Thousands of years ago, people mastered the technology of creating artificial stones high strength. For this, components of volcanic origin were used, from which, after grinding, a solution used in construction was prepared. After it solidified in special forms, a stone was formed.
About concrete stone
It was used in the construction of buildings and structures that have survived to this day. In the current understanding, this stone is called unreinforced concrete. However, such material did not receive distribution in antiquity, giving way to natural stone and brick. Only in the 19th century, on the basis of the then invented cement, concrete was created, which had a revolutionary impact on the mass development of construction.
Today, this is the name of an artificial building stone, which is obtained after molding and hardening a mixture of binder material diluted with water with various fillers and additives. Some of its types can be made without water. The wet concrete must be placed and quickly compacted by vibration. It hardens at a positive temperature. Products from it are strengthened with metal fittings. This is necessary to increase the strength of the future stone.
Leading industrial countries today are the main producers of concrete. It has become the main material for the construction of highways, high-rise buildings, plants and factories. Concrete structures are made at special factories, from where they are transported. Designs from monolithic reinforced concrete can be made directly at the construction site.
Concrete is classified according to various parameters. So, according to its purpose, it can be:
- Common and used in the construction of civil and industrial facilities.
- Special, used in road, hydraulic and other works.
- With special (sound-absorbing, heat-resistant, anti-radiation) and other properties.
It is distinguished by the type of binders and aggregates, by density and structure, by hardening conditions, volumetric indicators, etc.
The main indicator characterizing concrete is its compressive strength, which defines its class. According to existing norms it is denoted by the letter "B" and indicates the withstand pressure in megapascals. In accordance with the class, the age of the concrete is assigned, which is usually four weeks. In addition, its strength is determined by brands. They are designated by the letter "M" with numbers from 50 to 1000 showing the compressive strength in kilograms per square centimeter. Concrete also has indicators of bending strength, water resistance and frost resistance.
About cement mortar
Mostly concrete is made by mixing cement, sand, crushed stone with water in a certain ratio with water. large quantity additives in the form of water repellents, plasticizers, etc. The result is a cement mortar. The main component here is an artificial binder - cement. As a result of interaction with water and other liquids, it becomes plastic, after which it hardens and turns into stone. Its peculiarity, unlike other substances that harden only in air, is the ability to gain strength in moisture conditions.
Produce it at cement plants. There, the fired product, consisting of clay and limestone, in which calcium silicates predominate, is first ground into a powder. Gypsum is added to it and mineral supplements. Then this mixture, composed in compliance with the exact proportions, at a temperature close to one and a half thousand degrees, is fired for several hours in long rotating kilns. As a result of the complex physical and chemical processes and a unique powder is obtained, called cement.
He and water are the main ingredients that create concrete. The strength parameters of concrete directly depend on their strength ratio. Excessive addition of water to the solution significantly reduces the strength of concrete. An important component to ensure strength concrete mix is sand, which must not contain clay particles or clay. The main indicator here is the brand of cement, which means the compressive strength of concrete from the corresponding cement.
Cement M200 has low strength. On the other hand, M600 cement is used for the construction of missile silos, bunkers, and other military and strategic facilities. It is often called "military" or "fortification".
Cement or concrete mortar are made at concrete plants and sent to consumers in special mixer machines. In them there is a constant mixing of the solution.
What is the difference
The fundamental difference between concrete and cement mortar in that the first is a finished product of a stone-like state. The solution is semi-finished product, which, under certain conditions, has yet to become concrete. The main raw material for the production of cement mortar is cement.
Any construction is not complete without connecting technologies based on binders. You can buy high-quality cement in Moscow and buy ready-made concrete in Moscow by contacting MSK-Region. But what to do if a small volume is needed or there is no possibility of a concrete mixer entrance? You should read this article, look for additional clarifying information, and knead on your own. Drafting building mixtures- quite an accessible topic, compared with nanotechnology and other areas that require persistent education.
What is the difference between cement and concrete mortars?
Cement mortar includes: cement, sand, water. Plasticizers can also be used to provide plasticity, hardening speed, frost and water resistance. It is used as a connector for building materials and as a base for plaster mixtures.
