Concrete mortar is an essential component in the construction of foundations, and the durability of the entire structure depends on its quality. It is not always possible to order ready mix, and therefore it is desirable to know how to make concrete with your own hands. Here it is important not only to observe the proportions, but to choose the right components, otherwise the strength of the solution will not be high enough.
Strength
Concrete mortar is a mixture of cement, sand, filler and water in certain proportions, which vary depending on the purpose of the concrete and the brand of cement. If necessary, plasticizers are added to the solution. The most important characteristic of concrete is its compressive strength, which is measured in MPa (mega pascals). It is according to this indicator that concrete is divided into classes. But the brand of concrete indicates the amount of cement in the mortar.
| Concrete class | Average strength of this class, kg s / sq. cm | The nearest brand of concrete |
|---|---|---|
| AT 5 | 65 | M 75 |
| At 7.5 | 98 | M 100 |
| AT 10 O'CLOCK | 131 | M 150 |
| At 12.5 | 164 | M 150 |
| At 15 | 196 | M 200 |
| IN 20 | 262 | M 250 |
| At 25 | 327 | M 350 |
| At 30 | 393 | M 400 |
| At 35 | 458 | M 450 |
| At 40 | 524 | M 550 |
| At 45 | 589 | M 600 |
| At 50 | 655 | M 600 |
| At 55 | 720 | M 700 |
| At 60 | 786 | M 800 |
M100 and M150 (B7.5 and B12.5) are most often used as a layer under the main foundation, for the manufacture of screeds, concreting paths. Concrete M200-M350 is most in demand: it is used in the construction of foundations, for the manufacture of screeds, concrete stairs, blind area. Solutions of higher grades are used mainly in industrial construction.
Plastic
An important characteristic of concrete is its ductility. The more plastic the solution, the better it fills the formwork structure. With low concrete mobility, unfilled areas remain in the screed or foundation, which leads to the gradual destruction of the concrete slab. For standard structures, concrete with plasticity P-2 or P-3 is used, for formwork of complex shape and in hard-to-reach places it is recommended to use solution P-4 and above.
Waterproof and frost resistant
Water resistance depends on the amount and brand of cement in the solution. The higher the grade, the more resistant the concrete to moisture. Frost resistance of concrete is achieved by adding plasticizers to the composition. It should be noted that these seize very quickly; if it is incorrect to calculate the amount of the mixture or use it at a low temperature, the concrete will turn into a monolithic block right in the tank.
Concrete components
Cement performs a binding function for all other components concrete mortar and the strength of the concrete itself directly depends on its quality. In private construction, cement grades M400 and M500 are most in demand. When buying cement, you should be aware that it loses its qualities during prolonged or improper storage. Within a month after manufacturing, the binding properties of cement are reduced by 10%, after six months - by 50%, after a year it is not recommended to use it at all. But even fresh cement will become unusable if dampness pulls, so it must be stored in a dry place.
Sand is the second most important component of the concrete solution. In rare cases, it is replaced with slag, while standard concrete is always mixed with sand. It is best to use coarse-grained river sand without various impurities. If only ordinary fine sand is available, it should not contain clay, earth or silt, which reduce the adhesion of the mortar with the filler. Before kneading, the sand must be sieved to remove all excess.
Aggregate
The best aggregate for concrete mortar is considered to be from 5 to 35 mm. Often crushed stone is replaced with gravel, a little less often with expanded clay. It is very important that the surface of the aggregate be rough, then its adhesion to the cement will be as strong as possible. To compact the mixture, you need to take aggregate of different fractions. Like sand, the aggregate must be clean, so it should be poured onto a prepared and compacted area or onto a spread tarp.
Additives
To give concrete frost resistance, water tightness and other useful properties plasticizers are used. They provide the setting of the solution at negative temperatures, increase its plasticity or, conversely, impart viscosity. They should be used only if it is really necessary, and you should strictly follow the instructions for their use and observe the proportions.
If a thin or unstable screed is required, reinforcing fibers are mixed into the concrete solution. They are made of polyvinyl chloride and polypropylene, their strength is small, but they perfectly avoid concrete cracking. In standard foundations and screeds, reinforcing substances are not needed.
