Why is ordinary cement called Portland cement

What are the varieties of cement for strength. Types and properties of cements

In the first queue, we would like to note that cement is currently one of the most widely used materials. And, of course, not only a professional, but also an ordinary person understands this type of construction work incredibly well. They are made in industrial plants and in agriculture and mechanical engineering. This is when we talk about great construction. But each of us came across the usual renovation of an apartment or summer house. The work that needs to be done to complete the process is quite some. Here all the actions follow one after the other, after we get the execution also the end result - a renovated room or a new building on the property. We emphasize that for every type of work there is a certain type of cement and its brand. What is cement marking, deciphering it according to standards and GTA stations, we describe below.

Cement can be different, both in quality and in structural properties. It all depends on its marking. According to the brand, you can find out the load that this cement can withstand and the percentage of additive substances in it.

On bags with cement we come across such inscriptions as M300, M400, M500. Then you will find the letter D, example: D0, D5, D20. So, m and deciphered as properties of the strength of this raw material. That is, cement M500 withstands the load of 500 kg on the surface in one centimeter cubic. Similar with other brands. Mark M400 - withstands cargo in 400kg, M300 - at 300kg. D means d, what percentage of the additives is contained in this cement stack. The decoding has the form: D0 - 0% additives, D5 - 5% and D20 - 20%.

Consider how cement marking, decryption and percentage of additional elements will affect the properties of the solution.

  • CC - resistant to cement sulphate. Applicable to buildings that are in turn in a salt water environment with sulphates.
  • Pc. - decrypted as portland cement.
  • SPC - SlagoportlandCement.. The composition of the additional elements is more than 20% of the clinker section.
  • WRC cement that has the ability to expand. Waterproof. It is used to work on sealing seams in hydraulic buildings. It has the property of high speed strength.
  • N - cement normalized (Only normalized composition is carried out with clinker).
  • BC - white cement. Apply for final work.
  • PL cement plasticized. Has high frost resistance.
  • GF - cement hydrophobic. Ready for a long haul. It does not have the properties to quickly absorb the liquid. It is characterized by good frost resistance and plasticity.
  • B - cement fast (Use, for example, limited by repairs through temporary frames).

We tried to reveal such a concept as cement marking, and we deciphered all kinds of additives and in a short way the areas of use.

Anyone facing construction for the first time needs to be treated with materials. And first of all with such an indispensable material as cement. Difficulty, as a rule, with the marking.

New cement marking.

The thing is that there are already 3 types of markings in Russia. This is GOST-10178 from 1985 and GOST 31108 introduced in 2003, which corresponds to the EN 197-1 EN standard. In addition, the new GOST is used together with the old, habitual one in Russia.

The transition to this standard, which began in 2008, led to the fact that in the branches that you can meet, for example, two types of designation are on the old standard - M400 D0, PC 400 D0 and, along with them, also the third after one New standard - CEM I 42, 5N.

new gosts in cement marking

It often allows such a confusion in the notation to inappropriately overestimate prices, saying that this relates to the fact that this is done in Eurostandard, but this is in GOST. Although there is no difference! It is therefore useful to keep parallels between the old marking and the new. So let's get started.

What does letter mean?

According to the old GOST, everything was simple and understandable. The letter "M" indicated the word "trademark". Also used the "PC" texting which referred to the common portland cement. Then there was a digital designation of the stamp for strength or other parameters.

In addition, there were also the following book balances:
Cc - sulfate resistant;
SPC - Slagoportland cement;
Bc - white;
WRC - waterproof stretch;
Plasticized;
Gf - hydrophobic.


how to decipher cement marking?

According to a new standard, European Cyrillic symbols will also be used. As the cement sector has expanded somewhat, the complexity of the designations has increased.

Now it includes the designation that it is cement CEM. The next letter through the fraction symbol - "/" denotes the subtype of the mixture "A" or "B". Usually this is the amount of mineral and other additives. "A" - from 6 to 20%, "B" - from 20 to 35%.

According to the old standard, this number was indicated by an alphanumeric combination:
D0 - There are no additions;
D5 - additives not more than 5%;
D20 - additives not more than 20%.
For cements with additives of more than 20 and up to 80%, the first letter in the designation Portland cement was "sh" - the HPC - for the additives, especially here, domain chips. Examples of designation - PC 500 D5, M500 D20.

