What is cement composition made of. It's all about proportions: what cement is made of so that the foundation stands for a long time

Cement is one of the main building materials. It is used in the creation of binding mortars, cement is used in the manufacture of concrete and reinforced concrete products. The quality of this material determines how strong and durable the building or reinforced concrete structure will be.

The history of cement began in England, where a patent for its invention was registered in 1824. At that time, lime dust mixed with clay was used to make cement. The resulting mixture was subjected to a high temperature at which it was sintered.

The fired semi-finished product of cement is called clinker. It becomes cement after grinding the clinker to a powder state.

In construction, the main property of cement is used - when mixed with water, it gradually hardens, and then turns into a durable stone. The strength characteristic of the finished product, the material can acquire even in the air, if there is excess moisture.

Raw materials for the production of cement, what it is made of, manufacturing technology

Today, the process of making cement has changed. It is made in several ways, and the components included in it also differ from those used two hundred years ago.

In order to understand what cement is made of and how it is produced, it is necessary to know what types of raw materials are used today by manufacturers of this important building material.

Since the raw materials for the production of cement are natural rocks, the enterprises involved in its manufacture are most often located close to the mining sites of these rocks.

All fossils from which cement is made are divided into two types:

1. Carbonate fossils that differ in characteristics and structural features. It is the structure of the rock that ensures its effective interaction with the rest of the ingredients of the product composition.
2. Clay and rocks of sedimentary origin. Having a mineral base, when moistened, they acquire plasticity and increase in volume. Since this type of raw material is characterized by viscosity, they can be used by producing cement in a dry way.

Now it is necessary to name specifically which fossils belong to each of the types of raw materials used in the production of cement.

The carbonate rocks include the following types of natural raw materials:

• Chalk is a type of limestone. Has the ability to be easily crushed;

• marl limestone, found in nature in both loose and solid state. The rock may contain impurities of clay, so this type of limestone is considered a transitional raw material with properties characteristic of both limestone and clay;

• limestones - shell rocks that do not have silicon inclusions. The rock has a porous structure that easily collapses under compression;

Limestones - shell rocks

• dolomitic rocks and other fossils of sedimentary origin. They contain carbonates, which give the rock valuable properties.

Clay rocks include the following types of fossils:

• clay with mineral inclusions that swell on contact with water;

• loams containing an increased concentration of particles;

• shales with a clay base. This raw material is classified as a rock with increased strength. Under mechanical action, it is divided into lamellar plates. It is characterized by a stable composition and low moisture content;

• loess, porous rock, with inclusions of particles and silicate.

In addition to these types of raw materials, some types of industrial waste are used to produce a cement mixture at the plant. To improve the quality, additives are added to its composition, provided for by the technological process: alumina and silica, fluorspar and apatite.

The use of sand is simply necessary when carrying out a variety of repair and construction work. all about the use of quarry sand.

When carrying out finishing work in the kitchen, in the bathroom or in any other room, it is necessary to know the drying time of the tile adhesive. you can find out how long the tile adhesive dries.

Currently, decorative plaster is rightfully the most popular and progressive finishing method. Going to get acquainted with its independent preparation.

All additives, called plasticizers, are also of natural origin. They affect for the better the following qualities of cement:

• increase resistance to temperature changes;
• enhance strength;
• mobility and elasticity of the product;
• reduces the penetration of water into the finished product.

Depending on the properties of the plasticizers added to the cement, its solution will harden faster or slower.

The composition from which cement is produced

Some people working in the construction industry do not know what cement is made of.

The composition of cement may vary depending on the brand and purpose.

However, regardless of the type of cement, that is, the recipe used in its production, two components serve as the basis for it - limestone with the addition of clay.

The amount of limestone is three times the amount of clay. These are necessary to obtain high-quality clinker, which is a semi-finished product for the production of cement.

