What happens when soil is too dry during the compaction process?

When soil is too dry during the compaction process, the primary issue arises from increased friction within the particles of the soil. Without adequate moisture, soil particles do not have the necessary lubrication to slide past one another effectively. Instead, they tend to create more resistance due to friction, resulting in decreased compaction efficiency. This ultimately prevents the soil from reaching optimal density and strength.

When moisture is added to soil, it helps fill the voids between particles, allowing them to reorient and compact more effectively. In contrast, when the soil is overly dry, the lack of this moisture inhibits the compaction process, making it more difficult to achieve desired levels of density. Thus, the correct understanding of the compaction process highlights that when soil is too dry, the efficiency is significantly reduced primarily due to the friction between soil particles rather than an outright inability to compact.