Marking cement for new GOST

In a new standard, in addition to the amount of additives, the cement is specified by type, and then the labeling of mineral additives in the composition. Names are deciphered:
CEM I - PURE PORTLAND cement;
CEM II / A - Portland cement in a mixture of an "A" type, can be "in";
CEM III / A - Slagoporteceman of various subtypes;
CEM IV / A - cement with the addition of pozzolan of various subtypes;
CEM V / A is a composite cement of various subtypes.


new GOST designation for cement

Literal names of the additives in cement

G - burnt slate, glow;
S - oola tires;
Mk - silica;
P - Potszolan;
And - limestone;
K - composite additive;
Sh - slag.

Designation along the strength. According to the old GOST, the train limit was expressed by numbers after the label. Example - M300, PC 600. These numbers denote the destruction of the destruction in kilograms per centimeter. Cement was made in accordance with the standard range in the vicinity of 100 to 700 kg / cm with an interval of 100 units.

According to the new GOST, tensile strength is expressed in megapascals. For example, 52.5 MPa corresponds to the strength of 500 kg / cm, the designation is CEM I 52.5n.

  • 600 – 52,5;
  • 500 – 42,5;
  • 400 – 32,5;
  • 300 – 22,5;
  • 200 – 15;
  • 100 – 7,5.

And the last letter in the name is the speed of hardening - B - rapid hardening and N - normal hardening.

Here are examples of cement decoding on the modern standard of denominations:

1. CEM II / A-A and 52.5N - Portland cement with limestone content from 6 to 20% and the force equivalent to the M600 brand, normally harden.
2. CEM I 22.5b - Portland cement without additives The strength of M300, rapid setting.

Aside from these normalized parameters, there are a few, but they are either not reflected in the brand name or are negotiated separately for non-standard or special types of cement.

In England, in 1824, D. Aprind registered a patent for the manufacture of cement. Lime dust, which he mixed with clay and faded to high temperatures, at the same time a gray nasal material was obtained - clinker. After grinding and mixing with water, a strong material was formed which was named Inventor Portland Cement because of its resemblance to a brick quarried in England that is quarried in the city of Portland. They produce various types of limestone, merghelistics, clay rocks and various additives - slag, bauxite, etc. mainly deposit clay and carbonate rocks. You can use other natural raw materials and artificial materials: waste recycling of combustible slate, beliter sludge, ash, blast slag, alumina production waste.

This mineral powder, which when mixed with water results in a plastic mass, which is solidified in water and in air.

In addition to the main raw materials, various corrective additives are used in the manufacture of Portland cement, which gives it a wide variety of properties.

There is portland cement and slagoportland cement. Portland cements are quick, as well as with mineral additives. Concrete structures, in which one or another brand is used, acquire unique characteristics. This can be a concrete of a special force for the construction of airstrips at airfields and rocket launch sites. Designate the maximum strength with the mark. The 400 mark means that in an experimental test under the press, a hardened cube with a side of 100 mm stood up to the load at least 400 kg per square. See the most popular brands - 350-500. Each brand has a pretty quick cure time. The breakdown of 40-50 minutes begins, and the final solidification occurs after 10-12 hours.

Sorts:

  • pozzolan;
  • slagoportland cement;
  • aluminome;
  • sulfate-resistant PC;
  • portland cement (pc);
  • hydraulic pc;
  • burden
  • tampon-pc;
  • white PC (decorative).

Portland cement property.

Strength is the ability of materials to sense the load, not to destroy it. Strength is determined by its ability to solidify after mixing with water.

This is a binding hydraulic substance, the main component of which is calcium silicate. It is most common in modern construction. Get with the help of thin grinding of clinker and plaster (3-7%); It is allowed to add 10-15% of the active mineral additives. Clinker is the result of firing (1450-1500 degrees) the raw material mixture, which consists of 75% calcium carbonate (limestone) and 25% of the clay. The composition of the clinker and the grade is affected. Important Property - The ability to interact with water when cured. It is distinguished by a mark determined by compression of compressing and bending a standard sample of the solution after 28 days of rejection in wet conditions.

The most important property is the ability to harden upon interaction with water and acquire the old state. The greater the mechanical force of the H-shaped Campan solution or concrete, and the faster it is achieved, the better.

Therefore they differ:

  1. The ultimate power that solution can be acquired during the curing process.
  2. The curing rate characterizes the intensity of the growth in strength over time.

