Manufacture of concrete products: industrial methods and

In this article we will look at what is the production technology of reinforced concrete products on an industrial scale, and in addition, we will determine what methods of concrete casting are used in individual construction. But, before we consider the technological features, let's talk about the basic properties of reinforced concrete.

Features of the production material

Reinforced concrete is a material made using cement-containing solutions and metal reinforcing structures.

Manufacturing technology of concrete goods is not new, since the fundamental methods were patented in the second half of the 19th century. However, the massive use of reinforced concrete structures and structures in the construction industry came at the beginning of the twentieth century.

The use of this material in construction is not accidental, since reinforced concrete products are distinguished by the following qualities:

• resistance to mechanical stress;
• resistance to the negative effects of a number of environmental factors;
• operational reliability and durability;
• reasonable price, in comparison with designs made using other materials;
• resistance to critical temperatures (both low and high);
• resistance to chemical and biological factors;
• high degree of resistance to dynamic and static loads.

However, concrete products have some drawbacks. For example, the compressive strength of the material is less than the similar parameters of the pure metal. In relation to large structures and structures, concrete products "carry" its mass an order of magnitude more than the payload.

Diversity of ŽBI

To date, a wide range of various concrete products is manufactured and manufactured everywhere. And this is not surprising, since concrete goods are used not only in construction, but also in other areas.

For example, most of the lighting poles and power line poles are traditionally made using reinforced concrete. From the same production material, the most advanced and technologically advanced railway sleepers are made.

However, let us dwell on those modifications that have found application in construction.

Among them we note the following varieties:

• foundation blocks wall (PBS);
• floor slabs;
• road plates;
• reinforced concrete piles;
• concrete supports and fences;
• decorative products used in the finishing of construction objects.

We will tell about these varieties in more detail:

• Foundation blocks wall (FBS) - this is a modification of reinforced concrete products, which has found application as the main building material in the construction of precast foundations and basements of various buildings. Such structures significantly reduce the time required for construction, as the unit is large and allows you to abandon the long and laborious brick masonry.
• Floor slabs - These are reinforced concrete lintels installed between floors. For the preparation of such products, highly reinforced reinforced concrete grades are used, designed for high mechanical loads during the entire service life.

To reduce the weight of the plates are produced hollow, which makes them lighter and less thermally conductive. Again, due to cavities in the slabs, concrete is saved, which favorably affects the cost of the finished product.

• Road plates - These are concrete products used in the construction of the roadway, runways of airfields and other surfaces, to which the strength is increased requirements.
• Reinforced concrete piles - These are products that are used in construction, along with foundation blocks. Due to the increased resistance of concrete to the negative impact of environmental factors, such piles can be installed on various types of soil without compromising the quality of finished construction sites.
• Fences, supports and decorative items - This is a special kind of concrete products, which performs not so much utilitarian as an aesthetic function. Due to high consumer demand, the production of these concrete goods is currently mastered by various small and small enterprises.

Features of manufacturing concrete products

Instructions for the manufacture of concrete products is determined by the basic properties of production materials. Cement-containing solutions are liquid or semi-liquid, and therefore the main technological feature of the production process is to fill them in special forms.

In fact, the production technology involves the installation by hand of a reinforcing cage in the mold cavity and the subsequent pouring of the solution. As the mortar dries, the finished product gains the required strength. At the end of this process, the finished product is removed from the mold and can be used for its intended purpose.

The manufacturing techniques of reinforced concrete and precast concrete products include a list of individual operations that make up the production process. All operations carried out during the manufacture of concrete products, are conventionally divided into basic, auxiliary and transport.

Conventionally, the process can be divided into the following successive stages:

• concrete preparation;
• rebar manufacturing and frame production;
• reinforced concrete products;
• concrete molding;
• temperature-humidity treatment products;
• decorative finishing of a front surface.

Important: In the manufacture of exterior wall panels, concrete structures may be subjected to additional refinement. Heat-insulating materials can be laid in the panel, both during molding and at the assembly stage of individual shells.

Production equipment

Equipment used in the production of concrete products, in accordance with the purpose, is divided into technological - the main, as well as auxiliary and transport. Equipment for the production of concrete products, involved in a single production complex, is called the technological line.

In the manufacture of reinforced concrete products, special forms are used that can be made of metal, reinforced concrete, sawn timber of wood origin. Combined forms, constructed using several different materials, are also used.

Regardless of the type of materials used, the finished form must meet the following requirements:

• accuracy of ensuring the established standard sizes and configuration of products upon termination of carrying out all technological operations;
• rational design and as a consequence of a small mass of the form in relation to the mass of the finished product;
• lack of complexity and ease of assembly and disassembly;
• structure stiffness when pouring concrete with various indicators of density and specific gravity.

Important: The effectiveness of the use of production forms is largely determined by the correctness of the choice of lubricants. Properly selected lubricant prevents the solution from sticking to the inner surface of the formwork, thereby contributing to the durability of the form and improving the quality of the concrete products.

Current schemes of industrial production of concrete products

In accordance with the methodology for the implementation of the molding process, there are three main schemes for the manufacture of concrete products:

• Production in the forms of an unmovable type involves carrying out all technological operations, starting with preparation and ending with disassembling formwork in one place. An example of the implementation of such a scheme is the formation of concrete products in matrices, in cassettes or on flat stands.
• Production in forms of a relocatable type provides for the phased transportation of formwork with the cast solution from one production station to another. Such a production scheme applies to continuous aggregate and conveyor molding.
• Continuous-type molding is a relatively new production scheme that is characterized by efficiency, high productivity and relatively low energy costs. The method is carried out using a vibratory mill.

Concrete reinforcement

Regardless of what equipment is used for the production of concrete products, the most important technological step is the reinforcement of the mixture. And this is not surprising, since the method of realization of the reinforcement of mortars determines such parameters of the finished structure as the strength and cost of concrete goods.

Important: According to statistics, the price of the finished concrete product at 20-30% depends on the cost of reinforcement. Therefore, the approach to the development of features reinforcement of reinforced concrete structures is important both technically and economically.

Reinforcement of mortars in the production of concrete products is of two types: prestressed and ordinary - unstressed.

Let us consider in more detail the features of the implementation of each of these methods, since the strength properties of the finished products largely depend on them.

• Non-stressed reinforcement of reinforced concrete products is carried out using a spatial framework, as well as by means of flat grids made of wire rod or steel rods with an appropriate cross-sectional diameter.

Frameworks, during such reinforcement, can be made only using the welded method. Non-stressed reinforcement is divided into main (working) and auxiliary (assembly).

The main reinforcement is placed in areas undergoing maximum tensile stresses. Auxiliary reinforcement, on the contrary, is used in those areas of reinforced concrete where tensile stress is absent or compression is present.

• Tense reinforcement of reinforced concrete involves the creation of pre-compression, as in the area of ​​tensile stresses, and throughout the cross section of concrete products. For example, in the manufacture of foundation blocks or piles, the parameters of preliminary compression are up to 60 kg / cm ?. Compression is performed by tightening the reinforcement for a certain time.

Conclusion

So, we have reviewed the main points of the production process, and, in addition, we have listed the operational features of concrete products. You will be able to take this information into account when ordering ready-made concrete products, and when using reinforced concrete in individual construction.

Do you have any questions? Exhaustive answers can be obtained by watching the video in this article.