How to create your own cement production. It's all about proportions: what cement is made of so that the foundation stands for a long time

Instruction

For the manufacture of solution you will need a plastic or container, it can be an old, unnecessary bucket. It is important to remember that in order to prepare such a mixture river sand is not good, you need to dig up the sand in. And the cement itself must be dry and not have lumps.

After mixing, add water to the container, the volume of which should be equal to the volume of cement. Mix the components thoroughly until a homogeneous mass is obtained. You do not need a mixture of liquid, as it will not be able to stick to the spatula. The cement mortar is ready, you can get to work.

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note

The prepared solution should preferably be used within two hours. After that, it can become quite dry.

Useful advice

After the cement work is completed, thoroughly wash the container in which the cement mortar was mixed so that its residues do not stick to the surface of the bucket.

Execution of construction or repair work does not do without cement mortar. It is used for leveling walls, stone work, floor screeds, etc. It depends on him how strong the masonry will be, the strength of the structure and the durability of the structure as a whole. Therefore, every builder should know how to make a solution.

It's important to know

Materials for construction and repair have a shelf life. Therefore, before making a solution and using it for work, you need to find out how long the cement has been made and under what conditions it was stored. cement can
stored for 6 months, but always in a dry place. With an excess of moisture, it loses its properties, which is not in the best way will affect the quality construction works. Please note that for renovation of the premises with high humidity you need to use cement that is not afraid of contact with water, that is, hydrophobic.

You should also know that cement is produced under different brands - from M100 to M600. It indicates the strength of the prepared solution. The higher it is, the more cement is able to withstand the compressive load. But this does not mean at all that in order to make, for example, the M300, you should purchase the material of the M300 brand. Knowing in what proportions to mix sand and cement, you can make the required grade of the mixture. To do this, you need to divide the brand of the source material, that is, the brand of cement, by the number of buckets of sand. The result is a brand of the mixture. Here's what it looks like: M300/3 buckets=M100.

Types of cement mortars

Cement mortars are divided into several types, namely:

• 
  Normal. A normal mortar is one in which there is a sufficient amount of both aggregate and binder. It will stick to the paddle used for kneading in separate clumps.


• 
  Fatty. There is too much binder in the composition of such a solution. That is why it cracks when it freezes. You can determine it by the strong enveloping of the kneading tool.


• 
  Skinny. In this solution a large number of aggregate, because of which it becomes liquid and inconvenient to work with. It does not stick to the oar, but only stains it.

How to make a solution

Before proceeding with the preparation of the solution, you need to make a dry mixture of sand without impurities and cement.
Please note that the ratio of these materials depends on the brand of cement.

In a container intended for mixing, the components should be laid out in layers in next order: sand, cement, sand, etc. Please note that in order to obtain a quality solution, it is necessary to sift all materials. For plastering, you can use a sieve with a mesh size of 5x5 mm. For stone work, it is recommended to use a sieve with a mesh size of 10x10 mm. Add water to the dry mixture, it must be clean. The resulting mass must be mixed until smooth.

Knowing the solution, you can proceed directly to its preparation. That's right - this is a guarantee of high-quality construction and repair work.

Concrete is the basis of any building structure. Almost every building around us, one way or another, was erected using cement mortar. Building concrete, created on the basis of cement, can withstand multi-ton loads for decades, practically without experiencing negative impact from the outside. Why has cement been the most popular building material for decades? The editors of the site will try to reveal the very secret formula, thanks to which we will finally find out what exactly cement is made of and why it is considered one of the most durable materials worldwide.

Cement - connecting link any design. From entrance steps to elite skyscrapers

Read in the article

Regulations

Cement, like any other product, must pass the certification procedure. There are several GOSTs and SNiPs, which, to one degree or another, relate to the quality of the cement mixture. We list the main ones:

1. GOST 31108-2003 General construction cements. Specifications".
2. GOST 30515-97 “Cements. General technical conditions".
3. GOST 10178-85 “Portland cement and slag Portland cement. Specifications".

The chemical composition of cement

By itself, cement is nothing but a powder. It is created on the basis of clinker. The composition may contain various components and fillers.

Interesting fact! When the cement mortar hardens, its density is not inferior to the density of the stone. For creating artificial stone cement is also used.

Heating occurs up to +1450°C. The structure of natural components changes, and a new substance is obtained - clinker. After that, the resulting substance is combined with gypsum and ground, as a result, cement powder familiar to everyone is obtained.

