Floor slabs: dimensions according to GOST, types and their marking

Floor slabs are one of the most popular building materials used in the construction of buildings for various purposes, from apartment buildings and industrial buildings to private housing. Due to the combination of high strength and comparative ease of production, they have taken their niche in construction. Manufacturers offer products of this type for any purpose. In the article, we will consider the features of production, types and sizes of floor slabs in accordance with GOST.

general description

Floor slabs are a type of reinforced concrete products (reinforced concrete products) intended for installation as floor separators or forming a ceiling in one-story construction. As a building material, they are flat blocks with strictly defined geometric parameters and have a wide range of positive performance characteristics.

The technology for their production was developed in the middle of the XNUMXth century and has not undergone so many changes during its use, while over the decades of operation the material has established itself as an easy-to-use and reliable option. Subject to the observance of installation technologies and the use of special equipment, large volumes of work can be performed with the help of plates, which is one of the main advantages of reinforced concrete products in this category.

Manufacture

According to the structure, reinforced concrete slabs consist of reinforcement strapping and concrete mixture. Regardless of the variety and methods of manufacture, they must meet the requirements of strength standards and geometric accuracy of dimensions. In this case, we are talking about GOST 26434-2015, which regulates the basic requirements for reinforced concrete products of this type. And also in the production, the requirements of GOST 21779 (geometric accuracy of dimensions), GOST 13015 (quality of the concrete surface), as well as regulatory documents SP 112.13330.2011 and SNiP 21.01–97 (fire resistance of building material) are observed.

Plate strength and reinforcement tension

Concrete, by its characteristics, has good compressive strength, but for interfloor floors it is more important to maintain flexural integrity. To ensure the strength of the floor slab, reinforcement is embedded in it in such a way as to ensure not only the integrity of the slab, but also the resistance to bending. This is achieved by compressing the concrete with reinforcement, which was pre-stretched before pouring the solution, and released after the concrete hardened. Such products are called prestressed concrete structures.

There are four ways to tension reinforcement:

• electrothermal;
• mechanical;
• electromechanical;
• physical and chemical.

In the first case, stretching is achieved by heating the reinforcement with an electric current. In the second – jacks. The second name of this method is the hydraulic tension of the reinforcement. The third combines the first two methods. And finally, the fourth is based on the self-stress of the structure due to the use of the expansion property of cement.

Depending on the purpose and intended conditions of use, the plates are divided into several main categories. Each of the varieties also differs in the technology used, so they should be considered separately.

Classification

By design, reinforced concrete slabs are divided into three types:

1. Solid.
2. Multi-hollow.
3. Ribbed.

Different types of floor slabs differ not only in size, but also in the load capacity, as well as in places of application.

solid

One of the options for floors are solid or solid slabs, marked with the letter “P”. They are produced by pouring a concrete mixture into a special form, inside which the reinforcement is placed. After pouring, the mixture is compacted using special vibration machines, which makes it possible to obtain a product with high load-bearing strength. Depending on the conditions of further use, the reinforcing frame is mounted for laying the block with support on 2, 3 or 4 sides.

Among the significant advantages of using solid floor slabs, one should highlight the high compressive strength of products, while depending on the actual conditions of use, this parameter can vary in the range of 300–4000 kg/m². This solution allows you to choose the best option for a particular case, which has a positive effect on planning the construction budget.

multi-hollow

Hollow-core slabs differ from solid slabs both in terms of production technology and operating parameters. The main feature of reinforced concrete products of this type is the presence inside their structure of specially created voids located along. This solution allows to achieve a significant reduction in weight, while maintaining comparable strength indicators.

It is important to note that due to the presence of a certain volume of air inside the plates, they have reduced thermal conductivity and less contribute to the propagation of sound, which is in demand both in the construction of residential buildings and in the construction of industrial premises.

Within the category under consideration, there is a conditional division into two subgroups of products that differ in production technology.

• PC is a kind of hollow floor slabs, produced by pouring a concrete mixture into a special formwork with a metal crate installed inside. Before pouring inside the reinforcing structure, special pipes made of a special material are laid, which, after the mixture has solidified, are removed, as a result of which voids of the desired diameter are obtained along the entire length.
• PB is a more modern type of hollow core floor slabs, which is created using high-tech conveyor-type equipment. As a result of the production process, a workpiece with a given thickness and width is obtained, and the products are cut along the length already at subsequent stages. The production process is characterized by high accuracy and speed of execution, however, due to some limitations in the design of the reinforcing part, it is possible to lay the slabs only with an emphasis on two sides.

There are also lightweight versions of hollow core floor slabs marked PNO, 3,1PB and 1,6PB, which have an even lower weight, but strength indicators comparable to conventional analogues. This makes the products an excellent option for use in one-story construction of private houses. The advantages of such products can also be attributed to the reduced own load on the supporting structures.

In addition, reinforced concrete products provide greater fire safety, unlike wooden floors from beams.

