What is the Accelerating admixture used for?

What is the Accelerating admixture used for?

• A. A type of admixture added to speed up the setting time and increase early strength, often used in cold weather conditions.
• B. An admixture that creates microscopic air bubbles for freeze–thaw resistance.
• C. An admixture that slows the setting time for extended workability.
• D. An admixture that reduces the need for cement.

Answer: (A)

Accelerating admixtures are used to speed up the cement–water hydration, so the concrete sets faster and gains early strength. This is especially important in cold weather, where hydration slows and early strength may be insufficient for formwork removal or early loading. By boosting the rate of setting and early strength development, these admixtures keep construction moving in lower temperatures. The other descriptions refer to different types of admixtures — one creates tiny air voids for freeze–thaw durability, another slows setting to extend workability, and another reduces cement demand — none of which describe the purpose of accelerating admixtures.

Accelerating admixtures are used to speed up the cement–water hydration, so the concrete sets faster and gains early strength. This is especially important in cold weather, where hydration slows and early strength may be insufficient for formwork removal or early loading. By boosting the rate of setting and early strength development, these admixtures keep construction moving in lower temperatures. The other descriptions refer to different types of admixtures — one creates tiny air voids for freeze–thaw durability, another slows setting to extend workability, and another reduces cement demand — none of which describe the purpose of accelerating admixtures.