The cement, which is characterized by high strength growth, is called fast-setting notoriety, and if high strength is still achieved, then high strength.

The mechanical strength is determined in different ways, for example the tensile strength, in compression, in bending. At the same time, the selection of the mixtures, storage, production and testing of samples takes place in accordance with the requirements specified by the relevant standards.

Sulphate resistant

It has a low hardening rate and frost resistance.

In addition to the usual products, which are differentiated by properties, composition and area of ​​application: sulfate-resistant, hydrophobic, plasticized, fast-hardening, white portland cement (for the production of asbestos-cement products), etc.

A wide variety of portland cement is sulfate-resistant. It has high resistance to the effects of mineralized water containing sulfates, low heat dissipation, slow intensity of hardening and great resistance to frost. Sulphate resistant is obtained using fine grinding of a clinker with a normalized mineralogical composition. It is intended for the manufacture of reinforced concrete and concrete structures of hydraulic structures that experience the aggressive effect of the sulphate medium (for example, sea water), mainly in conditions of variable humidity (freezing and thawing).

The initial raw material is clay with a small amount of aluminum oxide and iron. This mixture should contain neither inert nor active mineral additives. Such raw materials have not been widely used, and this prevents the widespread manufacture of sulfate-resistant portland cement.

Slag is a crushed domain granulate slag with an admixture of activation additives.

Slag - This is a combined name for cements obtained by making a domain-grained slag with the addition of activators (lime, building plaster, anhydrite) or mixing these separate crushed components. A lime slag cement differs with 10-30% lime and 5% by weight of the mass and sulphate slag, which contained 15-20% anhydrite or gypsum, and a portland cement 5% or lime 2%. Apply the slag for reception to building solution. and concrete used in subsea and subsea facilities. The most effective lime slag in the manufacture of autoclave products is the most effective.

Poaceolne is a name for a group that has at least 20% of the mineral active ingredients. Compared to conventional Portland cement, it is characterized by increased corrosion resistance, lower hardening speed and reduced frost resistance. Apply it to the manufacture of concrete used in subway and underwater facilities.

Aluminous.

Features are waterproof, frost resistance and fire resistance.

Glazymatic - Hydraulic, binder is fast to drive; The resulting grinding of clinker, which is obtained by roasting the raw material mixture of limestone and bauxite. Melting and firing of the raw material mixture are made in Vagranca or Domain rotating furnaces.

The content of AL2O3 in the end product determines the type of aluminum cement: greatly reduced (up to 70%) and normal (up to 55%). It is characterized by increased corrosion resistance, rapidly increasing strength, large exothermicity during solidification and high fire resistance. With the help of Hydro-Grade, concrete and solutions are obtained that are more waterproof and dense than with Portland cement.

Hydrophobic Portland cement is obtained when grinding a clinker with a hydrophobic additive and a plaster of paris. The additive is introduced in an amount of 0.1 to 0.3% and forms thin hydrophobic films on particles, which reduce hygroscopicity and protect against damage even under high humidity. Solutions and concrete have a low water absorption, greater frost resistance and waterproof in contrast to conventional solutions.

The tightening cement is a quick grip, waterproof, frost resistance and crack resistance.

Tamponight is a variety of portland cement; what is intended for cementing gas and oil wells. It is made with a joint fine grinding of plaster of paris and clinker and is used in the form of a test with a water content of 40-50%.

Tension is a multitude of extensions. It is obtained by grinding 15% of the clay slag, 65% of the portland cement clinker and 5% of lime. It hardens quickly and grips quickly.

After hardening, it has a high level of waterproofness. Expanding when hardening reaches high pressure, which is used to create reinforced concrete structures, reinforcement in some directions. Tensioning is used in the manufacture of pressure pipes to build capacitive structures and thin-walled structures out of reinforced concrete.

quality assurance


The mark is a load indicator of the 28-day age, which has to withstand cement, kg per square meter.

An important feature is the limit of its compressive strength. Cements are divided into brands according to the strength of compression. The most common in construction in construction is 400. The mark is determined only in laboratory conditions. There are stamps from 300 to 600. With the use of a high stamp, most of all, on cement 400 stamps make concrete 500 stamps and above, 500 stamps concrete 300 stamps.

It believes that high quality, traditional brand is a guarantee of the building material. But every cement is a bond of artificial material. It is rarely used in its pure form.

Concrete strength depends on the brand of cement that is used to knead the solution.

