Any construction of a building begins with laying the foundation, and pouring the foundation begins with the purchase of cement. You can find various brands and types in the store, but the most common ones are M400 and M500. Before buying bags and starting to dilute the solution, it is worth deciding how cement 400 differs from 500. The correct choice, ease of use and operation of the building itself depend on this. After all, if the hardened concrete cannot withstand the load, the building will suffer greatly.
Source dom-stroy-24.ru
Cement M400. Specifications. Production
Cement is an artificially created building material.
It is an astringent mineral inorganic substance, which, as a result of reaction with water, forms a soft paste-like mass. As a result of the ongoing chemical reactions, the process of rejection and transformation into a durable stone-like substance is carried out. Cement has found wide application in domestic and industrial construction. Special types of cement are used for medical purposes, for example, placing fillings in teeth.
Types of cement
Cement is divided into types depending on the initial composition:
- Portland cement . It is primarily composed of alite, a calcium silicate-based chemical. One of the most used in civil and industrial construction.
- Aluminous cement . Its composition is dominated by substances based on compounds of aluminum, calcium and silicon oxides. Differs in speed of setting.
- Magnesia cement . The predominant phase is based on magnesite (compounds of substances that include magnesium). It has excellent adhesion to wood, high strength and fast setting. Area of application: production of glass-magnesium plates.
- Mixed cements are a composition of different cements with additional additives that give different characteristics to the substance.
Price
What is the price? Despite its positive technical characteristics, the M500 can be purchased at a hardware store at an affordable price. Depending on the region, the cost of M500 is 3700-4100 rubles/ton. Approximately 80 rubles per 50 kg bag.
Brand M500 is a frost-resistant, water-resistant and durable product that can be used in both private and industrial construction. Moreover, the construction process can be carried out even in severe frosts. Thanks to this, you can plan all your repair and construction procedures at any time of the year and not worry that this will somehow affect the quality.
Cement M500 D0 and D20, or as it is also called “five hundredth”, is the best offer in its class on the modern building materials market. It is used for masonry and plastering work, so it has a fairly wide range of applications.
This is the creation of concrete structures, beams, floor slabs, pouring foundations, housing, industrial and agricultural construction. In cement M500 D0 - “D - 0” indicates the absence of additives. Therefore, it quickly sets, hardens and dries. It is characterized by high strength, water and frost resistance, durability, as it consists only of cement clinker. Cement clinker is created by firing in special kilns at a temperature of 1450 degrees, with the following mixture composition: limestone, special quality clay. After which the clinker is crushed, sifted, and crushed gypsum is added as a percentage - no more than one percent of the mass of the original raw material. M500 D0 cement, due to its high-quality, long-term strength, is used for the construction of bridge structures, airfield pavements, reinforced concrete pipes, railway sleepers, supports and racks of power lines. Very effective when performing restoration and emergency work Cement M500 D20 in which the number 500 means that it will withstand a load of 500 kg per square centimeter. Cement M500 D20 is a powdery homogeneous mass - clinker, which is produced in several stages in factories with modern high-tech equipment. Modification of cement with the addition of certain properties is carried out by adding special impurities. The “D20” marking indicates that the cement consists of 80 percent clinker and 20 percent additives. Its price, accordingly, is less than pure “five hundredth” cement M500 D0. And hence such characteristics as strength, hardening speed, water resistance, frost resistance are lower, although compared to the “four hundredth”, a positive difference is obvious! Cement M500 D0 D20 is packaged in multilayer bags that prevent its contact with the environment. By following the storage rules, the buyer is provided with high quality goods guaranteed by the manufacturer for six months.
Therefore, it is very important that purchased bags must be protected from exposure to moisture, vapors and other liquids until they are opened and the solution is prepared. “Large-caliber” packaging in bags up to one ton, convenient for large construction companies for which small, fifty-kilogram bags are not practical to use
Thank you for your help in preparing the Elitastar.by materials.
Designation of cement. Stamps
The designation of cement characteristics is regulated by GOST of 1985. and 2003
“Old” designation, according to GOST from 1985:
- Name of cement based on its composition. Denoted by the abbreviation PTs - Portland cement or ShPTs - additives from slag are introduced into the cement.
- Strength of cement . Determined by the brand of cement - an alphanumeric phrase: the letter M and the numbers 300...600. For example, it stands for M300 – a grade of cement with a strength of up to 300 kg/cm²
- Supplements . A combination of the letter D and numbers indicating the percentage of additives in the total mass of cement.
- Characteristics of cement. It is designated by letters of the Russian alphabet, for example, B – quick-hardening; BC – white cement and more.
“New” designation, according to GOST of 2003:
- Compound . Pure cement without additives – CEM I; cement with additives – CEM II. The second subgroup is divided into subtypes: A – additive content up to 20% and B – number of inclusions up to 35%. The type of investment is designated: P – pozzolan and Ш – slag.
- Compressive strength class. The calculation takes into account information received after 28 days of exposure, from the moment of laying in the foundation. Subclasses are designated: N - normal-hardening and B - rapid-hardening.
The grade of cement determines the grade of concrete when producing the latter in accordance with technical documentation and compliance with technological processes in accordance with GOST.
Examples of using various grades of cement:
- civil and industrial construction: use cement grade M-400 (PTs-400 D20);
- road construction: various structures made of precast reinforced concrete, asbestos cement - cement M400...M500;
- production of reinforced concrete structures with increased strength requirements, for example, for military construction - M-600 cement;
- pre-stressed structures , high-strength concrete, for example, for the manufacture of elements of cosmodromes - M-700 cement.
