To shield concrete from harm all through freezing, bubbles will need to have the correct dimensions, distribution and volume. ASTM C 260 specifies prerequisites for air entraining admixtures. Silica fume enhances concrete in two methods The essential pozzolanic reaction, and also a microfiller impact. Addition of silica fume increases bonding https://www.tjcyindustrialchem.com/news/cement-additives-and-concrete-admixtures-key-differences.html