Solution proportions
To make high-quality concrete yourself, you need to know in what proportions to mix the components. Most often, the ratio of cement, sand and crushed stone is used as 1:3:6; At the same time, they take half as much water as total weight dry ingredients. It is recommended to add water not all at once, but in several portions, so it is easier to control the density of the solution. The moisture content of the sand also has its own significance - the more it is, the less water would need. You need to measure all the components in one container, for example, a bucket. When using containers of different sizes, achieve the right proportions will not work.
When mixing, the purpose of the solution should be taken into account. For the substrate under the screed, lean concrete is made without the addition of crushed stone, crushed stone of medium and fine fractions is used for concreting the paths and the blind area, for the foundation for the house, medium-fraction crushed stone and high-quality cement. Find out the exact different brands table will help.
Manual way of mixing concrete
Mixing the concrete solution is carried out manually or in a concrete mixer. If you need to fill a large area, the first method is not suitable, as it will take too much time and physical effort. If you need a little solution, it is more convenient to knead it with your hands.
Step 1. Preparation
To prepare the solution, you will need a low wide container, for example, a large metal trough, a pick-up shovel, a bucket and an ordinary hoe.
Step 2: Dry Mixing
A bucket of cement is poured into the container, then 3 buckets of sifted sand and 5 buckets of crushed stone. Dry ingredients are thoroughly mixed with a hoe. The proportions may be different, depending on the required brand of solution.
Step 3: Adding Water
If all the ingredients are mixed evenly, you can add water. First, 7-8 liters are poured out and the contents are intensively stirred with a hoe. This process will require effort, but you need to stir very well. It is advisable to lift the bottom layer and run the hoe around the corners where dry lumps may remain. If the solution is very thick and reaches for the hoe, you need to add a little water. Properly prepared concrete slowly slides off the shovel, does not delaminate.
There is another option for kneading: first, water is poured into the container, then cement is poured. For 2 buckets of water you need 2 buckets of cement. Thoroughly mix the cement with water and add 4 buckets of sand. Mix well again until smooth. Crushed stone is poured last in the amount of 8 buckets and mixed again. Which method is better, there is no unequivocal opinion, so you should try both and determine for yourself the most optimal one.
find out correct proportions how to do it yourself, from our new article.
If the resulting concrete is too thick, a little cement is added to the remaining water, mixed well and poured into a concrete mixer. It is not recommended to stir the solution for more than 10 minutes, otherwise the cement will begin to set. Ready concrete is poured immediately onto the site or into a wheelbarrow if the concrete mixer is at a distance. It is advisable to pour out the entire solution at once, but if this does not work out, part of the mass is left in the included concrete mixer. It should be used as soon as possible.
Video - How to make concrete with your own hands
Before mixing concrete, the proportions of which will be indicated below, it is necessary to choose the right components. Generally speaking, concrete is a mixture based on all kinds of aggregates and cement. Thus, concrete contains gravel, pebbles, crushed stone, sand and cement. Among other things, special additives such as plasticizers can be used. Their task is to give concrete certain properties. Can be distinguished main characteristic concrete, which is the compressive strength. Based on the strength of the solution after hardening, it is divided into grades.
Composition of concrete
If you are thinking about how to knead concrete, the proportions of which will be indicated in the article, you first need to know what is the most simple variety concrete consists of cement and coarse sand. Such a solution, as a rule, is used as a substrate under the base of the building. At the same time, a small amount of water is added to the composition so that the solution acquires a density similar to wet soil. If there is a need to prepare more durable concrete, it is necessary to use crushed stone as a filler, the fractionation of which varies from 3 mm to 35 mm.
Selection of proportions
Before mixing concrete, the proportions must be studied. For different purposes, it will be necessary to prepare concrete of different composition. For example, if it is supposed to form balusters, then when choosing a filler, it is necessary to prefer one that has a medium or fine fraction. The same applies to pouring garden utensils, decorative elements, as well as steps. The most common proportions for the preparation of concrete are considered to be 1:3:6, with regard to cement, sand and aggregate. Among other things, it is necessary to use half or one part of water, which will be determined by the desired fluidity of the solution.