Mostly different types of cement are used to create concrete. In asbestos-concrete products and reinforced structures made of reinforced concrete, a certain brand with a special characteristic applies. One type requires specific density, the other - and so the question of what is best is not entirely appropriate. However, you can know the main types and understand their characteristics.

The binders vary with qualities and properties. This informs the marker. It contains such information as:

  1. The ability to withstand the load.
  2. The percentage of additives in the composition.


The timing of the test depends on the type of cement.

The marking in letters such as M400 or M500 indicates maximum strength and functional purposes.

M400 is deciphered as follows: M - mark, 400 - compression load, i. H. 400 kg per square meter. See Additive Indexes the letter "d" and informs about their percentage of total weight. D20 means 20% additives. This parameter means elasticity and flexural strength. The larger the index M, the stronger the cement than the larger the index D - the more elastic. There are other designations in the letters.

Choosing the brand.


The letter "m" (or "PC") next to the number indicates the strength. The percentage ratio of additives to total volume is indicated by the letter "D". The designations "b", "pl", "ss", "gf", "n" indicate the appointment of cement.

Portland cement is the common one that is used to create concrete mixes and construction. It contains grass 400 and 500, they can still be called "cement PC400".

M 500 ensures density and high strength of the monolith. The PC I 500 brand is used to specify the surface and the heavy loads. Its properties are frost resistance, water resistance and, in particular, fast grippers. It is widely used in production. paving tile and tiles.

Slagoportland cement PC II A-W 500 contains 20% additives, it is the most suitable for construction work. Although it is not seized as quickly as the PC I 500, but after the last frost acquires similar properties.

Cement 400 is used to fill reinforced floors of foundations, beams, reinforced concrete products. The CP II / BC 400 Index grade comprises 20 to 35% of the additives. The density of this brand is less, and therefore the material has greater elasticity.

The note with the PC II / A-W 400 index is denoted by M400, it contains a clinker, although with less proportions.


The presence and number of additives affects the strength and plasticity of the solution.

Correctly correct the mark for specific building conditions - not too easy. Attention must be paid to the activity of the cement. There are several factors that affect its activity.

One of the factors is the composition, it shows which additives and impurities were used in the production. Often his astringent abilities fall before the use of additive brand or activity, their binding agents are reduced. This happens when the additive is replaced by part of the binder active. It is necessary to choose the additive, the activity of which is high, saving properties cement mix. For example, adding quartz or calcite to a mixture will reduce activity.

Cement grinding unit determines the activity of the cement test.

Another important activity factor is the thinness of the grind. It often happens that two mixes have the same composition, but one high brand cement, and the second is not. Pomol concerns the field of binders, and therefore the thinner of the grinding, the structure of concrete, is more dense.

The third and one of the main factors of activity is the use of clinker. The mineral composition of the clinker determines the activity. If you need permanent property with especially cement, it is necessary to add a clinker with a high content of aluminates and alite.

Storage conditions


Store in a dry room for a short time.

What to choose the view and decide on the intended consumption is known at the design level. It remains only to buy the required amountthe desired brand .. But is there always a bag of Cement and Applied Markings? There is a risk of purchasing poor quality goods. The reason for this is the wrong storage conditions. Long-term storage also contributes to cement losing activity as it implies the effects of moisture and carbon dioxide in the atmosphere. How do the activity and its loss reflect on the qualities? Due to the storage conditions, the cement can lose activity by up to 15% per month. Activity is the most important parameter responsible for its fastening properties and the brand as a whole.

The lost activity significantly affects the braking of the hydration process. The greater the initial activity of the cement, the most likely hydration is lost. For example, if M500 cement was purchased, after a few months it will be M400, and after six months the cement can be disposed of.

Do not forget that the cement, which has remained for a long time, is always lower than the brand that is indicated on the package, and therefore it is impossible to use it for responsible work. To compensate for the loss of quality, when it is used, the percentage of cement in the mix increases.

Cement - special bulk material, which is a special mineral powder. And when it is mixed with water, it is turned into a viscous, permanent mass in the desired proportion. It's a mix of dark gray that dries quickly in the wind.

The powder itself is obtained by simply grinding clinker in combination with plaster of paris and other minerals. Apply such a building material at all stages of construction. There are many types of such a material, each of which has its own properties that, in one way or another, affect the construction process.

