Estimating Practice Exam

What happens to backfill material when it is compacted?

1. It becomes less dense

2. It remains the same density

3. It becomes more dense

4. It expands in volume

The correct answer is: It becomes more dense

When backfill material is compacted, it becomes more dense. This process occurs because compaction involves applying mechanical force to reduce the voids or air spaces between the particles of the material. As the material is compacted, the particles are forced closer together, which increases the overall density of the backfill. This increase in density is crucial in construction and engineering, as a denser backfill provides greater support and stability for structures built above it. The compaction process also enhances the load-bearing capacity of the material, reducing the likelihood of settling or shifting over time, which can compromise the integrity of the construction. Hence, compacted backfill serves a vital role in ensuring the longevity and safety of various structures.