Antifreeze is an admixture that can harden concrete at negative temperatures and achieve expected performance under specified curing conditions. In northern my country, in order to prevent early freezing of concrete, antifreeze is often added during winter construction (when the daily average temperature is below 5°C). Antifreeze can lower the freezing point of water, enable cement to continue to hydrate at negative temperatures, improve the early strength of concrete, resist the expansion pressure caused by water freezing, and play an antifreeze role. Commonly used antifreezes include glycerol, diethylene glycol, dimethyl sulfoxide, calcium chloride, sodium chloride, ammonium chloride, potassium carbonate, ethylene glycol, calcium formate, calcium acetate, sodium nitrite, and nitrous acid. Calcium, calcium nitrate, etc.
. Applicable scope and dosage of antifreeze
Suitable sodium nitrite and calcium nitrite The dosage is 0.3% to 1.0%, which has the functions of lowering freezing point, preventing rust and early strength. The appropriate dosage of calcium chloride and sodium chloride is 0.5% to 1.0%, which has the effect of early strength and lowering the freezing point, but has a rusting effect on steel bars. Antifreezes of glycerol, diethylene glycol and dimethyl sulfoxide can be used in various concrete projects. Antifreezes containing nitrites and carbonates are strictly prohibited for prestressed concrete projects. Ammonium salts and urea are strictly prohibited for use in prestressed concrete projects. Office, residential and other indoor construction projects.
In order to improve the antifreeze effect of antifreeze, antifreeze is often combined with water reducing agent, early strength agent and air entrainment It is compounded with agents to give it better antifreeze properties.
微信扫一扫打赏