What to look out for when buying cement

When you come to the store and choose, you have to understand why you need it. The material has its own characteristics that are worth knowing about:

  • resistance to corrosion.. Negative impact on the material that is already frozen can put it in an aggressive environment and even in ordinary water. However, this property can be easily corrected by introducing into it various hydromatons, or additives of various polymers;
  • grind, its subtlety. The thinner of the meal of cement the better. This is because it sometimes freezes faster. In addition, all of its properties are much higher than those of coherent grinding. To determine the grinding, it is enough just to skip it through a sieve;
  • ideally 90% of the material should be suitable. It is worth understanding that if the cement is small, then it is necessary to dispense more water in order to dispense it. Ideally, material must contain both small and large particles.:
  • Another important feature is resistance to low temperatures. Since this material is used in the construction, it must be resistant to temperature changes;
  • this is due to the fact that water, which at low temperatures enters the preparation of the mixture at low temperatures, up to 8%, and it can easily spoil the construction;
  • Can just crush, damaging the whole design. Based on this, a woody, sodium area, etc. is added to the cement.
  • Strength. An important characteristic of the material, which is determined by the manufacturer's brand. In the building material market, many companies offer their goods. The thickness of the material can be calculated within 28 days;
  • grappling. The time for which the properties of the material change, that is, it becomes solid. It is worth understanding that the temperature of the air and water affects this property. Normal materials are packed after 45 minutes.

Choose a certain characteristic, the main thing difficult, since each of them has its own value. If for example, you focus on frost resistance or strength, you should understand that if the cement has a slow time of freezing then it slows down the process of the whole construction.

It can be said that each of the above properties has its weighty merit. And it is important to pay close attention to each of them.

When packing with cement, the manufacturer specifies all the necessary properties and characteristics so that the buyer can appreciate the goods before buying.

Today on the shelves of construction hypermarkets you can find universal materials that can combine the best properties.

Well worth understanding the process of making such a bulk material is quite expensive. It consists of the following processes:

  • receive a clinker directly;
  • transformation of the resulting clinker into powder.

The process of cement production can be of three types:

  1. Wet manufacturing method.
  2. Dry.


  1. Combined method.

Types and uses.

BTC.

Furious portland cement, the packaging can be found a decrease in BTC. This particular material that managed to imagine quite a large amount of mineral additives. Their role is to increase strength (especially in the initial period of hardening).

It is best to use such a cement when you need to create a reinforced concrete unit or a quick design.

Bulk Gray powder that contains certain hydropobic additives. This type of cement has its advantage: it won't absorb water for the next five minutes after it's added to the dry. It is logical to argue that it is this mixture that has smaller water absorption.

This type of material can be used in cases when you need to build in places with high humidity or in water (in places where there is a possibility of flooding). This is due to the fact that on such a cement-moisture-proof state.

For more information about the brands of cement and their application, see the video:

Pad

Material that consists of certain surfactant additives. They are added at the time of grinding. It is worth understanding that the mixture on the basis of such a cement has good plasticity / mobility. That is, it is convenient to work with this material.

Today river sand It is the strongest material that is used in construction and repair. Everything about its density.

Uneven ceilings and walls are common in residential and residential buildings. Learn how to line them up better, plasterboard or plaster of paris.

To properly make a screed, you need to know the nuances of the source materials, the type and condition of the surface, as well as the proportion of their mixing. Turn to familiarize yourself with the screed answers.

Portland cement tamponja.

The material that has the ability to disperse the object from the groundwater.

It is best to use gas wells, oil at work (tampony).

Its characteristic is that it has such a property as fluidity (the advantage is that this characteristic does not depend on temperature and pressure).

Portland white and color

Portland cement white / colored. The white material variant has almost no coloration of oxides. From the title it is obvious that he is easy. And if you make a concrete in such a type of cement, it will be almost white. It has good enough properties.


But most often it is used in enhancing the aesthetic type of building (than concrete white). Talking about the color version, then during its manufacture, in the material add a specific pigment, as a shadow as you want the developer to be. Just like the white cement, it is used in cases that improve the aesthetic enhancement of the building.

slag

This material is released in two ways:

  • The SPC used is widely used in port construction;

  • ISC is the material used in low hour concrete falls.

Known, I popular point of view material.

It does not contain any mineral additives or gypsum. But you can choose one important component - calcium aluminate.

However, it is worth understanding that when injected, the need for fluids themselves increases by 10%.


