How to make concrete in a concrete mixer. How to Use a Portable Concrete Mixer Properly: Instructions, Warnings, Pro Tips

In order to competently prepare a concrete mix at home, it is important not only to observe the proportions of the components and the rules for their preparation, but also to achieve its maximum possible uniformity. When kneading with your own hands in a conventional container, it is difficult to achieve the desired uniformity, some of the lumps remain dry. These problems are completely eliminated when preparing concrete in a concrete mixer. It is recommended to knead it in a mechanized way in case of large volumes of work: when pouring a foundation or screed, building structures, sidewalk paths, bases for fences.

It is believed that the use of a concrete mixer allows you to get a solution 40% stronger than with manual preparation. An additional advantage of automation is the saving of time and a significant reduction in the labor intensity of the process; if the well-established scheme of actions is followed, the kneading takes several minutes.

Preparing the Components

The composition of home-made concrete includes: cement, sand, crushed stone and water, sometimes modifying additives are introduced to enhance certain properties. The strength, frost resistance, water resistance and characteristics of the mixture depend on the quality of the incoming ingredients. It is necessary to carefully select raw materials and prepare them before loading into the concrete mixer. Special requirements are put forward for cement; concrete should be mixed from high-quality grades with a calcium silicate content of at least 80%. The fresher the binder, the better, it is not recommended to buy it earlier than 2 weeks before the start of work. Under no circumstances shall damp, unmarked or hardened cement be used.

To prepare a quality solution, dry and clean sand is required, without clay and debris. Optimal size fractions - from 1.5 to 5 mm, ideal - within 1–2. It is advisable to sift it through a construction sieve and dry it. Dust particles less than 1 mm impair the quality and strength of adhesion, it is better to buy river quartz or artificial heavy sand. In the latter case, the weight of concrete will increase, which will limit its use when pouring interfloor ceilings.

Gravel or crushed stone of large rocks is considered the optimal coarse-grained filler. When buying, attention is drawn to the flakiness and size of the fractions, these characteristics must be indicated in the instructions. Before starting work, they are washed and dried, large debris is removed.

It is recommended to mix concrete from cubic rough crushed stone with different sizes, voids are not allowed. The water used is clean and drinkable, without alkaline or acid inclusions; it is undesirable to take it from a river or lake. Additives deserve special mention, depending on the requirements for concrete, the following are introduced into the composition:

• Hydrated lime (fluff), to increase the workability of the solution (but in small proportions, otherwise strength will decrease).
• Plasticizers - to increase fluidity.
• Auxiliary modifiers that provide setting when negative temperatures or excess moisture.
• reinforcing additive.

The ratio of ingredients

The ratio is selected taking into account the intended purpose of the solution, grades with a minimum strength are used to fill the pillow under the foundation or for temporary formwork. For durable structures with expected heavy loads, it is necessary to prepare a concrete mixture of at least M300, which implies the choice of Portland cement from M400 and hard rock crushed stone. The main unit of measurement is the measure of the binder, it is better not to add more than 50% of the liquid from it. The proportions most in demand in practice are 1: 3: 6: 0.5 (cement: sand: filler: water, respectively).

The standard volume of a concrete mixer is 180 liters, given that the working container is placed at an angle, it is not recommended to load it by more than a third (the exact value of the free volume is indicated in the instructions). That is, in order to prepare a solution with a strength of M400, with the transfer of the mentioned proportions to the weight category, you will need at least: 14 kg of cement, 42 sand, 84 gravel and 7 liters of water. The output will be about 60 liters or 147 kg of finished concrete. It is not recommended to mix concrete with an overloaded concrete mixer, in addition to splashing out the solution, some of the components may not fit, which will lead to a violation of proportions.

step by step technology

Actions take place as follows:

1. Preparation of components.
2. Installing a concrete mixer.
3. Mixing, introduction of additives.
4. Unloading concrete.
5. Cleaning of equipment and tools.

For convenience, all components are placed near the concrete mixer (this is necessary for independent work). The solution should be kneaded in a specially designated area with a flat surface. Skewed axle of the concrete mixer leads to damage to the blades and uneven mixing. Therefore, bars, pieces of rubber or other types of sealant are placed under the equipment, they start work after checking the horizontal level in at least two directions.

