Characteristic analysis of concrete air entraining agents in different media

The effects of six concrete air-entraining agents (AEAs) in different media, including saturated calcium hydroxide solution, cement paste, mortar, fresh concrete, and hardened concrete (subjected to different vibration treatments), were compared. The results show that the lower the AEA concentration is at the surface tension inflection point of a saturated calcium hydroxide solution, the less AEA is needed to obtain the same air content in the concrete. Similarly, AEAs with better air-entraining performance lead to a higher initial cement paste foam height and a lower mortar density. The differences between the air content of fresh concrete and hardened concrete are large; high-frequency vibration can significantly optimize the bubble space of low-slump concrete.