Which type of material compacts with minimal effort?

Well-graded granular materials are known for their ability to compact effectively with minimal effort due to their particle size distribution. These materials consist of a mixture of coarse and fine particles that fit together well, filling the voids and creating a dense structure. This efficient packing allows for easier compaction with lower energy input, meaning that when compaction methods such as rolling or tamping are applied, they require less effort and result in a higher density.

In contrast, clay soils can be challenging to compact because their fine particles tend to clump together when wet, and they require significant energy to achieve the same level of compaction. Pulverized soil often consists of very fine particles that do not interlock effectively, which can lead to difficulties in achieving a dense and stable structure without additional effort. Loose sand, while it can be compacted, typically requires additional means (like vibration) to achieve good compaction, especially if it’s dry and lacks cohesion.