To protect concrete from harm during freezing, bubbles have to have the right dimensions, distribution and quantity. ASTM C 260 specifies needs for air entraining admixtures. Air Entraining Agents: Introduce air bubbles to the concrete, enhancing freeze-thaw resistance and lowering the potential risk of scaling and cracking. Log in to https://www.tjcyindustrialchem.com/news/cement-additives-and-concrete-admixtures-key-differences.html