Now we can name the main components of the composition, so that it is clear to everyone what cement is made of:

• clinker, the basis of the final product, which determines its strength characteristics. It is used in the form of granules with a diameter up to 60 mm. Its heat treatment is carried out at a temperature reaching up to 1500 °. When melting the clinker, a mass is formed, which is characterized by a high content of silica and calcium dioxide;
• these components affect the performance of the final product. Before firing, the clinker granules are crushed to a dusty state;
• gypsum, which determines the rate of cement hardening. The basic recipes provide for the addition of pure gypsum to the composition of up to 6% of the total number of components;

• special additives (plasticizers, frost-resistant additives, liquid soap, etc.) that enhance the properties already available in the product, or give it special characteristics that can expand the scope of cement.

Production - how cement is made, the process of receiving at the plant

The production of the material is carried out in a certain order, in stages. The technology of its production provides for the following operations:

1. The ingredients intended for the manufacture of clinker are pre-mixed. It is imperative to strictly observe the proportions of the composition - 25% clay and 75% limestone.
2. The resulting composition is fired at high temperature. During high-temperature firing, clay and lime combine to form clinker.
3. The finished product is crushed by ball mills, which consist of drums located in a horizontal position, inside which steel balls are placed. The clinker placed in them is crushed to a state of powder.
4. The finer the cement fractions obtained, the better performance characteristics it will have.

There are several methods for manufacturing this building material. Their choice is due to many factors, the main of which is the specifics of the equipment available at the enterprise and the demand for certain brands of cement.

The developed technologies have a difference in the methods of preparation of raw materials used in the production of the composition. The order of its manufacture remains the same.

The following methods have been developed:

1. Wet technology that replaces lime with chalk. In the process of mixing the components of the composition, they are crushed in a ball mill. This process is carried out with the addition of water. As a result, a mixture is formed with a moisture concentration of up to 50%.
2. The resulting material is then fired in a kiln. After firing, it already becomes clinker. Then it is crushed.
3. Dry technology significantly reduces the cost of production, as it combines several technological operations into a single process. When using this technology, the components entering the ball mill are simultaneously ground and dried.
4. Hot gases are used for drying. The finished charge mass has the consistency of a powder.
5. Combined technology combines the features of the above-described production methods. Depending on the equipment used in the enterprise, a semi-dry composition with a moisture content of up to 18% can be obtained.
6. In the second option, dry is initially prepared, then moistened to 14%. In both cases, the prepared composition is then annealed and ground.

For more information about cement production, see the video:

Classification of cement mixtures

There are many varieties and different of this building material. They are distinguished by their basic composition and additives, which give each species special properties.

Among the main types are:

• Portland cement, which began the production of a product popular in construction. It is not used for the manufacture of binder solutions. It is used to create high-strength concrete products, and mortars;
• aluminous cement, characterized by resistance to moisture, rapid hardening;

• acid-resistant cement, which uses quartz and sodium silicofluoride. The material is resistant to acids, but short-lived.

When purchasing any type of cement, you should be aware that its composition actively interacts with the environment, losing its strength during long storage.

Even if it is stored in a dry room, after a few months its brand will change down. Therefore, when purchasing it, you should pay attention to the date of manufacture. You can also read our article on technical specifications.

The most common bonding material in construction is cement, which is made on the basis of magnesia or carbonate-silicate rocks. The latter variety occupies more than 90% of the market and is called Portland cement. The production process includes several stages, the range of manufactured mineral binders is wide, it will be useful for every builder to find out by marking the scope of the powder.

What is cement made of - the main raw material

The starting materials for production are solid minerals, near which cement plants are located. Used in the manufacture of clinker - a product of joint firing of rocks - carbonate stones and clays. The first category of mineral formations is consumed in larger quantities and is represented by limestone varieties of an amorphous or crystalline structure, these are:

• chalk is a soft white rock, consisting of calcium carbonate with an admixture of magnesium, metal oxides and quartz grains;
• marl - a natural mixture of 50-75% calcite derivatives with 25-50% silicate clay formations, well suited for production;
• shell rock is limestone from the shells of marine animals, its variety metamorphosed by pressure at high temperature is called marble;
• dolomite - in addition to calcium carbonate CaCO3, it contains a magnesium component: MgCO3.

