Concrete Answers for the Cold Weather Quandary

The placement of concrete in cold weather is made possible by new practices and materials. A publication, American Concrete Institute (ACI) 306, Cold Weather Concreting, is a widely accepted source for project specifications. It describes when concrete can resist freezing in terms of its compressive strength. To speed up its achievement of compressive strength, accelerating admixtures are used more often, now that their costs are not as high. ACI 306 defines the weather conditions under which cold weather practices should be adhered to. Steps to maintain the temperature at which the hydration process by which Portland cement hardens are described. Various accelerant mixtures are discussed. In addition, planning techniques for coordinating cold weather concrete placement are described.