Why is it important to ensure that the sand used in construction is free of salts?

Explanation:

Ensuring that the sand used in construction is free of salts is essential because salts can cause efflorescence. Efflorescence is the formation of a white, powdery substance on the surface of concrete, brick, or stone, resulting from water-soluble salts rising to the surface and then evaporating. This can lead to unsightly staining and deterioration of the material over time.

Analyzing the Given Options

1. "Salts enhance the curing time of concrete." (Incorrect)

   • Salts do not enhance the curing time of concrete; instead, they can interfere with the hydration process and the overall integrity of the concrete.

2. "Salts can attract wildlife to the construction site." (Incorrect)

   • There is no direct relationship between the presence of salts in construction sand and the attraction of wildlife to the construction site.

3. "Salts can cause efflorescence, leading to staining." (Correct)

   • Efflorescence occurs when water-soluble salts migrate to the surface of the material and evaporate, leaving behind a white, powdery residue that can stain and deteriorate the construction material.

4. "Salts can change the color of the final construction material." (Incorrect)

   • While salts can cause efflorescence, the primary concern is staining rather than changing the inherent color of the construction material.