How to make concrete mortar in a concrete mixer? Preparing concrete in a concrete mixer: working tricks and correct proportions.

During construction, you can often encounter the problem that manually mixing the required volume of cement mortar becomes almost impossible.

The technology for loading a concrete mixer differs from the manual method - in volume and time.

But unlike the usual manual method, concrete mixers have their own loading technology. Moreover, the technology does not depend on size, because the principle remains the same. Thus, the loading order of the automixer will differ from an ordinary mixer only in volume and time, and everything else will remain unchanged. But sometimes conditions arise under which it is impossible to load correctly, in which case you will have to take a more difficult path.

Mixture parameters

The first step is to calculate the volume and quality of the material for a specific mixer. After which you can begin the mixing process itself. There are several options here:

Before the mixing process, it is necessary to calculate the volume and quality of the material.

Initially, water is added to 15% of the total volume of the mixture. And only then you can load sand and cement at the same time. If you don’t pour them in at the same time, you won’t get the required consistency. This option takes much longer, slightly reduces the results (sometimes lumps may form), but is almost always used due to its simplicity and lack of need for additional equipment.
Water and dry mixture are supplied simultaneously, but this is not always possible, because it is difficult to accurately control that their feeding is uniform. Although this option allows you to achieve an ideal result, it is used extremely rarely.

The rotation speed of the mixer (bucket) must be exactly the same as stated in the passport, because it is calculated experimentally so that the ideal result can be correctly created. If you artificially increase the speed, the centrifugal force will change, and then the solution will mix worse. In the process it will look like this: the ladle rotates, and along with it, a good part of the solution rotates on its walls. A similar experiment can be carried out by filling a container with water and making a revolution at a decent speed (the easiest way is with a bucket). As a rule, if the bucket is not completely filled, not a single drop will spill out even in a vertical position.

If the speed is reduced, the mixture will turn over in one place, which in best case scenario will lead to low quality solution, and in the worst case, lumps will appear in it. Each bucket has its own rpm, which depends on its volume and physical minimum and maximum limits (usually 12-20 per minute).

Mixing the solution

The duration of mixing the solution is calculated individually due to various circumstances.

The duration of mixing the solution is a very delicate matter. It is important to strictly monitor the limits, because... Prolonged mixing will increase the strength of the future concrete, while excessively long mixing will reverse effect. For example, for load-bearing walls of a building, the mixing time will be from 4 minutes, while for partitions this time will be more than enough. If an even greater effect is needed, for example, for the foundation, floors or other places where the load will be extremely high, then the time should be multiplied by 2. In cases where work is carried out in winter time you can safely increase the time by another 1.5 times. There are cases when something is being built that requires extremely high strength indicators, but here the time is calculated individually each time due to various circumstances.

There are several options for determining the mixture ratio, one of which is designed for industrial scale, the other for smaller volumes. So in the first case, the calculation is for 1 m³ of solution: 160 liters of water, 320 kg of cement, 763 kg of sand, 1100 kg of crushed stone. The data is taken relative to grade 200; if the grade increases, the amount of cement increases, the water ratio decreases slightly, and sand and crushed stone are adjusted in relative proportions.

Calculation of the mixture ratio has several options: industrial scale and smaller volumes.

When mixing in small concrete mixers, a ratio of 1 part cement, 3 parts ASG (sand and gravel mixture), and as much water as required is used. The process of loading the mixer is carried out correctly, starting with ASG, followed by cement, and only then water. This sequence allows you to initially mix the dry mixture, and then dilute it. The rules do not regulate this, but only in this case can you achieve maximum quality. The only thing you should not forget about is turning on the mechanism. For low-rise construction this will be enough, but multi-storey buildings or those requiring increased strength will no longer be possible to build.

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 preparation of concrete and its processing make it possible to elevate this material almost to the same level as such natural materials like 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 radiation background that is often present natural stones. If you decide to abandon purchased concrete, then you should figure out how to make concrete with your own hands required quality, which is suitable for solving the given problem 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:

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

In addition modern technologies require 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 type 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 good reason If you use concrete at lower temperatures, you will need special additives and plasticizers, but more on that later. For work in hot weather would be better suited Portland slag cement.