Technical characteristics of cement M-400
- Compound . Cement is a composition of chemical elements in a solid state of aggregation. The predominant oxides are calcium (Ca), aluminum (Al), magnesium (Mg), silicon (Si), iron (Fe), titanium (Ti). The volume of minerals reaches 98%.
- Density _ Depends on the condition of the cement - the loosened composition has a density of about 1000...1200 kg/m³; compacted, “packed” powder has a relative weight of 1500...1700 kg/m³.
- Setting speed. The parameters are determined under normal climatic conditions with a temperature range of 18…22°C. A stable setting process begins after two hours from the moment the cement is mixed with water and lasts 2...4 hours. Strength of 95...98% is acquired after 28 days.
- Frost resistance . Operating temperature range -60°…+300°C.
- Water resistance . Cement that has fully gained strength after setting is highly resistant to water.
- Durability . Amorphous to most organic and inorganic solvents, water resistance and frost resistance allow building structures made on the basis of M-400 cement to withstand loads for up to 100 years or more.
Features and Benefits
Cement mortar M 400 is considered a popular subtype of cement, which consists of the following components:
- Gypsum.
- Powder clinker.
- A number of additional components.
To produce quality material, it is necessary to carefully monitor each process and evaluate the condition of all additives. In addition to the basic ingredients, modern Portland cement contains the following additives:
- calcium oxide;
- silica;
- alumina;
- iron oxide.
When clinker comes into contact with water, it creates new minerals that form cement stone. For convenient classification of the material, its purpose and specific composition are taken into account.
The following subtypes of grade 400 cement are available for sale:
- PC - Portland cement.
- GF is hydrophobic.
- SS - sulfate resistant.
- BC - white and colored mixtures.
- Slag Portland cement (SPC).
- Sand-cement mixture.
Among the key advantages of the M400 mixture are the following:
- Easy to use and no complications during breeding. To prepare a good solution, you need to follow the step-by-step guide.
- Cheap and accessible. Bags of M400 cement are sold in any construction hypermarket and market. The only difficulty is choosing the right manufacturer.
- Improved performance properties and load resistance. Even if deviations were made during the production of the material, the likelihood of cracking or deformation will be minimal.
- Wide temperature range at which operation is allowed without risk of damage. It varies from -60 to +300°C. This allows the brand to be used in a variety of directions.
- Minimal shrinkage during hardening. Due to this property, builders can change dimensions when pouring a foundation or arranging another structure. This indicator also eliminates the problem of cracks appearing on the surface.
- Fast setting and hardening. The interval during which the cement hardens takes 8-10 hours. At the same time, it takes no more than two to three weeks to gain factory strength. If the temperature rises or humidity changes, the curing time will be shortened.
- The ability to change the initial properties by introducing plasticizers, anti-corrosion additives and other substances into the composition.
But despite all the advantages and differences, for the implementation of projects for the construction of multi-storey buildings, bridges and structures with increased strength requirements, it is better to use a more durable brand, such as M500.
Cement production. Features of technological processes
There are three main types used in cement production:
Wet production method
Based on the preparation of raw materials by grinding components in water.
Stages:
- Natural minerals - limestone and clay are crushed in an aqueous environment.
- The resulting mixture , which has up to 50% humidity, is loaded into a kiln.
- Raw materials are subjected to heat treatment in several zones:
- heating and drying - at a temperature of 200...600°C, excess moisture is removed, organic inclusions burn out, chemicals undergo dehydration with subsequent decomposition of components into oxides;
- decarbonization zone – limestone decomposes into calcium oxide with the release of carbon dioxide; under the influence of temperatures in the range of 900…1200°C, new chemical substances are formed;
- zone of thermal reactions - the final formation of chemical substances and their partial sintering occurs;
- sintering zone – at a temperature of 1350...1480°C clinker granules are formed;
- cooling zone – cooling of raw materials with a slow decrease in temperature to 1300°;
- The resulting material, clinker, is crushed to a powdery state.
- are introduced, according to technological processes .
Prices for cement grade M-400
Prices for the final product, M-400 cement, are made up of production costs, transport and overhead costs, and wholesale and retail trade markups.
Average prices for the sale of cement in bulk are 2800...5000 rubles/ton ; a bag of industrial cement weighing 50 kg costs 230...400 rubles/kg. The price range depends on the delivered batches of goods, their distance from the place of production and the sales markup of sellers.
Cement with mineral additives or Portland cement costs on average 10...15% more. A product with slag components will cost 5...10% less, but it is recommended to use it for the production of concrete, which is used for non-critical building structures, for example, for pouring sidewalks, making road tiles, curb stones.
The most popular type of binder in civil engineering is M400 cement. It has technical characteristics and operational properties sufficient to ensure the strength and reliability of the load-bearing structures of houses, outbuildings and industrial buildings.
What determines the volumetric weight of cement?
The specific gravity of cement as the main binding element in the solution depends on its brand, degree of grinding (grain size) and drying technology. Thus, freshly ground material will have a lower density (within 1100 kg/m3), since during grinding its particles are magnetized and, according to the law of electrostatics, repel each other.
As a result of long-term storage or transportation, the reverse process occurs - the grains lose their charge and are compacted to approximately 1500 kg/m3. This is why experienced builders recommend buying cement that was made at least 1 month ago, that is, stale. But if the mixture is more than 6 months old, it is most likely that it has already lost most of its quality characteristics.
According to the technical standards and rules used by most enterprises for the production of concrete and reinforced concrete structures, the weight of a cube of cement is assumed to be 1300 kg/m3.
Even in stale cement in bags, most of the volume is filled by air microvoids between its grains. But to obtain a high-quality structure, the structure of the mixture should not have voids. In order to ensure the required quality indicators, different sizes of aggregates (for example, sand) are selected. When cooking, large fractions are added first, medium ones after, and small ones are added at the very end of mixing.