Concrete consists of binders and filler. Binders - water and cement. Fillers - sand, crushed stone, expanded clay, gravel, secondary material (brick, concrete, asphalt). It is used as a base mixture for the creation of durable products, due to its ability to transform into an artificial stone after hardening.
The main difference lies in the use of coarse filler in concrete, which ensures the strength and density of the product.
To begin with, it is worthwhile to clearly understand that the proportions of the components used directly affect the fortress. And the fact that it is not reasonable to create maximum strength for minimum operating conditions.
It is better to focus on the source material. If you are using a hundredth grade brick, then the cement must also have the appropriate characteristics.
The classic version of cement mortar
The components are mixed in a dry form, after which they are diluted with water, and thoroughly mixed until a homogeneous mixture. The automated process contributes to the production of a more homogeneous mixture. Among non-professional builders, there is an opinion that as the solution dries, and this happens quickly enough, the composition can be diluted with water. But this is a violation of technology. Do not cook properly a large number of, which the master is able to use for one hour, before drying.
Grade of cement strength by purpose
As a plasticizer, liquid soap is added to most formulations. But, according to some experts, such an additive provokes the appearance of white spots (efflorescence). Therefore, intended plasticizers are recommended, which are sold in supermarkets in liquid form. According to the assurances of the vast majority - using liquid soap makes an excellent solution. For stability during laying in the cold, potash is added. If you wish to change grey colour, then the necessary pigment is additionally purchased. V plaster mixes the additive is slaked lime, which provides vapor permeability. PVA increases the adhesion of the mixture.
It is definitely better to use a concrete mixer or construction mixer because manually mixing crushed stone with sand and cement is difficult. The cooking process begins with mixing the dry ingredients, then water is added. The normal consistency is considered if the concrete is mixed with a shovel, but at the same time it is hard to come off the wall or other treated surface.
The strength of concrete is determined by the result after hardening (for example, M500, M300). The higher the number, the stronger the brand. But, it is worth considering that all strong compounds are additionally reinforced with steel mesh or stronger metal products.
If during kneading masonry mortar it is better to prepare small quantities, then with concrete, on the contrary, you need to prepare all the necessary weight in order to distribute the entire mass evenly. Calculating the volume for floor screed is quite simple:
length × width × height = number of cubic meters m of concrete.
If mechanized preparation is impossible for some reason, then it is more convenient to knead in a container, which is additionally covered with oilcloth. More often mixed with a shovel, the corners remain intact. The oilcloth is lifted from the corners and the dry mixture is mixed with the wet mortar.
Overhaul v high-rise buildings has weight restrictions. Crushed stone and gravel are characterized by heavy weight, so light expanded clay is purchased. Expanded clay also has excellent sound and heat insulation.
Such simple tips will help you make your own cement and concrete mortar.
Read also:
How to lay paving slabs with your own hands;
Laying ceramic tiles;
Types and features of sand;
Why do you need a hollow and solid brick?;
m-s-k-region.ru
Most non-construction people believe that concrete and mortar are one and the same.
Despite the fact that these Construction Materials, are compositional, they are characterized by a different structure, different properties, they differ in purpose.
Features of cement-sand mortar
The solution is made from sand, cement, water, and sometimes special building additives and plasticizers are added during mixing. That is, fine-grained substances are used without impurities of large particles, due to which it is possible to achieve a uniform consistency of the mixture.
Cement-sand mortar has the following properties:
- water resistance;
- strength;
- frost resistance.
The difference between concrete and mortar
Unlike cement mortar, in addition to water, sand and cement, concrete contains a large filler (gravel, expanded clay, pebbles, crushed stone). The presence of crushed stone fractions and stones with a size of 20 mm or more is allowed. For the manufacture of ready-mixed concrete, only high-quality cement is used with high level strength and clean river sand. In some cases, when making concrete, sand is not added at all.
The strength of the finished building structure is mainly determined by the type of filler used (gravel, crushed stone, etc.). To increase wear-resistant characteristics during concrete pouring, reinforcing impurities are additionally introduced into the composition:
- metal threads;
- fiberglass;
- basalt fiber;
- polymer fibre.
