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Until now, not a single construction or repair can be completed without the use of cement. When deciding how to prepare cement mortar, you must first take into account what is being used for brickwork, floor screed or finishing walls and ceilings can differ significantly both in composition and in the method of preparation.
During production concrete mixture cement serves as a binder that ensures its hardening.
Main components of cement mortar
There are two types of mortar - cement and concrete. Despite the similarity in components (concrete, in addition to the three common components, crushed stone or gravel is additionally added) and the method of preparation, these are two completely different products designed to solve different construction problems.
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 of hard lumps. It is best to use river sand, although in practice they often take ordinary sand from a quarry, but first sift it to separate debris and impurities.
To mix the mixture, it is better to use clean water at 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 cement solution being prepared 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 this solution you can 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 working with it significantly more difficult. That's why professional builders
When preparing cement mortar, they prefer to add various substances to its composition, making it more plastic and prolonging its hardening time by 2-3 times. The most common option for improving such a mixture is adding lime milk to its composition.
This mixture has almost the same astringent abilities as pure cement mortar, but its use time increases to 3-4 hours. large quantities detergent - at the rate of 50-100 g for every 10 liters of mixture (depending on the quality of the detergent).
This additive can significantly increase its plasticity.
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Brands of solution and their use
Like the vast majority of 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.
Marking ready solution does not directly depend on the brand of cement used for its preparation, as most non-professionals mistakenly believe. In fact, a mixture of the same brand can be prepared from different brands of 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 M300 cement, the ratio of sand and cement will be 3:1; when using M400 - 4:1; and when using M500 - 5:1.
When using cement mortar, professional builders advise using a composition of the same brand as the material used for construction. Those. if M75 concrete mortar is used to fill the foundation, then to screed the base you need to use cement mixture the same brand. If M100 brick is used for forcing walls, then the mixture for masonry must correspond to this brand.
But in practice this is not always possible. For example, when using M300 brick when forcing walls, there is no point in using a mortar of the same brand for laying it - it is difficult to work with such a mortar, and financial expenses for its production are very large. Brands in the range from M100 to M150 are quite suitable for use. 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 cement mortar correctly
There are several ways to prepare a high-quality cement mixture. But, regardless of the chosen method, you will need the following tools to prepare it:
- container for mixing components;
- shovel;
- trowel;
- buckets.
The most common classic way preparing the mixture - first, cement and sand are 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 during the process of preparing the mixture, gradually add it to the composition, achieving the desired thickness.
This rule must be observed especially if it is not a pure cement-sand mixture that is being prepared, but a cement-lime mixture. In this case, you first need to prepare liquid lime by diluting the lime dough with water until it becomes a thin sour cream. Then the solution is prepared in the same way as in the first option, but instead of the missing water, final stage lime milk is added to it.
The second method was invented folk craftsmen to prepare the solution manually. In fact, it is almost a mirror image of the first: first, water is poured into the container (approximately 4/5 required quantity), then it is added to it liquid soap or other detergent. After this, 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 the required volume of sand and the entire volume of cement are poured into the container. After this, all components are mixed together. Particular care in mixing at this stage is not yet required, the main thing is that the resulting mixture is more or less homogeneous in composition. Then the missing sand is added to the mixture, and here negligence in mixing is unacceptable - you need to knead until the mixture becomes homogeneous. The presence of areas of clean sand without cement is unacceptable.
The main advantage of this method is that in a liquid state, sand and cement mix much faster and better than in a dry state. But in order to properly make a cement solution, at the end of preparation you need to gradually add the missing water, bringing the solution to the desired thickness.
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Little tricks when preparing the solution
Despite the apparent simplicity of the process, even for experienced builders It is not always possible to immediately prepare the cement mortar correctly. Therefore, the prepared solution is divided into 3 types:
- skinny;
- normal;
- fatty.
To determine the type of mixture prepared, no special tools are needed. It is enough to pull out the shovel used for mixing or (in the case of a concrete mixer) stir the finished mixture a little with a trowel. If working surface If the instrument remains almost clean, then the prepared mixture is thin, since it lacks a binder - cement. If the entire surface of the instrument is hidden under a layer of the prepared mixture, then the latter contains too much cement and 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 turns out to be thin, then you need to add cement to it, and if it is greasy, add sand and water, bringing it to normal. You need to add the components little by little, otherwise it will cost nothing to turn a lean solution into a fatty one and vice versa.
