Additives to concrete are designed to improve the physical performance properties of the concrete mix. They can be used to solve the following tasks:
There are the following types of impurities:
Water binds the mixture and makes it workable. But the more water, the lower the strength of the mixture. It is the plasticizers that allow you to achieve the ideal proportion. They increase the mobility of the mixture, allowing you to reduce the percentage of water in it. At the same time, this mixture becomes more durable and frost-resistant.
Plasticizers are weak (add less than 5% mobility), medium (5%), strong (10%), and super strong (20% or more).
They help to achieve greater porosity of the mixture, which increases its frost resistance. However, at the same time, they reduce the strength of the concrete. Therefore, they are always used in a minimum amount.
They can reduce the hardening time of the concrete mixture by 2-3 hours. This is important for multi-layer casting and makes it possible to work with concrete at lower temperatures. Reduce the overall duration of construction work. They are also used in combination with mixtures that inhibit hardening.
Helps keep the mixture in a liquid state for longer. This is important when transporting over long distances and when handling concrete in stages.
Such additives help to achieve greater strength and durability of concrete. Also, the indicator of water resistance is further increased.
They help to protect iron reinforcement by forming an oxide film on its surface.
Increases water resistance and reduces mortar stratification. Needed in the production of aerated concrete. Along the way, the frost resistance of concrete increases, but the strength decreases.
Such additives are used to ensure work with the mixture at low temperatures in winter. They contribute to the speedy removal of moisture from the mixture.
Additives can be used separately. But, as a rule, complex mixtures are more popular, in which the components combine well and enhance each other's action.