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 amount 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 remains, construction garbage and any inclusions that may disintegrate or rot over time will adversely affect the strength of the 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 ravine sand, it has suitable size grains and does not contain silty inclusions and clay. Unlike cement mortars, which are used for the construction 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 by crushing rocks, differs in 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 using that the concrete will turn out to be much heavier; this is important if it is used in screeds on top 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 strong, but at the same time light. Below we will consider the principle by which you can select suitable material to prepare concrete that 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 solid foundation. In the very simple 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 be guided simple rule: water that is suitable for drinking is also suitable for making durable and good concrete Houses. Only if this rule is observed can one expect that the concrete will be strong and last for 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 makes the process of leveling the surface somewhat easier. concrete screed or a cast section of a 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 whether to resort to using lime or not remains with the master, when he knows exactly what is best in this moment. There is no longer any need to extinguish lime yourself. 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 dense enough or the foundation 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. In this way, additives can be used to ensure that concrete sets and hardens when negative temperatures or in the presence of large amounts of moisture. Appropriate additives are used for various purposes. It is important to determine the need to use them and select the necessary additive in 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 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

For various purposes it is required and different composition 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 proportions of concrete are 1:3:6 parts, respectively, of cement, sand and aggregate 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. Best according to the presented regulatory documents 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 in a practical way measuring 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 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. Next by 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. However, there is no way to control the mixing and addition of ingredients so that it happens 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.

Everything is very simple. There are two options for making concrete yourself:

In the first case, first all the ingredients, or at least cement and sand, are mixed dry, and then water is only poured in.
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. On appearance this will not affect the strength, yes. If you add everything to water, again the cement will be mixed for too long and will not be able to properly adhere to 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 cement mortar ready, all necessary additional components are added to it, such as plasticizers, additives, 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 stage All that remains is 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.

For uniform drying and protection of 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 the point 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. 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, walkway, etc. Or what else?
And therefore the ratio of cement to the amount of crushed stone or gravel is also important. But 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” to each other!
.

Concrete is not a simple mixture of key components, so to speak “by eye”. A truly high-quality solution is prepared according to a special recipe, in which the ratio of all components is strictly observed. But what if there are no scales at hand, but only an ordinary shovel and a universal household bucket? The answer is simple, you need to use the proportions of concrete in buckets that have long been verified experimentally for a conventional mobile concrete mixer.

What do you need to know about the main components?

The quality of prepared concrete, and as a consequence the durability and strength of the subsequent product made from it, is directly affected not only by the proportions of the components, but by their quality and correct modification.

Cement

What concrete cannot exist without is cement. It determines how quickly the embedded product will gain strength and how durable it will be. Of the variety of binders presented - Portland cement of a certain brand - the best choice. It provides better adhesion of materials.

The grade of cement is an identifying characteristic by which you can determine for what work it should be used. It is simply designated “M” and measured in kg/cm3, indicating the strength of cement.

In order not to make a mistake either in terms of quality or economics, you need to know which cement is best suited for certain jobs:

Masonry. If under construction bearing wall, then it is best to use M400 - M500 cement; for other structures, a solution prepared with M300 cement will be sufficient. When constructing a small building, for example, a barn or gazebo, you can use binder grade M200;
Foundation. For constructing the base of small or non-residential buildings, for example, a garage (without an attic) or summer kitchen use cement grade M200. When constructing more substantial residential buildings, cement M 400 or M500 is preferred;
Blind area. For carrying out such work, a good option would be binders of the M50 and M150 brands. For repairing any surfaces, the strength of cement does not play a special role. The same cannot be said about pouring floors. A specific brand is selected for the screed depending on the performance characteristics gender;
Plaster. Great quality any plaster mortar cement-based will be good if you use binder grades M300 and M400.

