If a soil has a liquid limit less than 20, it is typically classified as which soil type?

If a soil has a liquid limit less than 20, it is typically classified as which soil type?

• A. Organic soil
• B. Sand
• C. Non-cohesive
• D. Clayey soil

Answer: (C)

Understanding the Atterberg limits concept: the liquid limit is the water content at which a soil changes from plastic to liquid. When this limit is very low, around 20 or below, there isn’t enough clay to produce cohesion, so the soil behaves as a non-cohesive material like sand or gravel. Since non-cohesive soils lack the cohesive forces that clays have, they’re classified as non-cohesive. Organic soils often exhibit different, more variable behavior and higher plasticity because of organic matter; clayey soils typically have higher liquid limits due to the plastic nature of clays. A specific grain-size example like sand isn’t implied by the liquid limit alone, so the broader category non-cohesive is the best fit.

Understanding the Atterberg limits concept: the liquid limit is the water content at which a soil changes from plastic to liquid. When this limit is very low, around 20 or below, there isn’t enough clay to produce cohesion, so the soil behaves as a non-cohesive material like sand or gravel. Since non-cohesive soils lack the cohesive forces that clays have, they’re classified as non-cohesive. Organic soils often exhibit different, more variable behavior and higher plasticity because of organic matter; clayey soils typically have higher liquid limits due to the plastic nature of clays. A specific grain-size example like sand isn’t implied by the liquid limit alone, so the broader category non-cohesive is the best fit.