Such a cement can be found on the store shelves in three versions, 600 (). Each of them has its advantages and disadvantages. Mostly this type of cement it is used in emergency work or raw lighting.

Another good cement is expanding.

It is already clear that the essence of the material is that it increases in amount in order to create a solution.

Not adiky B. chemical composition material, there are several options for such a substance: cement waterproof, load, portland cement expands.


All of these materials have good and reliable properties.

Which means to pay attention to when buying cement, mark it

Of course, the types of cement are too much, but in any case you need to choose the one that will suit your case. The first thing you should know is what exactly you are going to create. In addition, it is necessary to understand that the environment is also important as a future building is being operated.

There are certain points that you should be aware of before you decide to buy the cement:

  • if the building is built on land, it is necessary to determine the temperature there, and how it fluctuates, it is necessary to choose cement that is resistant to temperature drops (especially if there are cold winters);
  • with the structural structure in water, it is necessary to find out the temperature differences and the composition of the water itself;
  • it is important to know if it rains often in this place, there are strong gusts of wind and the cutting of pressure and temperature jumps.

In fact, it is important to simply know where the building will be built And what weather conditions does a terrain have. Already in the store it is to act according to a certain scheme that will allow you to acquire high-quality and necessary material for future concrete.


When we get into hand-wrapping cement, you can see various alphabetical abbreviations and numbers. You should know all the letters and numbers. To get hold of exactly that material you need to know what they mean.

Since high quality is characterized by its strength, numbers are applied to packaging:

  • 52.2. The figure indicates that such a material has the ability to withstand the pressure of 52.2 MPa. You can use the length of concreting high-quality structures.
  • 42.5 - withstand the pressure 42.5 MPa;
  • 32.5 - Can hold pressure 32.5 MPa. This variant of the material can be used during the construction of monolithic and prefabricated concrete;
  • 22.5 - The ability to withstand 22.5 MPa.

Necessary understanding and alphabetthat determines the type of cement:

  • Pc-simple, neat cement;
  • SPC - 20% of the components of various impurities;
  • BC - white cement;
  • PL - material that tolerates temperature fluctuations well;
  • CC - material resistant to sulfate contamination;
  • VRTS - cement of waterproof type;
  • GF is a material that does not absorb water for the first 5 minutes.

Cement is a material without which it is difficult to submit construction. Over the years, this bulk powder is used in the assembly of various buildings. In order to keep your construction long and reliable, it is important to choose the right cement. He must have decent qualities.

It is also important to properly grow the powder with water so that a thick mixture is obtained. Knowing everything about cement, you can get exactly the type that will help you create durable concrete.

Cement is an binding powder that is used in the manufacture of building materials, construction buildings, and other structures. It consists of clinker, limestone, various minerals and gypsum. The range of use, features and properties of the cement depend on the composition and proportions of the components. The most common is portland cement. Limestone is added for its production to the clay.

The already hardened cement structure constantly affects the environment. If it is on the road, there will be precipitation, salt on it. She freezes and moves away. In order to improve the corrosion resistance, polymer additives are added to the cement powder at the production stage to the cement powder. They reduce the degree of micropore, which makes the material more reliable.

Not only the price of the binder component depends on such a parameter as a subtlety of the lattice, but its quality. The smaller the fraction, the better the source material. The solidification process of the fine-flowing Portland cement is much faster than powder with large particles. For the cement to have optimal properties, different fractions are mixed.

One of the main parameters to consider when choosing Portland cement is the degree of frost resistance. The more freeze and thaw cycles that can withstand, the longer the design will serve from it, and the fewer repairs it will require. From this property, the area of ​​use of cement depends entirely. Every time concrete freezes, the water it contains expands and destroys it from within. In order to improve the degree of frost resistance, mineral additives are introduced into the cement powder, for example sodium deflectors or neutralized wood spacing.

Cement varies with strength.To determine the brand, a solution is made from one part of the cement powder and three parts of quartz sand. Everything is thoroughly mixed to a homogeneous consistency and poured into the mold. After 28 days, the test sample is placed under the press and indicates. The print he started on and is his brand. 6 probes are tested for the determination. The arithmetic average is calculated from the 4 best calculations. The result obtained is considered his stroke. This indicator is measured in MPA and kg / cm2.

Another characteristic on which the area of ​​cement powder usage depends is its breakdown time. This parameter is especially important when emergency repair is required or in a cold climate. The rate of solidification of Portland cement can be adjusted with plaster of paris or other additives. Also affects the temperature. environment and water. As the air is colder, the longer the cement is free. Under optimal conditions and properly kneaded cement mortar crashes in 45 minutes.


