What is considered a major disadvantage of manufactured sand?

The consideration of manufactured sand highlights concerns about the uniformity and consistency of the grading of the aggregates used in construction materials. The correct choice emphasizes that one major disadvantage of manufactured sand is its potential to lead to either over-sanded or under-sanded aggregates. This inconsistency arises from the production process, which can affect the particle size distribution.

When the sand is over-sanded, it consists of particles that are predominantly fine, thereby failing to provide the necessary strength and stability when mixed with other materials such as cement. On the other hand, when the sand is under-sanded, it contains larger aggregates which can cause issues with compaction and workability in concrete mixes. The resulting impact can compromise the structural integrity of concrete, making it difficult to achieve desired performance standards within construction projects.

Conversely, the other options do not accurately reflect the major disadvantages associated with manufactured sand. For instance, while manufactured sand can occasionally be more expensive than natural sand, it is not always the case that this is true. Additionally, manufactured sand is often designed to meet specific grading requirements, thus it can be suitable for concrete rather than inherently too coarse. Lastly, the setting time of concrete can vary based on mix design and curing conditions, making the claim about slow