What happens to the amount of entrained air as the temperature of the concrete mix rises?

As the temperature of the concrete mix rises, the amount of entrained air decreases. This phenomenon is primarily due to the behavior of air bubbles within the concrete. Warmer temperatures can lead to increased fluidity in the concrete mix, which facilitates the coalescence of air bubbles. As these bubbles merge, the overall volume of entrained air diminishes.

Moreover, higher temperatures can accelerate the evaporation of water from the concrete mix, potentially affecting its viscosity and workability, further contributing to the reduction in air content. Effective air-entrainment is crucial for the durability of concrete, particularly in freeze-thaw cycles. Understanding the relationship between temperature and air content is vital for ensuring the concrete meets the necessary performance specifications.