Marking and decoding.

Each type of cement has a specific marking. It shows what a binding powder is suitable for. Consists of numbers and letters.

Table with the decoding of cement marking of different types:

The binding powder brand is based on the letter M and the number after it, for example M500. This means that the material can withstand the load of 500 kg / cm². This property can also be displayed with just one number - 22.5, 32.5, 42.5 and 52.5. In this case, it is not mentioned as a brand, but a class. This means that the product is under pressure in, for example, 22.5 MPa.


Table with new and old brands of cement:

OldNew
M300.22,5
M400.32,5
M500.42,5
M600.52,5

The rate of solidification is also indicated on bags, in addition to marking the strength properties and frost resistance.

The decoding marks look like this:

1. Come on - Portland cement, has the highest rate of hardening. Concrete reaches 50% as early as the second day after pouring the solution. Contains up to 5% of the additives from the total volume of cement powder.

2. KOMER II - Freezes slightly more slowly. Portland cement contains 6-35% supplements. It is from their quantity that the rate of solidification of the mixture depends. The more they are, the longer the solution will be taken.

3. CEM III - Slagoportland cement with normal hardening. 36-65% consist of a domain slag in the form of granules.

4. CEM IV - Pozzolane with normal solidification rate. It includes a microcarce (denoted by the letter M or MK), ash hunters (marking S), pozzolanes (P). The number of additives is 21-35%.

5. CEM V is a composite bond powder with a normal cure rate. Around 11-30% consists of ash underwear, 11-30% domain slag in the form of granules. Branded cement for starch - 32.5.


The amount of additives is indicated by letters A and B. as the following: and means 6-20%, in - 21-35%. This marking is used for all types of cement, with the exception of CEM I. Letter B means the presence of limestone, shlage. The speed of the determination rate is indicated by the letters n - normal and p - high early.

The marking of the binder powder begins with the type of cement CEM, after which the% content and the type of additives are indicated. Next, the strength class and the setting speed are determined. For example, CEM II / VC 22.5N is a Portland cement with a granular domain slag 21-35%, a strength class 22.5 with a normal velocity.

The marking can look different. First of all, the type of cement, the brand, the number of additives is indicated (with the letter D and the number according to IT - D0, D5, D20), plasticization PL or hydrophobized GF or H - with the normalized composition of the clinker


Types of cement and their application

1. Portland cement without additives (D0) produced brands M400, M500, M550 and M600. M400 and M500 have an average speed of strength speed, weatherproof, frost resistance mark high. Scope of use: Manufacture of prefabricated, monolithic concrete and reinforced concrete structures. The M550 and M600 have similar characteristics, but they gain power quickly.

2. Fast setting portland cement (BTC) is made by M400 and M500 brands. Quickly gain strength, steal frost. It is used for concrete and reinforced concrete structures, as well as for the construction of monolithic and precast systems.

3. Portland cement with mineral additives is made by M400-M600 brands. PC-D5 M400 and M500 M500 has an average durability rate. Scope - Manufacture of concrete and reinforced concrete teams and monolithic structures. Portland cement M550 and M600 are used for the same purposes, but they have a high rate of hardening.

4. Slagoportland cement is made of M300, M400 and M500 brands. M300 has a low rate of strength recruitment and poor frost resistance. Particularly effective with the thermal treatment, thanks to where it can be used for the construction of structures above and below ground and in water. The M400 SPC has an average speed of durability and frost resistance. The M400 and M500 SPC are a low thermal cement.


5. Sulphate portland cement is used for structures that are in aggressive environments. M400 and M500 brands are produced.

6. Pozzolana Portland cement has a low strength rate, but is resistant to aggressive media. Used for structures that are in water and underground. It happens M300 and M400 brands.

7. Hydrophobic Portland cement is suitable for the manufacture of concrete solutions that are used in the construction of roads and airports, as well as hydraulic structures.

Before buying cement, it is necessary to precisely determine the brand required. To do this, it is necessary to take into account the following factors:

  • operating temperatur;
  • percentage of humidity;
  • composition of water and soil;

If you use a low hourly cement for construction, the design may not be able to withstand gravity and the concrete will begin to collapse. Should also be paid attention to the durability. The material is fresh, the higher its strength properties.