What is the expected percentage of entrained air in concrete mixes?

The expected percentage of entrained air in concrete mixes, particularly for many applications aimed at improving durability, generally falls within the range of 5% to 8%. This level of air content is beneficial for enhancing the concrete's resistance to freeze-thaw cycles, reducing the permeability which helps in preventing water-related damage, and improving workability.

Entrained air serves to create tiny air pockets within the concrete, which act as stress relievers during freeze-thaw cycles. The air helps the concrete withstand the expansion and contraction that occurs with temperature changes, ultimately leading to increased longevity and durability of the structure.

While other options suggest varying levels of air content, ranges such as 1% to 3% may be adequate for specific structural applications where freeze-thaw exposure is less of a concern, and a lower air content might be preferred for strength reasons. High-performance scenarios typically don’t require such high entrained air percentages of 10% to 15%, which are generally excessive and might undermine the overall strength and performance. Meanwhile, having 0% entrained air might seem appealing for optimal strength and density, but could lead to significant risks of cracking and deterioration in environments subject to freezing and thawing. Thus, the 5% to