An important nuance of the technology is the order of loading the components into the concrete mixer. There are several opinions on how to prepare concrete correctly, in particular, when mixing with your own hands, sand and coarse filler are combined in a separate container in advance to avoid lumping. The use of a concrete mixer eliminates this problem, but for high-quality adhesion of all materials, a certain laying pattern is required.

First of all, water is poured into the bowl, then cement, sand and gravel, plasticizers and additives are introduced in portions last. A certain interval is expected between the bookmarks of individual ingredients - 1-2 minutes. About 10-15% of water and cement are left for later and added to achieve the desired consistency in the form of cement laitance.

The residence time of the mortar in the concrete mixer is limited, the norms are regulated by GOST 7473-94. The minimum mixing time depends on the W/C ratio and is:

• for forced action mixers - from 50 to 120 seconds;
• for gravity - from 60 to 150.

Concrete with porous aggregates should be kneaded even longer, and the time is increased for concrete mixers with a large volume. After loading all the components, the concrete mixer bowl rotates for about 2 minutes. Due to this, the risk of moisture evaporation and loss of plasticity by concrete increases. It is impossible to leave the solution in the concrete mixer, this leads to delamination and sinking of heavy fractions to the bottom. Therefore, the concrete is completely unloaded and, if the equipment is no longer needed, then it is washed. It is recommended to prepare the formwork or area for pouring in advance.

Nuances and tips

1. It is not allowed to put a shovel into a rotating concrete mixer, it is undesirable to bend over it.

2. Do not mix concrete for more than 5 minutes.

3. To check the quality of cement and filler, as well as the proportions, it is better to prepare a test mix of the mortar.

When performing construction and repair work often requires the preparation of a solution. To facilitate this operation, concrete mixers are used. The principle of operation of a concrete mixer is simple: a certain amount of water is poured into the device, sand, cement, gravel or other fillers are poured. When the unit is turned on, the blades inside the drum thoroughly mix all the components for a few minutes until an absolutely homogeneous mass. It remains to deliver the solution to the place of its use.

The use of a concrete mixer greatly facilitates the preparation process

For the preparation of the solution, concrete mixers of the gravitational type and the forced principle of operation are used.

A feature of the gravity-type concrete mixer is a movable drum with special blades on the walls.

In the first case, the mixing of the mixture occurs inside the rotating drum with blades. Such units are easy to transport, they are easily assembled and disassembled in a few minutes. The cost of installation varies from 4500 rubles and above.

The forced action agitator has a fixed drum. Rotating paddles inside the drum mix the ingredients. Such installations work more efficiently than gravitational ones. With their help, you can prepare a thick and dense solution with a minimum amount of liquid. But they cost 10 times more. It makes sense to purchase such units for your own use if you need to perform large amounts of work using the solution. For example, for the manufacture of concrete paving slabs at home.

The main advantage of forced concrete mixers is the high quality of mixing.

Working with a concrete mixer of any type allows you to prepare a mortar for the construction of brick and block walls, for plaster and concrete screed various surfaces.

In hardware stores, there is a large selection of concrete mixers for private use. All of them are gravity type. They are driven by a gear rim from an electric motor or a belt drive. The power consumption of the motor is about 700 W. This is 3 times less than the power of an electric kettle. Drum capacity is about 160 liters. This is enough to cook 100 liters. There are mixers with a drum with a capacity of 60 to 240 liters.

Beginning of work

When working with a mixer, you must follow some rules, follow the recommendations of equipment manufacturers. It is not recommended to change the angle of inclination of the working drum. By changing the angle of the drum, you can slightly increase the amount of mortar in each batch, but this will lead to poor quality and reduced uniformity, to an additional load on the engine and rotation transmission mechanisms.

The agitator must be properly positioned on a level surface before operation. Working blades are wiped with machine oil or technical grease.

Cooking

Before starting the mixing of the concrete mixture in the mixer, it is necessary to prepare the components in the required volume.

