Preparing concrete in a concrete mixer, we work correctly and safely

Although mixing concrete in a concrete mixer can seem intimidating, it’s simple and safe to do with the correct technique. It can save you time and guarantee the best results whether you’re working on a small DIY project or a larger construction job if you understand the process.

A concrete mixer is a necessary tool for producing concrete of superior quality. They assist in evenly blending cement, sand, gravel, and water to create a mixture that is perfect for your project. When mixing concrete properly, a mixer not only yields better results, but it also simplifies the process considerably when compared to hand mixing.

When using concrete mixers, safety must always come first. Accidents and injuries can be avoided by taking the necessary safety measures and adhering to regulations. You can operate with assurance and effectiveness if you are familiar with the tools and follow safety procedures.

In order to guarantee that your concrete has the optimal consistency and strength, this article will walk you through all of the crucial steps involved in preparing concrete in a mixer, from material preparation to mixing techniques. Let’s examine how to operate your concrete mixer safely and correctly.

Careful planning and adherence to safety precautions are necessary when mixing concrete in a concrete mixer in order to guarantee a high-quality outcome and avoid mishaps. You can create a robust, long-lasting mix by adhering to a few basic guidelines, such as accurately measuring the ingredients, adding them in the proper order, and cleaning the mixer. Furthermore, minimizing risks through the use of appropriate safety gear and cautious equipment handling makes the process safe and efficient for all parties involved.

What other issues will we touch on in the article

We’ll also give safety a lot of thought. Let’s talk about mixing other materials in a mixer, especially since industrial forced-action mixers are used to prepare concrete.

If they inquire, "What to interfere with concrete?," we will probably limit our discussion to the gravity kind. The procedure is demonstrated in the article’s video (below), albeit with a few minor mistakes.

Large volumes and light mixes are better suited for forced effects. You practically never find these kinds of devices at home because of their high cost and large size.

Preparing a concrete mixer for work

As mentioned in the introduction, the target audience for our piece is anyone who is unfamiliar with concrete mixers. As a result, we go beyond the tale of how to tamper with concrete in a concrete mixer. At the outset of the exercise, consider if you had previously purchased a comparable unit.

Having bought a new concrete mixer

Prior to using a concrete mixer on site, make sure you read the operating instructions. The first rule is this one, which is seldom followed because instructions are typically examined only after issues or breakdowns are detected.

I should point out that it covers the majority of the topics we discuss in this article, such as how to mix concrete correctly in a concrete mixer (assuming the manufacturer is a reliable and accountable one).

Then take these actions:

• Unpack and remove all devices and materials that were intended for transportation.
• If it was delivered disassembled, then assemble according to the instructions.
• Inspect the mechanism for visible damage.
• Remove the preservative grease.
• If specified in the instructions, check for grease in the gearbox – top up if necessary.

• For models with a crown drive, check for grease on the crown and drive gear. If necessary, lubricate.

• Connect the unit. In this case, we use cables with a cross-section of the cores corresponding to the power consumption of the device. Be sure to connect the ground. For safety reasons, it is advisable not to be satisfied with the presence of a grounding wire in the power cable (it may not be grounded, but only neutralized), but to additionally connect a reliable ground to the body. The connection line must have automatic fuses and RCDs that cut off the current supply in the event of a short circuit.

Pay heed. Pay attention to the cable’s insulation as well as its cross-section because the latter is what will shield it from the inevitable mechanical damage that comes with working on a building site.

• We install the mixer on a level surface, skewing is undesirable, as it causes additional vibrations. The base must be solid. An unstable unit can spontaneously "go", or even the preparation of a solution in a concrete mixer will end with it tipping over – and this threatens injury.

• Doing a test run. Many people do not recommend turning on the mechanism with an empty drum. But in fact, the mass of the drum quite loads the motor. After checking the operation at idle, load the mixer with sand for testing. We rotate the drum for several minutes at different angles of inclination of its axis.

If the examination turned up no issues with how it was operating, which include:

• Uneven rotation of the drum with jerks.
• Difficulty turning the drum relative to the vertical.
• Extraneous noises and squeaks.
• Activation of electrical safety devices.
• Rotation of the drum in the opposite direction indicated by the arrow (for three-phase electric motors it is not important; this can be eliminated by switching one phase)
• Also pay attention to the electric motor – it should not get very hot and emit a strong foreign smell (burnt insulation).

You can get ready for the initial mixing of the concrete.

Preparing the mixer for work

The first step in the process of preparing concrete in a concrete mixer is unit preparation. We perform the same procedures as when inspecting a new device if there was an extended period of inactivity on the part of the concrete mixer.

