Salt in concrete or antifreeze additives for building

At low temperatures, the process of hardening of concrete mixtures slows down significantly. This is due to the fact that water entering into the building mass crystallizes under such conditions, preventing the normal passage of the hydration process. For fresh concrete, this situation is destructive, and it has an extremely negative effect on the strength of the structure being created.

The process of crystallization of water from frost in a fresh solution leads to the fact that it becomes loose and is endowed with small frost-resistant indicators. The physics of this process is simple and clear even to the student. In the process of freezing, water expands, which breaks the cement mix with the aggregate.

Antifreeze additives

Monolithic structures created in warm weather, after drying, are durable and reliable structures.

Note! The high strength of reinforced concrete products causes the fact that if necessary, create a hole in this design or shorten it, you need to use methods such as cutting reinforced concrete with diamond circles and diamond drilling of holes in concrete.

But in order to provide the same level of strength for concrete structures created during the cold season, measures should be taken to preserve water in the building mass in a liquid state.

Antifreeze additives, which are also called accelerators for setting and hardening of concrete, can help in this matter. They allow to reduce the freezing temperature of moisture, thereby contributing to the normalization of the process of solidification of the concrete monolith design.

Types of antifreeze additives

Means of this type on the modern market are presented in two main types:

1. Compounds preventing the crystallization of liquids in building mixtures by lowering the freezing temperature of the building mass. They are also called retarders or weak cement setting accelerators. These substances include electrolytes of two types:

1. Strong - salt or technical salt for concrete (sodium chloride), sodium nitride;
2. Weak - ammonia solution, substances of limited origin (carbamide, polyhydric alcohols);

Accelerators of the process of hardening of concrete

As such substances are most commonly used aqueous solutions of chloride salts:

• Calcium Chloride (HC);
• Calcium nitrate (NC);
• Calcium nitrite nitrate (NNC);
• Sodium Sulphate (CH);
• Sodium Nitrate (HH);
• Trinitriophosphate (TNF);
• Sodium chloride (XH).

Sodium chloride in the fight against frost

NaCl - sodium chloride (CN) or ordinary technical salt. Concrete with salt technical is an excellent substance for the construction of works in the winter at low temperatures.

Main characteristics of XN

Technical salt in the concrete solution is added in order to give it antifreeze characteristics.

This additive has the following properties and characteristics:

• Salt introduced into the solution with your own hands allows you to reduce the freezing point of water, thus avoiding the destruction of the structure of the product and the formation of cavities in the monolithic structure that is poured in the winter;
• The price of this supplement is low;

Note! This component for concrete is the cheapest antifreeze additive.

• NaCl does not affect the rate of hardening of the mortar, so the concrete with salt in winter may be mixed long before it is poured. Thus, the mixing of the construction mass with this additive can be done, for example, at the factory long before it is transported to the construction site without losing its basic properties;
• Such an additive increases the mobility of the particles of the solution, which facilitates the process of the formation of products of the required shape from a given mass;
• It does not change the structure of the cement mass.

Council Calcium chloride is recommended to be used together with sodium chloride.

The availability of this type of antifreeze additive and its low price are often the reason why most builders resort to the use of completely different, more expensive means.

In addition to the many advantages of such an additive, it also has one major drawback, which often causes its inability to apply it to concrete. The fact is that salt has a high level of corrosivity.

And this suggests that the use of reinforcement from metal simultaneously with the cement mixture with the addition of sodium chloride will lead to a rusting process and peeling of this structure from concrete.

Thus, the reinforced concrete structure loses its integrity, which qualitatively reduces the level of strength of the entire product.

The process of adding salt to the solution

The instruction specifying the proportions of salt in a concrete solution is based on the average daily temperature and the expected strength:

1. The average daily air temperature from 0 to -5 degrees implies the addition of CN in the amount of 2% of the total mass of the mixture. The expected strength of the structure during drying in the cold for 7 days will be 30%, 28 days - 80% and 90 days - 100%;
2. The average daily air temperature from -6 to -15 degrees suggests adding HN in the amount of 4% of the total mass of the mixture. The expected strength of the structure after drying in the cold for 7 days will be 15%, 28 days - 35% and 90 days - 50%.

Council The proportions of salt in concrete suggest the addition of calcium chloride in the first case at a rate of 0.5% by weight of the solution, and in the second 2%.

Finally

Concrete in winter with salt is a great opportunity to preserve all the basic parameters and characteristics of a monolithic structure, even if it is cast during the cold season. Additive in the form of salt is a cheap and affordable opportunity for everyone to continue construction and repair work, even if they are conducted in conditions of sub-zero temperatures.

And the video in this article will allow you to learn even more useful information on how to save water in solution in a liquid state with the help of salt.