Ji: it's getting colder and colder! When people wear more clothes to keep out the cold, they always drink to keep out the cold. It's better to "drink" some "wine" when mixing concrete.

Tong: antifreeze is used for concrete antifreeze, not drinking.

Ji: drinking is an analogy. In fact, alcohol is added as the main antifreeze component.

Tong: so is it "Kouzijiao" or "Erguotou"?

Ji: neither. It mainly uses methanol, also known as Xylin.

Tong: Oh, isn't that the raw material of fake wine?

Ji: it's a fake wine for human beings, but it's a good antifreeze wine for concrete. At the same time, you have to add some other wine than the concrete is happy to drink!

Tong: two liang or half a catty for a meal?

Ji: that's what people drink. You have to use the word "ton" for concrete to drink. Drinking 250 grams (half a catty) of a ton of concrete can withstand the severe cold of minus 17 or 18 degrees, which is less than that of people!

Tong: that's interesting. How can you drink less than people?

Ji: you calculate, 65 kg people drink half a kilogram of spirits, 1KG weight of 3.8 grams, 1 tons of concrete drink 250 grams of wine, on average 0.25 grams per kilogram. However, wood essence alone is not antifreeze. It also needs to be supplemented with water reducing, air entraining and early strength ingredients. There are at least four or five kinds of seasonings. A few years ago, it was not known that concrete could also drink to keep out the cold. At that time, industrial salt was used.

Tong: is it coarse salt?

Ji: coarse salt is used to make antifreeze, but it is easy to rust the reinforcement. The "industrial salt" I mentioned is a popular name for sodium nitrite. It also has salty and delicious taste. It will make human red blood cells lose their oxygen carrying capacity, and it also has carcinogenic effect. People can't eat. "Industrial salt" is also not allowed in the concrete used as a water source pool. The effect of using sodium nitrite in a structure that has no connection with human consumption is actually very good. Antifreeze can reach minus 20 degrees, which can make the concrete workable and increase the strength rapidly after pouring. Even though the concrete surface is frozen, the internal strength is still growing slowly.

Tong: I have a project in the water source plant. What salt should I use in winter?

Ji: I recommend you to use urea. Although the frost resistance is only minus 5 or 6 degrees. But it has no toxicity to humans and animals. The use of ammonia containing antifreeze is not allowed in the national standard, which is limited to buildings with indoor use function.

What I want to solemnly declare is: "do not mix urea and sodium nitrite!" crude salt is sodium chloride. After crushing, adding anti rust components such as calcium nitrite (best) or sodium nitrite (second best) can also be used as antifreeze. The ratio is at least 1:1. More anti rust agents are safe. In addition, eating a bowl of authentic "Lanzhou hand-pulled noodles" can also be used for concrete -- exactly an additive for kneading -- skin ash. The local plant ash is rich in potassium carbonate and is a good antifreeze. Sodium sulphate alone can't prevent freezing. It doesn't have antifreeze effect, which has been proved by engineering accidents in Beijing.

In addition, if the superplasticizer is added to the saturation point and a sufficient amount of air entraining agent is added, as long as the total amount accounts for about 1% of the cementitious material in the concrete, it also has excellent antifreeze effect. However, the test block frozen out in the refrigerator at minus 15 degrees has no strength. The concrete seems to be hibernating and can be restored only after being placed at room temperature for a few days. This antifreeze is not easy to use in cold Inner Mongolia, Heilongjiang and Qinghai. The maximum content of inorganic salt in antifreeze is limited, which should comply with the national standard technical code for application of concrete admixtures (GB 50119). The content of organic matter has not been clearly specified. It will be when I talk to you again in 10 years.