ADVANCEMENTS IN COLD WEATHER CONCRETING PROMISE TO EXTEND CONSTRUCTION SEASON

Procedures for cold weather concreting are well established and readily available for those needing to place concrete during the winter. One source for this information on cold weather concreting is the American Concrete Institute Report, ACI 306R. Concrete placed within their guidelines at low temperatures will become strong and durable, and therefore serviceable. However, the minimum requirement is that the concrete mix be heated so that it contains no ice and does not freeze in the transfer between mixing and placing. If concrete freezes, it is believed, the overall volume of the mix will be increased, resulting in porous and weak concrete. And this requirement creates one of the primary disadvantages of winter concreting: the cost of heating. Since fall 1992, the CRREL in Hanover, NH, in a joint venture with private industry, has been experimenting with special compounds that, when added to concrete mix, are capable of protecting concrete while it is curing without requiring heat.