Typical behavior of silt (non-plastic fines): choose the characteristic response Which statement correctly reflects the behavior of silt particles under common field conditions?

Introduction / Context:
Field identification of fine soils often relies on simple tactile tests. Silts and clays behave differently in terms of plasticity, dilatancy, and dry strength—differences that help classify soils during reconnaissance and quality control.

Given Data / Assumptions:

• Silt is a low-plasticity fine soil (grain size finer than sand but coarser than clay).
• “Dilatancy” refers to a quick, glossy surface and water sheen that appears when a moist silt pat is shaken and disappears when squeezed.
• Clays, not silts, typically exhibit swelling and high plasticity.

Concept / Approach:

Identifying silt: rapid dilatancy, low plasticity, and low dry strength compared with clays. Clays usually show no dilatancy, have higher plasticity indices, and exhibit higher dry strength and potential for swelling (depending on mineralogy).

Step-by-Step Solution:

Verification / Alternative check:

Field manuals in soil classification emphasize the simple “shaking test” to distinguish silt from clay on site.

Why Other Options Are Wrong:

(b) Describes expansive clays; (c) reverses strength comparison; (d) generalizes disintegration behavior that is not diagnostic of silt; (e) is incorrect without cementing agents.

Common Pitfalls:

Confusing “silty clay” with “silt”; relying solely on color rather than simple hand tests.

Final Answer:

Silt shows dilatancy (quick, shiny surface response) when wet and disturbed.