If you are thinking about how to mix concrete, the proportions of the materials must be taken into account, but it is important to pay attention to the composition of the ingredients. Thus, if the sand has more high humidity than usual, it must first be dried, as it will have a more impressive weight than that required to prepare the correct solution. The same goes for gravel.
Proportions for the preparation of a certain brand of concrete
In order to prepare from M400 cement, it will be necessary to use cement, sand and crushed stone in the following proportion - 1: 4.6: 7. But for the manufacture of concrete grade M 150, it will be necessary to prepare all the same materials, but in a slightly different ratio, while cement must be used in the amount of one part, while sand will be used in a volume of 3.5, but crushed stone should be used in proportion 5.7. For the preparation of M200 concrete, it will be necessary to prepare the listed materials in a ratio of 1: 2.8: 4.8. In order to prepare a solution of brand M 250, you need to prepare materials in a ratio of 1: 2.1: 3.9. To prepare the solution, the master will have to take materials in a ratio of 1: 1.9: 3.7. Grade concrete will be obtained if you use the feedstock in a ratio of 1: 1.2: 2.7. Concrete grade M 450 comes out if a ratio of 1: 1.1: 2.5 is applied.
Ingredients Requirements
Before mixing concrete, the proportions must be carefully studied. But it is important not only to observe the correct ratio, but also to take into account the requirements that apply to each component of the solution. For example, if you use cement grade M 400, and not the structure after hardening will not be so strong. In any case, manipulations with concrete cannot be carried out at temperatures below 16 0 C. If such a need arose, then plasticizers will need to be used.
Before mixing concrete, study the proportions well. It is important to pay attention to the state of individual components. Cement, for example, must be not only loose, but also dry. You should not buy cement that contains lumps or has high humidity. You should not buy a product that is not labeled. It is preferable to purchase cement immediately before starting work, since during storage it is able to gain moisture and lose its qualities. The recommended time for the purchase of cement is 2 weeks before the start of work.
Requirements for sand
If you have thought about the question of how to mix concrete correctly, the proportions for its preparation can be seen above. It is necessary to take into account the quality of the sand that will be used in the work. It is preferable to use sand for concrete, the fractionation of which varies from 1.5 to 5 mm. It is recommended to use sand of a uniform size, it should not contain impurities. Make sure that the sand is not construction debris and plant residues. The presence of all these components can affect After you have learned in what proportions to mix concrete, you can start work. But do not use materials that have not been tested for quality. So, for reliability, it is preferable to pass sand through a sieve. It is recommended to use river sand for high-quality concrete, despite the fact that it is more expensive than the one called ravine.
Placeholders
If you are concerned about the question of how to knead concrete, the table will help determine the proportions. It is also important to consider the quality of the fillers. They are what give strength. concrete mix after freezing. So, you should not use a regular one or one that has a smooth surface and does not guarantee adhesion to the solution. It is recommended to use material that has been crushed by nature. Among other things, expanded clay is used for the preparation of concrete, which is strong enough, but at the same time has a small weight. When choosing gravel, you need to be guided by a fraction ranging from 8 to 35 mm. Larger fractional elements are used in production, which happens very rarely. In this case, it is also important to take into account that the aggregates should contain the least amount of foreign clay inclusions. If necessary, you need to free the raw material from foreign debris. It is important to choose a filler that has the greatest roughness. This will guarantee high quality clutch.
Additional components
If you are thinking about how to mix concrete in a concrete mixer, the proportions presented above can be used by you. It is important to take into account not only the ratio, but also the need for additional components. Among them is lime. It will be discussed below. Good quality water must be used when mixing the solution. It should be clean, it should not contain inclusions in the form of acids and alkalis. It is unacceptable to use untreated or river, lake water. Drinkable water can be used in the preparation of concrete.
Additives
If there is a need to make concrete more convenient for laying, lime can be used in the process of mixing the composition. After laying the mortar prepared with its use, it will be easier to level the surface. But it is worth remembering that lime can interfere with the bonding of cement with the aggregate contained in the composition, which can significantly affect strength. Thus, it is up to the master to decide whether to use lime or not. Do not think that its application will be extremely difficult, you do not need to extinguish it yourself. Instead, you can use ready-made slaked lime sold in stores. building materials.