In the case of adding additives, the price of concrete will be quite high, but the resulting product is guaranteed to withstand strong tension and compression.
Practical application of concrete and cement-sand mortar
Concrete and mortar are used in construction for various purposes. Solutions often fill the seams between individual elements, as well as process and level surfaces (for example, plaster). Concrete is used for the manufacture of medium and large parts of load-bearing structures, as well as for laying foundations. In addition, concrete is used in the production of reinforced concrete products. for various purposes.
One more distinctive feature concrete is its durability. A concrete structure made in accordance with all the rules only becomes stronger over the years, while even the highest quality cement-sand mortar over time, it begins to crumble, crack, crumble.
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What is concrete - definition, types, what should be correct concrete solution?
Concrete solutions and concrete structures are the basis modern construction. In this regard, I consider it necessary to write separate article about this amazing building material to dot the i's for those who are interested.
Concrete: definition
Concrete is stone material of artificial origin, which are made by hardening a correctly calculated and carefully mixed mixture of water, aggregates and a binder. For increase specifications composition, special additives can be used. The difference between concrete and concrete mixture is that the mixture is a material that is in an uncured state. Otherwise, it's the same.
Classification of concrete solutions
Concrete solutions are classified according to the following features: purpose, type of binder and aggregates, average density, hardening conditions, structure, characteristics of the modulus of elasticity and the protective layer, the level of water resistance (water absorption) and frost resistance, etc. Let's consider the main ones.
1. By type of binder:
Cement. - Silicate. - Asphalt concrete. - Slag-alkaline. - Polymer concrete (plastic concrete), etc.
2. By appointment:
Ordinary (for civil and industrial buildings).- Special (road, hydraulic, decorative, heat-insulating.- special purpose(heat-resistant, chemical-resistant, sound-absorbing, radiation-protecting, etc.).
3. By volumetric weight:
Particularly light (average density up to 500 kg / m3). - Light (average density 500-1800 kg / m3) - foam concrete, expanded clay concrete, wood concrete, aerated concrete, perlite, vermiculite solutions. - Heavy (average density 1800-2500 kg / m3) - granite, limestone, basalt, gravel. - Particularly heavy (average density over 2500 kg / m3) - limonite, magnetite, barite.
More about heavy concrete
More about lightweight concrete
4. According to workability according to GOST 7473-94:
Movable (subdivided according to the draft of the cone, the stiffness is less than 4 seconds). - Rigid (with a stiffness of 5-50 seconds).
Commodity (ratio of components according to a standard recipe). a small amount of binder, plus a high content of coarse aggregates).
Read more about ready-mixed concrete
General requirements
Modern concrete solutions, regardless of their type, type, brand or class, are subject to general requirements. In particular, mixtures, until the required hardness is reached, must be well mixed, transported and stacked without problems (characterized by decent workability and mobility), not subjected to delamination. In addition, the compositions must be characterized by the prescribed speed of solidification, which will correspond to the timing of stripping and putting the structure into general service. Also, it is important to determine the strength of concrete, which should not be lower than the minimum level. The cost of concrete, as well as the consumption of cement, should be as low as possible. To check the suitability of the solution general requirements special mechanical devices can be used, ultrasonic methods, moisture tests, destructive methods using a hammer, etc. If it is necessary to make a structure on the site using reinforcement, then after reinforcement, additional tests are carried out to properly iron the created element.
Correct selection of concrete composition
The quality of the concrete solution will depend on how correctly its composition is selected. In accordance with the standard recipe, the main components of the mortar are crushed stone, cement, water and sand. All components must certainly be of high quality and at the same time must be added in the correct consistency. Main characteristic concrete mortars and final structures from them - this is strength. To achieve maximum strength, when mixing, make sure that the binder coats all surfaces of the added aggregate particles with the binder. The enveloping should be uniform.
How to choose the right proportions?
For correct selection proportions, you need to use the calculation method optimal selection components. Next will be described step-by-step instruction this method, allowing you to mix the solution correctly.