How much cement is needed to prepare 1 m3 of concrete?
The amount of cement does not increase the volume of the finished mortar, as some builders believe. Excessively fine grinding promotes its uniform distribution in the voids between the filler particles during mixing. You can add 300 and 400 kg of cement per cube, while the volume of the finished product will remain the same.
Standard weight of cement to produce 1 m3 of concrete of various grades:
- to obtain M500 - 450 kg of binder;
- for M400 - 400 kg;
- for M300 - 350 kg;
- for M200 - 240 kg.
When purchasing cement for construction work, you should definitely pay attention not only to the brand of this material, but also to its volumetric weight. As we know, the grade of cement is responsible for its strength
Cement grade 400 can withstand a load of 400 kg per cubic meter of area. This material is widely used in various types of repair and. It is used in everyday life, for minor repairs, and in large industrial buildings. But, when choosing this cement, you need to record its volumetric weight (specific gravity). This is the ratio of the weight of cement to the volume it occupies (bulk density). The volumetric weight of M400 cement must be taken into account when drawing up optimal proportions for mortar.
The lowest density is for cement that has just been ground. This cement is called Portland cement. This is due to the fact that during grinding, the particles of the mixture are magnetized, and during friction they repel each other. During some subsequent processes, such as transporting the material, pouring it into containers, long-term storage, this property gradually disappears and the mixture becomes denser. Thanks to this, its volumetric weight increases.
- Volumetric weight of cement M400 (freshly ground) - 1100 kg\cub.m
- Volumetric weight of cement M400 (after time) - 1500 kg/cub.m
Let's consider the shelf life of M400 cement.
The shelf life of cement proportionally affects its activity, that is, bonding properties and grade. Also, activity slows down the hydration process of building materials.
If you do not want to use it immediately after purchasing it, then you should think about the storage conditions of this material. To preserve all the qualities and technical characteristics of cement, you need to store it in special containers. Packages with the solution must be placed on a wooden surface. The distance from the bag to the ground should be at least 15cm. It is advisable to cover the floor in the room where cement is stored with roofing felt. Storage of cement in bulk means storage in a barrel. The top of the container must be wrapped with polyethylene film.
If storage conditions do not meet proper standards and requirements, then cement quickly becomes unusable. This material can be stored at home. It is necessary to ensure the tightness of bags of cement, which should preferably be wrapped in polyethylene. The temperature in the room should be without sudden changes and be more than zero degrees. Manufacturers write on the bags the permissible air humidity when storing the material. If you follow all the recommendations, you can increase the shelf life of cement to one year.
Scope of application
M400 grade cement is suitable for general construction and finishing works:
- Arrangement of all types of foundations (strip, pile, slab);
- Construction of walls and columns;
- Preparation of plaster and repair mortars;
- Mixing concrete for laying paths.
From cement m 400, concrete M100...M450 is obtained. Moreover, the lower the grade of concrete, the lower the consumption of binder compared to the total volume of components. The mixing proportions are shown in the table:
| Expected grade of concrete | Proportions by weight (kg) C:P:SH* | Proportions by volume per 10 l PC (l) P:SH | Concrete yield from 10 liters of PC (l) |
| M450 | 1 : 1,1 : 2,5 | 10 : 22 | 29 |
| M400 | 1 : 1,2 2,7 | 11 : 24 | 31 |
| M300 | 1 : 1,9 : 3,7 | 17 : 32 | 41 |
| M250 | 1 : 2,1 : 3,9 | 19 : 34 | 43 |
| M200 | 1 : 2,8 : 4,8 | 25 : 42 | 54 |
| M150 | 1 : 3,5 : 5,7 | 32 : 50 | 64 |
| M100 | 1 : 4,6 : 7,0 | 41 : 61 | 78 |
*C – cement, P – sand, Shch – crushed stone.
How much concrete is the weight of a bag of cement calculated for?
Despite the fact that the volume in a bag of cement varies depending on the brand of Portland cement, storage conditions, date of manufacture and other parameters, the weight of the bag of cement remains constant. When preparing cement mortar, you need to know the proportions of the ingredients, just as when mixing concrete.
The volume of concrete is determined using a standard recipe
When performing calculations, a number of nuances should be taken into account:
- marking of the prepared concrete solution;
- the brand of Portland cement powder used;
- the amount of cement packed in the container.
For example, to prepare M200 concrete from one bag of M400 grade cement, the mass ratios of cement, sand and crushed stone are 1:2.8:4.8. The given proportion allows us to determine that a bag of cement will produce at least 270 liters of concrete. Tables with proportions for different grades of material, which facilitate calculations, are easy to find on specialized websites. The accuracy of the results is affected by the volume of added water and the density of the feedstock. The calculator will allow you to calculate cement per cube of concrete with higher accuracy.
How much cement is in the bag and how much concrete can be made from it
GOST does not stipulate the volume that cement occupies in a bag. However, the regulatory document clearly regulates the mass of material. Cement is packaged in standard bags of 25, 40 and 50 kg each.
Cement is packed in standard bags
If you need to calculate how many cubes of cement are in a 50 kg bag or container of another volume, you should follow the given algorithm:
- Read the weight and grade of the material on the packaging, for example, cement 50 kg grade M400.
- Take the specific gravity for a given brand of cement from reference sources, for example, 1500 kg/m3.
- Divide the weight of the material in the packaging by its density.
To do this, you must proceed in the following order:
- Find in the reference tables the weight ratios of cement, sand and crushed stone for preparing concrete of a certain grade.
- Calculate the volume of each component by dividing the weight of the material, according to the recipe, by the density.
- Sum up the volumes of ingredients and add the volume of added water to the calculation result.
