Soils described as a ML would have which of the following characteristics?

• A. Quick dilatancy
• B. Low plasticity
• C. Grain size smaller than a #40 sieve
• D. All of the above

Answer: (D)

In the Unified Soil Classification System, ML denotes a silty soil with low plasticity. Silts are fine-grained, so their particles are smaller than the #40 sieve (0.425 mm) and indeed pass through that sieve. The "L" tag means low plasticity, so these soils show little plastic deformation and have low plasticity index under typical moisture conditions. Quick dilatancy describes a tendency to increase in volume when sheared, which can occur in dense, fine-grained soils like low-plasticity silts as the particles rearrange. Because ML soils combine fine grain size, low plasticity, and the potential for dilation under shear, all three characteristics describe this classification.