending on the adhesion of the solution and its complete drying.

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  • What you need to know to...

    • There are several types of concrete mortar, which differ both in quality and proportional composition. The use of one or another solution option is determined individually, depending on the location of concreting. We will learn further about how to make concrete with your own hands.

    How to make concrete with your own hands, proportions and technology

    The most important component of concrete mortar is cement. Its function is to connect the other components with each other. Portland cement is an ideal option for making concrete. This is explained by the fact that it contains a large amount of calcium silicates. Thus, it is possible to achieve high adhesion between all components.

    The type of cement used in the process of making concrete mortar is determined by the individual indicators of the scope of its application. Most often, grade 500 cement is used. Lower quality grades are used to prepare concrete for surfaces that are not subject to high loads.

    Portland cement is used to improve adhesion between all components at both high and low temperatures. However, the minimum temperature for using concrete mortar is fifteen degrees. If concrete is still used at low temperatures, then its composition must contain special substances in the form of additives and plasticizers. The substance in the form of Portland slag cement is used if work is carried out at temperatures above 25 degrees Celsius.

    The amount of impurities in the cement substance should not exceed twenty percent. This is indicated in the marking indicated by the letter D. When choosing cement for the mortar, pay attention to its external indicators. It should be free-flowing and should not contain additional moisture. It is not recommended to buy material that has lumps and has a damp appearance.

    Critical elements are built from concrete, which will quickly collapse due to poor quality cement. The material should also be stored in specially designated conditions, at a temperature of 10 degrees Celsius and a humidity not exceeding 60%. Cement easily absorbs moisture and odors from the external environment and quickly loses its positive characteristics. We recommend purchasing fresh cement that will be used within one or two weeks.

    The second component of concrete mortar is sand. There are varieties of concrete solutions in which you can do without sand. This is only possible if the filler composition has no gaps or they are minimal.

    The optimal sand fraction is from one to five millimeters. When choosing sand, give preference to materials that have sand grains of equal size. Sand should not contain clay or other impurities. The presence of remnants of vegetation, stones, and construction debris negatively affects the quality of the resulting concrete solution.

    If you have sand that is not very clean, we recommend sifting it several times before use. The best option is to use river sand, the cost of which is slightly higher than regular sand. However, such material does not have clay or foreign inclusions and has good performance characteristics.

    The presence of clay in concrete is unacceptable; it negatively affects its strength and service life. The next point is to ensure maximum adhesion of concrete and coarse aggregate. These factors are the main ones in determining the overall strength of a concrete solution. In order to prepare the sand for work, we recommend washing it and leaving it to settle.

    If it was not possible to purchase high-quality sand, then the option of using artificial sand is possible. To make it, rocks are finely crushed. This sand has greater density and weight. Please note that a concrete solution made from such sand will be heavy.

    To increase the strength of the concrete solution, crushed stone or gravel is added to it. They act as a filler for concrete mortar. It is not recommended to use pebbles for these purposes, as their surface is smooth.

    When choosing a filler, ask what type of litter it is made of. The expanded clay material is lightweight, but at the same time connects all the components well. The filler size ranges from 0.8 to 4 cm. It is recommended to choose medium-sized substances. It is recommended to choose a substance that does not contain dust and clay inclusions. The reliability of adhesion is determined by the roughness of the material.

    Add a filler to the concrete solution that contains both large and medium particles. In this way, it is possible to achieve a tighter fit of the filler to the surface. Sand and filler should be located near the work site. In order to prevent contamination of sand or filler, we recommend pouring them onto a base previously covered with film.

    The last of the main components of concrete mortar is water. It should not contain alkaline or acidic inclusions.

    Substances in the form of:

    1. Lime.

    Using this material, the convenience of laying concrete mortar is increased. Thus, it is possible to improve the process of leveling the concrete solution. Lime reduces the strength of the mortar because the bond between cement and aggregates is reduced. Please note that lime must be slaked.

    2. Plasticizers.

    In order to make decorative concrete by hand, it is recommended to use substances in the form of plasticizers. With their help, it is possible to change the quality characteristics of the solution.

