Air entraining admixtures improve workability and have what effect on water requirements?

• A. Increasing water demand
• B. Reducing workability
• C. Improving workability and reducing water requirements
• D. Strengthening cement instantly

Answer: (C)

Air entraining admixtures introduce tiny, stable air bubbles in the concrete, which act like lubricants in the paste. This reduces internal friction between cement, water, and aggregates, so the mix flows more easily and is more workable. Because the mix becomes more flowable, you can achieve the same target workability with less water, or you can maintain the same workability with a lower water content. That’s why the best description is improving workability while reducing water requirements. It’s important to use the right amount, though, since too much air can lower strength and density.