How To Make Concrete That Will Be Immune To The Effects Of Freezing And Thawing

This paper describes how concrete will be immune to the effects of freezing and thawing if: (1) it is not in an environment where freezing and thawing take place so as to cause freezable water in the concrete to freeze; (2) when freezing takes place there are no pores in the concrete large enough to hold freezable water (i.e., no capillary cavities); (3) during freezing of freezable water, the pores containing freezable water are never more than 91 percent filled, i.e., not critically saturated; and (4) during freezing of freezable water the pores containing freezable water are more than 91 percent full, the paste has an air-void system with an air bubble located not more than 0.2 mm (0.008 in.) form anywhere (L less than or equal to 0.2mm), sound aggregate, and moderate maturity. Sound aggregate is aggregate that does not contain significant amounts of accessible capillary pore space that is likely to be critically saturated when freezing occurs. The way to establish that such is the case, is to subject properly air-entrained, properly mature concrete, made with the aggregate in question, to an appropriate laboratory freezing-and-thawing test such as the ASTM C 666 Procedure A. Moderate maturity means that the originally mixing water-filled space has been reduced by cement hydration so that the remaining capillary porosity that can hold freezable water is a small enough fractional volume of the paste so that the expansion of the water on freezing can be accommodated by the air-void system. Such maturity was shown by Klieger in 1956 to have been attained when compressive strength reaches about 4,000 psi.