Air entrainment is particularly effective in providing resistance to freeze-thaw cycles. When the moisture in concrete freezes, these air cells relieve internal pressure by providing microscopic chambers for the expansion of water as it freezes. Some air entraining mixtures contain a catalyst for more rapid and complete hydration of Portland cement. To protect concrete from damage during freezing, bubbles must have the proper size, distribution and volume. ASTM C 260 specifies requirements for air entraining admixtures and you should be sure to mention how the concrete will be used when ordering your mix design.



