Protection duration for high strength concrete at freezing conditions.

摘要

A study was conducted to determine if the protection durations specified by The American Concrete Institute in “Cold Weather Concreting” (ACI 306) are adequate for high strength concretes. Results are presented for 21 mix designs of high strength concretes industry would potentially use. This study looked at how one hard freeze-thaw cycle at different early stages of curing for high strength would affect the final compressive strength. Each mix design had a set of specimens that were frozen at 1, 2, 3, 4, 5, 7, and 14 days. Four common types of high strength mix designs were tested, including silica fume, fly ash, water reduced, and high cement content mixes. Compressive strengths at each freezing time were recorded and compared to a control and the other freezing times.; Based on the results of this study, the following conclusion can be made. After 24 hours of protection from freezing, none of the mix designs in this study were affected by one freeze-thaw cycle. It was noted that for the concretes in this study the protection times specified in ACI 306 were longer than necessary for these mix designs.