1. Take liter jar, a bucket and the necessary components of the solution (sand, gravel, cement, water). First, we will calculate how many cans of water fit in a bucket. Let's say we got ten cans. Write down the result on paper.
2. We fill the bucket to the brim with crushed stone, after which we pour water on top with a jar, simultaneously calculating how much water will fit in a bucket of crushed stone. It is not necessary to mix water with gravel. This method will help determine the volume of voids formed after crushed stone falls asleep. Let's say we got five cans. We write down on paper.
3. We remove the crushed stone with water from the bucket, wipe the jar dry, and then pour the number of cans of sand into the bucket, similar to the second result we got. That is, in our case, we need five cans of sand. Again, you don't need to mix.
4. Pour water again, but now to the surface of the sand. Let's say we have three banks. This indicator will necessary quantity cement required to fill the last voids.
5. As a result, in order to make, prepare or knead the right concrete, we need three shares of cement, five shares of sand, ten shares of crushed stone.
Before you start kneading Special attention you need to pay attention to the quality of crushed stone, regardless of whether you need to fill the floor, reinforce (iron) the wall or prepare a mortar in order to subsequently fill the foundation. If the crushed stone is heavy and durable, the concrete solution will be the same. This will improve the quality of the walls or foundation being built, as a result of which they will not vibrate and they will not need to be additionally drilled to make additional reinforcement.
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All about concrete
The brand or class is the main indicator of the quality of the concrete mixture, which is usually focused on when buying concrete. Other indicators, such as: frost resistance, mobility, water resistance - in this situation fade into the background. Initially, however, - the choice of brand or class. In general, the strength of concrete is a rather variable parameter, and during the entire hardening process it increases. For example: in three days - there will be one strength, in a week - another (up to 70% of the design, with appropriate weather conditions). After a standard period - 28 days of normal hardening - the design (calculated) strength is gained. Well, after six months it becomes even higher. In principle, the hardening of concrete and the set of its strength is long years.
The class of concrete is a numerical characteristic of any of its properties, taken with a guaranteed security of 0.95. This means that the property set by the class is provided in at least 95 cases out of 100, and only in 5 cases can we expect it to not be fulfilled.
Concrete is divided into classes: B1; B1.5; IN 2; B2.5; B3.5; AT 5; B7.5; AT 10 O'CLOCK; B12.5; B15; IN 20; B25; B30; B40; B45; B50; B55; B60.
The ratio between the class and grades of concrete in terms of strength at the standard coefficient of variation v = 13.5%
| Concrete class | Average strength of this class, kgf/sq.cm | The nearest brand of concrete |
| B3.5 | 46 | M50 |
| AT 5 | 65 | M75 |
| B7.5 | 98 | M100 |
| AT 10 O'CLOCK | 131 | M150 |
| B12.5 | 164 | M150 |
| B15 | 196 | M200 |
| IN 20 | 262 | M250 |
| B25 | 327 | M350 |
| B30 | 393 | M400 |
| B35 | 458 | M450 |
| B40 | 524 | M550 |
| B45 | 589 | M600 |
| B50 | 655 | M600 |
| B55 | 720 | M700 |
| B60 | 786 | M800 |
The cement mortar is mainly used for masonry and plastering works, as well as in the manufacture cement screeds floors. The main difference between mortar and concrete is the absence of coarse aggregate (crushed stone) in the composition of the mixture. As a single filler, in the solution is used building sand. By the way, there are frequent cases of errors when filling out an application: when instead of ordering concrete, they call it a solution, and vice versa. Such incidents happen regularly, and as a rule, they are not without excesses and mutual claims between the seller and the buyer.
Cement mortar grade m100 (B 7.5) is mainly used in masonry and plastering, as well as in the manufacture of cement floor screeds. The main difference between the m 100 mortar and concrete of a similar brand is the absence of coarse aggregate (crushed stone) in the mixture. Naturally, the composition itself is also different. Significantly higher content of cement and sand than in concrete of the same grade.