Clay rocks that introduce silicates into the clinker are loess, loams and shale. To reduce the cost of production and give cement special properties, alloying additives are used in the technology - alumina, iron, silicon, waste from metallurgical plants.

What is cement clinker

This is a product obtained by sintering at a temperature of 1450 ° C two rocks: 75% limestone and 25% clay. The clinker comes out of the kiln in the form of granules Ø10-60 mm.

According to the chemical composition, the calcined crushed stone of each of the manufacturers may differ, the average distribution is given in percentage:

• CaO - 67;
• SiO2 - 22;
• Al2O3 - 5;
• Fe2O3 - 3.

Crushed stone from the kiln is not the only component in the production of Portland cement. To slow down the setting time of the final product, the grinding of granules to a finely dispersed powder is carried out with the addition of up to 6% calcium sulfate CaSO3 contained in gypsum or gypsum stone to the clinker.

Grinding of ingredients is carried out by ball mills with pumping of the finished product into multi-ton silos by pneumatic transport.

The production of cement is regulated by state standards: GOST 30515-2013 - general technical conditions, GOST 10178-85 and 31108-2003 for building Portland cements. Separate standards have been developed for special types.

Product Main Features

Cement density indicators: bulk - 900-1100 kg / m³, with compaction - 1400-1700. The values ​​of the true specific gravity reach 3 t/m³. There are several technical characteristics by which the quality of the binder powder is judged:

1. Grinding fineness - determines: the smaller the particles, the larger the surface in one layer they cover. Control measurements are carried out by scattering on a sieve with a cell of 80 microns.
2. Water demand - the amount of moisture required to hydrate the cement and make the dough plastic. Excess water in the solution leads to the formation of pores and cracks, reducing strength.
3. Frost resistance is the ability of products based on cement powder to withstand repeated freezing and thawing without destruction. The required indicator is achieved by special additives when mixing the solution.
4. Setting time - depending on the density of the batch is in the range of 0.7-10 hours. The indicator also depends on the amount of gypsum added to the clinker during grinding.
5. Strength is determined by the destruction of a sample made of cement from each batch of released mortar. The age of the cubes is set by the standard - 28 days.

For all volumes shipped by the cement plant, quality certificates are filled out, in which the listed characteristics are entered. Consumers independently conduct input control to confirm the integrity of the supplier.

What is the brand of cement

The strength characteristic of Portland cement is its brand, which is established by the results of tests of cubic samples with a face of 10 cm for compression. The composition of the solution for filling forms: for 1 part of the binder powder, 3 measures of pure quartz sand.

After adding water, the mass is mixed and left to harden for 28 days. 6-10 metal molds are poured simultaneously.

Of these, 6 samples are randomly selected and crushed under pressure. The arithmetic mean pressure is calculated from the 4 cubes that collapsed under the greatest load. Values ​​measured in kg / cm² will indicate the brand of cement in accordance with GOST 10178-85. The display of stress in the metric system of units is performed in accordance with GOST 31108-2003 in MPa. Here, the distribution is carried out according to the cement strength class.

It turns out that the old and new classifications are simultaneously used to assess the strength characteristics. Digital range of brands: M200, M300, M400, M500, M600. Corresponding hardness class values: B15; B22.5; B32.5; B42.5; B52.5.

Marking

The given designations of the strength indicators of Portland cement are only a small part of the information about the properties of the manufactured cement encrypted in the full marking.

In the context of the simultaneous use of standards with the previous designations and from 2003, many codes carry identical information.

Cement manufacturers are trying to convey information about the quality and properties of products, using the terms of both standards.

What does the marking of cement by type of additive mean?

