What factor is critical for determining the compaction of soil during construction?

The moisture content of the soil plays a vital role in achieving proper compaction during construction. When soil is compacted, the goal is to remove air voids and increase density to enhance the soil's load-bearing capacity. The moisture content influences the cohesiveness and workability of the soil.

If the soil is too dry, it becomes difficult for particles to stick together, leading to ineffective compaction. On the other hand, if the soil is too wet, the excess water can create a lubricated state that allows the particles to move around rather than compact effectively, leading to instability. Therefore, achieving the optimum moisture content is essential to maximizing the compaction effort and ensuring the soil reaches its intended density.

The type of machinery used can affect compaction methods but is secondary to the proper moisture level. The age of the soil refers more to its weathering and development over time, which does not directly influence compaction during construction. Lastly, while temperature can impact the moisture in the soil, it is not a direct factor in the compaction process itself, making moisture content the most critical factor in determining soil compaction.