The use of concrete for the construction of various structures is very common, and the products themselves have rather high technical and mechanical performance.
Reinforced concrete is an improved composition that is used as the basis for the construction of various buildings. The production of reinforced concrete products is carried out by special enterprises, which are equipped with special equipment for this.
There are many varieties of such products, which differ in both size and technological purpose.
The concept of concrete products
Reinforced concrete products are products that consist of two main components:
- concrete;
- steel reinforcement.
The combination of these two components creates a very durable material called reinforced concrete. To obtain products with certain characteristics, different types of concrete can be used.
After the product cools down, it begins to transfer loads well, and with constant compaction that occurs during this, the structure becomes even more durable.
The reinforcement used in the formation of concrete products is quite durable and is able to withstand significant tensile forces. The compounds of these substances create a truly unique material.
Modern reinforced concrete can be obtained not only in production, but also at home by simply placing a certain amount of steel wire in concrete.
Products made from this material can be divided into two main types:
- Reinforced concrete products of monolithic type. The process of making them takes place during the construction itself, for example, to form a certain frame. Reinforcement is poured with concrete in a formwork that imitates a certain shape, so step by step a monolith is obtained. This technology is very effective, but significantly more expensive.
- Precast concrete goods. They are made in special factories, and after cooling they are used as a building material. There are many types of such products. These include all types of floor slabs that are used in the construction of bridges, roads and various buildings. Various reinforced concrete piles, columns, platforms, steps and many other types of structures are also used in construction.
With the advent of concrete products, it became possible to build more significant objects that can withstand enormous loads and operate for a very long time.
Flat reinforced concrete products:
Reinforced concrete has been actively used for over 100 years. And now, without reinforced concrete products, it is simply impossible to imagine the very possibility of constructing industrial facilities, buildings, roads. Today, precast concrete elements are made from molded concrete, which is reinforced with steel rods.
Varieties of concrete products
There are several classifications of concrete products. First, it is customary to divide them according to the presence of prestressing.
Secondly, separate groups of concrete products are distinguished by scope:
For residential, public buildings;
For industrial objects;
For general purpose buildings.
Thirdly, products are grouped by type in accordance with the direction of use:
Road plates;
Floor slabs;
Stiffness diaphragms;
Jumpers;
Foundation blocks;
Well rings.
The catalog of the Unimart company allows you to see what characteristics these reinforced concrete products have, here you can make an order.
Characteristics of the most demanded concrete products in construction
Road slabs... Without these products, it is impossible to equip a runway, a military training ground and lay a highway for busy traffic. Such slabs are used when laying roads in areas characterized by swampy soils, heaving soils, a difficult climate with temperature changes. They significantly increase the strength of the roadway. No road junction can be built without these products.
Floor slabs... These are products that are laid horizontally, forming floors and ceilings in buildings under construction, they also block heating mains. They can be solid, hollow and ribbed. Each of these varieties has its own scope. For individual construction it is possible to purchase custom-made slabs.
Stiffness diaphragms... This group is designed for vertical loads from floor slabs, beams, stairs and various engineering structures.
Jumpers... This type of product is needed for the design of openings (door, window). With their help, the rigidity of the entire structure is increased, because they take on a static load. Distinguish between load-bearing and non-load-bearing lintels. Cranes are used for the installation of load-bearing products.
Foundation blocks, beam - an irreplaceable part of strip, columnar foundations. They are also used when arranging a slab foundation. They are made in 2 versions - solid / hollow. The side of the products is supplied with grooves, into which the solution is poured during assembly. Blocks - pillows are made in the basic form of rectangles.
Piles - an element for the construction of a pile foundation. Depending on the method of installation, they can be driven, press-in and shell. According to the characteristics of production, monolithic and prefabricated ones are distinguished. The main advantage of reinforced concrete piles is the high density of immersion in the ground. The hammer not only drives the product in, but also compacts the soil around, thus increasing the strength of the structure. Such piles are used both on moving soils and in conditions with unstable moisture.
Well elements (rings and covers for them) - reinforced concrete products for the construction of inspection wells, gas, sewer wells. The diameter of the products varies from 70 cm to 200 cm, the height is usually within a meter. The wall thickness also varies. These products are of several types, for example, simple wall and castle. The difference between them is in the end joints (the lock has curly folds). Additional rings are needed to increase the height of the structure. Any rings are equipped with bottoms and covers that correspond to the design of the ring itself.
