When the daily average outdoor temperature is below 5 ℃ for 5 consecutive days, or the daily minimum temperature is below 0 ℃, it enters the category of “winter construction”.
At this time, concrete is most prone to “early freezing damage”: the volume of water freezing expands by about 9%, forming microcracks inside.
Even if it is later subjected to normal temperature curing, its strength can never be restored to its unfrozen level.
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