Why is it essential to use calibrated equipment for measuring air content in concrete?

It is essential to use calibrated equipment for measuring air content in concrete because the air content is a critical parameter that significantly affects the concrete's durability, particularly its resistance to freeze-thaw damage, and also influences its strength and workability. Air entrainment, the intentional incorporation of microscopic air bubbles into the concrete mix, is a common practice in cold climates to improve freeze-thaw resistance. The amount of air entrained must be within a specified range to....