Ribbed

This type of plate differs from the analogues mentioned above by the special shape of the products with special stiffeners, which make it possible to maintain a relatively low weight and high strength properties. In most cases, they are used in multi-storey construction or the construction of large industrial facilities, as they require the use of special equipment and materials for further finishing. Ribbed concrete products in low-rise and private construction are practically not in demand.

Slab dimensions

The technological solutions used in the production of floor slabs impose restrictions on the dimensions of the final products, and therefore the maximum length, width and thickness of the reinforced concrete products will differ depending on the variety.

The parameters of hollow core slabs differ in the ratio of the diameter of the longitudinal voids to the total thickness (mm), while depending on the indicated parameters, there will also be features of laying products.

There are 3 main categories for hollow core slabs:

• PC – reliance on two side.
• Fct — three side.
• PKK — four side.

In addition, they differ in design and manufacture, this is also indicated in the marking:

The table shows the dimensions of hollow core slabs and weight:

There is also a variety of slabs marked PG, which differ in a width of 260 mm and a special “pear-shaped” form of hollow channels.

As for the width and length of the slab, there is also a division into several types.

• Varieties 1PK-3PK are produced with a width of 1000–3600 mm, with a length in the range of 2400–7500 mm.
• Varieties 5PK and PG are made in three overall variations 1000/6000 mm, 1200/9000 and 1500/12000 mm.
• The 6PC version can only be supplied with a length of 6000 mm.
• Plates of category 7PK are made with a width of 1000 to 1800 mm and a length of 3600 to 6300 mm.

The use of lightweight slabs in construction with their smaller size and weight saves on several parameters: lower costs for foundation, transportation and purchase. Given this, lightweight plates (LNO) have become more popular and, as a result, more diverse in size. The table below shows this.

As for ribbed plates, the length of products of this type ranges from 2000 to 12000 mm, with a width of 1000 to 1800 mm.

The table shows the dimensions and weight of common ribbed plates:

The presence in the market segment under consideration of an abundance of product varieties ensures variability of use and simplifies construction work.

Marking

To simplify the choice of the optimal option for the manufacture of floor slabs for certain tasks, manufacturers use a single standardized marking. In order to simplify the understanding of the decoding, we offer an example of a plate PK 57-10-8 AtV-1.

• PC – in this case we are talking about a multi-hollow slab with round holes, which means the ratio of the diameter of the voids to the thickness of the product is 159/220 mm;
• 57 – displays the length (measurement is in decimeters);
• 10 – means width (measurement in decimeters);
• 8 – the parameter indicates the compliance of the product with the design load of 800 kg / cm²;
• AtV-1 – this implies the use of prestressed reinforcement of a certain class when creating a reinforcing crate.

For ribbed plates, the marking has the form PG, PR, PRT, etc. For example: PRTm-12 – here PRTm is a series, and 12 is a standard size.

It is simplified and does not display data on real sizes, they can be found in reference books

For solid products, marking may begin with the letters P, PTS, etc. For example: Marking 4P 30.66-6l stands for:

4 – type, 30 – length in decimeters, 66 – width in dts, 6 – load, л – light (concrete quality).

Also, manufacturers can accompany their products with additional information – the type of concrete (L – light, C – silicate), the presence of sealing inserts inside the hollow channels (a), and index 1 will indicate voids closed at the ends.

Features of use, transportation and storage

Reinforced concrete slabs, subject to technological standards at the production stage, are products with high mechanical strength. However, due to the nature of the structure of the materials used, it is necessary to observe a number of rules during installation, transportation and temporary storage of products in order to maintain the original performance characteristics.

The rules for transportation and storage are prescribed in the above GOST 13015-2012.

Storage

Of no small importance is the observance of the storage conditions for floor slabs after unloading at the work site. The limitations here are due to the peculiarities of the structure of concrete, which, due to its porosity, tends to absorb moisture. Of particular danger in this case are temperature fluctuations (passing through 0), which can cause a violation of the structural integrity of the plates.

• After transportation and storage of boards, they must be covered with a moisture-proof material (polyethylene film, thin sheets of steel, corrugated board, etc.).
• During long-term storage of floors, elements can be stacked in stacks no higher than 2-2.5 meters, which will eliminate excessive load on the bottom layer and simplify maintenance of the covering material in case of violation of its integrity.
• As during transport, to evenly distribute the load on the surface, during storage, wooden beam pads should be used, which minimizes static loads and the appearance of cracks.
  

• When choosing a place for storing slabs, choose the most horizontal surface, and, if necessary, level it. This will prevent the panels from shifting.
• For laying as leveling and shock-absorbing elements, the wooden beam must be of the same cross section, otherwise the resulting static stresses will lead to cracks.

By a combination of factors, reinforced concrete floor slabs are an example of a time-tested building material, which, subject to the rules of production, transportation and installation, is able to maintain its characteristics for decades.

Сonclusion

It is probably impossible to enumerate the size of all the plates. There are standard sizes of floor slabs, which are indicated in all reference books, but new non-standard ones appear.