In addition to the main components, additives are introduced into the composition of the binder mineral substance, which make it possible to use cement in special-purpose concretes. Information about special properties is included in the labeling of products. The letters encode the powder and additives:

• PC - Portland cement without improving additives;
• ShPTs - when grinding clinker, slag is added in an amount of ≥20%, the product is called Portland slag cement;
• PPC - used for concreting in flooded conditions (pozzolans are products of volcanic activity: ash, tuffs, pumice);
• SPTs, SSPTs, SSSHPTs - sulfate-resistant binders, anticorrosive;
• B - fast hardening powder;
• BC -; clinker for its production is made from kaolin and light grades of limestone;
• G - quick-setting alumina powder, raw materials for firing are carbonate rocks and bauxites;
• HF - hydrophobic cement for concrete products in water;
• PL - plasticized, provides ease of laying the solution even at low temperatures;
• VRC is a moisture-proof expanding cement that hardens in any environment.

In the GOST 10178-85 marking, the amount of additives is indicated by a letter and a percentage: D0, D5, D20. At the end of the code, the standard according to which the product is made is indicated. Example: PC 400-D20-B-PL GOST 10178-85 - Portland cement with a strength of 400 kg / cm² with additives in the amount of 20%, fast-hardening, plasticized.

Deciphering the marking of cement according to new standards

The coding of product information in accordance with GOST 31108-2003 is based on the division of cement types into 5 groups, denoted by Roman numerals. The first 3 letters are taken from the name of the powder - CEM.

Each association has signs indicating manufacturing features:

• I - Portland cement without additives, consists of 95-100% of cement clinker;
• II - this group is subdivided into subclasses A with additives of 6-20% and B - 21-35%. There are also pozzolanic cements containing<20% пуццолана, и композитные, в которых присадки суммарно не превышают того же значения;
• III - slag Portland cement with a slag content of 36-65%;
• IV - pozzolanic cement with the addition of 21-35%;
• V - composite powder, including 11-30% slag and pozzolan within the same range.

Each of the additives has its own letter in the designation: I - limestone, Z - fly ash, MK - silica fume, K - composite additive, G - glieg, Sh - slag, P - pozzolan. This is followed by the number of the strength class, followed by the letters: H - normal hardening time, B - quick setting. Example: Portland slag cement CEM III / A 32.5N GOST 31108-2003. It is deciphered as follows: cement strength is 32.5 MPa, it is normally hardening, contains 36-65% slag.

Grades of cement and their application

Portland cements are used in accordance with the labeling, which directly indicates special conditions, if any. For construction work, when choosing a brand, pay attention to the indicator of the strength class or brand of cement.

Arrangement steps depending on the hardness of the binder powder:

• M200 - cement is intended for plastering, manufacturing;
• M300 - corresponds to the M200 monolith, is used for concreting underlying surfaces for foundations, pouring foundations for low-rise buildings;
• M400 - construction of reinforced concrete structures with a strength of M300, road surfaces, paving slabs, supporting structures;
• M500 - all types of external concrete work, the manufacture of airfield slabs and hydraulic structures from the monolith M400.

The compositions of the solutions may vary and are set according to the conditions of the facility being built. The recipe of mixtures is determined by the project.

The quality of any artificial binder is determined by its manufacturing method and the percentage of raw materials. Cement is no exception, of all types it is one of the most difficult. This substance is obtained by grinding gypsum and burnt homogeneous multicomponent clinker to a powder state and combining them with special additives. As a result, the properties and scope of the binder depend on the ratio of these substances to each other, the processing temperature and the fineness of grinding.

Groups of cements by composition

The main components are oxides of aluminum, calcium and silicon, when mixed with water, they form chemical compounds that harden when solidified in a humid environment. General requirements are regulated by GOST 30515-2013, according to this interstate standard, all cements are classified into groups that differ in the type of clinker into Portland cement, alumina and mixed (PC and sulfate aluminates). In the first case, a typical composition contains CaO (67%), SiO 2 (22%), Al 2 O 3 (5%), Fe 2 O 2 (3%) and up to 3% foreign matter.

For the production of aluminous and high alumina cements, bauxites and limestones are used as raw materials (the share of low-basic calcium aluminates prevails, the percentage of Al 2 O 3 increases to 50%). The ratios of the remaining components in them depend on the intended purpose and vary within the following limits: CaO - 35-45%; A1 2 O 3 - 30-50%; Fe 2 O 3 - 0-15%; SiO 2 - 5-15%. For the manufacture of sulfate-containing mixtures, clinkers based on calcium ferrites are used.