Initially, you should always pour a little less water than normal.
The fact is that its amount depends on the absorbency of the sand - dry sand absorbs much more water than wet sand. Therefore, by pouring it according to the norm and adding slightly damp sand, you risk getting a liquid solution.
Despite the fact that there is such a thing as factory-produced cement, quite often builders of small projects, and even just in everyday life, are faced with the question of making it themselves. Often this is really more convenient and economical than purchasing ready-made material.
When mixing the solution with your own hands, you must strictly observe the proportions of the components and take care of their quality.
Exist various techniques How to make cement, allowing you to make it yourself.
Properties and composition of cement
The ratio of cement and sand in the solution for masonry work should be 1:3.
In housing construction, materials such as brick, block, Wall panel. And sometimes, in order to make the structure being built durable, you need to bind these materials together to form a monolithic system. Portland cement is used for such purposes. Its strength characteristics are calculated by the strength coefficient during bending or compression of the composition, the basis of which is sand and cement, proportioned in parts 3: 1. This solution has been kept for almost a month, subject to special temperature regime and humidity conditions. Exist various options of this type of cement, corresponding to different operational requirements. For example, special resistance to moisture.
In general, any composition used for construction includes water, sand, which is a filler, and binders: cement, lime, gypsum powder. Making such a solution yourself is extremely simple: mix dry cement with dry sand (lime), and there should be 2-5 parts of sand. Or mix 1 share of cement with 2 shares of lime, adding up to 9 shares of sand. The resulting mixture is used for the construction of foundations and walls, when installing screeds on the floor, plastering work (external and internal), and also where high humidity is possible.
The sand used to prepare the solution must be clean and sifted through a special sieve.
It is worth knowing that when mixing the solution with your own hands, you need to correctly observe the proportions of the components, depending on how the mixture will be used. So, for foundations we mix cement and sand in a ratio of 1:1 or 1:2, when performing masonry work - 1:3, plastering - 1:6. The quality of the mixtures produced will be influenced by the amount of liquid in their composition, which should not be less than 65%. This gives the mortar flexibility and plasticity, not only facilitating construction work, but also affecting the durability of the structure being built.
So, to comply with these standards, when preparing the solution, take only warm water, pour it into the pre-mixed components carefully, then the resulting mixture is stirred thoroughly. The homogeneity of the resulting mixture is also important, and for this Special attention attention should be paid to the quality of the sand used; it must be clean and sifted through a special sieve. You cannot take river or silted sand. If gravel is added, it should also be thoroughly washed and dried.
When mixing, no matter what volume you want to get, all components are poured in gradually. As an auxiliary tool, you can use an ordinary drill with a screw-shaped attachment. It will be convenient to make a solution using a large trough or old bath. The resulting mixture should be consumed quickly - no later than half an hour, then it loses flexibility, begins to crust and hardens.
In the process of purchasing materials for mortar pay attention to their storage conditions. Dry cement should be dry and not swollen from excess moisture. Ideally it should be stored in a warm and dry place.
Thus, the quality of self-made cement will invariably be affected by the properties of the original components, the conditions of their storage and use, and the correct and thorough mixing of the solution.
Protecting cement from frost
To prevent cracking of cement when exposed to sub-zero temperatures, you should use a regular soda solution.
A serious problem when conducting external construction work is the problem of cement cracking. Its main enemy is cold. Curious but true: to prevent this, you should use a regular soda solution. An Austrian engineer proved that such a solution protects Portland cement from exposure to sub-zero temperatures. For the purpose of conducting the experiment, lime was taken - 1 portion in relation to cement, 1 portion of lime and 3 sand, a soda solution was added to the finished cement so that for 1 liter of cement there was 1 kg of soda diluted in 3 liters of water. Next, the mixture was kept for about 15 hours at a temperature of -32°, then dried for 3 hours. As a result, the cement did not change its properties at all. Conclusion: by adding soda dissolved in water to Portland cement, you can guarantee the high frost resistance of the cement used.
