What effect does compaction have on soil density?

What effect does compaction have on soil density?

• A. Removes water from the voids
• B. Removes air from the voids
• C. Removes both air and water from the voids
• D. Reduces the movement of rollers over the soil subgrade

Answer: (B)

Compaction plays a crucial role in increasing soil density primarily by decreasing the volume of voids within the soil mass, which is achieved through the removal of air from those voids. When soil is compacted, the particles are forced closer together, displacing the air that occupies the spaces between them. This reduction in air voids leads to a denser soil structure. In contrast, while compaction can influence moisture content, it does not explicitly remove water from the voids in the same way it removes air. It is common for water to remain within the soil matrix after compaction, especially if the soil was compacted at optimal moisture content. Regarding the other options, they include inaccuracies or misunderstandings of the compaction process. For instance, saying that compaction removes both air and water overlooks the fact that air is primarily displaced while water can remain. Moreover, the impact of rollers on the soil subgrade is part of the compaction process but does not directly relate to the question about soil density itself. Therefore, the focus on air removal as the primary method for increasing soil density is the key reason for its significance.

Compaction plays a crucial role in increasing soil density primarily by decreasing the volume of voids within the soil mass, which is achieved through the removal of air from those voids. When soil is compacted, the particles are forced closer together, displacing the air that occupies the spaces between them. This reduction in air voids leads to a denser soil structure.

In contrast, while compaction can influence moisture content, it does not explicitly remove water from the voids in the same way it removes air. It is common for water to remain within the soil matrix after compaction, especially if the soil was compacted at optimal moisture content.

Regarding the other options, they include inaccuracies or misunderstandings of the compaction process. For instance, saying that compaction removes both air and water overlooks the fact that air is primarily displaced while water can remain. Moreover, the impact of rollers on the soil subgrade is part of the compaction process but does not directly relate to the question about soil density itself. Therefore, the focus on air removal as the primary method for increasing soil density is the key reason for its significance.