Depending on the proportions of the components and the material composition, the following groups are in demand in private and industrial construction:

• Portland cements are the most popular variety, representing a mixture of finely ground clinker with a predominant proportion of highly basic calcium silicates and gypsum. The raw materials are limestone (up to 78%) and clay (up to 25%).
• Aluminous, made by grinding raw materials from bauxite and limestone, burned or melted to a homogeneous state. These types are characterized by a high hardening rate, they are used both as an independent binder and for the production of special grades: waterproof, expanding, straining. Due to the increased hardness of the clinker, they lose to Portland cement in terms of energy consumption and cost.
• Portland slag cements - with a share of blast-furnace, electrothermophosphorus or fuel slags from 36 to 65%.
• Pozzolanic, with the addition of active mineral additives to the grinding products of PC clinker. Their proportion reaches 40%, due to the formation of chemical reactions with cement grains, they have properties different from conventional grades.
• Mixed - obtained by joint grinding of different types of clinkers or by introducing multicomponent mineral mixtures (for example, slag and fly ash).

Less commonly used types include romancement (a compound of grinding PC clinker and limestone and magnesia marls, not produced on an industrial scale), magnesia (mixed with salt solutions, characterized by a high setting speed and resistance to mechanical stress after solidification) and acid-resistant compositions based on quartz, diluted with liquid glass.

The chemical composition of cements of different groups

Proportions of clinker and other components:

The scope and main properties of varieties are given below:

Main brands

The type of binder selected determines the proportions and properties of building mixtures. It is important to check in advance what the cement consists of, its water demand, grain size and setting time. The main quality criterion is the compressive strength, in the laboratory it is determined for products from CPR, mixed in a ratio of 1:3 and hardened under normal conditions for 28 days. Depending on the withstand pressure, groups are distinguished from 100 to 600 kg / cm 2. Of these, brands from M300 to M500 are most in demand in private construction, but there are exceptions.

The next factor is the percentage of additives to clinker, in standard types the maximum is 20%. The marking of this indicator is indicated by the letter "D", the number following it characterizes the proportion of mineral impurities (example: PC M400 D0 is indicated for Portland cement with a compressive strength of at least 400 kg / cm 2 without additives). The given marking corresponds to GOST 10178-85, in addition to the above, it includes information on additional properties (marked only if available), also depending on the composition of the clinker and the additives introduced. Of these, the most in demand:

• H - normalized;
• B - fast hardening;
• SS - sulfate-resistant;
• VRTs - expanding waterproof;
• PL - with plasticizers;
• BC - white (decorative) cement.

Since 2003, GOST 31108 (corresponding to European standards) has come into force, according to which the composition is indicated first with a note on the presence or absence of additives (II or I). All options with mineral impurities are divided into two groups: A - with a percentage of 6 to 60%, B - from 21 to 35%. The type of additive is indicated by Roman numerals. The last are the strength class and the compression rate of the material. The standard range for general construction mixtures varies from 22.5 to 52.5 (corresponds to the brand from M300 to M600). To avoid errors, GOST is always indicated next to the marking, the introduction of cement is carried out with strict observance of proportions.

It is difficult to imagine an area of ​​construction where cement would not be used. It is necessary at all stages of any construction process, from the arrangement of the foundation to the interior decoration. Until now, analogues of this building material have not yet been found, which indicates the unique properties of cement.

What is cement made of, description

Cement is a crushed clinker powder in which modifying additives and fillers are introduced. In dry form, it is a free-flowing homogeneous mass of gray color. When diluted with water, a paste-like binder is obtained, which is easily applied to any rough surfaces.

After the cement hardens, a strong connection is formed, which is not inferior in its density to the stone. No wonder artificial stones are made from cement.