Cement for different needs
The most difficult thing to make is cement for stone laying and plastering work. The process will require special knowledge, strict adherence to proportions and the use of only high-quality components. There are technologies for producing solutions with special properties. For example, cement based on caustic lime is used for sealing indoor floors (lime on water based mix with ash and water until a viscous slurry is obtained); repair of iron products (30 portions of crushed graphite, 15 of lime, 40 of blancfix are mixed, a varnish based on linseed oil is added). To putty diamonds, take 30 portions of lead litharge, 10 of lime, 20 of soap, 50 of graphite, all mixed with linseed oil. Zinc putty is made from 20 portions of lime, 4 portions of sulfur, mixed with 10 portions of hot glue, of which 7 portions are water. Putty for ovens is prepared on the basis equal parts graphite, bone charcoal, sand, lime, mixed with ox blood or wet cottage cheese.
The prepared cement quickly loses flexibility, begins to crust and hardens, so it should be used no later than half an hour later.
“Ideal cement” is a cement made from oven-dried lead litharge powder and mixed with glycerin. The solution is superior in strength to the Portland variety. In addition, it is absolutely not afraid of moisture, high temperatures, does not form cracks (does not change volume when hardening), has unique property glue any materials.
Is there some more chinese recipe preparing cement that perfectly glues leather, marble, plaster, earthenware, porcelain and much more. Its viscous composition includes 54 portions of lime mixed with 6 portions of powdered alum, 40 portions of fresh beaten animal blood are added, mixing all this well. Such cement in liquid form becomes an excellent waterproof paint.
Optimal recipes
You can make cement for gluing minerals by mixing 6 portions of mastic with a portion of lead-based white, grinding the resulting composition into a fine powder, which is then slowly added, stirring, to white wax melted over a fire. The finished mass binds even stones very firmly, not to mention other objects. Desired color if necessary, you can get it by adding a little paint during the preparation process.
The enemies of cement are: moisture and carbon dioxide. The loss of cement activity can be up to 15% each month.
In order to cement slabs or stones, use the following composition. Combine one portion of sulfur and resin, dissolved in different containers, then add, stirring, 3 portions of lead litharge powder, 2 portions of ground sand. Dry slabs or stones are lubricated with drying oil, after which cracks and gaps are filled with the prepared mixture. This coating protects the stone well from precipitation and temperature changes.
You can also prepare the cement that glues glass with your own hands, and different ways. One portion of powdered lime is ground with 2.5 portions of egg white, 1 portion of water and 5.5 of gypsum are added, and the resulting mixture is immediately applied to the gluing surface. Or: 10 portions of gelatin are dissolved over low heat, combined with 15 portions of vinegar essence, then 5 portions of ammonium dichromate are added. This composition can be stored in a dark bottle and a dark room.
It can be quite difficult to glue glass onto metal surface. Such cement is suitable for these purposes. Take 125 grams of powdered rosin, 36 grams of white wax, 75 grams of red lead, heat them over low heat, when liquid forms, remove from heat, very carefully add 18 grams of high-quality turpentine, mix with a wooden spoon and cool. Or: melt 10 portions of resin and a portion of wax (yellow) over a fire, this mixture will glue the glass to the metal well.
How to make cement? The question, at first glance, is complex. But, following these recommendations, you can make cement not only for construction, but also for solving many other frequently encountered household problems.
If you decide to build, you will definitely need a cement solution during the work process. It is not enough just to buy cement, because before construction begins, the gray powder must turn into a real solution. Water, sand and cement - that’s all the components, but not everything is as simple as it seems at first glance. Let's figure out how to properly make a cement mortar.
History of cement
Cement is a well-known binding building material, which is classified as a hydraulic binder used for bonding different surfaces- bricks or reinforced concrete blocks. Without cement, concrete or foundation cannot be made. In addition to high viscosity, the material has excellent hydraulic properties, which make it possible to create a stable connection with water and other liquids when making a solution in the form of a plastic mass. After hardening of such a mass, a stone-like material is obtained, which has significant strength and rigidity.
Even in ancient times, binding materials began to be used for construction needs. The very first binding material was natural unfired clay. However, over time, it ceased to satisfy builders due to its low resistance to moisture and weak astringent properties.
Several thousand years alone binders airy lime and gypsum remained, but they were insufficiently water-resistant. And the rapid development of navigation in the 17th and 18th centuries required the creation of new water-resistant binders for the construction of port facilities.
In 1796, the Englishman Parker patented a cement called “roman”, which could harden in air or water. However, these qualities have also been lost in our time. practical significance. At the beginning of the 19th century, Academician V.M. Severgin described a binder that was obtained using marl firing followed by grinding. From the second half of the 19th century to construction practice Portland cement has become firmly established in our country.
