FREEZING AND THAWING DURABILITY OF EARLY-AGE CONCRETE

Freeze-thaw resistance of concrete with sufficient entrained air was tested at the ages of about 12hrs to 14 days by a conventional rapid freezing and thawing test. The effect of continued cement hydration during the test was eliminated from the test results by applying a data-analyzing technique which had been proposed by the authors. It was shown that the freeze-thaw durability of early-age concrete was dependent on its strength and degree of saturation, and that a minimum compressive strength of 24N/mm2 was required for a water-saturated concrete to possess a sufficient freeze-thaw durability. Also shown was that a curing method similar to sealed curing was preferable in cold weather concreting rather than a moist curing as recommended in Japanese specifications.