Chemical composition and formula

When limestone and clay are heated to a temperature of about 1450 degrees, the structure of these materials changes, resulting in the formation of clinker granules. These granules are mixed with gypsum and ground to a powder. The chemical formula of the finished cement is as follows: 67% calcium oxide (CaO), 22% silicon dioxide (SiO2), 5% aluminum oxide (Al2O3), 3% iron oxide (Fe2O3) and 3% other components.

quite complex and labor intensive. It requires special equipment and compliance with technological norms and conditions.

Specifications

The main technical characteristic is brand of cement. It is designated by the letter "M" and a digital indicator. The numbers indicate the maximum load in kilograms for a certain volume of hardened cement, i.e. its compressive strength.

In practice, this means the weight that the cement can support without breaking. For example, if it can withstand a weight of 200 kg, then the cement is assigned the M200 grade.

On the package, in addition to the brand, the percentage is also indicated composition of additives. It is denoted by the letter "D" and shows what this type of cement consists of. For example, the symbols "D10" mean that 10% of additives have been added to the dry mix.

Such additives are introduced to improve water resistance, corrosion resistance, frost resistance and other qualities of cement. Consider also other characteristics of cement, which should be paid attention to in the production of construction work.

M400. Its strength is 400 kg/cm2. This is the most popular brand of cement, used everywhere for all types of construction and finishing works. This is the construction of buildings, monolithic construction, the manufacture of concrete slabs, blocks, stair structures, foundations, well reinforced concrete rings, paving slabs and a number of other products.

M500. The strength is 500 kg/cm2. This brand of cement is characterized by rapid hardening and high strength. Cement is used for the monolithic construction of high-rise structures, the manufacture of load-bearing elements, floor slabs, prefabricated reinforced concrete structures, beams, as well as in other cases requiring increased strength and durability of structures.

In addition to brands, classes, types and degrees of grinding, which differ from each other by a combination of individual components and composition.

According to GOST. The production of general construction cements should be based on the requirements of GOST 31108-2003. The standard regulates the ratio of the necessary components in the composition of the dry mix and the cement manufacturing technology. This does not include special formulations.

Activity. This is the compressive strength of a single sample of cement mortar. The obtained indicators of activity are compared by specialists with the standards and appropriate brand is assigned to this cement. The activity indicator depends on several factors: the activity of the clinker granules, the grinding intensity, the presence of additives. For example, active additives will significantly increase the activity of the cement itself.

Application of an automatic cement activity meter CEMENT-PROGNOZ:

Density. The lowest density is fixed in freshly prepared cement. Electrostatic forces act on its individual particles, repelling particles from their counterparts. Then, during transportation and storage, the mixture is caked and compacted.

The density also depends on the degree of grinding of the clinker granules. When making calculations, the indicator of the average density of cement is taken equal to 1300 kg per cubic meter. But in practice, the density depends on the storage conditions of the material.

Specific and volumetric weight. The specific gravity of cement is determined by the ratio of its weight to the volume it occupies. This concept is necessary for the correct compilation of the proportions of cement mortars. The specific gravity of cement can vary considerably depending on the state of the mixture. So, a fresh powder can have a specific gravity of about 1000 kg/cubic meter, and a caked mixture - 1500 kg/cubic meter.

Volume weight calculated from the average cement density. The average density is approximately 1300 kg / cu. Therefore, a bag weighing 50 kg will have about 0.04 cubic meters. Bulk density increases when cement is caking or transported.

Best before date. Cement is characterized by a limited shelf life. Manufacturers guarantee its safety under normal conditions for 2 months. If sealed storage conditions are provided, the cement can lie without problems for a year.

It should be borne in mind that the higher the brand of stored cement, the faster it can lose some of its properties. So, cement M500, after being in a warehouse with high humidity, in a month will correspond in quality to cement M400, and after 2 months - M300.

Bulk density. This is the ratio of the mass of loose cement to its volume. That is, it is practically the same as the specific gravity, if we take a loose mixture. It is determined by experience. Cement is poured into a measuring container from a certain height. After filling the container, weighing is carried out. Knowing the weight of the empty container, determine the value of the bulk density. For fresh mixtures, this figure is about 1200 kg / cu. In compacted cement, the bulk density is about 1500 kg / cu.