Industrialization in the USSR and rapid pace capital construction predetermined the growth of the cement industry. In 1962, the USSR took first place in the world in cement production. Today, about 30 varieties of cement are produced in our country. At the same time, its quality is increasing and the prediction of the famous chemist Mendeleev, who claimed that cement is the building material of the future, is coming true.
Cement production process
Natural cement is a mixture of limestone and clay, which forms a high-strength stone-like material when hardened, which is most often odorless, free-flowing and has grey colour. The quality of cement is determined by the presence of various substances in it - granulated slag, magnesium oxide and sulfuric acid anhydrite. The grade of cement depends on the ratio of these components. Also, the quality of cement, setting time, compressive strength, and false setting will depend on the percentage of the listed substances.
As raw materials for the production of Portland cement, a mass of limestone and clay is used, as discussed above. What else is cement made from? In rare cases, a rock called marl is used, which is precisely a natural mixture of clay and limestone in the ratio necessary to obtain Portland cement during the production process. Marl was appreciated in the 19th century by the Englishman Aspdin, who collected dust on a road near the city of Portland, made briquettes from it, which were subsequently burned.
Cement factories usually have their own quarries required material- clay and limestone. This allows you to withstand the necessary chemical composition charge with high accuracy up to 0.1 percent, which is of great importance. The charge is fired in rotating kilns, which have a diameter of 3.6 - 7 meters and a length of 100 - 150 meters. The temperature in the sintering zone is maintained at a level of plus 1450 degrees Celsius.
The sintering product is clinker, which is round granules whose diameter reaches 5 - 100 millimeters. The clinker is ground in ball mills to a specific surface size of 3000 square centimeters per gram. IN mandatory during grinding, 5% gypsum dihydrate is added, which acts as a setting time regulator. Without gypsum, so-called quick cement is formed, which sets instantly and cannot be used to make dough. All clinker minerals are capable of interacting with water and forming new compounds - hydrates. Hydrates form a spatial structure that creates cement stone.
Application of cement in construction
Cement is used to build a foundation and make mortar for laying bricks, pouring screeds when laying floors, creating paths and blind areas. It is used for prefabricated and monolithic concrete, which serves as a raw material for the production of reinforced concrete, asbestos-cement products, various artificial materials, solutions, fastening individual parts of structures, and heat insulation. Large consumers cement are the gas and oil industries.
Cement and building materials obtained from it can successfully replace scarce wood, lime, brick and other traditional materials in construction. A little later we will talk about how to make cement and cement mortar with your own hands. The use of cement in various branches of construction is closely related to its technical characteristics. Let's take a closer look at this connection.
Frost resistance is a property that characterizes the ability of a material to be repeatedly frozen and thawed over a long period. Pure cement does not have this ability; it obtains this characteristic thanks to various modifying additives. If you live in a cold part of the country, and high frost resistance of the structure is important to you, then you should choose hydrophobic cement 500.
Corrosion resistance determines the ability of cement to withstand almost any aggressive environmental factor. Pozzolanic cement, which is intended for the construction of underwater and underground structures, is characterized by increased corrosion resistance.
Sulfate resistance is a property of a powder that construction mixture allows it to be stable in an aqueous environment that contains sulfate ions. This property is embodied in sulfate-resistant cement, which is used for the construction of hydraulic structures that are exposed to salt water.
Water resistance as a characteristic of cement has found application in waterproof expansive cement. Cement is capable of increasing in volume when hardening; the setting process occurs quite quickly - in approximately 10 minutes. Waterproof expanding cement is required for sealing joints and seams in concrete structures, which are located in the water.
Grinding fineness is a characteristic that affects the setting, hardening time and strength of concrete. The finer the grinding of the clinker produced, the higher the strength of the hardened cement. It should be remembered that grinding too fine provokes instead excellent characteristics excessive water consumption and decreased strength of concrete.
Making your own cement mortar
If you want to minimize the cost of repair work or construction, you should forget about ready-made mixtures, the price of which is much higher than the cost of cement and sand, which are necessary to obtain an equal volume of cement mortar. First of all, to prepare the solution you will need high-quality cement. ABOUT making the right choice We have already covered this material in a previous article. Let's talk now about how to make cement and its mortar at home.