The volume of concrete mixture varies for different types of concrete. Let's consider concrete based on M400 cement. Its volume increases from 0.092 m3 for concrete grade M400 to 0.231 m3 for mortar grade M100.
Table of ratio of cement, sand and crushed stone
Production
Cement binder is a product of clinker grinding with a standardized composition. The characteristics of raw materials are determined by GOST 10178-85. According to the document, the content of magnesium oxide should not exceed 5% (in some cases - 6%), and the amount of other components is determined by the type of binder and its purpose.
The raw materials for production are natural minerals (alite, alumina, magnesite, gypsum); each has its own compliance regulations. Clinker is produced from raw materials by firing.
The main component can be combined with mineral additives that affect the individual properties of the working solution and the finished stone. The number of the latter also determines the standard (Table 1):
Various additives can be added to the composition of M400 cement to improve the plasticity of the solution, the frost resistance of concrete, and the resistance of the structure to aggressive influences. Their total amount should not exceed 5% by weight of the binder component.
Clinker with the calculated amount of additives is crushed in drums up to 92%.
Varieties
Cement is a binding substance that can harden in water, as well as when exposed to air. Its main component is clinker. Cement is made by grinding clinker from gypsum and adding mineral additives.
Clinker may include: limestone, nepheline sludge, marl. After adding 20% of mineral additives from the entire mass of the prepared liquid, the characteristics and trends of the source material change. If the volume of additives is more than 20%, then pozzolanic cement is formed.
Types of cement include:
- marly;
- lime;
- clay cement in addition to additives of bauxite and slag. It differs from all others in its water resistance;
- sulfate-resistant, which hardens very slowly and has increased frost resistance;
Sulfate resistant
- grouting. It is intended for concreting oil wells;
- the strainer dries quickly;
- hydraulic;
Types of cement grade 400
Binder with strength grade M400 can be produced on the basis of different components; depending on this, the material is divided into several main groups:
- Portland cement (PC) is the most common type, produced on the basis of calcium silicates (alite). These are metamorphic rocks. It is characterized by medium-term hardening and high technical characteristics.
- Aluminous cement (GC or VGC) is produced on the basis of aluminum, calcium, iron and silicon oxides in accordance with GOST 969-91. The material is characterized by accelerated setting and hardening. Suitable for urgent construction, including in winter.
- Magnesia cement (MGC) is a product of grinding clinker with a high magnesium content. The hardened stone is characterized by high wear resistance and density.
- Pozzolanic cements (PPCs) are made from volcanic rocks that are carefully crushed to a powdery state. Suitable for production are siliceous and aluminous mineral substances, some types of slag and fly ash, which have significant viscosity.
- Slag Portland cement (SPC) is a binder made from clinker and blast furnace or electrothermophosphorus slag with the amount of the latter not exceeding 20%. This binder is cheaper than the classic one; it is used when it is necessary to equip structures in aggressive environments and mineralized waters.
Where is M400 concrete used?
Concrete M-400 class B 30 is a heavy building material and was developed for use in high-strength structures. These are objects such as subways, tunnels, hydraulic structures, storage facilities, reinforced concrete columns, crossbars, beams, swimming pools and building structures with special strength requirements. In large-scale industrial production and in the private sector, M400 concrete is rarely used, since it must meet special requirements for the operation of such structures.
Concrete grade M400 is also optimal for the construction of floors and swimming pools. In order for concrete to be strong and durable, you need the correct ratio of components and fast transportation, this will help you
Strength and compressive class are the main characteristics of concrete of any grade. The class is indicated by the symbol “B” and numbers from 3 to 40 (for example, 30), strength - by the symbol “M” and numbers from 50 to 1000. The numbers in the strength designation reflect the maximum load for a particular class of concrete. Thus, grade M 400 corresponds to a maximum load of no more than 400 kg per 1 cm 2.
In the private sector, grade 400 concrete is rarely used. It is unpopular for the following reasons:
- The strength of the material is much higher than required according to SNiP requirements for low-rise buildings. As a result, construction costs are higher;
- The fast setting time of the working mixture is harmful when transporting over long distances, even when using special equipment: automixers, concrete trucks or concrete mixers - workers may not have time to accept and place the liquid solution into the formwork;
- The high cost of grade 400 is due to the high percentage of cement. This brand is produced on crushed granite with plasticizer additives.
Properties and characteristics
Durable concrete of class B30 is used in construction areas that have special requirements for external factors. The technical characteristics of this building material are very high: frost resistance up to F300, water resistance up to W12. A structure made of such material can only be destroyed with a force of at least 395 kg/cm 2 . The table shows how the grade density of other materials differs in comparison with grade 400:
| Brand | Specific gravity, kg/m 3 |
| 250 | 2348 |
| 350 | 2502 |
| 400 | 2376 |
| 500 | 2298 |
Concrete grade M-400 class B 30 corresponds to moisture resistance classes W6-W12, frost resistance F100-F300 and mobility P3-P5. When W6 is waterproof, its density is 2430 kg/m 3 .