You’ll only be able to check for damage and grease buildup on the crown if there was no break. It’s also a good idea to lubricate the drum with grease at the end of the job to make cleaning its interior surface easier.

In industrial settings, a water emulsion based on mineral and synthetic oils, petroleum products, or their waste is typically used for this purpose. You can use "waste" (oil drained from the car when changing) when doing manual labor at home. The mixer is then prepared for use.

After work

As soon as the process of producing concrete in a concrete mixer is finished, we will explain what happens next. There are no particular needs; just use water to completely clean the mixer of any dirt or mortar residue before unplugging it from the network. It will be challenging to remove the fresh mixture later on once it has hardened, particularly in the areas where the blades are attached.

A weak solution of hydrochloric acid is used for cleaning in the construction industry in addition to mechanical methods. You can apply the same technique at home. However, frequent chemical cleaning is not recommended because it damages the metal.

In order to prevent corrosion, it is advised to lubricate moving parts and surfaces with thick grease before a lengthy work stop.

Mixing the concrete mixture

We must choose the type of mixture we will make before we begin to mix. As such, we ascertain the concrete recipe right away.

Calculation of the composition of concrete

Concrete recipe

We start by getting the initial data ready. At the factory, they precisely ascertain the required strength and study each ingredient in the mixture.

Knowing the class (brand) of concrete we must use and the cement’s brand is sufficient. This data will be our starting point. Next, you can locate the tables with the indicated proportions or utilize the online calculator. One of these tables is shown below.

Pay heed. Concrete is now categorized by classes rather than brands (the average compression strength expressed in kgf/cm2). Class is an MPa strength that is 95% guaranteed. Tables can be used for translation, or you can divide the brand into ten and identify a close one that differs in the smaller direction in the classes by 2.5–5. M100, for instance, is B7.5, and M400 is B35.

The class of ready -made concrete	For cement M400			For cement M500
	The ratio of mass (kg of sand; crushed stone, 1 kg of cement)	The ratio of volume (l sand; crushed stone per 1 liter of cement)	The release of the mixture by volume from the volume of cement (l of the mixture of 1 liter of cement)	The ratio of mass (kg of sand; crushed stone, on g cement)	Ratio by volume (l of sand; crushed stone per 1 liter of cement)	Mixture yield by volume from cement volume (l of mixture from 1 l of cement)
B7.5	4.6;7	4.1;6.1	7.8	5.8;8.1	5.3;7.1	9.0
B12.5	3.5;5.7	3.2;5.0	6.4	4.5;6.6	4.0;5.8	7.3
B15	2.8;4.8	2.5;4.2	5.4	3.5;5.6	3.2;4.9	6.2
B20	2.1;3.9	1.9;3.9	4.3	2.6;4.5	2.4;3.9	5.0
B22.5	1.9;3.7	1.7;3.2	4.1	2.4;4.3	2.2;3.7	4.7
B30	1.2;2.7	1.1;2.4	3.1	1.6;3.2	1.4;2.8	3.6
B35	1.1;2.5	1.0;2.2	2.9	1.4;2.9	1.2;2.5	3.2

This is a rough recipe for concrete that calls for crushed stone and regular sand. The numbers will inevitably alter if we prepare lightweight concrete using expanded clay or expanded perlite. We won’t go into more detail because calculating the composition is not the focus of our article. Locating the required reference materials is simple.

We also require water in addition to sand, cement, and crushed stone. The quantity of cement determines the quantity of water. Since both an excess and a shortage of it will weaken the final concrete, adding cement by eye is not worth the trouble. The term "water-cement ratio" is real.

The ideal ratio of water to cement varies between 0.6 and 0.4 and is contingent upon the aggregates and curing circumstances. Consequently, assuming an average value of 0.5, it means that twice as much water should be added as cement. It can be decreased by adding a plasticizer (the additive’s instructions will specify by what percentage).

Other additives are added to the mixture in addition to the plasticizer, including:

• hardening accelerators and retarders;
• pigments;
• compositions for performing work in winter (including regular salt);
• polymers to impart special properties to the mixture;
• microfiber to increase strength.

It is best to pay attention to volumetric proportions when mixing. It is simpler to measure the amount using a bucket or measuring cup than it is to weigh each component individually before loading.

Preparing the mixture

Once you’ve chosen the recipe, you can get to work. We’ll go over the steps involved in mixing concrete in a concrete mixer correctly.

