What is concrete?

Kira Dobrovolskaya
Kira Dobrovolskaya
March 18, 2013
What is concrete?

Concrete is one of the main building materials, it is used in almost all construction processes in different consistencies and types. It is used in the repair. If we talk in more detail about what concrete is, then we can give the following definition: it is an artificial stone material that can be obtained by molding and hardening a properly selected mixture consisting of a binder, aggregates and water.

Concrete classification

According to the standard classification, concrete is divided into types according to its purpose, type of aggregates and binders, its structure and the principle of hardening.

  • According to its purpose, concrete is ordinary (used for the construction of civil and industrial premises), special (thermal insulation, road, decorative) and special purpose (heat-resistant, chemically resistant, protected from nuclear radiation, sound-absorbing).
  • By the type of cementitious material, concrete can be gypsum, cement, slag alkaline, silicate, plastobeton and asphalt concrete.
  • According to the class of aggregates, concrete can be porous, dense or special.
  • According to its density, concrete can be porous, dense, cellular or large-pore.
  • Concrete can harden under natural conditions, with heat-moisture treatment, at different atmospheric pressure.

Concrete characteristics

The main indicator of concrete is the compressive strength. It is this characteristic that affects the class of concrete. The class is determined by the letter B and the numbers that indicate sustained pressure. Also, the strength of concrete can be determined by the letter M and the numbers between 50 and 1000 points.

The second main indicator is workability. It is in the classification determined by the letter P. For this characteristic concretes are:

  • movable;
  • hard;
  • superrigid.

Other indicators that determine the class and scope of concrete are:

  • frost resistance - determined by the number of defrost-freeze cycles, in which the concrete retains its properties;
  • bending strength;
  • water tightness - indicates the level of water pressure that a concrete grade can withstand.

To check the water resistance and frost resistance of concrete, climate cameras are used.

What is concrete made of?

Although many people know what concrete is, few people think about what it is made of. The main element for the production of concrete is sand. Any natural sand is used, but without clay. Even a small amount of clay particles in the sand can greatly reduce the strength of concrete. The sand is washed, filtered and mixed with special high-quality sand.