    3. Additional components.

    With the help of certain components, the concrete solution becomes more progressive. In addition, by using additives it is possible to improve the setting of concrete mortar. Before using additives, study their characteristics and instructions for use. If the work of pouring concrete is carried out at low temperatures, then additives cannot be avoided.

    4. Reinforcing components.

    With the help of special additives it is possible to perform additional reinforcement of the concrete solution. For example, it is recommended to add fibers based on polypropylene or polyvinyl chloride to the concrete solution used to screed. These components are soft and especially durable. In this way, it is possible to achieve ideal smoothness of the concrete and prevent its cracking.

    How to make foundation concrete by hand - composition proportions

    The composition of concrete and the amount of connection of its components is determined by the purpose of using the concrete solution. For example, in order to build a foundation, you need strong concrete, which contains large crushed stone and a mortar that secures it securely.

    At the same time, it is important to achieve fluidity of the solution, since it should not contain air bubbles or foreign inclusions. Before you start pouring the solution, it is recommended to make a substrate. To do this, it is enough to use a less durable solution containing inclusions of fine sand. At the same time, the consistency of the solution resembles wet soil.

    The foundation mortar can be made using concrete by hand. At the same time, the filler should be medium in fractional size, and the consistency should be fluid. In this way, it is possible to distribute the solution on the surface. In addition, fine or medium fraction filler is used for the manufacture of flowerpots, garden elements, and concrete balusters.

    The composition and quantity of components that the concrete solution contains are determined by SNiP. In this case, the density of each ingredient should be taken into account. We recommend using a medium-density concrete solution. After completing the calculations, proceed to connecting the components together.

    The most popular component ratio involves using one part cement to three parts sand and six parts filler, with the amount of water varying from 0.4 to 1. Water makes the solution more or less fluid.

    After determining the optimal consistency of the solution, you should measure the components. Please note that it is not recommended to use wet sand for work; it is recommended to dry it before adding it to the solution.

    Before you make concrete steps with your own hands, you need to prepare a concrete solution. Most often, a concrete mixer is used for this. This device allows you to mix all ingredients evenly and quickly. The manual method of preparing concrete mortar is relevant only if the amount of work is small. At the same time, there is no possibility of controlling the recipe in this case.

    There are two ways in which you can build a concrete solution yourself:

    1. First, the dry ingredients are mixed together, and then water is added.

    2. Sand, aggregate and cement are added to the water.

    The first option is also called dry, in which all components are uniformly mixed together. In this case, water is added last. Sometimes, this composition contains dry lumps that reduce the strength of the solution. In order to avoid their appearance, we recommend using the second method of mixing the solution. It is suitable for mixing concrete in small quantities.

    In any case, we still recommend using a concrete mixer to mix the solution. If you do not have this device, then rent it. The concrete mixer must be located near the work site. Thus, it is possible to avoid delamination of concrete during transportation.

    A standard concrete mixer contains about two hundred liters of solution. This amount should be used as a guide when calculating the amount of ingredients. The process of preparing a solution in a concrete mixer is as follows:

    1. Measure out the required amount of water and pour it into the concrete mixer. Do not fill in all the water, leave about 10% for later to bring the solution to the desired consistency.

    2. Put cement in the required quantity, also leave some cement.

    4. After preparing the cement mortar, add substances to it in the form of additives and plasticizers, if necessary.

    5. At the final stage, filler is added. If the solution needs to add water, then it is mixed with cement, the resulting mixture is added to the concrete mixer at this stage.

    All work is completed within 10-15 minutes. If it was not possible to extract the entire solution at one time, then it is constantly stirred until complete extraction.

    How to make colored concrete with your own hands

    Before making a concrete flowerpot with your own hands, we recommend painting the solution with color pigments. Modern technologies make it possible to make various concrete surfaces colorful and bright.

    Pigments are added either at the stage of preparing the solution or after the composition has hardened. There are two options for color pigments:

    • natural;
    • synthetic.

    The color palette and saturation are determined by the chemical components of the pigment. It is recommended to add pigment to the composition at the mixing stage. In this case, it is possible to achieve a uniform and beautiful color. In order to maximize the color effect on the surface, we recommend using sand and white cement when preparing the solution.

    Before adding pigment, it is diluted with water. The quality of mixing affects the homogeneity of the solution. Moreover, such a composition is prepared exclusively in a concrete mixer. It is impossible to prepare concrete mortar manually.