Freeze time. The prepared cement mortar sets and hardens in a few hours. In summer, this process can occur in 2-3 hours. In cold weather, the setting process is delayed up to 10 hours. So, at a temperature of 0 degrees, the solution can harden only after 20 hours. Additives introduced into the solution can speed up or slow down the solidification process.

With the help of cement, they equip the foundation, plaster the walls, make the floor screed. Each of these operations requires, which in any case must be prepared with high quality.

Grinding fineness. The smaller the size of the crushed cement particles, the faster the mortar hardens, and the more reliable it will be in the solidified state. The fineness of grinding directly depends on the equipment used for this. The recommended particle size should be between 40 and 80 µm.

Certificate of conformity

Certification of cement in Russia is carried out according to GOST 10178-85, 30515 97, but more often according to GOST 31108-2003. All major Russian enterprises have already switched to the new GOST 31108-2003, which was adopted in 2004. It spelled out more stringent criteria for the quality of cement, as well as its testing. The new requirements fully comply with European quality standards.

What is the difference between cement and concrete

Cement is a dry mix that is used specifically for the preparation of concrete mortar. Concrete is a hardened artificial stone, consisting of cement, water and fillers. Gravel, sand, screenings, slag, expanded clay and other materials are usually used as fillers. Until the moment of solidification, concrete is a mobile concrete mix.

Not only in construction and repair work. If you want to make something solid and strong, cement is indispensable.

Strength class of cement and strength test methods

According to GOST 31108-2003, such a term as "cement grade" is transformed into the term "strength class". Therefore, the digital marking of cement means its strength class.

Strength tests of cement are carried out in factory laboratory conditions using modern equipment and advanced analysis methods. At the same time, the fineness of grinding, the density of the cement paste diluted with water, the setting time of the cement mortar are determined. The compressive or bending strength of the hardened samples is also determined.

Determination of the normal density of cement paste in a virtual laboratory:

What cement is made of: types and varieties of the mixture + manufacturing process + necessary equipment + how clinker cement is made.

A business can be built in a variety of areas, but it is the construction industry that is the base for humanity, because even primitive people were engaged in the search for shelter and housing.

Today, the way has already been passed from primitive caves to modern skyscrapers or comfortable mansions. All this became possible thanks to the invention of cement, for which there is always a demand.

What is cement made from? We will answer in the article.

Cement business: basics

Cement is a binding substance that is used in construction. The binder has the property of almost tightly fixing the elements that have fallen into it under the influence of water and air.

Drying, it creates a monolithic surface, which is very important in the construction of modern buildings. In addition, it is resistant to temperature extremes and most other climatic factors, and most importantly, when frozen, it is not harmful to health.

Since it is always necessary to build or patch holes in the walls, regardless of the economic situation in the country, the demand for this product is high, and consumables are cheap.

Therefore, the profitability of the business model of enterprises that make cement is always high. Isn't this an entrepreneur's dream: low costs with stable income?

But there are also disadvantages, the most important of which is relatively high start-up capital, which is needed to launch a full-fledged cement production.

The next deterrent to investment in this area is strict quality control: do not forget that the safety of buildings depends on this. If a high-rise building collapses because of your cement, then who will be in demand?

But all these problems do not stop, which means that all this is quite feasible.

Types and types of materials from which cement is made

To date, the basic component of cement is clinker, but another 15% is accounted for by the mineral mixture, as required by state standards.

By the way, if you bring the share of industrial chemicals in the mixture to 20%, then it will already be “pozzolanic cement”, for which there are separate standards.

So, GOST 10178-76 regulates the production of a pure composition, and GOST 21-9-74 - mixtures with various chemical additives.