A comment

"This is what it looks like chemical composition finished cement powder: 67% calcium oxide (CaO), 22% silicon dioxide (SiO2), 5% aluminum oxide (Al2O3), 3% iron oxide (Fe2O3), 3% other components.

Main characteristics

For cement, the main technical characteristic remains its brand, it is this marking that will indicate such important feature, as an indicator maximum load in kg.

The numbers indicate maximum rate load that the cured cement can withstand. It is also called the compressive strength index. In practice, this value indicates the weight that the material can withstand without collapsing. For example, when using M200 cement, the load that 1 cm³ can withstand is 200 kg.

Interestingly, it is allowed to test cement only after complete drying, and this happens after 28 days and not earlier. After that, the test sample of cement is placed under the press and compressed. The pressure at which he began to collapse is his mark. Moreover, the procedure is repeated six times, and then out of 4 best performance calculate the arithmetic mean. This indicator is measured in MPa and kg / cm².

A comment

Head of the team of the repair and construction company "Dom Premium"

“The letter “D” indicates data on special additives used in cement. For example, D10 indicates that 10% additives were added to the dry mix. Thanks to them, it is possible to give the finished structure additional strength and frost resistance.

Types of cement by use

As we noted earlier, various additives affect the quality of the cement mixture. From this depends on its scope and strength. For example, frost-resistant samples are used in the construction of residential buildings and buildings in areas with a harsh climate, in seismically hazardous areas, additives are used that increase the stickiness of the mixture. They, in turn, do not concrete structures crack.

Interesting fact! During the freezing process, the water contained in the concrete expands and begins to destroy it from the inside. However, modern technologies make it possible to improve the degree of frost resistance; mineral additives are added to the cement powder, for example, neutralized wood pitch. They create a strong shell around water particles.

Most often in cement mixture various additives are added, the percentage of which can reach 10 and 20%. For the construction of monolithic buildings I use cement grade M500. Such a material has a higher solidification rate and strength. Usually it is from such a cement mixture that ceilings and load-bearing structures are erected.

What is cement made of?

Typically, cement plants are built where there are deposits of limestone and other rocks that are used to create clinker. The main natural elements from which cement is made are:

• fossils of the carbonate type: crystalline rocks that can be burned;
• clay materials, as well as sedimentary rocks of mineral origin. The raw material is characterized by viscosity, it is used in the dry method of production.

A comment

Head of the team of the repair and construction company "Dom Premium"

When choosing cement, pay attention to such an indicator as the fineness of grinding. The finer the powder structure, the stronger the mixture will be.”

Carbonate rocks

What carbonate rocks are used in the production of cement:

• a piece of chalk(limestone variation) - easy to process, cheap and versatile;
• marl, or marl limestone. The advantage of these rocks is that they contain a sufficient amount of moisture, in addition, they contain the necessary particles of clay;
• limestone raw material, shell rocks, characterized by the absence of silicon inclusions. The rock has a porous structure, is easily destroyed under the influence of compressive forces;
• carbonate rocks. They are characterized by valuable physical properties.

Clay raw materials

Clay rocks include:

• clay containing mineral inclusions that swell when water is added;
• loams− diluted with sand fraction;
• shales- strong clay rocks;
• loess- inelastic porous rock with inclusion of quartz.

Corrective additives

In addition to mineral raw materials, special plasticizers are used in the production of cement. Most often, additives based on fossils containing fluorspar and apatite are used.

Important! The basis of any binder is cement clinker and only 15-20% of mineral additives. The strength of the future cement and its other characteristics depend on it.

How cement is made in production

Like any production, the creation of a cement mixture takes place strictly according to a special technological scheme. And it consists of the following steps:

1. Creation of clinker. It, recall, is made of limestone and clay in percentage 75×25. The mixture is placed in an oven, at a temperature of approximately +1500°C, the composition changes. A viscous substance is formed that securely fastens all clinker granules. The resulting clinker is cooled in special refrigeration units.
2. Then the granules are further crushed. Grinding takes place in special grinding mills. They are drums with steel balls placed there.
3. Finely dispersed gypsum and mineral additives are also added to the crushed clinker.

Exist different technologies preparation of raw materials. Let's consider the main ones.

wet method

Wet technology involves the mandatory addition of water at the grinding stage; in this case, chalk is used instead of lime. In this case, a special mixture, or charge, is formed, which is then re-dried in an oven, turning into a kind of glass ball, which is then crushed again. At the same time, the cost of cement increases significantly. Do you think that the mixture prepared in this way is more durable.