The preparation of concrete in a concrete mixer begins with the preparation of the required amount of cement, sand, crushed stone or expanded clay of the desired fraction. All ingredients must be pure, without clay additives. Subject to these simple conditions you can get high quality concrete. Cement and sand are mixed in a dry state (you can do this in another container). After crushed stone falls asleep. Water is added last. After loading the ingredients into a working drum, after 3 minutes, you can check the quality of the concrete: a small amount of it is laid out on a smooth horizontal surface and several “ribs” are made with the back of the shovel. If they keep their shape, the solution is mixed correctly.

For high-quality mixing, it is necessary to change the working blades in a timely manner if they break or deform.

You can often hear: "I clean the drum with a shovel." How to clean the concrete mixer correctly? With repeated use of the technique, the drum is periodically washed with a stream of water from a hose or from a bucket. When washing, gravel can be added to the water: it absorbs the remains. The solution cannot be left in the working drum, since after hardening it will be very difficult to remove it. When trying to knock out dried pieces of concrete from the drum, you can damage the mixer mechanism and deform its shaft.

After use, the drum of the concrete mixer must be washed with a jet of water from a hose.

All solutions are prepared on the basis of cement, sand and water. Depending on their purpose, gravel, expanded clay, additives and plasticizers, pigment dyes are added to the composition. To obtain lightweight concrete, granulated polystyrene foam is added to the composition. This additive helps to increase the thermal insulation of concrete. To properly lay the floor on it, it is necessary to make a screed with reinforced concrete 4 cm thick.

The frost-resistant additive allows the use of the ready-made solution at low temperatures.

Epoxy additives are used to increase the plasticity, water resistance and hardness of concrete.

Depending on the purpose, concrete is added different kinds additives.

There are water-repellent and waterproofing additives. They are used in mortars in the construction of swimming pools, other tanks for liquids, underground parts foundations.

Appropriate accelerators and retarders are used to slow down or accelerate the setting of concrete.

If you add special dyes to the solution, you can get brighter seams when laying bricks or blocks.

Plasticizers saturate the solution with many air bubbles and make it more convenient to use.

For the construction of the foundation, for screeding floor surfaces, for casting all kinds of beams and slabs, a concrete mixture is kneaded. Before it is poured into concrete, metal reinforcement in the form of rods and meshes is added. The result is reinforced concrete.

Practice shows that when working with a mixer, it is better to take cement grades M400 or M500. A bucket of cement consumes 3 buckets of sand. For cement M500, you can take 4 buckets.

There are 2 ways of loading components: 1) water-sand-cement-sand; 2) cement-sand-crushed stone-water.

How to mix the solution correctly? There is such a method of mixing. Water is poured into the concrete mixer, and the unit is put into operation. 2 buckets of sand and a bucket of cement are poured into the drum. The last bucket of sand comes after the cement. After 5 minutes, the solution is ready. If it is too thick, add a little water. The mixer then works for another 3-4 minutes.

The mortar for laying bricks and foam blocks is prepared somewhat differently. All blades are removed from the drum. Sand is poured, cement is added in small portions, then water (everything is done with a rotating drum). The solution sticks to the walls, so it must be periodically removed with a small spatula. After obtaining a homogeneous mass, the mixer is switched off. The solution is correct. In addition to cement, sand and water, lime and plasticizers can be added to the mixture.

When working with a large volume of concrete, the best option may be to deliver it with a special concrete truck. It is also called a concrete mixer, concrete mixer. Outwardly, it looks like a large barrel, standing on a car frame with a slight slope. During the movement of the car, the barrel rotates around its axis, so the solution in it is constantly mixed. Such a concrete mixer is capable of delivering up to 10 cubic meters to the construction site at once.

http://youtu.be/SnAbUMtmpGs

The composition and quality of the solution depends on its purpose. A good batch has the consistency of a fairly thick dough. It should not have lumps. If posted on flat surface, then the mass should be slightly blurry, but not spread. A freshly prepared solution must be used up within one or one and a half hours. Some builders fill the unused solution overnight with a small amount of water and cover it with a film, and mix again in the morning. This should not be done, since the quality of the solution after repeated mixing will be very low.

http://youtu.be/Jgh-7tV_y-8

Delivery

To deliver the finished solution to the place construction works it is best to use polymer buckets.

