For the cold weather conditions that normally prevail in the United Sates the following procedures are recommended for winter concreting to obtain maximum success and economy: (1) know the conditions to be expected and plan for them accordingly. (2) Use a mix containing entrained air and possibly 1 to 2 percent of a calcium chloride accelerator. (3) Ask the ready mix producer to heat the mixing water, and possibly the fine and coarse aggregate, to get a final mix temperature of from 50 to 70 degrees F. according to the size and shape of the concrete member and the prevailing ambient temperature. (4) Place the mix quickly on a subgrade that is not frozen and against forms, reinforcement and fixtures that are preheated and free from ice and snow. (5) Keep the forms in place for 4 days and insulate them to retain the concrete's own heat. Pay particular attention to vulnerable corners and edges. (Alternatively, if the overall site operations justify it, erect a safe enclosure to be heated, preferably with live steam; otherwise carry out normal moist curing). (6) Remove protection gradually to avoid thermal shock. Remove forms and false work as strength development allows for the expected loading.