Cement at home
Producing cement at home allows you to obtain this material, which is indispensable in construction, using a minimum amount of resources and endow it with the desired characteristics. We invite you to familiarize yourself with popular methods self-made cement.
Putty for sealing cracks and crevices in floor covering made in this way: mix lime with coal ash and dilute with water until the consistency of rich sour cream is formed. For the manufacture of cement intended for filling iron utensils, wells, steam boilers and holes in metal products, take forty parts of barite white, thirty parts of graphite dust, fifteen parts of lime and mix the resulting mixture to the required density with linseed oil with the addition of varnish.
To fix iron in stone, make cement with your own hands from the following components: sand (20 parts), kaolin (2 parts), ground chalk (4 parts), slaked lime (3 parts), liquid glass(15 parts), mix everything until a homogeneous dough-like mass. For ceramics you will need cement next preparation: grind 2 parts slaked lime with 5 egg whites, dilute the mixture with 2 parts water, grind with 10 parts gypsum.
To prepare cement for stone, it is recommended to mix 10 parts of sulfur and bitumen with 1 part of beeswax. Melt the mass, then add 2 parts of brick powder. Immediately before applying the solution, dry the stone and lubricate it with drying oil. For pipes, mix 15 parts of drying oil or linseed oil and 85 parts of lead oxide in a heated mortar until a plastic mixture is obtained.
To produce glycerin cement you will need lead litharge, which should be carefully ground into powder and dried at high temperature. Mix the resulting dust with glycerin. Technological characteristics cement made according to this recipe is several times greater than the characteristics of factory-made Portland cement. Similar material is different high density and the level of resistance to negative environmental influences.
Homemade glycerin cement is absolutely not afraid of high temperatures: it can withstand temperature increases even up to plus 300 degrees Celsius. Another important practical characteristics glycerin cement is the ability to firmly glue objects made of porcelain and earthenware. It is safe to say that this material is a real ideal cement.
Europeans recently invented new way production of cement, which has unique characteristics. Such Chinese cement is capable of gluing leather, plaster, marble, porcelain, earthenware and other materials. To prepare cement you need the following components: slaked lime (54 parts), quartz (6 parts), fresh blood! (40 parts). The resulting mixture must be thoroughly ground until a homogeneous mixture is formed.
Preparation of materials
The first stage of making cement mortar is preparation. Select a container in which you will dilute the cement. The volume of the container must necessarily correspond to the volume that is planned to be made. If the dishes are smaller than the planned volume, then you will probably pick up the solution from the ground. If the container is too large, then you will not be able to create a uniform mass that will not form lumps.
In addition, you need a fairly stable container. Pay attention to how strong the walls of the container are. It is also not recommended to take a container with low, thin walls, because they do not allow mixing a high-quality solution. The most the best solution at home will become an old cast iron bathtub.
In addition to the dishes for the resulting mass, you will need special tool for the most convenient solution creation. It is usually customary to use a special construction mixer, but our skillful compatriots adapt it for this purpose a regular drill with nozzles.
Preparing the Components
If you have had a bag of cement in your garage for many years, you should stop using it. To obtain a high-quality solution, it is also important specifications sand - uniformity, purity and absence of impurities. The best option is washed quarry sand.
Arrange everything before work necessary tools and materials in maximum proximity, so as not to find yourself in an uncomfortable situation when you need to “run” for the components of the solution. Next, it is necessary to sift the powder to make a cement solution in order to avoid the formation of lumps and debris entering the mass, which significantly worsens its astringent properties and quality. When preparing a cement solution for plastering work, you need to use a sieve with cells of 5 by 5 millimeters, for stone - with cells of 10 by 10 millimeters.
After this, the ratio of each element in the solution should be determined. At this stage, it must be remembered that the admixture of sand when using high-quality cement should be insignificant or nominal. Also remember the classic ratio that builders have been using for a long time: 1 part cement is usually mixed with 3 parts sand. All incoming components are usually measured using certain utensils or scales.
During construction, it is often necessary to prepare cement not according to traditional recipe, which is accepted at all global construction sites in the world. Non-standard mixtures are obtained due to various impurities. They are able to change the properties of the cement solution, for example, change the rate of hardening of the substance or slow down the speed for long-term work with the solution, improve the viscosity characteristics of the mass so that it becomes plastic and more pliable for working in difficult areas.
