Which type of soil has cohesion and can stick together?

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Clay is the type of soil known for its cohesive properties, allowing it to stick together effectively. This cohesion arises from the small particle size of clay, which increases the surface area in relation to volume. The particles are often plate-like and have a high water retention capacity; when wet, they can easily form a plastic mass that holds together due to molecular attraction between the particles.

This cohesive property is important in engineering and construction, as it affects the soil’s behavior under load, its compressibility, and its ability to support structures. In contrast, silt and sand have larger particles and generally exhibit less cohesion, relying on other forms of mechanical interlocking rather than molecular attraction. Gravel, being composed of even larger particles, typically lacks cohesion altogether, relying on the friction between larger grains to provide stability. Thus, the key characteristic of clay that allows it to effectively stick together differentiates it from the other soil types.