Dry way

The dry method is a cheaper option. In this case, in practice, two technological operations– grinding and drying of the mixture. Hot gases are sent to the ball mill, which carry out drying. Here, the output is a ready-made powder.

Combined techniques

The combined version combines the features of the wet and dry methods. Technology is different in every enterprise. Sometimes instead wet process, allowing clinker moistening up to 50%, use options with a decrease in humidity at this stage to 18 or 20%. The second method involves the preparation of a dry mixture, followed by moistening up to 14%, granulation, and final annealing. It all depends on the tasks that the technologist faces.

How to make cement at home

Despite the apparent complexity of cement production, it is possible to make it yourself at home. It is clear that this option will not be as technologically advanced as at the factory, and it will also not work to burn it at the required temperature. However, we can tell you some tricks. Consider one of the popular recipes for creating a composition that is quite suitable for sealing cracks and screeds. To create a mixture, we need water lime, rock ash and plain water.

“And they said to one another, Let us make bricks and burn them with fire. And they became bricks instead of stones" ( Old Testament, Genesis, 11-3)

This material is a logical continuation of the article about Saman and is published as a continuation to with his permission;).

We are not talking about houses and shelters, but about the use of "nanotechnology" in construction - about building mixtures and concrete. Basically, of course, about building mixtures, because. concrete is mortar with filler.

To begin with, about a couple of things that few people paid attention to in the daMIR article. Namely, “they tamp, fill it with a 6 mm layer of lime mortar of normal fat content and lay another layer of soil”, “if you add 1-2 bags of cement to the ground, then it will stand forever ”and one unpublished comment of my colleague (voiced in a conversation) who advised adding a little rotted manure to the adobe.

The fact is that in all these cases, an additive of a binder (inorganic or organic) was used, which significantly increased the moisture resistance and strength of the adobe walls. And you can judge the strength of building mixtures based on lime for yourself using the example of the Roman Colosseum - there the stones are connected by a similar solution.

Well, now to the point.

To be honest, I wanted to start the presentation with the OFFICIAL history of cement and suggest using the intermediate result of this evolution after BP. But the day before yesterday I watched episode 4 of the cycle “History. Science or Fiction" called "Alchemy of the Pyramids" and it turned all my thoughts.
This film tells about the hypothesis of the French chemist Joseph Davidovich, confirmed by a group of researchers Russian Academy sciences that the pyramids were built of concrete (artificial stone - i.e. cement with filler, please do not confuse with Portland cement). If you cannot watch this film, you can familiarize yourself with the hypothesis, for example, or. The film and articles detail the evidence for this.

All cheese is boron due to the fact that modern technology the production of cement (Portland cement) requires quite complex intermediate technologies to create firing temperatures of about 1450 degrees, which was not possible in ancient Egypt. Davidovich suggested that the Egyptians used COLD technology cement (i.e. a mixture of natural materials it was not burned, but also turned into stone under the influence of water) and called it geopolymer (indicating that both mineral and organic substances are included in the composition) cement, he even demonstrated it.

THAT'S IT, I think. I'll find the recipe and everything will be good.

But not everything is so simple - Davidovich does not disclose his recipe, anyone else is not particularly looking for this recipe - due to the fact that it is unlikely that anything will be cheaper than Portland cement, and research requires money. Only historians are interested in this. And the materials for the manufacture of geopolymer cement will be much more expensive than for modern cements.

In short, there is no recipe for Davidovich in open sources. It got to the point that some individuals with a physical and chemical education claim that the very idea of ​​\u200b\u200bcement with the main binder not subject heat treatment- is absurd. Let's leave it on their conscience - this is not my goal. My goal is to find an easily accessible analogue of Portland cement.