Preparing the solution is the beginning of the work. It still needs to be delivered to the place of use. In domestic conditions, ordinary buckets are most often used for this purpose. It is not recommended to use galvanized ones: their handles quickly become unusable. Such buckets are very poorly washed, the solution on their walls accumulates more and more each time. It is better to use polymer buckets. Containers from under the finished putty showed themselves especially well. They can last for several years without losing shape or breaking handles. Their volume is usually 17 liters. They have a reliable and durable design, are made of high-quality material, do not stick to the solution, they are easy to clean, and also have very comfortable metal handles.

Not a single construction event can do without the use of mixtures and concrete for a long time. Even if the house is wooden, it still needs a foundation, and the surrounding area needs landscaping and the construction of engineering structures. Role cement mortars is very significant and the durability of the structure directly depends on the quality of their preparation.

That is why the question of how to properly mix concrete in a concrete mixer is so relevant today for private developers.

Components of concrete mixtures

To obtain high-quality concrete using a concrete mixer, first of all, it is necessary to observe the correct ones, which include:

• cement, as a binder;
• sand;
• gravel or crushed stone;
• water;
• specialized additives.

Proportions of concrete mix.

Special additives include (substances that prevent the rapid freezing of the mixture at low temperatures and accelerate the hardening process), dyes and others.

The ratio of the main components determines the brand of concrete, its physical and mechanical characteristics. Same way big influence the quality of the prepared mixture is affected by the amount of water, which should not exceed half the mass of the cement being added.

Gravity type concrete mixer.

Types of concrete mixers

For the preparation of concrete solutions, equipment manufacturers today offer gravity, forced and vibration types.

Gravity mixing devices are a rotating mixer mounted on a frame and having a drive, which can be manual, electric or with an internal combustion engine. The most common mechanisms are electrically driven.

When the mixer rotates, the components are picked up by the blades inside it, rise to the top of the container and, under the influence of gravitational forces, fall down. A few minutes of this rotation guarantees a well-mixed solution.

The volume of the working capacity of gravity mixers for private construction varies from 60 to 250 liters, which allows you to choose the most suitable model for any type of work performed.

The relatively low cost of these mechanisms contributes to their widespread use both by individuals and in construction teams.

Forced-type concrete mixers are more complex in design and less common than gravity mixers. They are a fixed, horizontally located container, inside of which there is a rotating auger with blades. When the screw rotates, the embedded components are thoroughly mixed, allowing you to get quality material. The main disadvantages of such mixers include:

• the presence of sealing elements on the screw;
• more complex loading of components and unloading of the finished solution;
• high cost due to more complex design.

Vibratory concrete mixers are used in industrial preparation concrete mixtures. These are large-volume vertical containers with top loading of materials and bottom unloading of the finished product. Simultaneously with the components, one or more mechanical vibrators are lowered inside this container, due to which the solution is mixed. In private construction, devices of this type are used extremely rarely.

General technology for mixing concrete mixtures

Before working with a concrete mixer, you should know that technological process concrete preparation and mortars consists of several stages, each of which can affect the quality of the resulting material:

• proper installation of the concrete mixer;
• preparation of the mixing mechanism for operation;
• mixing;
• unloading the resulting solution;
• care of the mixer after the end of work.

Loading components into the concrete mixer.

The concrete mixer must be installed on a level ground in order to prevent it from tipping over during operation and excessive load on the moving mechanisms. The disconnecting device must be located on the mixer or in its immediate vicinity. Before working with a concrete mixer, it is necessary to provide a place for placing the constituent components and a container into which the finished material will be unloaded.

So that when loading dry sand and cement, they do not stick to the walls of the mixer, it is recommended to moisten inner surface liquid cement laitance. The loading of the constituent components is carried out as their specific gravity decreases.

Half of the required volume of sand is poured first, then gravel and, finally, cement. Water is added gradually and last. Any special additives are pre-dissolved in water and added along with it.