Cement mortar grade m150 (B 12.5) is mainly used in masonry and plastering, as well as in the manufacture of cement floor screeds. The main difference between the solution m 150 and concrete of a similar brand is the absence of coarse aggregate (crushed stone) in the mixture. Naturally, the composition itself is also different. Significantly higher content of cement and sand than in concrete of the same grade.
Cement mortar grade m200 (B 15) is mainly used in masonry and plastering, as well as in the manufacture of cement floor screeds. The main difference between the m 200 mortar and concrete of a similar brand is the absence of coarse aggregate (crushed stone) in the mixture. Naturally, the composition itself is also different. Significantly higher content of cement and sand than in concrete of the same grade.
Mortar m-200 (V-15) can also be referred to as: cement, building, masonry, plaster mortar. If sand with a large particle size modulus is used as part of the solution, such a solution can be called sand concrete or fine-grained concrete.
Solution cement grade m300 (B 22.5) is rarely used in classical types of work, where cement mortars are usually used: masonry, plaster, etc. The main scope of the m300 solution is the manufacture of high-strength floor screeds and the device monolithic floors. In most cases, a similar brand of cement mortar is used in structures with increased requirements to strength and durability. It is advisable to use the m-300 solution when constructing monolithic ceilings from lightweight concrete, where expanded clay is used as a coarse aggregate, and mortar 300 acts as a connecting element. The main difference between mortar m300 and ready-mixed concrete of the same brand is the absence of large aggregates (crushed stone, gravel) in the mixture. The basic composition and proportions of cement and sand are also different. Sand also plays the role of large aggregates in cement mortar. Mortar m-300 (B-22.5) can also be referred to as: masonry, plaster or mortar. One of the varieties of m300 solution is m300 sand concrete. And if as part of the usual mortar sand with a standard size modulus for concrete mixtures is used, then special types of sand with a large size modulus (MKR) are used in sand concrete.
Not a single do-it-yourself construction is complete without the presence of certain knowledge. Whether Vacation home, a residential complex or a solid extension to a residential building - you need to have a certain knowledge base that will eliminate errors during construction. After all, a house is for decades, and any mistake can be fatal, especially if it concerns the foundation pit, foundation, walls, ceilings and materials used for all this.
One of the most popular materials in construction is concrete and reinforced concrete, which are used in the vast majority of buildings in our country. It is about them that we will discuss in our article.
Concrete and reinforced concrete, their features
Concrete is an artificially created stone material used in construction.
Concrete is a hardened material of artificial origin, formed after the combination of a special mixture of binder, various aggregates and water. In order to improve the quality of the concrete mix itself, it was invented to make all kinds of additives. Concrete aggregates are different, depending on the purpose of the concrete. About that - we talked about in previous articles.
We will not be mistaken if we call concrete the main building material, since it is the foundation of the house. The foundation is poured from it, the floor is made in the cellar and on the first floor of the building, it is used for the production of various ceilings of the same name, etc.
Concrete is a fragile material because it does not have a high tensile strength. Even with a small load on this building structure, consisting solely of one concrete, it may not withstand and collapse. But the embedded rods made of steel have a rather high strength and do not undergo severe deformation when stretched.
Reinforced concrete is a durable building material that combines hardened concrete and steel reinforcement.
In fact, reinforced concrete is concrete, inside which is built metal carcass from rods. It is produced as follows: mounted steel frame(the bars are connected to each other by welding or wire), then this frame is lifted (it will have to be in the center of the structure) and then concrete is poured. Depending on the type concrete structure the frame can be two-tiered.
Concrete and steel, joined together, can withstand quite large loads, increasing the bending strength of the structure several times. In this regard, steel reinforcement with a certain section of the rod is placed in the concrete structure, due to which a large load is maintained. The reinforcement prevents the deformation that the plate is constantly subjected to: compression or tension. In addition, it creates a solid foundation that can withstand heavy loads.
Why does the design combine these particular materials? It depended on the properties of concrete and steel. High tensile and compressive strength of reinforcement, as well as high degree adhesion of steel and concrete. And with temperature fluctuations, identical elongation of both materials occurs. As you know, having begun to harden, concrete will reduce its volume and firmly compress the reinforcement, perfectly connecting with it.