In general, all the properties of cement can be combined into 7 points that allow you to customize production for a different client - from a farmer who needs to close a hole in a barn, to a large construction company from Moscow City:

In addition, cement is divided with an eye to what it is made of and how it is used:

№	Type	Brief description of properties; what is cement made of
1.	Lime	Standard cement without additives.
2.	marly	A mixture based on marl rocks.
3.	Clay with additives of slag and bauxite	Slag and bauxite make cement waterproof, fire and frost resistant.
4.	Portland cement and slag Portland cement	A mixture with carbonate or slag additives, as well as with alumina residues. The peculiarity is that it is processed at a temperature of 1500 degrees. When dried, it turns into a strong stone mass, which is actively used in the construction of large buildings and monuments.
5.	Plugging	Blend with improved airtight properties. This cement is made for the needs of gas production and other industries that require high-quality insulation.
6.	Hydraulic	Mixture for interaction with high pressure.
7.	Straining	Quick dry mix.
8.	Sulfate resistant	Slow drying mixture with increased frost protection.
9.	Decorative	The mixture is made for decorative purposes, therefore it has a white color due to the large percentage of gypsum.

How is cement made?

We figured out what cement is made of, now a little about the technologies for its production.

Modern technology includes several stages and elements, forming a vertically integrated structure - from the extraction of rocks to the sale of a cement mixture or clinker in the wholesale market.

The production of cement on an industrial scale begins with the demolition of an entire mountain, which is why small businesses can hardly afford it.

This will require expensive mining equipment, as well as a whole factory shop with sophisticated equipment, so the initial investment can exceed 500,000,000 rubles, and, taking into account inflation and exchange rate fluctuations, up to 1 billion rubles.

Or CJSC, with all permits (especially in terms of ecology).

At the first stage of production, a mountain is demolished or a deep pit is made for access to the "mainland" - under a layer of soil and black soil there are clays and limestones, which are needed for these purposes. The depth of the pit is about 10 m.

Equipment used to make cement:

After that, limestone and clay are brought by dump trucks to the plant, where they are crushed to a powder.

Then the mixture is fired at a temperature of 1500 degrees, resulting in granulated clinker - the base from which cement is made. Some producers sell the clinker itself to smaller companies.

To obtain clinker, the maximum of all costs will be required, since you will have to purchase limestone and clay or purchase dump trucks, excavators, etc.

Plus, crushers are needed that work in three stages - from crushing large stones to turning the mixture into powder. You will also need a special industrial oven. All this is connected by a conveyor belt.

According to market players, the production of clinker accounts for over 70% of the cost of the finished product. To pay for itself, you need to produce about 800 tons of mixture per day, or 176,000 tons per year.

How is cement made from clinker?

The finished mixture is made from clinker, gypsum, sand and mineral additives. After grinding and roasting, large clods are crushed to a granule size of 1–100 microns, as required by state standards.

At the same time, the technology requires successive crushing of individual components before mixing. So, for example, first of all, the frozen clinker is crushed, then crushed gypsum is added, and only then the cement mixture is made, adding industrial chemicals there. Then comes drying and final grinding.

If you intend to sell a dry product, then packing in bags comes next. If you intend to sell it ready-made, then before loading onto cement trucks, water and other liquid chemicals are added to the mixture, which prevent premature solidification inside the car.

It is important to understand that if you decide to build your cement manufacturing enterprise without intermediaries, and sell the finished product with a higher added value, then it makes sense to complete this process.

To do this, it is necessary to purchase another furnace and crushers, a cooler, as well as a dosing unit.

Plus, you need to immediately decide how you will send cement to the market. Large construction companies make their choice in favor of cement trucks, where they transport a ready-made liquid mixture - with sand and other chemicals (if necessary) so that it can be used in work right now.

Small firms, as well as retail chains, give priority to dry mix packages, which are made in several versions - from small packages up to 5 kg, to bags of 40 kg or more. use disposable paper.

If you choose this dry method, then you will need special equipment for packing and sorting cement, as well as a warehouse.

Dealing with that what is cement made of, you can safely take up its production at your enterprise.

Do you want to know how and from what cement is made?

The whole technological process in one video:

The situation during the crisis is not easy, but people will still build, which means there will be demand for cement.

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