Columns for industrial buildings on the 1st floor. They are of 2 types: with consoles, without consoles.
Reinforced concrete products are much cheaper than brick, and it is easier and faster to work with them, which is why they are in such demand in construction. For example, for everything
Reinforced concrete products (concrete goods) are widely used in all areas of construction, from housing to engineering. For the erection of prefabricated reinforced concrete structures, pre-fabricated concrete products are used, the production of which is carried out by injection molding in the factory.
This article discusses concrete and reinforced concrete products, their scope, classification, varieties and marking. We will also tell you how the installation of reinforced concrete structures using crane technology is performed.
General information about concrete products
Reinforced concrete products are prefabricated building elements of increased strength, which is achieved through the joint work of metal and concrete. Concrete, as a material, is distinguished by its increased resistance to compressive loads, but it has a strong vulnerability to bending and tensile loads, the resistance to which is almost 15 times less than to compressive deformation.
These loads are taken over and compensated by steel reinforcement, by means of which reinforced concrete structures are reinforced. The metal has a high tensile strength, as a result of which reinforced concrete products, reinforced with reinforcement, are equally resistant to loads of different nature.
The joint work of steel and concrete is achieved due to the strong adhesion of the two materials to each other, while they have almost the same coefficient of thermal expansion, which guarantees the solidity of reinforced concrete. An additional plus is that the concrete protects the reinforcement embedded in it from corrosion.
All types of concrete products, depending on the method of reinforcement, are classified into two types:
- reinforced concrete structures with conventional reinforcement;
- prestressed reinforced concrete structures.
Concrete items with conventional reinforcement are reinforced exclusively by reinforcement. However, this reinforcement technology does not provide crack resistance of structures in the phase of maximum tension of concrete, since its tensile capacity is 2 mm / r.m., whereas for steel it is 5 mm / r.m. In the future, moisture can enter the cracks that appear, which will lead to corrosion of the reinforcing cage.
In order for reinforced concrete structures to obtain resistance to cracking, the technology of prestressing reinforcement is used. Its essence lies in the fact that the reinforcement placed in the formwork is tensioned using a hydraulic jack (the second edge of the rods is fixed on the stop), after which the formwork is filled with concrete, its partial hardening is expected and the rods are released. As a result, with the tightening of the rods, the concrete adhered to them is compacted, which increases the density, rigidity and deformation stability of concrete goods.
Reinforced concrete products of prestressed type are superior to structures with conventional reinforcement in terms of strength, crack resistance and durability. Therefore, modern industry is focused on increasing the volume of their production.
1.1 Classification of concrete products
The technology of production, operation and quality requirements for reinforced concrete products are given in the normative standard SNiP №2.03.01-84 "Concrete and reinforced concrete structures", according to which the classification of products is carried out according to the following factors:
- method of reinforcement;
- type and volumetric weight of concrete;
- internal structure (solid and hollow);
- appointment.
The varieties of concrete products by type of reinforcement were discussed in the previous section. Depending on the volumetric weight of concrete, all concrete products are classified into:
- reinforced concrete structures made of extra heavy concrete - weight over 2500 kg / m 3;
- from heavy concrete - weight 1800-2500 kg / m 3;
- their lightweight concrete of cellular type - weight 500-1800 kg / m 3;
- heat-insulating reinforced concrete structures made of extra-lightweight concrete - weight up to 500 kg / m 3.
Reinforced concrete products of the same type are often produced in different shapes and sizes, for example, wall blocks are angular, U-shaped and window-sills. Note that the concrete solution used for concreting factory-made structures differs from ordinary ready-mixed concrete in a smaller fraction of crushed stone (3-10 mm) , which ensures uniform filling of the injection mold.
1.2 Precast concrete production technology (video)
2 The main types of reinforced concrete structures and their marking
The nomenclature of concrete goods includes more than 20 different positions, consider the symbols of the main ones:
- beams - B (crane - BK, rafters - BS, strapping - BO);
- columns - K;
- stair steps - LM, platforms - LP;
- support cushions - OP;
- jumpers - OL;
- crossbars - P;
- piles - C;
- sleepers - W;
- roof trusses - FS, roof trusses - FP;
- non-pressure pipes - TF, pressure pipes - BT.