And a couple of simple BP recipes:
There is such a book "Encyclopedia of Forgotten Recipes" of 1994, and although it contains recipes for handicraftsmen and artisans of the late 19th and early 20th centuries, some things can be used after BP. I climbed into the section of cements and found a recipe for waterproof white cement for BP: 75% chalk + 25% red-fired kaolin. And that's all. For me, it’s not very costly - chalk mountains exist in nature, and kaolin (white clay) can be replaced with another baked clay.
Pliny ( Ancient Rome) gives the composition of hydrotechnical concrete made of lime, pozzolans (rocks consisting of loose products of volcanic eruptions of ash, pumice, etc. in the USSR, there are deposits of P. and a route in the North Caucasus (Nalchik), in the Crimea (Mount Karadag) and the Armenian SSR) and broken tuff in a ratio of 1:2:1

And what should we do if there is neither the Nile nor the chalk mountains nearby. Our ancestors, for example, added crushed garlic or egg white to cement. At first I thought it was very expensive, but as it turned out, it is possible to add only about 0.1 to 1 percent of the total cement mass with an organic binder to increase strength, if it is introduced in parallel with the inorganic one.

Therefore, after reading everything, I decided to give a damn about the history of cement and try to study the patterns of cement mixtures. What came out of it is up to you to judge.

To begin with, I decided on the requirements - the building mixture after the BP must meet the following requirements:
Affordable raw materials, no expensive / rare or difficult to obtain components.
Enough simple technology production
I don't need the strength of modern Portland cement. And although even now there are buildings "on the egg", picking a piece of cement from the wall of which is not entirely easy. Such a fortress without observing a complex recipe is not achievable. And is it necessary? Look at the real stones of the Egyptian pyramids - let's be honest - crumble. And by the way, if you open any textbook on concrete, then it says that concrete parameters such as strength, water resistance, etc. MUCH depends on the filler (gravel, expanded clay, etc.), and not only on cement.

Let's define what exactly we call cement - a powdered building binder material, which - has hydraulic properties. That is, when interacting with water or other liquids, cement forms a plastic mass (cement paste), which, when hardened, turns into a stone-like body.

To start some theoretical part, naturally not mine, and by the way, more than half concerned the plaster. But you yourself know "husband and wife - one Satan."

Binder materials, depending on the origin, are divided into inorganic - lime, gypsum, cements, soluble glass and organic - bitumen, tar and resins.
Binder additives - materials added to mortars to speed up or slow down the hardening of binders, as well as special additives.

Inorganic hydraulic binders that we may be interested in are lime-slag, lime-pozzolanic (volcanic), lime-ash binders and hydraulic lime.

Depending on the properties of additives, they can be divided into the following groups: active mineral additives; surface-active additives; additives for accelerating and retarding the setting of binders.

Active mineral waterproofing additives are called natural or artificial substances, which, when mixed in finely divided form with fluffy lime and mixed with water, form a dough that, after hardening in air, continues to harden under water.
Active mineral additives are used in the production of various types of cement to save its consumption and the consumption of other binders in the preparation of the mortar and to impart waterproofing properties to the mortars.
Natural active mineral additives include rocks of sedimentary origin
- diatomites - solid rocks, consisting mainly of accumulations of microscopic shells of diatomite algae and containing mainly silica in an amorphous state; - tripoli - rocks consisting of microscopic, mostly round grains and containing mainly silica in an amorphous state; - flasks - compacted diatomites and tripoli; - rocks of volcanic origin; - ashes - rocks containing aluminosilicates and found in nature in the form of loose , partially compacted deposits; - tuffs - compacted and cemented volcanic ash; - pumice - stone-like rocks characterized by a porous spongy structure - silt (and although it is organic, I myself stuck it here, because this is the only thing I can imagine how it looks and where search;))

Artificial active mineral additives include: - silica waste - substances rich in silicic acid, obtained by extracting alumina from clay; - burnt clay - a product of artificial firing of clay rocks (expanded clay, clay, tartar) and spontaneously combustible in dumps of empty mine rocks (clay and carbonaceous shale); - fuel ash and slag - a solid by-product formed after burning at a certain temperature of certain types of fuel, the mineral part of which is dominated by acid oxides; - blast-furnace granulated slag - acidic and basic, obtained during the smelting of iron and converted into a fine-grained state by rapidly cooling
(Note: for me, after BP, the easiest way is crushed brick, the more it is clear where to get it or burnt clay)

Surfactants are predominantly organic substances capable of changing the bond between water and the surface of the binder particles. There was a lot of incomprehensible writing here - I won’t give it, I just say that you can experiment with soap or alcohol - theoretically, their small increase can VERY change the properties of cement.