Stirring continues until the mass becomes completely homogeneous. It should be remembered that too long mixing of the solution can lead to a decrease in the plasticity of concrete. Do not allow the loading of components in an amount exceeding the nominal volume of the mixer, as this sharply reduces the quality of mixing.

The unloading of the finished material should be carried out only in an intermediate special container, with its subsequent transfer to a wheelbarrow, buckets or stretchers. Unloading the mixture from the mixer with a shovel is unacceptable.

After finishing work, it is necessary to draw water into the mixer and turn on the concrete mixer in order to rinse the internal volume well. It is also necessary to wash the unloading container and other tools involved in the process.

control edges.

If this is not done, then the next time the remaining particles of the set solution will not affect the quality of the prepared mixture. The concrete mixer with an electric drive after work must be de-energized and completely disconnected from the electrical network.

Finally

High-quality preparation of concrete and mortars in a concrete mixer is based on the correct ratio of the components of the mixture and proper care behind the operating mechanism. Therefore, even before starting work, you should accurately determine the brand required material and strictly follow the technology of its preparation. The rest is simple. Even a person with no experience in construction can prepare a concrete solution using a concrete mixer.

A concrete mixer or concrete mixer has been working on large construction sites for several years now, replacing a lot of workers and saving time.

Outwardly, this equipment resembles a large barrel with an open top, which is placed on a frame at a slight slope. The drive of the equipment can be both automatic and manual.

There is a mass various types concrete mixers - their classification depends on the principle of operation of the concrete mixer. The simplest and most popular option is a concrete mixer with special blades inside the bowl that mix the mixture.

There are other types of technique that are used if it is necessary to obtain homogeneous compositions: the blades inside the bowl move, periodically stirring the mixture.

Even if you buy an electric concrete mixer, the main thing is to set up the equipment correctly, since the fraction of concrete depends on the movement of the blades.

How to work with a concrete mixer - simple rules for work

Hardware stores offer a large number of models of concrete mixers for domestic needs and construction in private households. All of them are quite simple, use the gravitational principle of mixing (in the vast majority) and are driven by a belt drive or a cast iron gear from an electric motor. The average power consumption is about 700 watts.

All variants of models are quite affordable. With proper operation, the question of how to prepare concrete in a concrete mixer is successfully solved by all models. With an average drum volume of about 160 liters, the output of ready-made concrete or mortar is standard 2/3 or about one hundred liters.

But, as in any business, you need to know how to work with a concrete mixer. First of all, follow the instructions in the user manual. Do not change the recommended drum angle. The gain in increasing the volume will be “compensated” by the deterioration in the quality of mixing and the decrease in the uniformity of the composition, the increase in the time for its preparation and the additional load on the electric motor.

For the manufacture of concrete, cement must be poured directly into the equipment tank and sand must be added there, observing the proportions indicated on the cement bags. Having started work, it is necessary to switch the relay of the unit to the smallest speed. Initially, it should work at low speed for a minute, until the cement and sand become one mass, and then you need to add water in a certain amount and increase speed.

The concrete mixer should work until a homogeneous mass is formed, that is, until the concrete is completely ready. After that, you can turn it off and use the finished product for its intended purpose.

The resulting mixture in its consistency must certainly be of medium density and homogeneous. To get the resulting concrete, you need to lower the concrete mixer latch a little, after which the concrete itself will pour into the container intended for this.

In addition, to strengthen the concrete, you can additionally add crushed stone to it, which is poured at the very end of the batch after adding water and obtaining a homogeneous mass.

Important operating notes

To understand how to use a concrete mixer, you must first study our recommendations. As a result, it turns out that due to ignorance, money for repairs is lost.

The engine housing must not be covered, as this will disrupt the cooling process. If the engine overheats, it will automatically "shut down" from work. After the device has cooled down, you can turn it on again. But it's better not to let that happen.

Careful attitude - this is what will serve as a "guarantee" of the normal operation of any equipment. In no case do not leave the solution inside the drum after work, since you are unlikely to be able to remove the hardened cement without harming the device. That's why the best way keeping the concrete mixer in its normal condition - maintaining cleanliness during periods of use.

At the end of the last construction season, I once went to hardware stores. Without any specific goal, just to see what is being sold and at what price.