You should not buy cement in large quantities. After a month it begins to lose its brand strength, after two it will be -10%, after six months -50%, and after a year it is better to throw out the cement, since it will still be unusable.

When using different grades of cement for one grade of concrete, keep in mind that the higher the grade, the lower the content in the solution. The proportions of the remaining components will change accordingly.

Sand

Sand is an integral component for cooking concrete mixture. It is best to use clean river or quartz sand with a particle size of 1.2 - 3.5 mm. If there are lumps of clay in the total mass, then this is the first sign of a low-grade aggregate, because clay significantly “eats” the strength of the concrete mortar. In some cases, the use of crushed gravel is acceptable.

Crushed stone

Crushed stone is a coarse aggregate that gives concrete high strength for compression. The criterion by which it is selected for private construction is size - 1-2 cm. Larger fractions are intended for factory work. Also pay attention to the cleanliness of the crushed stone and the presence of clay inclusions.

Water

In individual construction, the quality of water used is not critical. You can use any, the main thing is that it is clean and does not contain oil or other chemical impurities.

Concrete mix proportions

The recipe for a concrete mixture for any brand is calculated in kilograms, but if it is not possible to weigh each component to prepare the solution, then you can follow correct ratio measuring the ingredients into buckets. Since each such universal tool has a different displacement, we will consider the recipe in relative parts to the proportion of cement. The calculation is given for plastic mixtures that require subsequent vibration or careful manual laying.

Designation: C – part of cement; P – part of the sand; Ш – part of crushed stone; W/C – quantitative ratio of water to cement. Having this indicator, you can easily calculate the amount of water, for example, 1 part of cement is equal to 10 kg, and W/C = 0.5, then you need 10 kg of cement * 0.5 = 5 liters of water per part. It is not recommended to increase it, as this may lead to poor quality concrete. But if the aggregates are wet, then it is worth reducing the amount of water, gradually adding it to the desired consistency.

One more nuance, if you need to produce concrete for a foundation, or for other purposes with special properties, for example, with increased strength, then superplasticizers are suitable to impart such properties. The instructions included with the supplement will tell you the correct dosage. Its calculation is based on the amount of cement used in one batch.

Preparing the concrete mixer for work

Before you start directly concrete work We’ll give you a little instruction for those who are tormented by the question: “how to use a concrete mixer?” The answer is simple: there is no trick to it. First you need to carefully study the attached instructions. But if, after studying it, you still have an open question about how to work with a concrete mixer, then search the Internet and watch a video review of how to mix the solution in your model.

The main rule is that after each batch, especially after the last one, always thoroughly clean it of any remaining concrete. Hardened stone will affect the ease of use, quality of batches and performance of the concrete mixer.

To make preparing concrete in a concrete mixer as convenient as possible, place the concrete mixer based on three criteria:

Ensuring an unhindered supply of electricity;
Location in close proximity to ongoing work;
Place it so that it is as convenient as possible to load materials.

If your plans are to pour the foundation with a concrete mixer yourself, then you can position it so that the finished solution is immediately poured into the formwork. To avoid losses when supplying the solution, you can make a metal damper, as shown in the photo.

So that the prepared batch of heavy concrete in a concrete mixer is different good quality, you need not only to know how to knead it correctly, but also to correctly position the mixing drum. The more horizontally it is set, the better the components are mixed and the better the quality of the mixed concrete. The correct location is clearly shown in the attached video.

Making your own concrete

Few people know how to properly mix concrete so that all components are mixed as much as possible, the solution is of the required consistency and avoid sticking of a large amount of the resulting composition.

To solve these serious issues at once, you need to know how to mix and the procedure for loading a concrete mixer and strictly follow it.

Before preparing concrete, you need to prepare the materials in advance, calculating the proportions in buckets, so as not to be distracted during the process.

Step 1. Fill with water. But not the full amount, but about an eighth.

Step 2. Fill in most of the crushed stone and turn on the concrete mixer. The first material to be loaded is the coarse aggregate so that it breaks up the solution in the concrete mixer, preventing the formation of lumps.

