What property of soil is primarily influenced by its moisture content during compaction?

The property of soil that is primarily influenced by its moisture content during compaction is density. When soil is compacted, the moisture content plays a critical role in achieving optimal density.

At low moisture levels, soil particles may not be adequately lubricated, leading to less efficient packing and lower density. Conversely, as moisture content increases, it helps to reduce friction between soil particles, allowing them to slide past one another more easily and compact more effectively.

Optimal moisture content leads to the highest possible density because it allows for the maximum arrangement of soil particles while minimizing voids. This relationship between moisture content and density is crucial in various engineering applications, including foundation support and road construction, where specific density requirements must be met to ensure stability and performance.

While plasticity, permeability, and shear strength are also influenced by moisture content, they are affected in different ways that do not relate as directly to the compaction process as density does. Therefore, focusing on the connection between moisture content and density provides a better understanding of the fundamental principles of soil compaction.