Lime stabilization targets which soils?

Lime stabilization targets which soils?

• A. Coarse-grained sands.
• B. Gravelly soils.
• C. Bedrock.
• D. Expansive clays and silts.

Answer: (D)

Lime stabilization targets soils with high plasticity and shrink-swell behavior. Expansive clays and silts fit this, because their clay minerals (like montmorillonite) swell when hydrated. Introducing lime raises the soil pH and causes calcium to exchange with the clay minerals, promoting flocculation and forming cementitious compounds with silica and alumina. These reactions bind the soil particles, reduce plasticity, and lessen volume change with moisture, improving stiffness, strength, and bearing capacity. Coarse-grained sands, gravels, and bedrock don’t respond as well because they contain little reactive clay; lime has limited cementing effect there.

Lime stabilization targets soils with high plasticity and shrink-swell behavior. Expansive clays and silts fit this, because their clay minerals (like montmorillonite) swell when hydrated. Introducing lime raises the soil pH and causes calcium to exchange with the clay minerals, promoting flocculation and forming cementitious compounds with silica and alumina. These reactions bind the soil particles, reduce plasticity, and lessen volume change with moisture, improving stiffness, strength, and bearing capacity. Coarse-grained sands, gravels, and bedrock don’t respond as well because they contain little reactive clay; lime has limited cementing effect there.