What is a disadvantage of using rounded aggregates for compaction?

Using rounded aggregates for compaction does present a disadvantage in terms of stability. Rounded aggregates tend to have lower interlocking ability compared to angular aggregates. This is due to their shape; rounded aggregates do not fit together as tightly, which means they can shift more easily under load. Consequently, this lack of interlocking can lead to decreased shear strength and stability in the compacted material, ultimately affecting the overall performance of the base layer. Stability is crucial in construction, particularly in road and pavement applications, where the structural integrity of the base directly impacts the durability of the overlying materials.

In comparison, angular aggregates generally provide more interlocking features, enhancing their ability to form a stable matrix when compacted. The other options relate to traits not typically associated with rounded aggregates, such as needing more water for compaction or difficulties in sourcing, which are not inherent disadvantages when considering the compaction characteristics.