How does concrete admixture sodium nitrite work?

It is mainly used in the process of mixing cement and concrete materials, which can reduce the effect of freezing damage at low temperature. To a certain extent, it also has the effect of rust prevention and partial coagulation promotion. When using sodium nitrite as antifreeze, we must pay attention to the use of problems, most of which are used at around zero temperature.

As a concrete admixture, sodium nitrite can play three roles:
1) As an early strength agent, improve the early strength of concrete;
2) As rust inhibitor, prevent steel corrosion;
3) As an antifreeze, prevent construction concrete from freezing damage in winter.

Under the premise that the additive content is 2.0% of the adhesive material, the total amount of antifreeze will increase by 1% for every one degree Celsius decrease in temperature. The temperature given in the figure is the lowest temperature of the day. The dosage in the column of 2.0% admixture can ensure that the admixture itself does not freeze.

The main principle that can ensure that the water reducer does not freeze is that the salt can reduce the freezing point of water. The chemical sense of salt is a broad term, the formation of strong acids and bases of compounds can be called salts. Sodium chloride is the food salt we call it salt, sodium nitrate, calcium nitrate, sodium nitrite are also chemical salts. Icing is a purely physical phenomenon, and also related to the volume of storage, the admixture in the large jar can maintain a liquid state as long as the average temperature of the day is not lower than the freezing point of freezing.