(1)
When the air temperature is below 5 ° C, concrete shall be
(a)
kept at a temperature of not less than 10 ° C or more than 25 ° C while being mixed and placed, and
(b)
maintained at a temperature of not less than 10 ° C for 72 h after placing.
(2)
No frozen material or ice shall be used in concrete described in Sentence (1).