Concrete strength and other advantages
For the first time, concrete was talked about in the distant distant centuries. However, during this time interval, this material, like other construction products, has gone through a long way of transformation.
The very first concrete was discovered by archaeologists on the banks of the Danube River in Yugoslavia in 5600 BC. At that time, this building material was made of gravel and local lime red.
Today, concrete should be understood as stonematerial of artificial origin, which is formed by solidifying a well-mixed mixture with water, as well as coarse and fine aggregate, which are taken with a certain proportion.
Strength of concrete
The most important characteristic feature for concrete is its strength. The strength of concrete depends on many factors. The hydration process itself consists of two stages:
- Grasping. This stage lasts about a day. Here a lot depends on the temperature. So, for example, at a temperature of more than 20 degrees, for grasping concrete it will take three hours. If the zero temperature, then this stage will last 15-20 hours.
- Hardening. This stage begins immediately after the previous action and lasts for several years.
In any case, it should be noted that theThe strength of concrete passes only if there is moisture. The strength of concrete and the structure itself is generally increased due to the interaction of this material with water.
It is also necessary to take into account the fact that the strength setConcrete is suspended in hot and cold weather. That is why at a high temperature freshly filled concrete is recommended to cover with a wet burlap to prevent the evaporation of water. Negative temperature values lead to freezing of water, which is part of the concrete mix. In the event of positive temperatures, the hydration process continues, however, by this time the characteristics of this structure are deteriorating, including the strength of the concrete. For this reason, experts recommend adding a special substance during the preparation of concrete solution.
Classes of concrete for strength
The main indicators of concrete are:
- Class of concrete for strength in the case of axial compression.
- Class of strength of concrete in case of axial extension.
There are several classes of concrete composition, the main of which are:
- The grade of concrete solution, depending on frost resistance. This mixture is used in the construction of structures that are alternately subjected to freezing and thawing.
- The grade of concrete solution, depending on water resistance. This composition is used in the construction of hydroelectric power stations, pools, canals and so on.
Application of concrete
Depending on the technical and economicindicators, for the construction of each structure the selection of the required class and brand of concrete mixture is carried out individually. The strength of concrete in this case plays an important role. Experts recommend that concrete concrete of class not less than B-15 be used for reinforced concrete compressed rod-type elements. For arches and columns it is best to use concrete of class B-20-B-30. For concrete slabs and beams, concrete of class B-15 is suitable.