There are different types of cement mortars: normal, fatty and thin. Fat cement mortar is a mixture that contains too much binder. This solution can harden quickly, but after use it dries out and forms cracks, therefore it is short-lived.
Normal cement mortar is a mass where the proportions of the elements are observed correctly. Such a solution does not cool too quickly, but cracks do not form in it, it is strong and durable. Lean cement mortar is a mass in which there is not enough binding component; such a mortar will not work unless you decide how to dilute the cement.
Regardless of the recipe for preparing a cement solution, a mixture that does not spread during operation and is characterized by a high or medium level of viscosity is considered to be of high quality. At the same time, the mixture should not be too dry, as this provokes a loss of the fastening qualities of the cement mortar, laying in in this case doesn't hold up.
Preparation of the solution
So, pour a layer of cement into the container, then a layer of sand, then again cement and then sand again. The number of such layers should be at least six, this will allow the components to be mixed thoroughly. Cement and sand are poured in layers in the form of a bed to a total height of about 200-300 millimeters.
To begin, mix the sand and cement properly. Shovel this bed several times with shovels until smooth. When stirring, remember the concept of “intensity.” Without a certain technological mixing procedure, you will not be able to obtain a high-quality solution. It is recommended to then sift the mixture through a fine sieve, which has cells measuring 3 by 3 millimeters, but no smaller. The homogeneity of the mixture should be close to absolute.
Do not add water or other liquids once you have mixed the dry ingredients. Adding liquid to the resulting mixture should be done gradually and very carefully. Pour in water slowly until the mixture reaches the desired consistency. If you found more water than required, then it is the gradual infusion that will allow you to stop on time.
Remember that the temperature of the liquid should not be too high or extremely low. Take water at the optimal temperature, the same as environment. Masonry requires the preparation of a thicker solution, and the pouring process requires a more liquid one. Do not mix a lot of cement mortar at once, especially if you used wet sand. Now you know how to make cement mortar at home.
And finally, remember that cement mortar is a material that cannot be stored. This is due to the high viscosity properties of cement, due to which the solution can quickly harden and become unsuitable for use for construction work. The composition that you received after proper mixing is available for work for another hour when using wet sand and up to three hours if you dried dry sand.
Any construction cannot do without cement. This inorganic binder is part of plaster and putty mixtures, without it it is impossible to prepare concrete, mortar mixture. Cement is not a natural resource; to prepare it, the raw material must be burned, then the resulting clinker must be crushed to a powder state and mixed in certain proportions with appropriate additives.
Basically, technological process Preparing cement is not very difficult; you can make cement with your own hands.
How cement is made
Carbonate and clay rocks are used to prepare cement. Industrial waste (slag, etc.) can also be used to produce cement. The technical process includes 3 stages:
- Preparation of raw materials. At the end of this stage, it is necessary to obtain sludge - a mixture of limestone and clay in a ratio of approximately 3:1. Although this ratio strongly depends on the properties rocks and is constantly adjusted to obtain cement of the required quality.
- Next, the sludge is fired in a furnace (1450°C), under the influence of high temperature the mixture of limestone and clay is sintered. After firing, the clinker is ground to a powdery state.
- To obtain cement, it is enough to add 5% gypsum and a number of additives to the resulting powder (depending on the required properties of the cement).
Depending on the additives used, the following types of cements are distinguished:
- hydrophobic – resistant to moisture contained in the atmosphere. Its use gives concrete increased water resistance and frost resistance up to F1000;
- white - most often used for preparing dry mixtures, ready for use;
- expanding cement. While other types of cements decrease in volume as the concrete mixture hardens, expanding cement allows the opposite effect to be achieved;
- pozzolanic cement – characterized by reduced heat generation. Most often used for concreting volumetric objects, due to reduced heat generation, the risk of uneven settlement (and therefore cracking) is significantly reduced;
- colored cement - used for the manufacture of products that do not require further processing. Either white clinker is used, or dyes are added to the concrete mixture;
- aluminous cement - its distinctive feature is that it gains up to 50% strength within 24 hours after laying the concrete mixture. Due to the release of large amounts of heat, it is often used during construction in winter.
Do-it-yourself cement production
The main problem in making cement with your own hands is the need for firing at high temperatures. Therefore, you will need at least a kiln and a mill to grind the prepared clinker. But even in this case, at home it is unlikely that it will be possible to obtain cement for preparing concrete grades above M200. Although this result is possible only subject to the strictest adherence to the proportions and stages of the technical process.
