Antifreeze has three characteristics according to its mode of action:
One type is that after being mixed with water, it has a very low co-dissolution temperature and can lower the freezing point of water so that the concrete can Hydration is still occurring at negative temperatures. Such as sodium chloride. However, once the concrete freezes due to insufficient dosage or excessive temperature, it will still cause frost damage and reduce the final strength of the concrete.
The other type can not only lower the freezing point of water, but also seriously deform the lattice structure of ice containing such substances, so it cannot form ice expansion stress to destroy the hydrated mineral structure and reduce the strength of concrete. Damaged, such as urea,. When the dosage is insufficient, the strength of concrete stops growing at negative temperatures, but it has no effect on the final strength after turning to positive temperatures.
The third category is that although its aqueous solution has a very low co-dissolution temperature, it cannot significantly reduce the freezing point of water in concrete. Its function is to directly react with cement to accelerate the setting and hardening of concrete. Hardening is conducive to the development of concrete strength, such as calcium chloride
It should be noted here that antifreeze and antifreeze components are not the same concept. Antifreeze is a type of admixture, which consists of water-reducing components, antifreeze components, air-entraining components, and sometimes early-strength components. Its function is to not only harden the concrete at negative temperatures, but also enable it to eventually reach the quality level of concrete cured at normal temperature. The antifreeze component refers to a chemical substance that protects the concrete mixture from freezing damage in negative temperature environments.
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