Finally
Before mixing concrete, the proportions (they do not differ in a concrete mixer) must be carefully studied. This will allow you to get high-quality concrete, which, after hardening, will be highly durable.
2015-07-25, 22:23
Preparing the concrete mixer for operation Installing the concrete mixer Making concrete in a concrete mixer Making mortar in a concrete mixer Making expanded clay concrete in a concrete mixer Making a cushion paving slabs Washing the concrete mixer
A concrete mixer is a very simple tool, but when working with it there are many little things that can significantly facilitate the process.
Let's talk about them.
The most inconvenience in working with a concrete mixer is the sticking of the solution on the surface of the container.
It sticks both outside, from splashes, and inside, due to non-mixing. It accumulates in the spaces between the shoulder blades and at the outlet constriction.
The simplest, and usually the most popular, but at the same time the most harmful way to remove such buildup is to tap the concrete mixer with a hammer after the adhering mortar has dried. And I will certainly not be mistaken if I assume that 90% of the mixers constantly ring under the blows of hammers and sledgehammers.
And what is the result?
1. Dents on the body, which then collect the solution even more.
2. Upholstered branded paint, and as a result, rust.
3. The impossibility of completely knocking out the dried solution, especially in the places where the blades are attached to the body.
4. The inevitable gradual destruction of the central support bearing, and the failure of the concrete mixer.
All this can be avoided, and work with pleasure with this tool for a very long time, if the container of the concrete mixer is treated with an anti-corrosion, water-repellent composition before starting operation.
Automotive anticorrosive and silicone sold in hardware stores are best suited for these purposes. One such treatment is enough for 2-3 months of continuous work, after which it can be repeated.
Autoantikor is still better. At first I covered the constriction with silicone, inside and out, but then I applied only anticorrosive. Moreover, it is the one that is done after sales training in car dealerships.
Almost nothing sticks to anticorrosive, and even to silicone, and what does catch on is easily washed off with water, but they themselves have excellent adhesion and wear resistance, which allows them to stay on the surface for a long time, in extremely extreme conditions.
A separate question on the gear, namely, can / should it be lubricated or not.
Some manufacturers say this in the instructions, but not all, and those that do, directly prohibit doing this, and here's why.
The gear is open, and in the presence of lubrication, much more debris will stick to it, even relatively large pebbles can stick and get on the tooth.
As a result, instead of the intended benefit, there will be guaranteed harm.
Let's move on to the installation.
Proper installation of the concrete mixer will save you in the future from unnecessary fuss during operation.
A stirrer is a rather heavy tool, and constantly vibrating, especially when not fully loaded, or when preparing a solution.
On soft ground, she strives to sink into it, one of her three points, and warp, and on a solid base - to move in one direction or another. Therefore, the concrete mixer must immediately be installed firmly and fixed, but at the same time mobile.
The same applies to the bath, if you use it as a container for receiving the solution. By the way, an old iron bathtub is more convenient than a square construction tub.
Firstly, it is easier to find it on the ball, secondly, it is lighter, thirdly, it is easier to wash it, and fourthly, the solution is easier and cleaner to remove from it, you just need to slightly trim the edges of the shovel, i.e. make them a little more rounded.
These conditions are achieved very simply. You need to make the following supports:
Another prerequisite is a solid platform on the loading side. It can be a sheet of iron, or at worst, wood flooring, on which sand or ASG will be poured.
It is more convenient to take them from a solid base, which is very important for large volumes. If the concrete mixer is installed on a concrete platform, this problem is eliminated.
The issue with the bath stopper is also very simple. So that it does not interfere with the selection of the solution, a piece of soft rubber is nailed to the board and brought to the hole from below. Easy to close and easy to open.
Now you can get to work.
Making concrete in a concrete mixer.
I have a separate post on proportions - here I will show the order of loading the ingredients, since it is very important, and I recommend that you follow it.
1. Water is poured
2. Cement is poured, resulting in cement laitance.
3. PGS is loaded. 
All this is done in the first boot position.