Before preparing cement with your own hands, you need to evaluate 2 factors:
- work front. Creating a homemade production line is justified only if there is a relatively large amount of work;
- working conditions. Considering the low strength of concrete structures using homemade cement, it is advisable to use it only for structures that do not experience serious loads.
Taking these factors into account, it is necessary to evaluate economic efficiency"handicraft" production.
The actual preparation of cement at home takes place in the same order as at a cement plant: raw materials are prepared, fired in a kiln, ground and mixed with additives. “Handicraft” production also has its advantages - cement can be given any properties by experimenting with the raw materials.
To obtain ordinary Portland cement, it is recommended to use ground chalk and ground kaolin (75% chalk and 25% kaolin). This raw material must be thoroughly mixed. Then it is fired in a kiln and ground in a mill. 5% gypsum powder must be added to the resulting powder.
There are also exotic recipes for preparing, for example, glycerin cement, Chinese cement, and diamond putty. Similar options are not considered, since they are used only for solving highly specialized problems.
Preparation of cement mortar
Any cement mortar consists of water, binder (cement itself) and filler (usually sand). The ratio of binder and filler depends on the type of work performed. So, for a plaster mixture, you can take the ratio of cement and sand to 1:6, but, for example, for laying bricks, the ratio of binder to aggregate should be reduced to at least 1:3.
If the mixture is being prepared for pouring a foundation, then the filler content can be further reduced, in which case the ratio of binder and filler is 1:1 or 1:2. In addition, crushed stone is often added to the mixture for pouring the foundation.
In construction, mixtures with the addition of lime or clay are often used, but they also use cement to increase the strength of the mortar after hardening.
Also, when preparing the mixture, you need to pay attention to the water-cement ratio. Of course, the optimal ratio is established for each type of mixture, but it should be remembered that excessive water content worsens the quality of the solution after hardening.
The process of preparing the solution also has some nuances. It is recommended to mix the binder and aggregate dry, and only then add water. It also matters in what order the components are loaded into the container. Layer-by-layer loading of sand and cement and their uniform distribution in a container. If it is necessary to prepare a large volume of solution, layers of sand and cement can be alternated several times.
Construction is part of the lives of many citizens, especially those who live in the private sector. It surrounds people everywhere. Today, private construction is developing very actively. It is known that the most commonly used building materials are wood, concrete, brick, cement. Cement occupies important place in this industry. With its help, roads, foundations for houses and garages and some other structures are built. To prepare a cement mortar, you need to have all its components on hand. Many people do not know how to make cement with their own hands.
For cooking yourself plain cement you will need chalk and kaolin.
The cement mixture consists of three main parts: sand, water and cement powder. This makes it different from concrete in many ways. In concrete, in addition to all the listed components, there is one more - coarse-grained material. It can be represented by crushed stone or gravel. It is important that cement comes in different forms. The grade of the mixture is determined by the type of work performed and the basic requirements for structural strength. Let us consider in more detail the main stages of preparing cement mortar at home.
Types of cement mortar
To do it yourself cement-sand mixture, you need to decide on its type. Currently, lean, normal and fatty solutions are distinguished. They all have their advantages and disadvantages. If in a normal solution the proportion of cement powder does not exceed the norm, then fatty ones contain a lot of cement. All this contributes to the fact that such a mixture will quickly crack after hardening. As for lean mortars, they contain more sand than cement powder. This makes them less durable. In addition, in the construction business there is such a thing as the brand of cement and the mortar itself.
The grade determines the compressive strength of the mortar after hardening. The most commonly used in construction are mortar grades 25, 50, 75, 100, 150 and 200. To make cement with your own hands, you need to choose it correctly. The nature of the work is taken into account. For example, for masonry and plastering work, a cement mixture of grade 100 or 150 is often used. For the construction of blocks, it is recommended to use a mortar of grade 100. As for the proportions of the main components, they can be different. This largely depends on the quality of the cement powder. Sand-cement mortars can be masonry, construction or plastering.
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Stages of preparing cement mortar
When making a cement mixture, you need to remember the main stages of the work. They include:
- correct selection of the brand of mixture and brand of cement powder;
- preparation of water, sand and various additives;
- direct cooking.
