Why must the mass of moisture in a soil sample be determined accurately?

The mass of moisture in a soil sample must be determined accurately primarily to ensure proper compaction. Moisture plays a critical role in the compaction process, as it affects the soil's density and stability. When soil is compacted, the right moisture content allows for optimal particle interaction and bonding, resulting in a denser and more stable base. If the moisture content is too low, the soil may not compact effectively, leading to potential voids and weak spots. Conversely, if it is too high, it can lead to a condition known as "over-saturation," which can also hinder effective compaction and create issues such as soil displacement or instability. Therefore, knowing the exact moisture content is essential for achieving the desired compaction results and ensuring the integrity of the base.