Which statement about the effect of slump on curling is correct?

Which statement about the effect of slump on curling is correct?

• A. Increasing water to reach higher slump will increase curling
• B. Increasing water decreases curling
• C. Slump has no effect on curling
• D. Slump is only influenced by cement content

Answer: (A)

Curling in slabs is driven by moisture and temperature differences that cause restrained shrinkage. When you increase water to reach a higher slump, the mix becomes more workable but less stiff, reducing the amount of cement paste per unit volume. This lower stiffness and paste content let the slab move more as it cures and dries. The surface dries and shrinks faster than the interior, so the softer, more fluid mix curls more readily. In short, higher slump (more water) tends to increase curling because the slab is more prone to movement under the same gradients. The idea that slump has no effect or that it’s governed only by cement content isn’t accurate, since water content and resulting workability directly influence shrinkage and movement.

Curling in slabs is driven by moisture and temperature differences that cause restrained shrinkage. When you increase water to reach a higher slump, the mix becomes more workable but less stiff, reducing the amount of cement paste per unit volume. This lower stiffness and paste content let the slab move more as it cures and dries. The surface dries and shrinks faster than the interior, so the softer, more fluid mix curls more readily. In short, higher slump (more water) tends to increase curling because the slab is more prone to movement under the same gradients. The idea that slump has no effect or that it’s governed only by cement content isn’t accurate, since water content and resulting workability directly influence shrinkage and movement.