Step 3. Add all the cement. How long to knead the concrete at this stage? It is enough for the solution to be homogeneous.

Step 4. It’s time for the sand. We fill in the entire prepared volume and do not stop mixing the concrete in the concrete mixer. It is very important at this stage to achieve a uniform consistency without lumps of sand.

Step 5. To finish preparing the solution, you need to add the rest of the crushed stone. When everything is thoroughly mixed, pour two parts of the prepared volume of water and bring the composition to a homogeneous mass.

Step 6. To unload the resulting concrete, carefully turn the running concrete mixer down so that the mixture is poured into the prepared bucket.

Step 7. Don’t forget to clean the used unit using water and a trowel, even if you still planned to prepare concrete in a concrete mixer today.

In conclusion, to learn in more detail about how to properly mix concrete in a concrete mixer, check out the prepared video material.

Every master who takes up work for the first time preparing concrete in a concrete mixer, the question invariably arises: how to do this so that the resulting mixture is of truly high quality. Some of the secrets and subtleties of working with a concrete mixer will be discussed in the article.

Making concrete in a concrete mixer - types of units

To begin with, let's briefly talk about the two main types. The first of them are gravitational-type devices. In concrete mixers of this type, blades rigidly fixed to the drum body are responsible for mixing the solution. The angle of inclination of this drum, which rotates around its axis during operation, can be changed. This is done in order to regulate the intensity of the kneading. They are very convenient to transport because they can be easily disassembled if necessary.

The second type of concrete mixers is forced action devices. Unlike gravitational “brothers”, they have a stationary body, inside of which the blades rotate. Mixing concrete in a concrete mixer of this type occurs much more thoroughly, so they are used to prepare thick solutions in which the amount of water is small. Buy such a unit for a not very large volume construction work not worth it, since its price is about ten times more than that of a gravity-type device. Typically, such concrete mixers are purchased if you plan to produce wall blocks.

The process of preparing a solution in a concrete mixer

Final concrete grade depends on what kind of cement is used to mix it and what the proportions are. As a rule, most craftsmen use “four hundredth” and “five hundredth” cement. For example, when using cement M400, crushed stone or gravel, sand and water, taken in proportions 2:8:4:1 (this is the ratio used in most cases), you will get concrete grade M250. If the same mixture is made based on cement M500, then the output will be the composition of the brand M350.

When purchasing cement, be sure to ask the seller for a certificate of conformity.

When loading a concrete mixer, you need to pay attention to the total quantity of all components - you cannot overload the unit. This quantity is determined by the nominal capacity of the drum, which must be indicated in the instructions for the device. When adding “ingredients” you must follow a strict sequence. First, water is poured into the drum, then cement, then sand and gravel or crushed stone. The solution is kneaded until completely homogeneous - this applies to both the color and consistency of the “dough”.

How to mix concrete in a concrete mixer - the intricacies of working with the unit

There are several rules for working with concrete mixers that will help make the unit more efficient and durable. Before you start loading components, you need to install the device on a strictly horizontal surface; if necessary, wooden spacers can be placed under its legs. If the mixer is installed even at a slight angle, the mixing may not be of very high quality, and the unit will deteriorate over time. This is especially true for forced action machines.

The operating time for gravity and “forced” devices is different - in the first case it is usually two minutes, and in the second - one. An increase in this time can lead to the evaporation of a certain proportion of water and, as a result, to a decrease in the plasticity of the composition. You can check the readiness of the concrete by pouring a small amount of it into a wheelbarrow or trough, and creating several “ribs” with the back of a shovel. If they do not fall off, then it is ready, otherwise it is sent for revision.

Naturally, a certain amount of concrete is glued to the surface of the drum and blades during the mixing process. Because of this, the amount of cement and sand in the finished mixture may decrease, so during the first batch, their original amount should be increased by about a tenth. However, you can somewhat reduce sticking by wiping the blades and drum "working out". Don’t forget to wash the inside of the concrete mixer after finishing work, otherwise the concrete will harden and can only be removed by disassembling the structure.