According to the parameter of functional purpose, concrete and reinforced concrete structures are divided into 4 main groups:
- Concrete goods for housing.
- Reinforced concrete products for industrial buildings.
- Reinforced concrete products for engineering structures.
- Reinforced concrete products for general construction.
The group of concrete products for the construction of residential buildings includes floor slabs, piles, wall panels, foundation blocks, trays, lintels and beams. This class of reinforced concrete products is allowed to be made of concrete grade M150 and higher, and for piles - at least M200.
The use of slabs and blocks for precast foundations is widespread. The slabs are available in sizes from 120 * 80 * 40 cm to 320 * 120 * 50 cm, the standard block size is 300 * 60 * 60 cm. The weight of one element of prefabricated foundations, in accordance with the requirements of SNiP, should not exceed 3 tons.
In multi-storey construction, the use of prefabricated building frames is practiced. Frames consist of columns, roof beams, rafter beams, crossbars and purlins. For the manufacture of frame elements, concrete of grade M200 and higher is used. After assembly, the supporting structures are sheathed with wall panels.
Floor slabs are produced in a rectangular shape with round or oval voids, stiffeners are provided for large-sized structures. Slabs can be made from both heavy concrete and concrete with porous aggregates.
2.1 Technical characteristics and features of the choice of concrete products
The design of reinforced concrete structures is carried out taking into account the characteristics of the concrete used for their production. The main property of concrete is compressive strength, which determines its grade. This characteristic is indicated in the marking of concrete goods with the letter "M"; in total there are 16 strength grades from M50 to M800. The numerical nomenclature indicates what kind of load (in kilograms) 1 cm 2 of concrete can withstand.
Also, reinforced concrete and stone structures have such characteristics as tensile strength (BT marking) and bending resistance (BTb), which are determined by the properties of the reinforced cage embedded in the concrete products. Requirements for the properties of reinforcement for reinforcing concrete goods are given in the standard GOST 5781-82 "Hot-rolled steel for reinforcing reinforced concrete structures".
Also an important characteristic that must be taken into account when choosing concrete products is its frost resistance class. It is this parameter that determines the durability of the structure, since it indicates the maximum number of freeze / thaw cycles that a particular brand of concrete can withstand. Frost resistance is indicated by the F nomenclature, which can vary from F15 to F200.
We also note such an indicator as the degree of water tightness (W), the maximum water pressure that can withstand reinforced concrete products while maintaining the tightness of their walls depends on it.
When buying concrete products, you must be guided by all of the above characteristics and choose products that are suitable in terms of characteristics for use in your region. Thus, you will receive durable building materials and save money in the future, since the repair of reinforced concrete structures is not cheap.
Pay attention to the presence of obvious defects - protrusions of reinforcement from the concrete plane, improper location of mounting loops, cracks on the surface. Such concrete goods cannot be used. If a network of microcracks is found on an already operating structure, they can be repaired with a special repair mortar or a mixture of cement and PVA glue. Large damages are repaired with a conventional cement-sand mixture.
For more detailed information about concrete products, we recommend that you study the textbook "Technology of concrete and reinforced concrete products" by Yu.M. Bazhenov. The book describes in detail the design and calculation of reinforced concrete structures, their production technology and installation rules.
Such products are reinforced concrete products - a building material that is used in construction. Such concrete is obtained by pouring it together with iron reinforcement.
This method has been officially used since 1867. It was in this year that this invention was officially patented. The French scientist Joseph Monier acted as the patent holder. Currently, concrete products, including reinforced concrete products Stavropol are the most durable material for construction.
What results in such strength?
This is due to the product frame. Compression of this frame occurs, and it is thanks to this that the reinforced concrete product becomes durable.
What is the main disadvantage of this product?
If the concrete is stretched, then its strength becomes several times less. But this problem can be solved. It was decided to introduce wire. And this wire was not simple, but steel.
Now let's look at the advantages of reinforced concrete products.