| Components of B-30 mixture | |
| Mass of cement, kg/m 3 | 400 |
| Water mass, l/m 3 | 160 |
| Filler weight, kg/m3 | 660 |
| Total mass of gravel, kg/m 3 | 1166 |
| Mass of gravel size 20 mm, kg/m 3 | 700 |
| Mass of gravel size 10 mm, kg/m 3 | 466 |
| Mass of plasticizer in l/m 3 | 2,4 |
| Water/cement ratio | 0,4 |
To obtain grade 400 concrete, it is necessary to add cement of the same strength or higher to the solution. When adding smaller grades of cement, their low density will result in a low specific gravity, resulting in an overconsumption of the constituent materials. The table shows the correct proportions of materials for preparing M400 concrete:
| Cement | Proportions cement/sand/crushed stone | Volume of sand/crushed stone components | Volume of concrete in liters from 10 liters of cement |
| M 400 | 1 : 1,2 : 2,7 | 11 : 24 | 31 |
| M 500 | 1 : 1,6 : 3,2 | 14 : 28 | 36 |
What necessary components are needed to prepare concrete M 400 per 1 m 3 using cement grade M 500:
| Class | Density | Ease of installation | Cement, kg | Sand, kg | Crushed stone, kg | Water, liters |
| B 30 | 2430 | P 2 | 420 | 770 | 1080 | 155 |
| B 30 | 2430 | P 3 | 445 | 765 | 1040 | 165 |
How to prepare the solution
To prepare concrete M 400 (B-30), specially prepared components are used. High-quality cement with a small particle size, purified sand, granite crushed stone and water, which regulates the mobility of the solution. Concrete M 400 and its components must be added in strict proportions.
Marking
Cement M400 is a general designation for a binder; the full marking contains complete information about the material in accordance with GOST 10178-85. Using the example of PC 400-D20-B-PL GOST 10178-85:
- PC – Portland cement on alite clinker;
- 400 – grade of binder when tested in compression;
- D20 – designation of the amount of mineral additives as a percentage, that is, in this case, impurities 20%;
- B – fast-hardening, maybe “N” – normally hardening;
- PL – plasticized, maybe “GF” – hydrophobized. This paragraph reveals the function of additional additives;
- GOST 10178-85 is a regulatory document on the basis of which the material is manufactured and tested.
According to GOST 31108-2003, the designation of the same cement is different: TsEM I 32.5B GOST 31108-2003. This standard summarizes groups of cements of different strengths within a certain framework, reflected in the table:
| Cement strength class | Compressive strength, MPa, aged | |||
| 2 days, no less | 7 days, no less | 28 days | ||
| no less | no more | |||
| 22.5N | — | 11 | 22,5 | 42,5 |
| 32.5N | — | 16 | 32,5 | 52,5 |
| 32.5B | 10 | — | ||
| 42.5N | 10 | — | 42,5 | 62,5 |
| 42.5B | 20 | — | ||
| 52.5N | 20 | — | 52,5 | — |
| 52.5B | 30 | — | ||
The compressive strength of cement PC 400 at the age of 28 days according to GOST 10178-85 is 39.2 MPa, which is within the range of values for class 32.5 N/B.
Cement type designations according to GOST 31108-2003:
- CEM I – PC;
- CEM II – PC with mineral components;
- CEM III – ShPTs;
- CEM IV – PPC;
- CEM V is a composite binder made from several fundamental components.
Cement grades according to GOST 31108
The new standard was developed in 2003 to harmonize the current labeling with that adopted in the EU countries.
At the moment, the latest version from 2016 is working. As usual, the previous standard has not been canceled - both work in parallel. Labeling can also be mixed
Name and material composition
In a new way, cement grades are determined by their material composition. The marking contains three Cyrillic letters - TsEM and Latin numbers behind them. The composition is encrypted in Latin numerals:
- The abbreviation CEM I stands for Portland cement. There can be no additives in it. It consists only of ground burnt clinker and technological additives in an amount of no more than 5% by weight.
- CEM II - Portland cement with mineral additives. The mass fraction of additives is from 6% to 35%. Based on the number of additives, they are divided into two groups: group A with a content of 6% to 20%;
- group B indicates that additives were introduced from 21% to 35%.
- A - from 6% to 20%;
Cement from CEM II to CEM V can have subtypes depending on the additives. They are designated by the Latin letters A, B and C. After the group designation, put a slash, followed by a letter indicating the type of additive, then, separated by a dash, the letter used to code the additive itself. For example, TsEM N/A-I. If there are several additives, their designation is indicated by a dash, and the entire group is placed in brackets: for example: CEM IV/A (P-Z-Mk).
Additives in the composition
Additives and the designation of concrete grades with them are in the table. As you can see, CEM I is made only from crushed clinker with a small amount (no more than 5%) of technological substances. The second group of Portland cement has the most modifications and varieties.
Brands of Portland cement depending on additives in the composition
Portland slag cement and lower grades of cement also have additives, but the variations are much smaller. All additives and additives in the labeling are displayed in capital letters:
- Ш - granulated slag;
- Mk - microsilica;
- P - pozzolana;
- G - gliezh;
- Z - ash;
- C - burnt slate;
- And - limestone.
Cement grades depending on the composition of additives
Pure Portland cement - CEM I, always comes without additional components, since, by definition, it cannot have them. Let's look at a few examples of labeling of other brands of cement. If we see CEM II/V-SH. This means that we have Portland cement of the second type, that is, with additives. This is indicated by the letters that appear after the slash. The letter “B” indicates that the amount of additives is more than 21%, and the letter “W” indicates that slag was used. The inscription CEM III/C denotes Portland slag cement with the addition of burnt shale. In general, the way to decipher the markings is probably clear.
Compressive strength class
In the new standard, the composition must indicate the compressive strength that this brand of cement is able to provide. According to GOST, there are only three values:
- 22.5 N;
- 32.5 N;
- 42.5 N;
- 52.5 N.
Designation and rate of strength development according to the standard for cement of different grades
Strength is checked on days 2, 7 and 28. Almost all cements are checked 7 days after mixing, and CEM III (slag Portland cement) is checked after 2 days. Based on the hardening speed, the grade of cement can be:
- normal-hardening - indicated by the letter N after the compressive strength class;
- slow-hardening - M;
- fast-hardening - B.
