What is lime stabilization and when is it used?

What is lime stabilization and when is it used?

• A. Adding lime to concrete to increase early strength.
• B. Mixing lime into fine-grained soils to improve strength and reduce plasticity; used on expansive clays and silts.
• C. Using lime to treat asphalt surfaces.
• D. Applying lime to organic soils to raise pH.

Answer: (B)

Lime stabilization is the process of mixing lime into fine-grained soils to change their behavior, mainly to increase strength and reduce plasticity and swelling. Quicklime or hydrated lime is spread and worked into the soil, then allowed to cure with moisture. The lime reacts with clay minerals in two important ways: it causes cation exchange and flocculation, which makes the clay particles clump and harden, and it participates in pozzolanic reactions with silica and alumina to form cementitious compounds that bind the soil together. The net effect is a stiffer, stronger subgrade with less tendency to swell when wet, which is especially valuable for expansive clays and silts in foundations, embankments, and pavements. While lime does raise soil pH, the primary purpose here is improving mechanical properties, not simply adjusting acidity.

Lime stabilization is the process of mixing lime into fine-grained soils to change their behavior, mainly to increase strength and reduce plasticity and swelling. Quicklime or hydrated lime is spread and worked into the soil, then allowed to cure with moisture. The lime reacts with clay minerals in two important ways: it causes cation exchange and flocculation, which makes the clay particles clump and harden, and it participates in pozzolanic reactions with silica and alumina to form cementitious compounds that bind the soil together. The net effect is a stiffer, stronger subgrade with less tendency to swell when wet, which is especially valuable for expansive clays and silts in foundations, embankments, and pavements. While lime does raise soil pH, the primary purpose here is improving mechanical properties, not simply adjusting acidity.