What type of soil is considered cohesive?

Cohesive soil is characterized by its ability to stick together and retain its shape when wet, which is a significant property of clay. Clay soils have fine particles that are tightly packed, creating significant cohesion among the particles. This cohesion allows clay to hold moisture and forms a plastic state when wet, making it suitable for various construction purposes.

Sandy soil, gravel, and loamy soil do not exhibit these cohesive properties to the same extent as clay. Sandy soil consists of larger particles that do not stick together, leading to poor cohesion and drainage. Gravel, with its even larger particles, composes a loose structure with minimal cohesion. Loamy soil, while a mixture of sand, silt, and clay, offers good fertility and drainage but does not demonstrate the strong cohesive qualities of clay. Thus, clay is the definitive example of cohesive soil.