Since ASG is of very different quality, the mixture is controlled purely visually. Make sure that there are no lumps left in the mass of concrete.
Making mortar in a concrete mixer.
Load order.
1. Water is poured.
2. The plasticizer is poured.
3. Cement is poured.
4. Sand is being loaded. 
Work is done in the second loading position.
The solution is mixed much longer than concrete, and sticks to the walls more strongly, so you need to twist it longer.
About expanded clay concrete a little more. The main difference in its manufacture is that milk for it is made not only from cement with a plasticizer, sand is also added to it.
It’s just that more water is taken for expanded clay concrete, so that even after adding sand, a relatively liquid milk is obtained.
The order of work is as follows: milk is made in the first loading position, half of the volume of expanded clay is poured in the same position.
Then the concrete mixer is lowered to the third loading position, otherwise the expanded clay will not mix, due to its buoyancy, and after everything has been mixed, it rises to the second position, and half of the remaining expanded clay is added to the mixer.
When this expanded clay is mixed, raise the mixer to the first position, and fill up
leftovers. 
So, in parts, the result is a complete expanded clay concrete mixer.
Promes is also controlled visually. Make sure that all expanded clay grains are evenly covered with a film of mortar, and all of it has acquired grey colour, without red light.
Load order.
1. Water is poured.
2. The plasticizer is poured.
3. Cement is poured.
4. Sand is being loaded.
5. Expanded clay is being loaded.
Production of a pillow for paving slabs.
In a concrete mixer, you can make both liquid solutions and dry mixes. One of them is a pillow for paving slabs, which is obtained in a mixer of much better quality.
Load order.
1. Sand is being loaded.
2. Cement is poured.
Washing is crucial point working with a concrete mixer. It is especially important in the manufacture of solutions with plasticizers, which are characterized by increased stickiness, so let's talk about this in more detail.
How often to wash? After each batch when working with mortar, and before any break when working with concrete. And of course, at the end of the working day.
To ensure that there are no stickies left, it is better to wash the working mixer with strong pressure immediately after unloading.
The water left in the tank after washing is used for the next batch. And here comes the question; how to determine the amount of water remaining in the mixer after washing in order to maintain proportions.
It is determined as follows: at the beginning of work, after the first batch, in which you decide on the amount of water for the batch (it depends on the moisture content of the CGM or sand), pour this amount into the unloaded mixer, in the third loading position.
Then you estimate “by eye”, or measure the distance from the edge of the water to the edge of the mixer, and in the future, just maintain this distance for each batch.
I note that less water is used for washing than is required for the solution, and it has to be added.
Important! After finishing work, you can not leave the concrete mixer, with water from washing inside the tank, in the loading position.
You can leave it overnight only by tilting it vertically, so that everything that is washed out flows out. The fact is that cement and plasticizer remain on the walls to a greater extent than sand, and they seize under water.
In those rare cases when it is impossible to fail tap water, rinse the agitator by filling it with the required amount of water, and turn it from position to position.
True, in this case it is more difficult to rinse the outer surface of the container, and you have to do it with a brush.
I wish you success in working with such useful tool like a concrete mixer
♦
I lie on the couch, watch TV - lafa.
Suddenly there is a persistent feeling that somewhere they are thumping without me.
I’m also lying on the couch, watching TV, but already furious.
♦
-Izya and who do you think came up with celebrating this on March 8?!
-I know. This is Clara Zetkin and Rosa Luxembourg.
And why did they need it?
- I kind of think they were selling flowers.
Allowed amount from 10 rubles. up to 15,000 rubles
Exaggerate the importance of concrete in modern construction quite difficult. It is used at various stages of building a building, starting with the creation of the foundation, ending with the final decorative work on the design of the landscape of the green zone near the house.
According to its physical properties, concrete is fake diamond prepared from a specific set of components.
What is concrete made of?
All components are divided into four groups in accordance with the principle of operation of the component:
- astringent base
- mixing liquid
- aggregate
- additional substances.
Important! The materials of the last category are used mainly when laying concrete in difficult conditions or at the request of the manufacturer.
What are the main ingredients of the solution?
To create a concrete mix, prepare:
- Cement
- Rubble.