Finally, additives to accelerate and retard the setting of binders
To slow down the setting of gypsum, the following retarders are used: an aqueous solution of animal glue (mezdrovy, bone) 10% concentration, slaked lime, lye.
An aqueous solution of glue is injected at the rate of 0.2-0.5% (per dry matter) from the mass of gypsum; this lengthens the setting time by 20-30 minutes. In the summer, due to the tendency to rot, this supplement is prepared at the rate of no more than a three-day requirement.
Slaked lime is introduced in an amount of 5-20% by weight of gypsum - the setting time of gypsum slows down by 15-20 minutes.
Lye is introduced into solutions in the amount of 1-2% of the gypsum mass.

It is also possible to add organic binders - substances org. origin, able to move from plastic. state into a solid or low-plasticity as a result of polymerization or polycondensation. Compared to miner. binder materials, they are less brittle, have greater tensile strength. These include products formed during oil refining (asphalt, bitumen - it will be difficult to do), thermal product. decomposition of wood (tar - much more interesting). (I moved the silt to the top, although not scientifically - but more realistically). And the same notorious ones: crushed garlic, egg white, manure, etc.

And finally - Practical Tips or a few particulars about binders:

Clay. is a soft, fine-grained variety rocks. When diluted with water, it forms a plastic mass, which is easily subjected to any shaping. When fired, the clay sinters, hardens and turns into a stone-like body, and when more high temperatures firing melts and can reach a glassy state.
Clay is made up of various minerals, so it happens different color. Serves as a binder for the preparation of clay mortars used in laying stoves, plastering, making bricks, adobe walls, clay-straw roofing and other works.
Clay has the ability to absorb water up to a certain limit, after which it is no longer able to absorb or pass through itself. This property of clay is used to create bulk waterproofing layers.

Gypsum. Raw material for receiving building plaster serves as natural gypsum, or, as it is often called, alabaster stone. deposits gypsum stone available in many parts of the country. It is made by firing and grinding or grinding and firing.
Depending on thermal conditions processing, setting and hardening rates of gypsum binders can be:
1) fast-setting, fast-hardening and low-firing (firing temperature 110-190 ° C). Low-firing ones include building, molding, high-strength gypsum and gypsum-cement-pozzolanic (volcanic) binders.
2) slow-setting and slow-hardening high-firing (firing temperature 600-900 ° C). Anhydrite binders are used after joint grinding with hardening catalysts - lime, burnt dolomite, etc. Gypsum-anhydrite binders are used for the manufacture of panels, partitions, slabs, wall stones, architectural and decorative products, models and forms in porcelain and faience and ceramics. . prom-sti, orthopedic. corsets, etc.

Lime. Lime kills microbes, and cleans the air from harmful aerosols better than any air conditioners with filters.
The lime production process is not difficult, but it requires a stove and coal. The burning process takes place at a temperature of 800 and above. On wood, such a regime is difficult to create. In an ordinary home stove, one firebox can burn a kilogram and a half of raw materials. It will turn out after extinguishing about half a bucket of lime sour cream or a bucket of lime for whitewashing.
On average, the stove is heated five to six months a year. It is easy to calculate how much you can work out for heating season. Enough for a good building.
The raw material for the production of lime is limestone. They are distinguished from ordinary stones by the fact that they are lighter than rubble stones and granite and are gray-blue in appearance. Easily scratched metal objects. And most importantly, if you drop acid on them, then they begin to hiss and foam, but this is concentrated acid - you will agree that it is difficult to get it after BP. Therefore, I can tell you something else for the search: limestone is sedimentary rocks that were formed by compaction of the sediments of the world's oceans. Therefore, when struck with a hammer, they split in layers. And railway embankments are very often made with such stones. Sometimes surface treatment of roads is made with such gravel. If there is a factory in your area silicate brick, it's generally excellent. This production uses the raw materials you are looking for. I think that you will find a way to "purchase" stones from the factory.
The burning process is as follows: the coal must be sieved on a sieve with a cell of 10 by 10 mm. Lime stones are not thicker than 20 mm, 10-15 mm is even better. Large stones are easily hollowed out with a hammer, in layers.
You fire up the oven. Pour in a bucket of coal, when it is well lit, level the firebox with a poker, pour in another half a bucket of coal. After that, you begin to lay the raw materials on the coal, lay them out evenly in one layer, then let the stove flare up again, then fill in half a bucket of coal so that the raw material is covered. After that, take a couple of scoops of the coal that was sifted out (dust) and pour it on top so that the heat lasts until the morning. You can start taking out in the morning.
The excavation is better special pincers. After the stones are pulled out, inspect them. Well annealed stones white color and much lighter raw materials.
Then the lime should be extinguished. The extinguishing process is carried out on the street. It is necessary to pour water into metal dishes, and then the resulting products are gradually dumped there. The decomposition of lime is very rapid, so you should be very careful.
After a couple of days, the lime is ready for use. The slaked lime turns into a dough that can be stored for many years. From prolonged storage, the properties of lime can even improve. To obtain a binder solution, lime paste is mixed with sand. Such a solution is used when laying foundations for furnaces, chimneys up to 4-5 m high and used for plastering the walls of houses and stoves.