    Before making a concrete path with your own hands, it is also recommended to prepare a solution in a concrete mixer. This device not only saves time, but also significantly improves the quality of the finished solution.

    When pouring concrete mortar, it is recommended to use a concrete vibrator. With its help, it is possible to remove air bubbles and improve the quality of the finished coating. Additional reinforcement is provided by steel reinforcement bars. The optimal setting time for the solution is about two days. Complete drying of the solution takes about two weeks or more.

    Make concrete with your own hands video:

    Construction almost always involves the use of concrete, namely a concrete mixture, which is an artificial stone. When building a house, garden greenhouse, or fences, the foundation must be poured. Concrete is also used to make blind areas, and even pedestrian paths in summer cottages. The wide range of applications indicates the versatility of concrete as a building material.

    Concrete is made in production or the main components are mixed with one’s own hands. Mixing is carried out in wooden or metal boxes, bathtubs, and mobile concrete mixers. The latter provide the greatest productivity and high-quality mixing of mixture components (crushed stone, sand, cement, water). When making concrete with your own hands, it is extremely important to prevent foreign impurities from getting into the mixture, as well as to follow the technology and take into account the proportions (dosage).

    Concrete, classification

    In addition, specialized concretes have been developed, characterized by the presence of special impurities in them that improve certain characteristics (thermal conductivity, strength, density, etc.). For example:

    • heat-resistant (resistant to heat up to 1000 degrees);
    • road (especially bending and frost-resistant);
    • hydraulic (highly resistant to corrosion, waterproof, increased density);
    • airfield and other types of concrete for special purposes.

    Main components of concrete mixture

    If you are thinking about preparing concrete yourself, it is worth considering not only the quantity of “ingredients” used for the mixture, but also their quality, which will affect the characteristics of the finished foundation.

    Sand

    To prepare a concrete mixture, use sand with a fraction of 1.2 to 3.5 mm. Sand that is too fine is not suitable for making concrete. When choosing sand, pay attention to its purity - the presence of clay inclusions, silt no more than 5%. Otherwise, the concrete will lose its strength due to the high fat content provided by the clay and, accordingly, will quickly crumble.

    How to check the quality of sand? Just pour a little into a container with running water and shake. Clear or slightly cloudy water will indicate high quality. If the liquid immediately turns the color of clay or sediment appears, the sand is unsuitable for making concrete.

    Construction sand for concrete - photo

    Crushed stone, gravel

    The next component of the concrete mixture is crushed stone (gravel, granite screenings, scrap bricks, expanded clay, etc.). It is selected with a particle size of 1 to 8 centimeters (for self-production of concrete - from 1 to 2 centimeters), checking for cleanliness and the absence of debris and clay impurities. The use of a larger fraction of crushed stone will lead to the loss of proper strength of the foundation and at the same time to the inconvenience of the work being carried out.

    Construction crushed stone - photo

    Cement

    In addition to crushed stone and sand, cement must be added to concrete. In this case, cement consumption depends on its brand. The amount of cement is calculated strictly according to proportions; the rule “the more, the better” does not affect the quality of the future concrete.

    Cement can be:

    • Portland cement - used for all types of construction, as well as for pouring foundations, optimal for preparing concrete yourself;
    • slag Portland cement - differs from the previous one in reduced frost resistance and increased moisture resistance;
    • pozzolanic Portland cement - used in the construction of underground and underwater structures due to its high moisture resistance;
    • other types of cement with special additives that allow the mixture to harden faster, which reduces the maturation period of concrete to 14 days.

    Water

    Water must be used warm and clean, without impurities of oils, petroleum products, paints, enamels.

    Of course, it is difficult to guarantee absolute cleanliness, especially when preparing concrete yourself. It is also quite difficult in practice to verify the absolutely exact proportions of crushed stone, cement and sand up to a liter or kilogram. Additionally, it is worth considering that cement loses some of its properties over time. After just a month of storage, it will lose a tenth of its properties, and accordingly the strength of cement will decrease. During 6 months of storage, cement loses up to one third of all its properties.