Suggestions. It’s usually not a good idea to prepare an entire drum at once. You might not have enough time to lay a big quantity at once if the mixer has a respectable capacity. Determine the volume such that one batch will last for one to two hours; the mixture won’t have time to solidify during this time.

Next, carry out the following actions:

Pay heed. The engine is turned off during the entire process of loading components and unloading the mixture. Avoid using your hands or any other object while the mixer is running. Even with the low rotation speed, this can still cause injury.

• If we are going to introduce additives, then measure them, as well as the amount of water needed to dissolve them (this water is taken into account in the total volume needed to prepare the mixture) and mix.
• Put the mixer drum in the loading position, add crushed stone and part of the water (with the volume in which the additives are dissolved). Thus, we will achieve the fact that before the introduction of cement into the mixture, the surface of the crushed stone will already be well moistened, and the cement dough will envelop it well. With this mixture, turn on the mixer for 15-20 seconds.

• Then add sand, cement and the remaining water in small portions, the drum rotates all the time.
• When all components are loaded, tilt the drum to the mixing position 35-40 degrees. If we are stirring a drum that is not full, we can lower it lower – the main thing is that the mixture does not splash out. In general, the best mixing quality is achieved with a horizontal position of the drum axis. But in this case, the number of components that can be loaded decreases – and, consequently, the yield of the mixture. Continue stirring the mixture for 1-2 minutes.

• Do not delay the mixing time too long. For the task: how to prepare concrete in a concrete mixer with high quality, the rule “longer means more thoroughly” does not work. The fact is that with intense mixing, water is evaporated, which is needed to clip the solution.
• When mixing is finished, do not rush to unload the entire solution at once. Check the quality, at least visually. Most recommendations: how to prepare concrete in a concrete mixer, suggest this method. Take a shovel of the mixture and put it in a wheelbarrow or on a platform. Run the shovel over the top. A good mixture should be uniform and smooth and retain its shape. If you see any defects, then throw the solution back into the mixer and turn it on for a while.

Safety requirements

Even though we have already discussed the concerns surrounding safe work, we will revisit this subject. Nonetheless, work ought to be enjoyable and shouldn’t be detrimental to one’s health.

Keep an eye on the following:

1. Monitor the serviceability of the unit, be especially responsible for its electrical equipment. The power cable must be intact and the ground must be connected.
2. Clothes and shoes for work should not only be comfortable, but also not to have hanging ends (floor, belts) that can be captured by the mixer mechanism. It is better to use special clothing, as in the photo.

• Free the area where you work from all unnecessary things, so as not to accidentally trip or catch. This also applies to the paths along which we bring or transport concrete components and the finished mixture.

Step	Description
1. Gather Materials	Get cement, sand, gravel, and water. Ensure you have the right proportions.
2. Safety First	Wear gloves, goggles, and a dust mask to protect yourself.
3. Prepare the Mixer	Set up the concrete mixer on stable ground and check it for any issues.
4. Add Water	Pour a small amount of water into the mixer first to prevent dry materials from sticking.
5. Add Dry Materials	Gradually add cement, sand, and gravel into the mixer.
6. Mix Thoroughly	Let the mixer run for a few minutes until the mixture is even and smooth.
7. Check Consistency	Ensure the concrete is not too dry or too wet; it should hold its shape without crumbling.
8. Clean Up	Clean the mixer and tools immediately after use to prevent the concrete from hardening on them.

For a variety of construction projects, mixing concrete in a concrete mixer is a productive way to produce a high-quality mix. You can make sure the concrete is mixed correctly and safely by adhering to the correct protocols and safety guidelines.

First, assemble all required tools and supplies. To ensure that the proportions are correct, measure your ingredients precisely. This aids in getting the concrete’s desired strength and consistency. It’s important to add water gradually to prevent overly wet mixes.

Keep a close eye on the mixer’s rotation and mixing times as you operate it. To make sure all the ingredients are combined evenly, don’t fill the mixer to capacity. When the concrete is ready, move it quickly to the work area to avoid it hardening inside the mixer.

The first priority should always be safety. To protect yourself from dust and debris, put on safety gear like gloves and goggles. Keep your workspace clear of obstructions and spotless to avoid mishaps.

You can efficiently and safely produce high-quality concrete by following these guidelines. This guarantees that the foundation for your building projects is sturdy and dependable.

Video on the topic

RBG-200 Gambit concrete mixer. Preparation of concrete, launching loaded, review.

CONCRETE M 300. Mixing in a 120-liter concrete mixer. Reinforcing the foundation.

Concrete mixer for 1 bag of cement. Please write in the comments your proportions of the solution

What is the optimal volume of a concrete mixer.