North Carolina Building Contractor License Practice Exam

Which of the following practices improves the long-term durability of concrete exposed to harsh weather conditions?

1. Curing with heat

2. Using high-water content

3. Using air-entrained concrete

4. Reducing the aggregate size

The correct answer is: Using air-entrained concrete

Using air-entrained concrete is a recommended practice for enhancing the long-term durability of concrete that will be exposed to harsh weather conditions. Air-entrained concrete contains microscopic air bubbles that are intentionally introduced during the mixing process. These tiny pockets of air act as shock absorbers when the concrete freezes and thaws, allowing for expansion and contraction without cracking. This is particularly important in climates with significant freeze-thaw cycles, as the presence of these air bubbles reduces the risk of damage from ice formation within the concrete. The ability of air-entrained concrete to withstand the stresses of freeze-thaw cycles directly contributes to its long-term performance and integrity, making it a crucial choice for outdoor structures, pavements, and other applications subjected to severe weather. This practice is well-documented and endorsed by guidelines in concrete construction, particularly in regions where environmental conditions can be extreme.