    Marking of concrete and cement

    The grade of cement characterizes its compressive strength (kilogram per square centimeter of a concrete cube with a side of 20 cm 28 days after its manufacture). If there are additional impurities in the cement, then additional letters are indicated in the marking (for example, M (PTs) 400 - D20).

    The most commonly used grades of cement in concrete preparation are: M350 and M500.

    The grade of concrete (M50 - M1000) also reflects its average characteristics. In this case, the marking of concrete depends on the amount of cement used in the preparation of the mixture. The marking of concrete also indicates its class - B1 - B60, which is an indicator of strength.

    How to calculate and find out the volume of concrete

    The actual amount of concrete used is measured in cubic meters. Calculate the amount of concrete for the foundation not difficult.

    If you need to prepare 10 cubic meters of concrete, and M500 grade cement is used for its production, then you should take 1 part cement, 2 parts water, 4 parts crushed stone. From the resulting seven parts, 10 cubic meters of ready-made concrete will be made, which means 10÷7 = 1.42 m 3. This volume accounts for each part of the concrete components. Respectively:

    1. sand 1.42 m 3 × 2 parts = 2.84 m 3;
    2. cement one part, 1.42 m 3;
    3. crushed stone 4 parts 1.42 m 3 × 4 = 5.68 m 3.

    Approximate weight of materials(kg/1 m3): cement - 1500, sand - 1800, crushed stone - 1400.

    The optimal amount of water is half the volume of cement used to prepare concrete (in this case, ½ part). More water will result in a worse consistency of the mixture.

    Concrete preparation proportions

    When using cement grades M400 and M500 to prepare concrete mortar, the proportions of crushed stone, cement and sand will be as follows.

    Concrete, brand Proportions of cement M400 Proportions of cement M500

    (C), sand (P), crushed stone (Sch), kg - C:P:Sch

    		Amount of concrete produced from 10 liters of M400 cement, l Amount of concrete produced from 10 liters of M500 cement, l
    M1001: 4,6: 7,0 1: 5,8: 8,1 78 90
    M1501: 3,5: 5,7 1: 4,5: 6,6 78 73
    M2001: 2,8: 4,8 1: 3,5: 5,6 54 62
    M2501: 2,1: 3,9 1: 2,6: 4,5 43 50
    M3001: 1,9: 3,7 1: 2,4: 4,3 41 47
    M4001: 1,2: 2,7 1: 1,6: 3,2 31 36
    M4501: 1,1: 2,5 1: 1,4: 2,9 29 32

    After the amount of crushed stone, sand, cement and water is known and prepared, the mixture should be prepared. To do this, add a small amount of water to the concrete mixer, then add cement, mix, add sand, mix again, achieving homogeneity of the mass without lumps. And only now can you add crushed stone and the remaining amount of water. We immediately use the mixture for construction work.

    Maturing of concrete and gaining proper strength

    Traditionally, all work with concrete is carried out in the warm season at above-zero air temperatures. In this case, water reacts with cement and the composition hardens qualitatively. When pouring concrete in cold weather, water can turn into ice, which will cause the bud to lose strength and collapse from the inside.

    The concrete “sets” within 12 hours, hardens during the first week, after two weeks the concrete gains almost 80% of its strength, and becomes fully ready for use only after a month (provided the ambient temperature is about 20°C). If you used special types of quick-hardening concrete for pouring, the “maturation” period may be shorter.

    Video - preparing concrete

    Concrete is a unique material. It is used not only in construction for the construction of buildings, from the strongest foundation to the complete construction of walls and roofs. You can also make piece items from it, such as balusters, vases, and even for the kitchen or living room. Modern methods of concrete preparation and processing make it possible to elevate this material almost on par with natural materials such as granite or marble. Although it is not as aesthetically pleasing as the latter, it is certainly known what it is made of, and there is no obligatory background radiation that natural stones often have. If you decide to abandon purchased concrete, then you should figure out how to make concrete with your own hands of the required quality, which will solve the problem at hand and will have sufficient strength and durability.

    Although the process of preparing concrete is quite simple, it is necessary to take into account a number of features and points that will determine its quality and suitability. Depending on the purpose for which it is prepared, both the recipe and the method of its use change. So, first of all, let’s define what concrete is and what main characteristics it has.

