Which additive is used to improve pumpability of concrete?

Which additive is used to improve pumpability of concrete?

• A. Hydrated lime
• B. Portland cement
• C. Sand
• D. Water-reducing admixture

Answer: (A)

The correct additive used to improve the pumpability of concrete is a water-reducing admixture. This type of admixture is specifically designed to reduce the amount of water needed in the concrete mix while maintaining its workability. By decreasing water content, these admixtures enhance the flowability and pumpability of the concrete, allowing it to be easily transported through pumps and placed into forms without segregation or separation of the components. On the other hand, while hydrated lime, Portland cement, and sand are important components of concrete, they do not serve the same purpose in terms of improving pumpability. Hydrated lime is typically used to enhance workability or as a pozzolanic material, Portland cement is the primary binder in concrete, and sand provides bulk and aggregates but does not specifically enhance the fluidity or pumpability needed in many construction scenarios. Therefore, the use of a water-reducing admixture is the most effective way to achieve better pumpability in concrete.

The correct additive used to improve the pumpability of concrete is a water-reducing admixture. This type of admixture is specifically designed to reduce the amount of water needed in the concrete mix while maintaining its workability. By decreasing water content, these admixtures enhance the flowability and pumpability of the concrete, allowing it to be easily transported through pumps and placed into forms without segregation or separation of the components.

On the other hand, while hydrated lime, Portland cement, and sand are important components of concrete, they do not serve the same purpose in terms of improving pumpability. Hydrated lime is typically used to enhance workability or as a pozzolanic material, Portland cement is the primary binder in concrete, and sand provides bulk and aggregates but does not specifically enhance the fluidity or pumpability needed in many construction scenarios. Therefore, the use of a water-reducing admixture is the most effective way to achieve better pumpability in concrete.