To improve water resistance lime mortars, they are injected with finely ground burnt clay, broken bricks or volcanic rocks (ash). With a fine selection of the recipe, you can get the hydraulic lime invented in 1756 by the Englishman D. Smith. Obtained by roasting limestone with clay impurities - a product of moderate firing (not before sintering) marl limestone (unfortunately this does not tell me anything), containing from 6 to 20% clay impurities. Hydraulic lime tends to harden not only in air, but also in water.

At the end of the article I want to give a method for determining the optimal proportion of concrete components.
It is based on the method of selecting the composition of concrete by absolute volumes, which implies the complete absence of voids during preparation. concrete mix.
All we need is a bucket liter jar and, in fact, those fillers that the concrete will consist of, as a rule, are crushed stone, cement, sand, and water.
To begin with, let's count how many cans of water fit in the bucket, pouring them there one by one. We get, for example, 10 pieces. Let's write down.
Then, we will fill the bucket with rubble to the brim and we will pour water into it with a jar filled with a glass too, in order to know how much water we filled the bucket with. When the water reaches the edges, remember the amount of water poured. This will be the volume of voids after loading the rubble. Let's say we got 5 cans.
Now let's dump everything out of the bucket, wipe the jar dry and put as many cans of sand into the bucket as we poured into the bucket filled with rubble, in our case 5 pieces.
Pour water again and count the cans until the water reaches the surface of the sand. Let's say we got 3. This figure will show us the volume of cement that will be required to fill all the remaining voids, after loading crushed stone and sand.
That's actually all. In our case (for our crushed stone and sand), the proportions of aggregates and cement for our concrete will be as follows: crushed stone - 10 parts, sand - 5 parts, cement - 3 parts.
Note that crushed stone is mainly responsible for the compressive strength of concrete, therefore the strength of concrete will also depend on the quality of crushed stone. As a result of the use of crushed stone, we will improve such characteristics as: strength, durability, reduce shrinkage and creep of concrete, as well as save cement - the most expensive component in the composition of concrete.
Fine aggregates are responsible for the shear strength of concrete; for this, they must evenly and densely fill the voids between the crushed stone grains.
With regards to the mortar for laying brick or stone, the technique is similar, but we measure only sand, cement and water.

And finally, all this is THOROUGHLY mixed - this is the secret of successful builders.

At the very end, I’ll say that, as you yourself already guessed, I didn’t come up with all this myself - there were VERY many sources, so there may be errors. But my main goal was to show that, if necessary, a replacement for cement can be invented and shown possible directions search, as one of the colleagues said, when everything gets better;)

Cement mortar is widely used in construction. It is used for laying stone and brick, interior decoration walls, foundation pouring, plastering. Naturally, depending on the application, this building material will have different composition. For example, for the construction of the foundation, in addition to sand and cement, crushed stone will also be required. The preparation of the mortar is a very important stage, because the strength of the masonry, the strength and durability of the structure under construction depend on the quality of the mixture.

In order to properly mix the cement mortar, you need to know what grades exist, consistency requirements, mixing sequence and proportions of the base materials. Usually use:

• sand;
• water;
• cement;
• less often: plasticizers and other additives.

Types of cement mixtures

Depending on the composition and purpose of use, the solution is divided into grades:

• M150 and M200 - for screeds;
• M50, M100, M150, M75, M200 and M125 - for masonry;
• M10, M50 and M25 - for plaster.

All varieties differ in quantitative sand content and proportions. Changing the ratio of the main components allows the use of such a building material for various works.

The grade of the solution is an indicator of the strength of the structure built using it. The proportions of the ingredients depend, as a rule, on which brand of cement mortar is needed. Often, cooking instructions are printed on the packaging by the manufacturer.

Of course, you can order the finished mass desired brand(Currently, dry ready mixes for foundations, plasters or screeds are being sold, in which you just need to add the right amount of water). But doing it yourself can save you money.