    In general, the composition of concrete is a mixture of cement mortar and filler. So the main ingredients are:

    1. Cement;
    2. Sand;
    3. Filler (gravel, slag, crushed stone, pebbles, etc.).

    In addition, modern technologies involve the use of special additives - plasticizers. Their role is to give concrete some unique properties.

    The main characteristic of concrete is its compressive strength. We will not go into detail about how concrete was assessed for strength at different times, and will focus on the modern, universally used system. The strength of concrete is expressed in mega pascals (MPa), which determine the pressure that a certain class of concrete can withstand. Based on strength, concrete is divided into grades. In the CIS countries, according to GOST, classes are designated as B7.5 - B80. The difference depends on the type of cement used (M300-M600), sand and fraction, as well as the type of crushed stone. The number in the class name indicates the pressure in MPa that concrete can withstand in 95% of cases.

    The simplest version of concrete is a simple mixture of cement mortar and coarse sand. This type of concrete is mainly used as a base for foundations. Preparation can be done directly at the bottom of the formwork under the foundation. In this case, very little water is added so that the mixture acquires the density of wet soil. There is no need to talk about strength in this case, but such concrete is excellent as protection for the main foundation from subsidence and excessive moisture.

    More durable concrete involves the use of a variety of crushed stone as a filler with a fraction from 2-3 mm to 30-35 mm. The quality of concrete directly depends on the purity and composition of all its components. So before you figure out the proportions and preparation methods to make a concrete solution correctly, it’s worth considering each component separately.

    Requirements for concrete components

    Cement

    Cement is the main and only ingredient of concrete that binds all components together. Portland cement is the most suitable for preparing concrete. It is distinguished by an increased and prevailing content of calcium silicates (up to 78-80%), which ensures improved adhesion and bonding of materials. However, depending on the task at hand, other types of cement are also used.

    The most suitable grade of cement for private construction is 500. You can also use standard M400, but this will affect the durability of the same foundation.

    In addition to good adhesion, Portland cement is better suited for working at low temperatures. Even so, you cannot work with concrete at temperatures below 16 degrees. If there is a good reason to use concrete at lower temperatures, then special additives and plasticizers will be required, but more on that later. For work in hot weather, Portland slag cement is better suited.

    In the domestic marking of cement, in addition to the designation of its declared strength in the same MPa, which is marked as a brand, there is also the designation “D”, after which a number is placed indicating the amount of foreign impurities in the cement. Actually, for the preparation of high-quality concrete, cement M500-D0 or M500-D20 is suitable, that is, with impurities from 0 to 20%.

    The cement must be dry and free-flowing. Under no circumstances should you purchase damp or lumpy cement, and you should also not save too much and buy unlabeled, stale or discounted cement. After all, concrete will be used to construct important elements of the house, so your well-being and safety depend on it. In unsuitable conditions, cement can very quickly absorb moisture from the air and lose a significant part of its qualities.

    It is better to purchase the required volume of cement a maximum of 2 weeks before direct use or a few days in advance. Check the presence of markings and the integrity of the packaging.

    Sand

    Regardless of the aggregate used, crushed stone or gravel, sand will also be required. Only in some cases do they do without it, when it is possible to compact and select large aggregate so that the gaps between all components are minimal.

    Sand suitable for preparing concrete should have a fraction of 1.5 to 5 mm, best when it has a uniform size with a variation of no more than 1-2 mm. The sand should not contain foreign impurities. All kinds of plant debris, construction debris and any inclusions that may disintegrate or rot over time will adversely affect the strength of concrete. To be on the safe side, if the sand is not completely clean, it is better to pass it through a sieve with fairly small cells. Actually, the same applies to crushed stone.

    River sand is best suited; although it is more expensive than gully sand, it has a suitable grain size and does not contain silt inclusions or clay. Unlike cement mortars, which are used for the construction of brickwork or plastering, in which the presence of clay can only help, because it will be easier to level it, it is not permissible in concrete. It is important to ensure maximum adhesion of the cement mortar with large aggregates, which determine the overall strength of concrete. So it is better not to use sand with loam or grains less than 1 mm at all for preparing concrete, because it is very difficult to get rid of them. To do this, they use the procedure of washing and settling the sand, which, even in industrial conditions, is not always profitable or easy.