And it so happened that in Castorama I saw concrete mixers at a price of 4,000 rubles, when in the season they cost all 7,500 rubles.

My economical soul could not resist such a temptation, and the concrete mixer was bought and settled for the winter.

And at the very beginning of this construction season, when I started building a garage for 2 cars, a concrete mixer acted as the main supplier of mortar for the foundation at this construction site.

When the mortar for the foundation can be made in a concrete mixer

When is it advisable to mix the foundation mortar in a concrete mixer?

Firstly, when the volumes of the required solution are small. If you need to fill the foundation, and you decide to stop at the option with a basement or with a slab with an area of ​​​​100 sq.m., then mixing the mortar for the foundation with a concrete mixer looks at least unreasonable.

The volume of concrete for a foundation of this size will exceed 20 cubic meters, which you will not mix with your "mini-mixer" in a digestible time.

But when a small volume of mortar is required, then a concrete mixer is what you need.

Look, the average batch with a small concrete mixer is from 150 to 300 liters of mortar. You will be pouring a large foundation at this pace for 20-30 days.

And there is nothing worse for the strength of the foundation than layering concrete in small layers over a long period of time.

Secondly, it is possible to mix the mortar for the foundation with a concrete mixer when it is not possible to adjust the mixer to the place of acceptance of concrete or it is not possible to reach the concrete pump supply pipe there.

When might such a situation arise? For example, when pouring screeds over large areas under already installed or indoors, on the floors of the house.

Then it makes sense to install a concrete mixer on the ceiling and mix the mortar right on the spot, pouring screeds or monolithic ceilings right through the premises.

There is one “but” in this option… The volumes of produced concrete should also be relatively small. For 10 batches, you must make 1.5-2 cubic meters of mortar, which will be laid within 2-3 hours.

The proportions of the solution for the foundation in a concrete mixer

In order for concrete to gain the required strength in a timely manner (see the graph of strength gain by the foundation), it is necessary to withstand correct proportion solution.

For a foundation mix made in a concrete mixer, you need to take one part of cement, three parts of sand and five parts of gravel.

For example, for one batch in a 180 liter concrete mixer, you will need 2 buckets of cement, 6 buckets of sand and 10 buckets of gravel. You can use crushed stone instead of gravel when kneading - the mixture for the foundation will turn out even stronger. It is only better not to use crushed granite, stop at crushed dolomite, it will provide better adhesion in the prepared solution.

We begin to produce all batches in the morning, while it is still not hot, in the chill. Before lunch, we manage to make 15 batches and pour one section of the foundation for the garage. After that - a smoke break and lunch. Foundation work is one of the most difficult construction jobs. You have to fiddle with a mass of rubble and cement, which literally "pull" the strength out of the workers - the most inconvenient materials for moving around the construction site.

We make all loads with shovels, measuring once how many shovels of sand, crushed stone and cement should be thrown into the concrete mixer for one batch. I have a 200 liter concrete mixer. The proportions of the mortar for the foundation when mixing in a concrete mixer, which must be maintained, see above - I already wrote them.

Foundation mortar in a concrete mixer - we consider finances

What can be said about the financial component of this process? There is no particular money gain when mixing a mortar in a concrete mixer if you buy all the ingredients - sand, gravel and cement.

However, one of my neighbors dumped gravel directly from the river in several steps with his trailer. Then he brought two trailers of sand from the quarry. He bought cement through acquaintances somewhere at the base very cheaply. He, when mixing concrete with a concrete mixer, gets an almost free solution for the foundation when he pours the base under his own.

So, in this matter, it increasingly depends on the initial price of cement, sand and gravel, and only then, on the advisability of using a concrete mixer in small batches or in hard-to-reach places.

After all, now they carry concrete with small mixers, 3 cubes each. These small cars can drive through an area with unprepared access roads. A concrete pump can reach generally to any corner of the site. But it costs a lot of money.

Therefore, the financial factor still plays the main role in the use of a concrete mixer for mixing mortar - did you manage to buy cement, sand and gravel cheaply.

If so, use a concrete mixer. If not, do you think, is it worth it, and why not call a small mixer with concrete?