In some cases, builders need to determine the brand of the resulting solution. This is done quite simply. You need to divide the brand of cement powder by the amount of sand (in buckets). For example, if the main component of grade 400 was used, and there were 4 buckets of sand, then the resulting solution will be grade 100. The first stage includes the selection of cement powder. The brand determines the quality of the material. The higher it is, the stronger the mixture and the entire structure will be.
An interesting fact is that for the same solution you can use different brands cement. The difference will be in the volume of cement used. Accordingly, the higher the grade of powder, the less it will be required. Ideally, the brand of the mixture should match the brand of the material (if plastering or masonry work is carried out).
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This is necessary to ensure that the entire structure has the same strength.
Preparing sand for the mixture
The second very important and responsible stage is the preparation of all other components. First of all, it is sand. To make quality cement, you need to use river sand. It must be cleaned and sufficiently dried. Otherwise, excess moisture may change the water-cement ratio. You need to take the choice of sand for facing masonry very seriously. Such sand should not contain clay particles. The thing is that during the operation of the structure, the clay will leave the solution. All this will ultimately lead to the formation of defects: cracks, holes, voids. The quality of sand can be determined with the naked eye. river sand
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has a somewhat grayish color, while clay gives the sand a yellow tint. Unrefined sand can also be used in construction, but not for facing masonry. It is suitable for backfill masonry. The amount of sand available must correspond to the volume of work. It is advisable to let the sand sit for several days immediately before use. It must be protected from moisture and stored in a dry place.
Preparing water for solution Before making cement, you will need to stock up on water. Only used pure water . Groundwater is most often used. It is not advisable to use salt water
. For greater convenience, you can extend the water supply hose. How much water is needed? The volume of water depends on the brand of the required mortar and the quality of the cement. The volume of water when preparing the mixture is approximately equal to the volume of cement powder. If you take a bucket of powder, then the same amount of water is required. Much attention is paid to the quality of the sand. If it is wet and contains a lot of water, then its amount needs to be reduced. The solution should not be too liquid. Ideally, it has a consistency similar to sour cream. Great importance
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It also has the fact that water is poured into the concrete mixer first. This ensures optimal mixing. It is best to divide the water into 2 servings. First add one, and at the very end the second (if the mixture turns out thick).
Cement consists of more than just cement powder, water and sand. Often other ingredients are added to it. These are various detergents. What are they needed for? Any cement has characteristics such as plasticity and mobility. The simplest solution is to add liquid soap or any other detergent to the mixture. The volume of detergent is 50-100 ml. It will give the solution good plasticity. It must be remembered that this component is added immediately after water, that is, at the very beginning. Water and detergent must be mixed thoroughly to form a slight foam.
If you overdo it with this component, the mixture will lose its strength and the structure will be short-lived. Today there are special additives on the market that can improve the quality of cement. These include various plasticizers and water repellents.
If liquid cement will be used for brick joints, then it is advisable to use dyes. It must be remembered that with a higher grade of liquid cement, the solution turns out darker.
Additives also include an elasticizer. It is used to make tile mortar. Superplasticizers give a good effect. With their help, it is possible to reduce the volume of powdered cement used.
Latex and reinforcing additives are successfully used in the construction industry. The latter increase the strength of cement. In conditions low temperatures It is recommended to add additives that increase the frost resistance of the solution.
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Mixing the main components
You can prepare liquid cement without the involvement of specialists. This is done manually or using a concrete mixer. A concrete mixer allows you to save energy and also obtain the most homogeneous mass. First of all, water is poured into the concrete mixer. Not all of it is used; some of it is left for last. Detergent or other liquid additives are then added to the water. In order for the solution to dissolve well and mix with water, you need to wait about 3-5 minutes and only then add the bulk components. Sand is put in first. Only 50% of the required volume of sand needs to be added.
At the next stage of work, all the cement powder is placed. After this, the mixture must be mixed very thoroughly and only then add the remaining sand. To obtain high-quality liquid cement, you will need to very accurately calculate the ratio of the main components. If you plan to prepare a mortar of grade 100 in the presence of cement powder of grade 500, then the ratio of cement to sand should be 1:5. This means that for 1 bucket of cement powder you will need 5 buckets of sand. If the grade of cement powder is 400, then the ratio will be 1:4. To prepare a mixture of grade 200, the ratio will be 1:2 (if cement 400 is available). Water must be added until the mixture reaches the desired consistency.