Concrete work: execution technology

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

The use of concrete is almost always associated with plans for the construction or installation of immovable load-bearing structures of one type or another. At the same time, even simple events are accompanied by a complex of technological operations. The reliability and durability of the target operation site will depend on the quality of the concrete work.

Varieties of concrete

Traditionally, concrete is associated with a cement base, which is quite right, since it is the most common filler for building mixtures. Today, by the way, Portland cement is especially popular in this class, which allows you to build structures of a high degree of strength.

But in addition to cement, the following mortar fillers are also used in concrete work:

• Silicates. The autoclave curing method produces a mixture based on lime. Quite rare, but functional concrete, characterized by insulating qualities.
• Gypsum. The concretes on this filler are suitable for the devicesuspended ceilings, partitions and finishing elements.
• Slag-alkaline fillers. Relatively new and inexpensive mortar component that can be used in the same partitions or structures that experience light loads.

To assess the possibility of using concrete for certain purposes, it will not be superfluous to deal with the bearing capacity of the future structure.

For this there is a classification according to the degree of density:

• Lightweight concrete. The resistance index is 500-1800 kg/m3. The basis for the solution is prepared on pumice, expanded clay, tuff and other porous aggregates. Such concrete is not suitable for critical load-bearing structures.
• Heavy. Due to the combination of limestone, granite and diabase, the density reaches 2500 kg/m3, which makes it possible to use the construction of such a solution in the construction of internal partitions and screeds.
• Especially heavy. The filler for such mixtures are metal shavings and iron ore, which leads to a density degree above 2500 kg/m3. Such concrete is also suitable for the construction of industrial structures.

General Concrete Technology

The whole workflow can be conditionally divided into two stages with small intermediate operations - this is preparation and directly laying / pouring the solution. As for the first stage, in each case a mixture of several components is prepared, including the same filler or other binder, sand or crushed stone (gravel), water andplasticizers (if necessary).

The prepared mixture is mixed with special equipment or, if we are talking about small volumes, with a construction mixer. The second stage of concrete work involves the use of a prepared solution. Again, this can be laying, pouring, spreading the mixture, or spot embedding. But the work does not end there either. Concrete surfaces may need to be sanded after curing.

Types of work activities with concrete

The most common works of this kind include the following:

• Foundation device. A wooden or non-removable polystyrene foam formwork is created, into which a concrete solution is poured. In the future, a frozen platform or a system of strip formwork walls will become the supporting foundation of the structure.
• The erection of columns. Casing pipes are installed vertically along the perimeter of the building, the cavities of which are filled with concrete mortar. Similar structures also serve as a carrier base.
• Building walls. The most common type of concrete work. The device of walls can be carried out using a monolithic scheme or by laying blocks. In the first case, a form for pouring the mortar is also pre-mounted, and in the second, the mixture is used as a binder mass for laying bricks in particular.
• Flooring installation. Screed is also a common way to use concrete mortar. In this way, solid bases are formed for decorativecoatings.

Features of winter concrete work

To begin with, it is worth noting that "winter" for concrete structures are temperature conditions when the average daily values drop to 5 °С with the possibility of at least one-time (per day) reaching 0 °С. Such a regime for the use of a concrete solution is disastrous for the reason that hardening of water crystals will begin in its structure, which will create conditions for the formation of pores. In the future, the ice particles will thaw, and the porous structure will retain a reduced level of strength. How is concrete work done in winter?

If it is not possible to reschedule construction activities for a more favorable time, then there are two ways out:

• Use cold-resistant additives and plasticizers. Such additives are added to the solution at the stage of its preparation. But it is important to consider that some of these modifiers adversely affect other properties of concrete.
• Maintain optimal temperature conditions during the preparation and laying of the solution. To do this, use heat guns, steam generators, systems of thermal purge with flue gases, watering with hot water, etc.

Work on the device of reinforced concrete structures

This type of work differs from the usual concrete installation activities in that an additional stage of reinforcement integration is introduced into the technological process. Its purpose is determined by the need to strengthen the structure, giving it rigidity and durability. Both concrete and reinforced concrete worksare similar in that mortar is prepared for them.

But if in the first case the same filling is performed as a self-sufficient procedure, then in the second it is supplemented by the laying of reinforcing bars. These can be metal or fiberglass rods with a diameter of 6-12 mm, which are mounted according to different schemes depending on the requirements of the project.

Completion of works

After laying, the workflow does not end either. Depending on the characteristics of a particular mixture and environmental conditions, the following operations on an arranged structure may be required:

• Sheltering concrete with moisture-absorbing material.
• Heat insulation.
• Water every 3 hours
• Limitation of possible mechanical damage.
• Introduction of external technological coatings for protection.
• Deairing with surface spiked rollers to seal the structure.

The simplest and most common advice for outdoor concrete workers is to cover the laid screed with polyethylene or a vapor barrier. This is a basic measure to protect the material from external influences.

Assessment by the technical and operational qualities of concrete

Quality control of concrete structures and structures is carried out taking into account the following characteristics:

• Strength. It is determined by how correctly the solution formulation was selected, taking into account the ratio of sand, gravel, crushed stone, cement,water and other ingredients.
• Density. It is estimated by the presence of voids in the structure itself. Again, this parameter will depend on the presence of ice and air in its mass.
• Plasticity. It is expressed in such a property as mobility. In practice, the ability of concrete to fill the smallest cracks and voids depends on this quality.
• Water permeability. In essence, the resistance of a material to water pressure. The higher it is, the more resistant concrete is to contact with aggressive aqueous media.

Conclusion

With all the responsibility of using cement mortars, such events are quite common not only in the professional, but also in the domestic sphere. For example, conventional plastering or tiling may be associated with concrete work. Another thing is that large-scale operations for laying a foundation or pouring a screed over a large area will not only require careful preparation, but in rare cases will do without the use of special equipment. In other words, in each case, an individual approach is needed with a specific technological map for the preparation, preparation of the solution and its application in accordance with technical standards.