The mix proportion, production and curing, of concrete placed in cold weather such as the average ambient temperature under 4°C and the 4weeks accumulative temperature below M. 370 D.D. (3.2°C), are specified in the code of JSCE and AIJ, respectively. Especially the temperature and duration of the initial curing, in order to prevent the early damage due to frosting, is carefully specified in these codes.
1)2)Consequently the thermal insulation to keep concrete warm and (or) the heated curing during the cold weather concreting are the customary practice although the expense for such special treatments become a considerable level in the total cost.
This report describes the results of performance tests on ANF-28, a special AE water reducing agent which is newly developed by Nisso Master Builders. ANF-28 concrete can resist to early freezing without heated curing down to -10°C and gives satisfactory strength without any deterioration of performance of concrete. Furthermore, this report includes two field test results at cold weather sites (forecasting temperatures, 5 to -10°C and 0 to -20°C).
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