Every person who has ever had to pour screed or masonry knows that manually mixing concrete is the most labor-intensive and time-consuming process. It requires a lot of effort from the builder. Usually everyone uses a metal trough, in which a shovel is used to make a working solution in a small volume. However, when it comes to large-scale construction (pouring the foundation, erecting walls of the house, etc.), a concrete mixer is simply necessary.
The volume of concrete that is manufactured using this equipment (per day) is several times higher than the amount of solution kneaded manually. And this allows you to significantly speed up the construction process. But how to choose a suitable device? To understand this issue, we will consider what the volume of the concrete mixer can be, what types of this special tool are, and by what criteria it should be chosen.
Types of Concrete Mixers
The choice of household and professional units for mixing concrete is so diverse that it is very difficult for an unprepared person to immediately decide and stop on one or another model. It should immediately be determined that the devices differ:
- By the principle of work (gravitational or forced kneading).
- By type of device (gear or crown).
- According to technical indicators (concrete mixer working volume, engine power and various design features).
Next, we consider each species separately.
Forced Mixing Concrete Mixers
The main difference between such units is a fixed tank. Then the solution is mixed with special blades. They are driven by a powerful engine. The dry mixture is poured into a large drum, where arachnid lobes mix all components as thoroughly as possible. It should be noted that the solution in this case is of the highest quality. However, these units are not adapted to work with coarse-grained fillers.
Usually such a concrete mixer (large volume) is used at large construction sites. For private needs, its acquisition is impractical, since a powerful engine consumes a huge amount of electricity. In addition, a large volume of concrete for small construction is not required.
Gravity devices
Concrete mixers of gravitational type of mixing are for all familiar devices of a pear-shaped form. Their principle of operation is based on the rapid rotation of the drum, inside which fixed blades are installed. They raise the solution up, after which it falls down under the influence of its own weight, mixing thoroughly. The presence of the blades prevents the mortar from slipping off the walls of the drum, so that the concrete is of good quality.
This kind of mixing devices is able to work with both small and large fillers. With its help, you can mix heavy concrete to pour a solid foundation. And also make light mortars for plastering walls or arranging screeds. Gravity concrete mixer, the volume of which can reach 300 liters, is a universal unit that is actively used both on large construction sites and for private purposes.
Types of Gravity Concrete Mixers
Gravity-type devices are divided into two groups: gear and coronal. As practice has shown, the first models are much more reliable in operation. Their mechanisms are well protected from sand and other construction debris, which eliminates the occurrence of breakdowns and increases the life of the unit itself. However, if the mechanism nevertheless fails, the concrete mixer will only have to be thrown out, since this type cannot be repaired. At the same time, the crown mechanisms are completely open, which often leads to various breakdowns. Nevertheless, they are quite easily repaired. Therefore, compared with the first type, they are much more popular.
Concrete Mixer Selection Criteria
When choosing a device for mixing concrete, it is first of all necessary to take into account its purpose. When shopping, ask yourself: how much concrete mixer will satisfy your needs and how often do you plan to use it? Based on the answers, you can understand what characteristics a suitable option should have. There are not so many criteria for choosing a concrete mixer. Here you should pay attention to the following indicators:
- Bucket capacity
- Engine power.
- The material from which the drum is made.
- Mode of operation.
- The degree of protection of the engine.
Let's consider each item in more detail.
Concrete Mixer Volume
This is the most important factor that is taken into account when buying. The main criterion by which a concrete mixer is selected is volume. Each device on the shelves of a construction store has its own technical documentation (passport). It indicates the capacity of the bucket. However, note that this figure is not an indicator of the performance of this special tool. In fact, due to some design features, the volume of concrete in the concrete mixer is only 2/3 of the declared capacity of the bowl.
If, according to the documentation, the container can accommodate 100 liters, then using this unit you can produce about 65 liters of the finished solution (for one kneading). Of course, you can fit more material into the drum. But in this case, the concrete will have a very low quality, and the unit itself will fail more quickly. But how to understand how much bucket you need for various purposes? Let's consider what capacity of a bowl should be chosen for each type of work.
How to determine the capacity of the bucket?
All units are divided into groups according to bucket capacity:
- Concrete mixers with a bucket up to 100 liters. Such units are most often purchased for home use. Their total weight does not exceed twenty kilograms, which makes it easy to move the device to the desired object. Most often they are used in the process of building small structures: baths, sheds, gazebos, etc.
- Devices with a capacity of up to 150 liters. A concrete mixer, the volume of which does not exceed this indicator, can be used to fill the foundation and erect the walls of one-story buildings. The weight of such units usually varies within 40 kilograms.
- Concrete mixers up to 300 liters. Such devices are used in multi-storey construction (houses up to three floors). They are already equipped with a loading and unloading function. And their weight usually does not exceed 50 kilograms.
- Mixing devices with a capacity of more than 300 liters. The weight of such concrete mixers directly depends on their performance. However, in any case, it does not exceed 160 kg. These units have a fairly high cost and are used only on global construction sites.
If you decide to build your own house for which you want to purchase a ready-made mortar, most likely, you will be interested in the volume of KAMAZ concrete mixer (they are popularly called mixers designed for mixing and transporting the mortar). They can accommodate from 6 to 10 m³ of concrete. Thanks to constant mixing, the material retains its original qualities for a long time. Such a quantity of concrete will be enough to fill the foundation for a small house. Moreover, in the process of work, you do not need to spend your time preparing a new portion of the solution, which greatly speeds up the pace of construction.
Material of which the bucket is made
In almost all modern models of concrete mixers, the drum casing is made of steel. Only its thickness is different. When choosing a device, consider the fact that concrete in itself is capable of corroding metal. Therefore, if you expect long-term operation of the unit, do not purchase options in which the thickness of the steel is less than 1-2 mm.
Engine specifications
The next parameter that you should pay attention to is the engine size. In the most primitive models, engines with a capacity of not more than 1 kW are installed. For the operation of such a unit, a power source with a voltage of 220 V is required. If the volume of the concrete mixer (m3) is 0.5-1, it will already have a more powerful engine that works from a network of 380 V. Since it is not always available at construction sites , you will have to install an additional generator that provides the necessary voltage.
Due to the fact that most often concrete mixers work in the open air, special attention must be paid to protecting the engine. It should be in a metal box or covered with a special casing. The mode of operation of the concrete mixer should also be considered. If during the construction you need to stop the mixing process, choose models that can work periodically. Continuous mixers are not designed to work with pauses.
What else do you need to pay attention to?
We have listed the most important characteristics that you should pay attention to when choosing a concrete mixer. Among other things, it is worth asking the seller about the manufacturer of the unit, its warranty obligations and the availability of service centers (where you can contact in the event of a machine breakdown). The country and the manufacturer are selected depending on the personal preferences of the buyer. Remember that in both domestic and import models there are both worthwhile and low-quality options.
But customer service points must be present in your city. If there are none, be prepared for the fact that in the event of a malfunction of the concrete mixer it will need to be sent to the supplier, which will take a lot of time. And most importantly - do not forget that when choosing a concrete mixer, you should give preference to models whose capacity is one third more than the volume you need.