Adding ingredients and pouring concrete is only possible with the drum rotating.

So, now you know how to prepare a solution in a concrete mixer. By following these rules, you will not only be able to make high-quality concrete, but will also extend the life of this simple, but so indispensable unit at a construction site.

Despite the advantages of ready-mixed concrete, builders are often forced to prepare the concrete mixture themselves. Most often, this need arises when it is necessary to fill small screeds, paths, reinforced concrete structures, steps.

Self-production of concrete - cost

Let's look at the recipe for creating the M300 concrete mixture.

Raw materials required to create 1 m 3 of ready-mixed concrete M300:

Cement M500 (see cement grades) - from 300 to 350 kg. average cost A 50 kg bag of cement of this brand costs 190 rubles. To prepare ready-made concrete, you need 6 bags of cement, therefore the cost of purchasing it will be 1140 rubles.
Sand – 600-700 kg. Difficulties may arise in purchasing this raw material, since many companies supply it only to large volumes. But there is sand on the market, which is packaged in 50 kg bags. The cost of one bag is 150-200 rubles. Based on these data, the cost of purchasing sand will be 1,800 rubles.
Crushed stone - 1200 kg or 0.8 m 3. The average price of crushed stone is 1,200 rubles per 1 m 3. The cost of purchasing raw materials will be 960 rubles.
Water – from 150 to 180 liters. Water tariffs are quite low, so we do not take water costs into account in the cost of finished concrete.

The total cost of purchasing all raw materials will be 3,900 rubles.

It is worth noting that on the market ready-made M300 concrete costs from 3,500 to 4,000 rubles.

So when self-production There is practically no saving mixture, but it is advisable to create it when construction work is carried out at intervals or the object is located remotely from the nearest concrete plants.

Features of self-preparing concrete using the mechanized method

Depending on the required amount of concrete, mechanized and manual method kneading. The mechanized method involves the use of a concrete mixer (the most correct name is a concrete mixer).

The device has the following characteristics:

The motor power of an electric concrete mixer can vary from 550 to 800 W.
Action type. In accordance with this characteristic, concrete mixers are distinguished that can operate continuously and with mandatory downtime intervals.
Drum volume. Equipment with a drum capacity of 125 to 140 liters is well suited for small construction work, and concrete mixers with a capacity of 150, 160 or 180 liters are designed for large-scale work.
The operating principle is gravitational and forced action type concrete mixers.

The cost of concrete mixers varies from 6,000 to 15,000 rubles.

In this material we will look at the features of preparing concrete using the ZITREK Limex 125 LS concrete mixer, the drum volume of which is 125 liters and the price is 9,599 rubles.

So, to mix M200 concrete yourself in a concrete mixer you will need:

1 bucket of cement;
2.5 buckets of sand;
5 buckets of crushed gravel;
1 bucket of water.

The sequence of actions when preparing a concrete mixture yourself:

1. Turn on the concrete mixer and pour water into it.

2. Pour a bucket of crushed gravel into a concrete mixer.

4. After a few minutes, add 2.5 buckets of sand to the solution.

5. Then add the rest of the crushed gravel to the mixture.

This completes the preparation of concrete.

The concrete mixer mixes the mixture well for a few minutes and then it can be used.

If you need to prepare concrete manually, then you need to use a special rake, an old trough or bathtub.

Useful tips to help you prepare high-quality concrete

When choosing raw materials, it is worth remembering that river sand is best suited for preparing concrete. There are no clay inclusions in it, which is of decisive importance during winter concreting.
Crushed stone must be washed. The choice of a specific type of this component depends on the requirements for the structure being poured. For example, gravel and crushed granite have high frost resistance and strength. Concrete containing such crushed stone is more resistant to water, frost and other external factors. It is advisable to use dolomite crushed stone to create low grades of concrete mix.
Water for preparing the mixture should not contain sulfates and salts. In winter, the water needs to be heated to 40? C.