Rules for determining the desired grade of sand-cement mass

According to the technology, it is required that the brand of the solution correspond to the brand of the material used (brick, blocks). For example, if the masonry is being built from brick grade 100, then the cement mass should be M100. Subject to this rule as a result, you will get a whole homogeneous brick structure.

In the event that the brand of the material used is high, for example 350, then it is not worth striving for a match, as this will significantly increase the cost of construction. The generally accepted proportions are 1 part (for example, a bucket) of cement and 3 of sand (1 to 3). When preparing concrete for pouring the foundation, 3-5 parts of crushed stone are added to this proportion.

On sale there is a huge range of different types of cement, differing in brand, manufacturer, properties and shelf life. Among professional builders, Portland cement is especially popular, characterized by high level water resistance, frost resistance and strength. It hardens well in almost any weather.

Methods for preparing cement mixtures

When choosing this building material, be sure to pay attention to its shelf life, since best blend obtained if fresh cement is used.

Currently, the preparation of cement at home is carried out in two ways: mechanical and manual. The first method involves the use of a concrete mixer.

Do-it-yourself kneading will require significant physical effort. In this case, all the necessary building materials are mixed bayonet shovel in a trough or an old bath. To relieve this process, water is first poured into the container, after which sand and cement are added. Then everything is stirred until smooth. At the very end, crushed stone is added and everything is mixed well again.

How to prepare a solution yourself

The foundation of the building must be reliable and durable, as it is the foundation of any building. To fill the base of the building, the sand-cement mass is prepared in the classic ratio - 1 to 3. Usually crushed stone is added to it, although concrete is already obtained in the following ratio: 3 buckets of gravel (crushed stone) and sand, 1 bucket of Portland cement.

An important role is played by the ratio of water to components, which should be proportional. Ideal is a solution in which water is 25%, but it is difficult to work with. Therefore, when kneading, water is added “by eye” at your discretion.

When mixing concrete, Portland cement grade M400 or M500 is used. For the foundation, the consistency of concrete should resemble thick sour cream. The preparation of a mass for leveling walls and plaster implies the following proportions of the components: 2 parts of sand and 1 part of cement.

To prepare a cement mortar for a conventional screed, the same components are used as for the preparation of concrete, only screenings are added instead of crushed stone. The quantitative composition of the main components is taken in the ratio: Portland cement M400 or M500 - 1 bucket and 2 buckets of screenings and sand. To improve the plasticity index, it is recommended to add a little (50-100 g) of detergent to the solution. Remember that before mixing all materials should be sifted - this will improve the quality of the solution. The main thing is that there are no foreign impurities in the components. After that, doses are measured required amount sand and cement in accordance with the proportions of the desired composition.

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Until now, no construction or repair is complete without the use of cement. When deciding how to prepare a cement mortar, you must first take into account that the one used for brickwork, floor screed or wall and ceiling finishing can differ significantly both in composition and in the method of preparation.

In the manufacture of a concrete mixture, cement serves as an astringent that ensures its solidification.

The main components of cement mortar

There are two types of mortar - cement and concrete. Despite the similarity in the components (in addition to the three common components, crushed stone or gravel is additionally added to concrete) and the method of preparation, these are two completely different product designed to solve various construction problems.

A classic cement mortar consists of only three components mixed together in a certain proportion: cement, sand and water. The cement must be dry and free from hard lumps. It is best to use river sand, although in practice they often take ordinary, quarry sand, but they pre-screen it to separate debris and impurities.

For mixing the mixture, it is better to use clean water, which has room temperature or a little warmer - 21-23 ° C.

The optimal proportions are: 1 part cement to 3 parts sand. Water is added to the prepared cement mortar as needed, its amount can vary from 80 to 95% of the volume of cement used (i.e., 8 to 9.5 liters of water should be consumed per 10 liters of cement).

With such a solution, you can both expel brickwork, and perform plastering work. However, it has a number of disadvantages - excessive rigidity and limited time (1-1.5 hours) for using the prepared solution, which makes it difficult to work with it.

Therefore, professional builders prefer to add various substances to its composition when preparing a cement mortar, making it more plastic and extending its hardening time by 2-3 times. The most common way to improve such a mixture is to add milk of lime to its composition.

Such a mixture has almost the same binding abilities as a pure cement mortar, but its use time increases to 3-4 hours.