    Alternatively, for areas near which there are stone quarries, artificial heavy sand can be used. It is obtained as a result of crushing rocks and is characterized by greater mass and density. If it is washed properly and separated by particle size, it will be even slightly better than river sand. It is only important to take into account when preparing and when using that the concrete will turn out to be much heavier; this is important if it is used in the construction of screeds over interfloor ceilings. A significant obstacle to the use of heavy artificial sand may be the possible increased background radiation, which depends on that of the parent rock.

    Aggregate. Crushed stone, gravel

    The main strength of concrete comes from filling it with gravel or crushed stone. Sea or river pebbles are in no way suitable, because their surface is polished with water and does not provide proper adhesion to the solution. The best material is obtained from crushed rock.

    It is important to take into account the characteristics of the breed that was used. Expanded clay or other similar materials are also often used, which are quite durable, but at the same time light. Below we will consider the principle by which you can select the appropriate material for preparing concrete, which will provide the necessary strength and reliability for specific situations. The size of gravel or crushed stone can vary from 8 to 35 mm; larger pieces are used mostly in production, and even then rarely. As with sand, it is desirable that the aggregate contains as little dust or clay inclusions on its surface as possible. The debris must be picked out before the gravel goes into the solution. The higher the roughness on the particle faces, the better. Reliable grip depends on this.

    To prepare concrete yourself, it is better to choose either an aggregate, which itself has particles of several sizes, or mix coarse gravel with medium gravel. In the absence of professional equipment for compacting concrete, this will ensure a tighter fit of the aggregate particles to each other and will prevent the formation of large voids. Otherwise, the latter will be filled with mortar, and this will affect both the strength of the concrete and the consumption of the mortar itself.

    For storage, it is better to store both sand and crushed stone or gravel in bulk near the place of use. In order to prevent contamination of materials and moisture from the soil, it is better to place the embankments on a spread tarpaulin or an area with a solid base. In the simplest case, when materials are poured directly onto the soil, the lowest layer that is in contact with it should not be used.

    Water

    The moment of choosing water is very important. There is, of course, no question of using any special water. However, it must be clean and free of alkaline or acidic foreign matter. You cannot use river or, especially, lake water, which contains more than enough inclusions. It is best to follow a simple rule: water that is suitable for drinking is also suitable for making strong and good concrete at home. Only by following this rule can you expect that the concrete will be durable and last a long time without any damage or destruction.

    Supplements

    • Lime. Some craftsmen add a little slaked lime to the concrete composition, this increases the workability of the solution. This somewhat facilitates the process of leveling the surface of the concrete screed or cast section of the porch or outlet. And yet, in addition to this, lime can interfere with the normal bond between cement and aggregate, which will affect the strength. The choice of whether to resort to using lime or not remains with the master, when he knows exactly what is best at the moment. There is no need to extinguish lime yourself for a long time now. Instead, ready-made slaked lime is used, which is sold in construction stores and is called fluff.
    • Plasticizers. To give the concrete solution greater fluidity or reverse viscosity, various plasticizers are used, which change the properties of the solution in a given direction. The use of plasticizers can increase or decrease the amount of water required to prepare the solution. For work such as pouring a foundation, plasticizers may not be used, but they can play an important role if the reinforcement is quite dense or the foundation has a complex shape. At the same time, more fluid concrete will fill all voids and branches faster and more reliably, which will speed up the process and improve the result.

    Plasticizers for concrete

    • Auxiliary components. In addition to the above, special additives can be used to impart more advanced properties to concrete. Thus, additives can be used to ensure that concrete sets and hardens at low temperatures or in the presence of large amounts of moisture. Appropriate additives are used for various purposes. It is important to decide whether to use them and select the necessary additive at a hardware store. Carefully study the instructions for use and properties of the additive. If the conditions in which concrete will be used have limiting parameters in terms of temperature or humidity, then additives and plasticizers will be indispensable.
    • Reinforcing substances. In addition to concrete aggregate, specific additives are often used for additional reinforcement. So, when using concrete, a special polypropylene or polyvinyl chloride fiber is used to make a fairly thin screed. It itself is soft and not particularly strong, but it will help to avoid situations where concrete cracks at the points of convergence of floor slabs or in the case of an unstable base when forming the main floor on top of soils.