Important! A wide range of dry concrete mixes is presented on the building materials market, which are enough to be diluted with water exactly according to the instructions. But, making concrete with your own hands, with the right components, is also not difficult.
In the process of choosing a finished building mixture, be attentive to the presence of specific additives. Some of them affect frost resistance, hardening rate, degree of plasticity of concrete.
Criteria for the selection of concrete components
Water
In production processes, for the preparation of concrete mix, water is used, the composition indicators of which comply with GOST standards. At self-manufacturing prepare drinking water.
Important! Check the quality of the water, it should be free of alkalis, sugar, oils, acids and other impurities.
Cement
Common name binder, which is based on marl, calcareous, clay rocks. Most often today, Portland cement is used in construction, with a high percentage of calcium silicates in the composition.
Cement classification:
- Without additives, that is, their content in the composition does not exceed 5%. Marking "TO" or "CEM I".
- With additives, the percentage of which varies within 35. Marking D + Indicator of the content of additives in percent, for example, "D15" or "CEM II".
When buying, pay attention to the following nuances:
- admissible period of use of the mixture
- storage conditions
- make sure that the moisture level is correct, that is, that the cement is not damp
- check the flowability of the substance (it should not be stale, compressed)
- make sure each bag is labeled accordingly
- the grade of cement should exceed the grade of the planned concrete (see below) by 2-3 times.
Important! Do not buy cement too early, enough for 1-2 weeks. If the terms and conditions of storage are not observed, it loses its quality, which will affect the strength characteristics of concrete.
The choice of sand has its own conditions and requires the right approach.
Pay attention to the following points:
- Granule size. There are several types, the size range of which varies from 1.2 to 3.5 mm. Give preference to coarse sand.
Important! Please note that the smaller the granules, the greater the consumption of sand in the manufacture of the concrete mixture and the lower the strength of the finished hardened composition.
- The purity of the substance. Use the cleanest material without impurities and dirt (plant particles, silt, clay, glass, soil, dust). Check for their presence by sifting or washing the sand.
Important! This criterion affects setting degree, consumption of cement for the preparation of concrete and water.
- Flowability. The sand should be well dried, not wet, since the recipes indicate the amount of dry matter.
Important! In any state of sand, there is a certain percentage of absorbed moisture in it, which is usually taken into account when compiling the proportions of substances. In dry - this figure does not exceed 1%.
rubble
Pay attention to the following criteria:
Important! Please note that most often it is the quality of crushed stone that affects the strength of concrete.
Expanded clay
This material does not belong to the main components of concrete, but to create a lightweight solution (to reduce the load on the floors and frame of the structure), expanded clay is often used instead of crushed stone.
When choosing this material, pay attention to:
- fraction size — from 3 to 5 mm
- flowability of a substance
- purity and uniformity.
Concrete marking
The classification of concrete is carried out according to:
- class (B)
- brand (M).
The brand of concrete indicates the compressive strength and load capacity. The indicators vary from 50 to 1000 kgf / cm2. That is, for example, M300 concrete can withstand up to 300 kg / cm2.
The mortar class indicates guaranteed strength in 95 cases out of 100. The range of indicators is from 3.5 to 80.
Plan the specific type of mixture based on the purpose.
The table below shows the acceptable grades and classes of concrete with strength indicators.
How to prepare a concrete solution?
You can prepare the mixture yourself in two ways:
- manual
- mechanical (using a concrete mixer).
The first will, of course, be more laborious, but, with a small amount of work, it is quite acceptable and economical.
Use a concrete mixer for large volumes or increased requirements for the strength characteristics of the concrete mixture.
Preparatory work
Preliminary work is necessary regardless of the further method of preparing the solution. They consist in the preparation of materials.
Sequencing:
- Sift the sand.
- Wash gravel.
- Dry both substances.
Norms for the preparation of concrete
In order to get concrete of a certain brand and strength, follow the recipe.
Choose the most convenient principle for calculating the consumption of components:
- kilograms
- liters
- percentage
- number of parts.
Please take a look at the tables below for the various possible options proportions for the preparation of concrete.