The second option is to prepare a cement solution with the addition a small amount detergent - at the rate of 50-100 g for every 10 liters of the mixture (depending on the quality of the detergent).

This additive can significantly increase its plasticity.

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Mortar grades and their use

Like the vast majority building materials, the prepared cement mortar also has its own marking. There are solutions M10, M25, M50, M75, M100, M125, M150, M200, M250, M300, but in private construction grades from M75 to M150 are usually used.

The marking of the finished mortar does not depend directly on the brand of cement used for its preparation, as most non-professionals mistakenly believe. In fact, a mixture of one brand can be prepared from different brands cement.

For example, a mixture of M100 can be obtained from cement M300, M400, M500, and in all cases the amount of cement used for its preparation will be the same. But the amount of sand changes: when using cement M300, the ratio of sand and cement will be 3:1; when using M400 - 4: 1; and when using the M500 - 5: 1.

When using cement mortar, professional builders advise using the composition of the same brand as the material used for construction. Those. if for pouring the foundation is used concrete mortar M75, then a cement mixture of the same brand must be used for the basement screed. If brick M100 is used to extrude walls, then the mixture for masonry must correspond to this brand.

But in practice this is not always possible. For example, using an M300 brick when distilling walls, it makes no sense to take a solution of the same brand for laying it - it is difficult to work with such a solution, and the financial costs for its manufacture are very large. Quite suitable for the operation of the brand in the range from M100 to M150. In practice, such masonry is most often performed using a mixture of sand and cement M400 in a ratio of 3.5: 1, i.e. approximately M115.

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How to make a cement mortar

There are several ways to prepare a quality cement mixture. But, regardless of the method chosen, tools will be needed for its preparation:

• container for mixing components;
• shovel;
• trowel;
• buckets.

The most common classical method of preparing a mixture is that cement and sand are first mixed dry until a homogeneous composition is obtained, and then this mixture is diluted to the desired consistency with water. Water should not be added all at once, but 80-85% of the required amount, and already in the process of preparing the mixture, gradually add it to the composition, achieving the desired density.

Especially this rule should be observed if not clean cement-sand mixture, and cement-lime. In this case, you first need to prepare liquid diluted lime by diluting the lime dough with water to a state of thin sour cream. Then the solution is prepared in the same way as in the first version, but instead of the missing water, milk of lime is added to it at the final stage.

The second method was invented by craftsmen for preparing the solution by hand. In fact, it is almost a mirror image of the first: first, water is poured into the container (approximately 4/5 the right amount), then add liquid soap or other detergent. After that, the water must be vigorously shaken for 4-5 minutes so that the detergent is completely dissolved in it and forms the maximum amount of foam.

Then half of the required volume of sand and the entire volume of cement are poured into the container. After that, all components are mixed with each other. Special care in mixing at this stage is not yet required, the main thing is that as a result the mixture is more or less homogeneous in composition. Then the missing sand is added to the mixture, and here negligence in mixing is already unacceptable - you need to knead until the mixture becomes homogeneous. The presence in it of areas of clean, without cement, sand is unacceptable.

The main advantage of this method is that in liquid state sand and cement are mixed much faster and better than dry. But in order to properly make a cement mortar, at the end of preparation, you need to gradually add the missing water, bringing the solution to the desired density.

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Little tricks when preparing the solution

Despite the apparent simplicity of the process, even experienced builders are not always able to immediately prepare the cement mortar correctly. Therefore, the prepared solution is divided into 3 types:

• skinny;
• normal;
• fatty.

To determine the type of prepared mixture, no special tools are needed. It is enough to pull out the shovel used for mixing from it or (in the case of a concrete mixer) interfere a little ready mix trowel. If working surface the tool remains almost clean, then the prepared mixture is lean, because it lacks a binder - cement. If the entire surface of the tool is hidden under a layer of the prepared mixture, then there is too much cement in the latter, it is greasy.

Only a normal solution is suitable for work, in which the proportions of cement, sand and water are correctly maintained. If the solution turned out to be lean, then cement should be poured into it, and if greasy, add sand and water, bringing it to normal state. It is necessary to add the components little by little, otherwise it costs nothing to turn a lean solution into a greasy one and vice versa.

Initially, water should always be poured a little less than the norm.

The fact is that its amount depends on the absorbency of sand - dry sand absorbs water much more than wet sand. Therefore, pouring it according to the norm and filling it with slightly damp sand, you risk getting a liquid solution.