What does a soil compaction test measure?

A soil compaction test measures the degree to which soil particles are packed together, commonly referred to as the soil's density. This metric is crucial in determining how well a soil can support structures, as denser soil typically has greater strength and stability. The compaction process involves applying a specific amount of energy to the soil, allowing particles to rearrange and reduce air voids, thus increasing density.

Understanding soil density is essential for various applications in construction and civil engineering, particularly in ensuring that the ground has adequate support for foundations and other structures. A higher degree of compaction usually correlates with improved load-bearing capacity, enabling the engineered structure to withstand environmental stresses and weight.

In contrast, options focusing on moisture content, force needed for compaction, or the type of soil do not directly assess how compacted the soil particles are. While these factors can influence compaction, they are not the primary focus of a soil compaction test itself. This distinction helps clarify why measuring the degree of packing of soil particles is fundamental in assessing soil suitability for construction projects.