Soils having 50% or more passing the No. 200 sieve are classified as what?

Soils that contain 50% or more passing the No. 200 sieve are classified as fine-grained soils. This classification reflects the particle size distribution within the soil. The No. 200 sieve has a specific opening size that determines the fineness of the particles that can pass through it, which generally corresponds to particles that are less than 0.075 mm in diameter.

Fine-grained soils primarily consist of silt and clay particles. These particles are smaller than those classified as coarse-grained, which retain a larger proportion of aggregates that do not pass through the No. 200 sieve. The properties of fine-grained soils, such as their plasticity and moisture retention, play a crucial role in engineering and geotechnical applications. Understanding this classification is fundamental for predicting how these soils will behave under various conditions, including loading and drainage.