Important! Please note that in each individual case, deviations from the norm are permissible, which are regulated by the quality of the materials.
Cooking conditions
When preparing concrete on your own, be sure to observe not only the technical aspects of the process, but also the conditions under which the solution is produced:
- air temperature 15-20
- humidity level within 90%.
Important! If pouring is carried out in conditions of severe aridity or low temperatures, use special additives that regulate the hardening process, thermal insulation materials and additional irrigation.
Manual method for making mortar
The procedure for preparing concrete:
Mechanical concrete preparation
Types of concrete mixers
There are two types of concrete mixers:
- gravitational
- coercive action.
In the first case, mixing occurs due to the rotation of the drum with fixed blades installed inside it. In the second, mixing is performed by blades rotating in a certain mode with a stationary bucket.
Each type has its own advantages:
- compactness, a light weight, low cost inherent in gravitational devices
- get a better mixing quality when using a forced-type concrete mixer.
Important! For self cooking concrete at home, a gravitational apparatus is quite enough. Please also note that with a very large amount of work, you will most likely need not one, but 2-3 concrete mixers.
How to prepare high-quality concrete?
In the process of preparing concrete in a concrete mixer, an important factor is the sequence of loading the components. The quality of the prepared mixture directly depends on how correctly the technology is chosen.
There are many opinions on this matter. Below is a technology for a more rational approach to doing this work.
Cooking technology
- Place the concrete mixer on a level surface.
- If necessary, create additional underlays to increase the stability of the machine.
- Lubricate the blades and walls of the concrete mixer with a mixture of water, cement and fine aggregate.
Important! This action will prevent the solution from sticking.
- Turn on the machine.
- Pour in half of the prepared water.
- Pour crushed stone into the drum - half of the total volume.
- Wait 2-3 minutes for mixing.
- Add cement.
Important! When supplying cement after crushed stone, larger aggregate fractions prevent cement from sticking to the walls and blades. Plus, crushed stone helps to break up the resulting lumps.
- Wait for some mixing time (about 3-5 minutes).
- Add sand.
- Leave to stir for 2-3 minutes.
- Add the remaining gravel.
- In the process of mixing, pour in the rest of the water, bringing the solution to the desired consistency.
Important! After adding all the components, rotation for more than 2-3 minutes is not recommended. This can lead to loss of plasticity, delamination and water evaporation.
- Switch off the unit.
Important! Observe the following safety precautions during all work:
do not stick your hands and shovel inside when rotating
wear protective gloves
do not lean close to the drum.
- Pour a small portion of the prepared mixture into a wheelbarrow.
- Check the quality of the concrete.
Important! One way to check the quality of the mortar is to make a few ribs with a shovel. If the concrete is of the right consistency, they will retain their shape. But, at the same time, the mixture should be fluid.
- Unload into a container if the desired plasticity is achieved.
- Pour the mixture back and mix again if the concrete is not ready, then unload into a container.
- Wash the concrete mixer.
Important! Consider the allowable mixing volume of the particular apparatus you have chosen. The main criterion is a large aggregate, which, if excessive, interferes with making a full-fledged batch of the proper level. For example, for a concrete mixer with a capacity of 132 liters, the maximum amount of crushed stone in one preparation is 4 buckets.
Video of concrete mix preparation
Conclusion
Ready-mixed concrete can only be used for a limited period, so plan your actions and time to avoid long-term storage mass and premature drying of the solution. This will lead to a decrease in the initial quality, and, accordingly, will affect the strength during operation.
Concrete is not an easy mixture of key components, so to speak "by eye". A really high-quality solution is prepared according to a special recipe, in which the ratio of all components is strictly observed. But how to be 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 empirically for a conventional mobile concrete mixer.
What you need to know about the main components?
The quality of the prepared concrete, and as a result, the durability and strength of the subsequent product from it, is directly affected not only by the proportions of the components, but also by their quality and proper modification.
Cement
What concrete cannot be without is cement. It depends on him how quickly the pledged 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 brand of cement is an identification characteristic by which you can determine for which work it is worth using it. It is designated simply - "M" and is measured in kg / cm 3, showing the strength of the cement.