    Selection of ratios of materials for preparing concrete

    Different purposes require different compositions of concrete. So, to form a foundation for a house, you need strong concrete with the inclusion of large crushed stone with elements ranging in size from 20 to 35 mm, and the amount of mortar is sufficient to fix the aggregate. In this case, the solution must be fluid, because it is necessary to firmly compact the concrete and remove all air bubbles from it. However, before pouring the main part of the concrete, you should equip the substrate. For this purpose, the easiest to prepare and less durable concrete, B7.5, is used, which in addition to cement mortar may contain only coarse sand. Moreover, for this purpose the concrete solution is not made liquid, but more similar in consistency to wet soil.

    To construct foundations, you will need an average size fraction of filler and still a liquid solution. This will ensure ease of distribution of the solution over the surface in a fairly thin layer. Also, the fine and medium fraction of the aggregate is indispensable when forming elements such as balusters, decorative elements or garden utensils and fills, small elements such as a porch or steps.

    The composition of concrete in terms of ingredients and their ratio must be carried out in accordance with GOST 7473-94 and SNiP 5.01.23-83. This takes into account the density of each of the ingredients used and the required average density of concrete, which is necessary in a particular situation. After the weight and volume ratios of the ingredients have been calculated, you can begin the planned preparation and pouring of concrete.

    The most common concrete proportions are 1:3:6 parts of cement, sand and aggregate, respectively, and 0.5-1 part of water, depending on the required fluidity of the solution. However, more often than not, adhering to such a layout results in an unsatisfactory concrete result, and this will be visible only after a while, when it will be quite difficult to correct anything. It is best, in accordance with the presented regulatory documents, to perform an essentially simple calculation and protect yourself from unpleasant consequences. All this is due to the fact that both aggregate and sand, and cement, can vary significantly in density parameters and bonding characteristics.

    After the calculations, you should decide on a practical method for measuring the ingredients. After all, we now only have volumetric and weight parameters, and they are somewhat incompatible with those in a real situation. The same sand can be quite wet or excessively loose, so that a 10-liter bucket will contain far less than the weight that would be expected from calculations of the density-to-volume ratio.

    In terms of the moisture content of the same sand and gravel, it is better to dry them than to try to roughly calculate the number of servings of a particular ingredient. And to determine the looseness and remove portions, it is enough to weigh the portions of each ingredient in relation to one volume. That is, take a bucket or other convenient container and fill it without compacting it with sand, cement and filler alternately, and weigh the resulting portion. Then, through simple calculations, it will be possible to convert the previously obtained calculations into the ratio of buckets.

    With what and where to mix concrete?

    Whatever one may say, for mixing concrete it is best to use concrete mixers specially designed for this purpose. This is the only way to quickly and efficiently mix all the components and deliver the concrete to its destination before it begins to set and delaminate. The old-fashioned manual method in a tub is not particularly suitable for more or less large volumes. At the same time, there is no way to control the mixing and addition of ingredients so that this occurs according to the recipe. The last statement requires clarification. After all, many people don’t understand how, if everything is done by hand and under constant supervision, you can violate the recipe and ruin the concrete.

    It's very simple. There are two options for making concrete yourself:

    1. In the first case, first all the ingredients, or at least cement and sand, are mixed dry, and then water is only poured in.
    2. In the second case, cement, sand and aggregate are poured into poured and measured water.

    With dry mixing, the materials seem to be distributed evenly, but when adding water and manual mixing, there is no guarantee that the entire volume will get wet quickly and efficiently. As a result, it turns out that a dry, unmixed composition remains at the bottom, and therefore a violation of the proportions. If you mix thoroughly and for a long time so that there are no dry lumps left, then too much time will pass, and again the solution will begin to set and separate. This will not affect the appearance, but the strength – yes. If you add everything to water, again the cement will be mixed for too long and will not be able to bond properly with the fillers later. The second option is at least a little better than the first, so this is how concrete should be mixed in small quantities.

    So, the hand kneading option is not particularly good. It’s better to rent a concrete mixer, or buy one and mix everything in it. The concrete mixer should be located no further than 40 meters from the place where the concrete will be used. This will prevent the concrete from delaminating during transportation and mixing. All ingredients should also be nearby, or at least in parts, delivered to the concrete mixer.