1) A small price for such a design. Firstly, these products are sold in a ready-made assembly, and therefore you do not have to buy various additional materials. Such a ready-made assembly significantly reduces the construction time. You no longer need to assemble the entire structure yourself; you will not need to paint this entire structure with paint, since it is already painted.
2) The second advantage is the ability to save your finances. Currently, the construction of reinforced concrete structures itself is quite expensive. Hence, you will need a large financial investment to collect it. And in order not to waste either your time or your money, there are special firms that supply ready-made concrete products to Stavropol. But even this essence of the matter has its drawback. Many companies simply save on this and supply low-quality products. So, if you have decided to take a reinforced concrete product already in finished form, then be sure to find a good company. You will also need highly qualified specialists who will be able to advise on all emerging issues in order to supply ready-made reinforced concrete products.
3) But not only the experience of the builders themselves plays a key role in the construction of a building. The key factor is often (oddly enough) the weather. The weather in Russia often cannot be foreseen and that is why it is so important in the construction of reinforced concrete products. But this problem is being solved. There are special factories. In them, the production of reinforced concrete products is carried out in covered areas. This method eliminates the interference of weather conditions such as rain, snow and wind. In such companies, all production is carried out in specially equipped premises. That is why water cannot interfere with the production of reinforced concrete products.
4) These products are made of reinforced concrete, and therefore do not undergo aging or corrosion. If you suddenly want to compare some materials (for example, wood and reinforced concrete), then you will see that reinforced concrete is the most resistant and durable compared to wood.
Special factories for the production of reinforced concrete products are engaged in the manufacture of not only such products, but also the production of supports, poles and racks. These products are highly durable.
When purchasing reinforced concrete products, you must definitely choose the plant that produces such concrete products, the quality of which is beyond doubt. Our company is recognized as one of the leading manufacturers of reinforced concrete and products from it. We distribute our concrete products in Stavropol, Krasnodar, Rostov and other cities of the Southern Federal District.
Structural concrete is used in the production of reinforced concrete products. Reinforcement in reinforced concrete structures is very dense.
● The main difference between structural concrete and commercial - this is a finer fraction of crushed stone - about 3-10 mm. In order to avoid the formation of voids in reinforced concrete, not commercial, but structural concrete is used, the main difference of which is the finer fraction of crushed stone. In order to avoid the formation of voids in reinforced concrete, not commercial, but structural concrete is used, the main difference of which is a smaller fraction of crushed stone. Ready-mixed concrete with a larger fraction of crushed stone would unevenly fill the place intended for it in the structure of the future reinforced concrete product.
● Prestressed reinforced concrete products - types of reinforced concrete that are subjected to rather strong bending loads. During the production process, the metal rods of the reinforcing cage are pre-tensioned with jacks or by heating with an electric current. In this stretched form, the rods are fixed in a formwork and poured with concrete. After steaming and hardening of the reinforced concrete product, the excess reinforcement is cut off. Thus, a reinforced concrete structure is obtained that is not subject to sagging under the influence of an increased load: floor slabs, lintels, beams, purlins, crossbars.
Foundation blocks
are used in the equipment of prefabricated strip foundations, basement walls and technical rooms.
Foundation block marking
includes designation of block length, width and height. Example
:
FBS 12-5-6 T - solid-type foundation block 1200x500x600 mm in size
FBS - solid foundation blocks
FBV - solid foundation blocks with a cut-out for laying lintels or skipping communications
FBP - foundation blocks with open downward voids
Foundation pillows
are used when laying tape-type foundations, which allows to reduce labor costs during the construction of the foundation and significantly increase the speed of work.
Foundation cushions marking
denotes the type of product, followed by the width and length in decimeters, the last digit indicates the symbol of the reinforcement. Example
:
FL 12.24-3 - foundation pad with dimensions of 2400x1200x300 mm
FL- foundation pad
Reinforced concrete piles.
The main task of reinforced concrete piles is to transfer the load of the pile foundation to the ground. Reinforced concrete piles with a section of 300x300 mm can be up to 12 m long, piles with a section of 350x350 or 400x400 mm can be up to 16 m long. Driven composite piles can be long.
