What is a benefit of entrained air in concrete?

Entrained air in concrete significantly improves its resistance to freezing and thawing. When air is intentionally introduced into the concrete mix, tiny air bubbles are created within the concrete matrix. These bubbles provide space for water to expand when it freezes, which helps to alleviate the internal pressure that could otherwise lead to cracking or damage.

This is particularly important in climates where freezing and thawing cycles are common. Without the presence of entrained air, water trapped within the concrete can freeze, expand, and create changes in volume that compromise the integrity of the structure. Therefore, the inclusion of entrained air is a crucial factor in enhancing the durability and longevity of concrete in environments subject to severe temperature fluctuations.

In contrast, increased water demand, decreased workability, and higher density do not pertain to the benefits of entrained air, making them less relevant to the question at hand.