    Mixing concrete

    The volume of a conventional concrete mixer is equal to 200 liters of the mixed solution. It is to this figure that all calculations for the amount of each ingredient should be made. Next, we begin preparing the concrete, gradually adding everything to the concrete mixer.

    • The required amount of water is poured. About 10-15% can be left to add later. This will make it easier to mix once all the materials have been added.
    • Cement is being laid. If water was left, then the same amount of cement should be put aside.
    • Sand is poured in next. At this stage, stir until all ingredients are evenly distributed, this is about 2-3 minutes.
    • When the cement mortar is ready, all the necessary additional components are added to it, such as plasticizers, additives, and reinforcing compounds.
    • Lastly, the main aggregate (gravel, crushed stone) is poured. If it is necessary to add water, first mix water with cement and then only the resulting laitance is poured into a concrete mixer.

    The entire process should take approximately 10 minutes. If you stir for too long, the cement in the solution may begin to set.

    The solution is transported by wheelbarrow. If the entire batch does not fit into the wheelbarrow, the remaining solution remains in the turned on concrete mixer and is mixed.

    Video: mixing concrete by hand

    Pouring concrete

    Now you need to properly pour and distribute the concrete. The result depends on this no less than on the two previous stages. Concrete is a heterogeneous solution, and therefore for its correct distribution it is necessary to compact it so that the aggregate is packed as tightly as possible inside the solution. In addition, you should make sure that there are no air bubbles left in the solution.

    Vibration is used for this task. The use of specialized vibrating units allows for high-quality and quick compaction of concrete. For foundations and walls, a special tool is used that has a vibrating hose. It is immersed in the solution, and thereby compaction occurs. For thin layers, such as screed, surface devices that have a long lath are used. Under the influence of fine vibration from the drive, it is moved along the surface. In this case, the surface of the concrete is leveled, and it is immediately compacted.

    In the process of pouring concrete, it is necessary to use a sharpened rod of reinforcement and pierce the solution to the entire depth. This releases all the air that could be stuck in the reinforcement mesh and in the solution itself. Since the pouring is done gradually, when piercing a new portion of concrete, you should go at least 10 cm deeper into the previous layer to securely fasten them.

    As a result of the described actions, the concrete filler should be compacted tightly, and an even layer of mortar should appear on the surface. The last step will only be to level the top layer. This can be done in several passes as the solution adheres and dries within two to three hours.

    If it is not possible to purchase or rent professional equipment, then you should try to do the same manually. In the case of a foundation, vibration must be created. To do this, apply uniform blows to the sides of the formwork with a sledgehammer. You should hit not on the boards of the shields, but on the beams that hold them together.

    To ensure uniform drying and protect the concrete from external factors, it is necessary to cover it with film. This will prevent the surface of the concrete from drying out too quickly ahead of the interior and will protect it from external factors such as sun, heat, cold, etc.

    The approximate time for concrete to dry to a state where you can safely step on it is 36 hours. Everything naturally depends on the thickness of the layer. It may take up to a week or two to dry completely. The concrete, in fact, will completely dry and strengthen within six months after this. Maximum strength will be achieved only after more than a year. Further work can be carried out within a week.

    Video: features of pouring concrete

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    Discussion:

      Gosha said:

      When preparing concrete, it is important to know for what purpose the concrete will be prepared! Foundation, path, etc. Or what else?
      And therefore the ratio of cement to the amount of crushed stone or gravel is also important. But the classic scheme, I think, is this: 1 bucket of water, 1 (1.5) bucket of cement, 3 buckets of sand, 3 buckets of crushed stone or gravel.
      In appearance, the solution should look like thick gray “fat” sour cream. If the solution looks a little darker (blacker), but in general the crushed stone and sand “float” separately from the water and are weakly “connected” with each other, then it means a) either a lot of water, or b) LITTLE cement!
      Then you need to add more cement until the solution again seems like thick GRAY sour cream! Gray thick sour cream is the “face” of a good concrete solution.

      In the matter of concrete (and not “mortar” for laying bricks, for example), the key and “connecting link” is still cement! It is the “main” material in the solution. Without it, everything else will not “knit” and “stick” with each other!
      .