Graph of cement strength gain according to the new standard in mPa
All this information is displayed in the labeling. For example: CEM III/V-SH 32.5M. Designates Portland slag cement with type B additives - granulated slag, compressive strength 32.5 M, slow-hardening.
Specifications
General characteristics for all types of M400 cements:
- Compressive strength at the age of 28 days for cement 400 spts, pc and others - 39.2 MPa, which corresponds to grade 400;
- The bulk density of dry cement m400 depends on the clinker grinding fraction and the presence of impurities, on average it is 1000...1200 kg/m 3. Caked cement weighs up to 1700 kg/m3, and moistened cement weighs like concrete - up to 3000 tons per cubic meter. For calculations, the specific gravity of cement m400 is taken at an average value of 1100 kg/m 3 ;
- Hardening speed: start of setting no later than 2 hours, strength gain up to 98% - after 28 days;
- PC has insufficient resistance to aggressive environments, including sulfates. To increase stability, use cement m400 d20 with special additives (slag, additives);
- Frost resistance not less than F100;
- Operating operating temperature range -60…+300°С;
- The water resistance of mature stone is high; to achieve absolute impermeability, structure sealants are introduced into the composition and additionally waterproofed.
The volumetric weight of M400 cement varies due to storage conditions, transportation and production details. Various additives affect the density of the mixture. However, knowing this indicator will help you avoid purchasing a poorly-made, outdated or moistened binder!
The average weight of 1 m 3 of m400 cement should be 1100-1200 kg/m 3. Exceeding the value may indicate long-term storage of the material, which is why compaction has occurred. The reason for the increase in weight may be depressurization of the packaging and moistening of the binder.
The shelf life of cement m400 in paper bags is 6 months; for polyethylene containers and packaging, GOST specifies 12 months. However, it is possible to obtain concrete or cement mortar of the expected grade only using PC within 2 months from the date of shipment. Over time, the design strength of dry powder decreases at different rates, on average - minus 100 positions in 2 or 3 months. That is, the M400 will turn into the M300 in a season.
Today, cement manufacturers supply the construction market with various brands of this material. Among them there are both those that have a narrow scope of application (depending on the purpose of the finished solution) and widely used products.
The latter include Portland cement (PC) M400, whose characteristics allow it to be used even by default, that is, in cases where a specific grade of material is not specified.
What are the differences
From the listed characteristics it is easy to understand how the cement grade 400 differs from 500. M400 cement is more often used in private construction than M500. Concrete M300 and M600 are also produced, but the first is rarely used, and the second is more often used in military construction.
The main differences between M400 and M500 cement are as follows:
- Strength level . M400 is less than M500. It is suitable for pouring floor bases, building walls, reinforced concrete slabs and products, and sealing joints during plastering work. M500 is used if the structure will be subject to high loads (for example, it is used when pouring a foundation); it is also used in the manufacture of tiles and paving slabs.
- Moisture resistance . M400 is less moisture resistant than M500.
- Hardening speed : for M400 it is 10-12 hours, for M500 it is 5-8 hours. We are talking about primary solidification. Both cements will set completely after 28 days.
- Beginning of hardening : M400 begins to harden after 75 minutes, M500 after 45 minutes.
- Price : M400 is cheaper than M500. Also usually there is less M500 in a bag than M400.
Source sense-life.com
Thus, all the differences between brands are clearly visible. M500 is recommended for use in large-scale tasks, in cases where a serious load on concrete is expected, or if construction is carried out in conditions of high humidity. For less significant cases, the M400 is suitable.
It is worth noting that M500 cement is not recommended for use in highly aggressive environments. Sulfate-resistant concrete is better suited for this.
Experts do not recommend mixing both brands or buying too many bags, as cement loses its properties over time.
To learn how to choose the right cement and what to pay attention to, watch this video:
Manufacturing
What is cement made from, what is its composition? The production of this brand of cement is regulated by GOST No. 10178, approved in 1985. In 2003, the document was updated to GOST 31108, which does not completely cancel, but only supplements the provisions of the previous one.
Manufacturing the material in accordance with the current standard allows us to obtain a product that is not inferior in quality to products manufactured in the EU and CIS countries.
M400 is made from crushed clinker (obtained by firing limestone and clay), which is mixed with gypsum and special impurities. The M400 marking means that after hardening the solution is able to withstand loads of up to 400 kgf per cm2.
Characteristics
Portland cement has higher strength characteristics compared to other types of cement, which is due to the characteristics of its composition. Certain additives can react, changing the technical properties of the material. The latter are associated with its mechanical resistance and operational capabilities.
It cannot be said that one of the technical characteristics is of higher priority. For example, strong, but too slow-hardening Portland cement can increase construction time. And the frost-resistant, but susceptible to corrosion composition can only be used to solve a narrow range of problems.
Today, manufacturers strive to create universal compositions in which the most important properties for cement are equally manifested.
At the same time, there are specialized compounds that have a special purpose. This can be considered pozzolanic Portland cement, which has maximum corrosion resistance and moisture strength, but rather low strength indicators at the initial stages of work (in the first days of setting).
Technical
Among the technical characteristics it is worth highlighting:
- The specific gravity of the product is 1100 kg/m³ for bulk mixtures, 1600 kg/m³ for compacted ones.
- The grinding fineness is on average 40 microns (determined by the ability of the mixture to pass through sieve No. 008), which provides the necessary strength of the cement and its hardening time, and also affects its performance.
- Water consumption, the optimal liquid content in the composition should not exceed 25-28%, since this indicator affects the strength of the composition (if there is excess, the concrete dough delaminates; if there is too little, cracks appear in the finished product).