In order not to miscalculate 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 cement M400 - M500, for other structures a solution prepared on cement M300 will be sufficient. When erecting a small building, for example, a barn or gazebo, you can use a binder with the M200 brand;
- Foundation. For arranging the foundation of small or non-residential buildings, for example, a garage (without an attic) or summer kitchen use cement brand M200. When building more solid residential buildings, cement M 400 or M500 is preferable;
- Blind area. For such work, a binder of the M50 and M150 brands would be a good option. For the repair of any surfaces, the strength of the cement does not play a special role. What can not be said about pouring floors. A specific brand is selected for the screed, depending on performance characteristics gender;
- Plaster. The excellent quality of any cement-based plaster will be good if you use the M300 and M400 binder grades.
Do not buy cement with a large margin. 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 brands of cement for the same brand of concrete, keep in mind that the higher its brand, the lower the content in the solution. The proportions of the other components will change accordingly.
Sand
Sand is an essential component for the preparation of concrete mix. It is best to use clean river or quartz sand with a particle size of 1.2 - 3.5 mm. If clods of clay come across in the total mass, then this is the first sign of a low-grade aggregate, because clay fairly “eats” the strength of the concrete solution. In some cases, the use of crushed gravel is acceptable.
rubble
Crushed stone is a coarse aggregate that gives concrete high compressive strength. The criterion by which it is selected for private construction is fineness - 1-2 cm. Larger fractions are intended for factory work. Also pay attention to the cleanliness of the gravel and the presence of clay inclusions.
Water
In individual construction, the quality of the water used is not critical. You can use any, as long as it is clean, does not contain oil and other chemical impurities.
Concrete Mix Proportions
The concrete mix recipe for any brand is calculated in kilograms, but if it is not possible to weigh each component in order to prepare the solution, then you can maintain the correct ratio by measuring the ingredients in 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 vibrating or careful manual laying.
Designation: C - part of the cement; P - part of the sand; U - part of the gravel; W / C - the 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 \u003d 0.5, then you need 10 kg of cement * 0.5 \u003d 5 liters of water per part. Increasing is not recommended, it can 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.
Another nuance, if it is required to manufacture concrete for the foundation, or other purposes with special properties, for example, with increased strength, then superplasticizers are suitable for giving them. correct dosage the instructions that come with the supplement will tell you. Its calculation is based on the amount of cement used in one batch.
Preparing the concrete mixer for work
Before proceeding directly to concrete work we will conduct a short briefing 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, an open question remains for you about how to work with a concrete mixer, then go over the Internet and watch a video review of how to knead the mortar in your model.
The main rule is that after each batch, especially after the last one, always carefully clean it from the remnants of concrete. The hardened stone will affect the convenience of work, the quality of the batches and the performance of the concrete mixer.
To make the preparation of 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;
- Arrange so that it is most convenient to download materials.
If your plans include pouring the foundation with a concrete mixer with your own hands, then you can position it so that the finished solution immediately pours 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 adjusted, the better the components will mix and the better the mixed concrete will turn out. The correct location is well shown in the attached video.
Do-it-yourself concrete preparation
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. a large number the resulting composition.
To solve these serious issues at once, you need to know how to knead and load the concrete mixer and follow it strictly.
Before you prepare concrete, you need to prepare the materials in advance by calculating the proportions in buckets so as not to be distracted in the process.
Step 1. Fill in water. But not the full amount, but about an eighth.
Step 2. We fill up most of the gravel and turn on the concrete mixer. The first of the materials is loaded precisely with a large aggregate so that it breaks the mortar 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 that the solution is homogeneous.
Step 4. The turn of sand has come. We fall asleep the entire prepared volume, while we do not stop mixing concrete in a concrete mixer. It is very important at this stage to achieve a uniform consistency without lumps of sand.
Step 5. To complete the preparation of the solution, you need to add the rest of the rubble. When everything is well 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 working concrete mixer down so that the mixture pours into the prepared bucket.
Step 7 Do not forget to clean the used unit with water and a trowel, even if you still plan to prepare concrete in a concrete mixer today.
In conclusion, to learn more about how to properly mix concrete in a concrete mixer, check out the prepared video.