Pile marking means
: the first number is the length in decimetres, the second number is the height in decimeters. Example
:
STs 9-30 - a solid pile of square cross-section with stressed reinforcement in the center measuring 900x3000 mm
FROM - solid square piles, composite and solid square piles with transverse reinforcement of the trunk
SC - composite and solid hollow piles of circular cross-section with a diameter of 400-800 mm
SP - solid piles of square section with a cavity
CO - piles-shells solid and composite with a diameter of 1000-3000 mm
SC - solid piles of square section without transverse reinforcement of the shaft with stressed reinforcement in the center
1SD - piles-columns solid square cross-section two-cantilever, located along the extreme axes of the building
2SD - piles - solid square columns with two cantilevers located along the middle axes of the building
Floor slabs
P - floor slabs and coverings
PT - floor slabs of communication tunnels and channels
PB- floor slabs without formwork
PTP - flat floor slabs
PPP - cut slabs
PBO - lightweight floor slabs
| ● Basic principles of laying reinforced concrete slabs ● Do-it-yourself monolithic concrete floor ● Types of anchors ● Armopoyas under the Mauerlat ● Construction of concrete retaining walls ● Concrete canvas ● Additives to cement and concrete |
● Plasticizers for concrete ● Bearing nodes on brick walls ● Interfloor overlap on wooden beams ● Concrete slabs with bubbles ● Lintels for openings in a brick wall ● Stages and methods of installing anchors in the foundation |
Road plates used for the construction of temporary or permanent road surfaces. In places with difficult soil, hydroscopic and climatic conditions, prestressed road slabs are used.
Road slab marking means: the first digit is the length in decimetres, the second is the width in decimetres (rounded off value), the third digit is the design load in tons. Example :
1P 30-18-30 - rectangular road slab for a permanent road with a size of 3000x1800 mm, designed for a load of 30 tons.
PAG-18 U - airfield slab with a thickness of 18 cm with prestressing longitudinal reinforcement
1P - plates for permanent roads
2P - slabs for temporary roads
PD - road plates
PDN - tense road slabs
PDG - corrugated road slabs
RAP - pavement slabs
PAG - airfield corrugated plates
Jumpers. are used to cover openings and increase the strength of the structure.
Marking reinforced concrete jumpers
means the following values: the first digit means the serial number of the given cross-section, the letter values \u200b\u200bindicate the type of jumpers, numbers by letters indicate the length of the product in decimeters (rounded off value) and the value of the calculated load; the presence of a mounting loop is indicated by the letter P at the end. Example
:
8PB 16-1 - bar jumper 1600x120x90 mm
PF - front lintels
PG - beam lintels L-like
PB - bar jumpers
PP - slab jumpers
Rigidity diaphragms
are designed to take on the vertical loads they receive from floor slabs, stairs, crossbars and engineering structures.
Stiffness diaphragm marking
: the first digit indicates the length in decimetres, the second digit indicates the nominal height in decimetres (rounded values). Example:
D 12-20 - flat diaphragm with 1200x2000 mm
D - the diaphragm is flat
1D - diaphragm with one shelf
2D - diaphragm with two shelves
DP - flat diaphragm with aperture
1DP - diaphragm with one shelf and opening
2DP - diaphragm with two shelves and aperture
B - beams
BC - crane beams
BO - strapping beams
BP - truss beams
BS - roof beams
BT - floor beams of communication tunnels and channels
Bf - foundation beams
BE - beams of span structures of overpasses for pipelines
TO - columns
CE - trestle columns for pipelines
LB - staircase beams, stringers
LC - channel trays
LM - stair steps
LP - staircases
LS - steps
OP - support cushions
PG- partition panels
PD - plates of the bottoms of communication tunnels and channels
PC - cornice slabs
PLP - loggia slabs
BY - window slabs
PP - parapet plates
ETC - jumpers
PWG - runs
PS - wall panels
R - crossbars
FROM - piles
Sat - wall blocks
SBC - basement wall blocks
ST - retaining walls
FB - foundation blocks and basement wall blocks
FD - foundations for equipment
FP - sub-ramp farms
FS - roof trusses
Sh - reinforced concrete sleepers
Pipes:
T- reinforced concrete non-pressure bell-shaped pipes
TF - reinforced concrete non-pressure folded pipes
BT - concrete pressure pipes
TN - reinforced concrete pressure vibrohydropressed pipes