- The duration of setting after mixing with water does not exceed 40-45 minutes, further hardening depends on the characteristics of the composition and environmental conditions (in winter the process slows down), but does not exceed 10-12 hours (measured using a Vika device).
- The change in volume during hardening means a decrease in volume of the cement body by 0.5-1 mm/m in open air and its swelling to 0.5 mm/m in water. An important point is the uniformity of changes throughout the entire volume of the solution.
Physical
- Anti-corrosion resistance is achieved through the introduction of hydroactive materials into the composition, which prevent the chemical activity of salts, as well as the addition of impurities that reduce the porosity of concrete.
- The storage duration is no more than 12 months, provided that the original packaging is preserved (3-4-layer, hermetically sealed paper bags), since after 3 months of storage up to 20% of the activity of the composition is lost, after a year - up to 40%. Such cement can only be restored to its former qualities through secondary grinding.
- Compressive strength. In accordance with this characteristic, 4 strength classes are distinguished - 22.5; 42.5; 42.5; 52.5. This indicator is directly related to the speed of setting of the solution.
Mechanical
The mechanical strength of Portland cement is no less than 42.5 mPa on the 28th day after pouring. The determination is carried out in laboratory conditions using a sample as an example. In accordance with the results obtained, the cement is marked (for example, M 500). The coefficient indicates how much pressure the sample can withstand (measured in kg/cm³).
Strength indicators, in turn, affect the degree of setting of the solution (determined using a Vicat needle).
Marking and scope of application
As already noted, the compressive strength of M400 reaches 400 kgf/cm2.
The compressive strength characteristics make it possible to use the material both for the manufacture of blind areas and for a solid foundation for a private brick house.
The grade is also influenced by the volume of plasticizers contained in cement, the quantity and characteristics of which determine the scope of application of M400:
- D0 – does not contain plasticizing additives and is a material for general construction purposes. Used for the manufacture of a variety of concrete structures used in conditions of high humidity (in particular, underwater and underground structures);
- also used to create prefabricated reinforced concrete products and obtain specialized building mixtures;
- D5 - primary purpose - production of load-bearing elements with high density (blocks for foundations, floor slabs, etc.). It has good water repellency and corrosion resistance.
- D20 - used to create various reinforced concrete and concrete products (from paving slabs to prefabricated foundation blocks). A special feature of this cement is the ability to very quickly gain strength during the initial period of hardening.
Despite the fact that the above designation method is used by many manufacturers, it can still be considered outdated. When GOST was updated in 2003, the labeling became more consistent with European parameters, and now the mineral components contained in the product are also taken into account:
- CEM – corresponds to Portland cement that does not contain mineral additives;
- CEMII - this designation is used for cement with the addition of slag . Depending on the amount of slag additive, the material is divided into two groups - A (6-20% impurities) and B (20-35%).
Also, the traditional designation defining the characteristics of cement was replaced by the strength class parameter, as a result of which M400 began to be called in a new way - B30.
A high rate of hardening is indicated in the marking by the letter B, which is used to mark a fast-hardening material (D20). In addition, plasticization or hydrophobization marks (PL, GF) are applied to the packaging.
For more information about cement marking, watch the video:
Types and characteristics
Despite the fact that GOST for construction cements, issued to replace GOST 31108-2003, provides for a new designation of grades of building mixtures, many still rely on the previous numbers and letters. Therefore, manufacturers, in an effort to facilitate consumer choice, indicate the following markings on the packaging:
- M400 D0 - does not contain any additives and consists only of clinker. This mass is characterized by high frost resistance, average hardening speed and shrinkage deformation. As a rule, this is a mixture for general construction purposes.
- M400 D5 - contains up to 5% additives that improve the water-repellent properties of the product and increase resistance to corrosion. Recommended for the construction of load-bearing structures and floors.
- M400 D20 - it contains up to 20% active additives, allowing it to be used for both residential and industrial premises. This cement is used both in Russia and in Europe. It has very good frost resistance and is excellent for underwater structures as it is water resistant.
Oddly enough, but an increase in additives in cement leads to a decrease in its cost. The most expensive brand is considered to be M400 D0, and the more budget option is M400 D20.
There are also specific types of cement that give the product the required properties. For example, a sulfate-resistant composition that allows the use of cement products in aggressive environments and mineral waters. Products with such cement have very high resistance to aqueous environments. Such mixtures can be distinguished by the CC marking in the brand name.
Another example is expansive cement, which is essential for repairing cracks in walls and for gluing pipes in mines and tunnels. It fills cracks and seams and contains additives that help the mixture dry to increase its volume. This restores the tightness of the product.
Another feature is its low deformability and fire resistance. Typically, this type of mixture is used for quickly installing foundations, as well as for repairing underwater structures. For quick-drying cements, use the additional letter “B” in the marking.
Of course, the specificity of the additive always leads to an increase in the price of cement. However, we should not forget that such additives are used in small quantities and their use is economically justified.
The characteristics of cement are influenced by the conditions and period of its storage after production. For example, the bulk density of fresh cement depends on the degree of grinding, but on average it is 1000-1200 kg/m3. If cement is stored in conditions that do not comply with the manufacturer’s recommendations, then it cakes to a density of 1700 kg/m3, and at high humidity it can weigh up to 3000 kg per cubic meter. This can lead to premature hardening or loss of strength properties of concrete. Instead of mass for active chemical interaction, you get inert mineral chips.
Cement is sold weighing up to 50 kg in durable paper bags. The packaging clearly indicates the brand of the mixture, recommendations for use, as well as the batch number and production date. It is the freshness of cement that is the key to the quality of future products. Therefore, you should choose packaging with the latest possible release date.
Looking at the production date, it should be borne in mind that every 3 months cement loses about 15% of its original properties. If old cement is still used during construction, it is necessary to provide for its increased consumption in order to obtain concrete of the given strength.