The entire reinforced concrete structure requires low thermal conductivity, which concrete has. It perfectly protects the fittings placed in it from temperature extremes.
These building materials are widely used in various types of construction. positive side reinforced concrete and concrete are considered to be economical when receiving reinforced concrete product. Since the material is obtained from local raw materials and is used in many designs for various purposes. Plastic concrete mass contributes to the manufacture of products of the required shape.
The resulting material has good properties: non-flammable and durable. If necessary, you can change the strength and in fairly large parameters. Concrete, as mentioned earlier, has a low tensile strength, but in compression it can withstand heavy loads, and when connected to reinforcement, this disadvantage is compensated.
Types of concrete
Now, together with the experts of the site, we will consider the varieties of concrete.Concrete has the following types:
- plaster;
- cement;
- silicone;
- Mixed;
- Special (for special requirements).
Each type of concrete is applicable for a different kind of tasks. That is why, before using it in construction, it is necessary to familiarize yourself with the characteristics of its types in order to use the most suitable option regarding your terms and conditions.
Concrete in particular can be classified according to the type of density:
- Very light. Suitable for insulation, its density is not more than 600 kg / m3;
- Light. It is subdivided into large-pored and cellular, density is about 1000 kg/cu.m.;
- Lightweight. One of the most used types. Density 2100 kg/cu.m.;
- Heavy. It consists of gravel and sand. Density 2300 kg/cu.m.;
- Particularly heavy. Applied in special types protective structures. Density 2400 kg/cu.m.
Cellular concrete consists of inorganic constituents. Speaking of this concrete, they mean a material of non-natural origin. Its basis is the air that fills most volume. You can get it if you expand a hardened mixture of water and a binder component with a construction blowing agent. In the process of such swelling inside the mixture, a cellular concrete base is formed, which has a large number of pores consisting of air. After production, such concrete has a low density and has a low thermal conductivity.
When making cellular concrete, you can change its density. It depends on where it will be used. Aerated concrete is one of the types of lightweight concrete. The porous base of concrete depends on the method used, the binding properties of the substance and the conditions of formation.
Designing reinforced concrete structure, are guided by the requirements:
- Resistance to low temperatures, waterproof;
- Brand of concrete and its strength.
This is actually all that we wanted to talk about concrete and reinforced concrete materials.
Concrete and reinforced concrete are among the most popular materials. Such popularity is due to the simplicity of their production and wide opportunities. But not everyone knows how concrete differs from reinforced concrete. Let's consider this question in detail.
Definition
Concrete- a material created artificially. Its main components are traditionally cement, various aggregates and water. Sometimes water is not added, but another is used instead of cement. suitable material. Concrete becomes ready for use after the curing process.
Concrete
Reinforced concrete- a material that combines ordinary concrete and reinforcement.
Reinforced concrete Comparison
Thus, it can be seen from the definitions that reinforced concrete does not act as a separate material, but as the same concrete, but strengthened in a special way. The production of reinforced concrete begins with the installation of a reinforcing frame, when metal rods are fastened together by wire or by welding.
At the next stage, the frame, which is provided with an elevated position, is poured with a prepared concrete composition. As a result, a structure is formed, which is a solid mesh, surrounded on all sides by concrete. The frame inside can be two-level.
The resulting product is very valuable properties. The difference between concrete and reinforced concrete is that the latter has increased strength. The load from which ordinary concrete can crack and lose its bearing capacity, reinforced concrete calmly withstands.
Such strength is due to the fact that concrete, hardening, firmly “sticks” to steel and the materials begin to work together. Temperature fluctuations have identical effects on concrete and steel, and this also ensures complete solidity of the product. Of no small importance is the fact that concrete protects the frame enclosed in it from corrosion.
What is the difference between concrete and reinforced concrete other than the strength of both? It consists in the fact that from reinforced concrete, thanks to its metal base, you can create any architectural forms. In addition to the above, we should also mention the greater weight of reinforced concrete relative to ordinary concrete.