Increasing the amount of sand in concrete usually decreases the amount of water needed to make the concrete workable.

Increasing the amount of sand in concrete usually decreases the amount of water needed to make the concrete workable.

• A. True
• B. False
• C. Depends on cement content
• D. Not enough information

Answer: (B)

Increasing the amount of sand raises the surface area of the solid particles and the internal friction within the mix. That means the cement paste has to wet and lubricate more surface to achieve the same flow, so you typically need more water (or a water-reducing admixture) to get the same workability. Therefore, the statement is false: more sand usually increases water demand, not decreases it. The role of cement content can affect overall water needs, but the general trend remains that fines like sand increase the water required to reach the same workable consistency.

Increasing the amount of sand raises the surface area of the solid particles and the internal friction within the mix. That means the cement paste has to wet and lubricate more surface to achieve the same flow, so you typically need more water (or a water-reducing admixture) to get the same workability. Therefore, the statement is false: more sand usually increases water demand, not decreases it. The role of cement content can affect overall water needs, but the general trend remains that fines like sand increase the water required to reach the same workable consistency.