Bulk technical cement is also sold. It is more convenient to purchase for large volumes of work. Its cost is 15-20% lower than packaged. This is due to both the lack of packaging and large volumes of purchases. However, with a bulk mixture it is more difficult to track the date of manufacture, and, consequently, the quality of the starting material.
Specifications
The material of this brand has the following technical parameters:
- the density of loosened cement is from 1100 to 1200 kg/m3, compacted cement is from 1500 to 1600 kg/m3;
- setting speed at temperatures from +18 to 22 degrees 2-4 hours from the moment of mixing with water;
- temperature indicators at which it is possible to use the PC M400 – from -60 to +300 degrees;
- water demand – 22-26%;
- specific gravity;
- hardening time – 10-12 hours;
- maximum shelf life is 12 months (if storage conditions are violated, it can be significantly reduced).
PC M500 - technical characteristics, quality control and price level
Portland cement, quick-hardening, without mineral additives, plasticized can have one of the designations:
- PC 500-D0-B-PL GOST 10178-85. Technical characteristics: compressive strength - 49.0 (50.0) MPa (kg/cm2), setting after 45 minutes, mineral additives are not allowed.
- TsEM I 42.5B GOST 31108-2003. Technical characteristics: strength class - from 42.5 to 62.5 MPa, setting after 60 minutes.
PC m500 has more than 20 parameters, but they are of interest only to specialists.
Quality checking
When purchasing, check the packaging carefully to make the right decision. It should indicate: weight, manufacturer, brand, name of special additives. And if you buy in bulk, you may end up with a counterfeit product. And don’t chase a low price, then you will bite your elbows, drawing up estimates for new construction work in 2-3 years.
How to spot a fake:
- Analysis in a special laboratory. This is a rather labor-intensive method, so it is not always suitable for consumers.
- Home method.
Wearing safety glasses and gloves, mix a portion of the proposed cement in mineral water. When mixing, the solution may heat up and boil; protective equipment for this. From the resulting “dough”, quickly form a pancake thick in the middle. High-quality cement will set in 15-25 minutes and the mixture will heat up. The counterfeit product will not set or heat up in an hour, although it can boil like a kettle on fire.
The cement sets poorly in parts and then cracks severely. After 2 days of being wet in the plastic bag there should be no cracks. With poor cement, the disc will crack and break in your hands.
Sale
PC brand M500 is sold in bags or in bulk - in wagons or cement trucks at wholesale prices. This is due to the size of the purchase.
Considering the retail market, the price, depending on the manufacturer and brand of cement, is from 170 to 250 rubles per 50 kg bag. In particular, a bag of Eurocement M500 D0 (CEM I 42.5H) costs 200 rubles on the market. But it is worth remembering that if you buy 50 kg of such Portland cement, you will bring 35-40 kg of cement grade 400, and possibly 300, to your dacha.
M500 cement is one of the most widely used types of building materials. Ready-made concrete based on it is durable and can withstand both temperature changes and high humidity.
The characteristics of the M500 are more than worthy:
1. Compressive strength – 500 kgf/cm2 or 59.9 MPa.
2. Bending strength – 5.9-6.4 MPa.
3. High water-repellent properties and frost resistance.
4. Drying time for M500 is standardized in the range from 45 minutes to 10 hours, although it belongs to normally hardening cements.
5. Bulk density, depending on the degree of compaction of the dry mixture, can vary within 1100-1600 kg/m3. For calculations, the average figure is 1300 kg/m3.
6. Actual density: 3000-3200 kg/m3.
Advantages and disadvantages
The advantages of the M400 include the following features:
- high strength properties;
- resistance to moisture, temperature fluctuations, corrosive wear;
- duration of service life of reinforced concrete products;
- possibility of use in different climatic zones, without adding antifreeze components to the solution;
- wide scope of application. M400 can be used both for finishing (plastering) work and for the construction of masonry and reinforced concrete structures;
- the cost of this type of cement is lower than the price of higher grades.
As for the disadvantages, the M400 has only one - it is not strong enough to be used in the construction of high-rise buildings.
Short
Many novice developers ignore the study of the quality properties of the cement mixture - they are only interested in the price of the material. Meanwhile, some unscrupulous manufacturers do not comply with production technology. Experts recommend avoiding building components whose cost is 15-20% lower than the market price. This is especially important when organizing cement-sand screed in private housing construction.
You should also wisely select the appropriate type of material required for certain work. There is no need to be embarrassed to ask the seller for documentation on cement products, and also to visually check its quality.
What should you consider before purchasing?
Storage conditions also play a significant role . The material must be in a dry place, since if moisture gets into it, it will turn into mineral chips, unsuitable for use.
When purchasing cement, you should first of all pay attention to the release date. The longer the material is stored, the worse its quality becomes, resulting in a lower grade of the product. Therefore, when purchasing stale goods, there is a risk of receiving an M300 at the price of an M400.
Following these simple recommendations will help you purchase high-quality Portland cement M400, which can be characterized as a universal material suitable for use for various purposes .
Concrete composition m400 per 1m3 table
For the construction of any building, a concrete foundation is initially formed. Its quality and durability depend on how competently each cube of concrete is mixed not only according to the algorithm of actions, but also the proportional ratio of all the components in it.
- Properties of applied elements
- Marking and classification of concrete solutions
- Main components
- How to form concrete
Properties of applied elements
The combination of the most important components, such as water and cement, allows you to obtain cement stone. Unfortunately, the resulting solution does not have the required strength. It is very easy to deform, and with slight impact small and numerous cracks appear. Such a foundation cannot be used, as it will certainly sag in the future.
