What is the maximum PI value allowed for stabilizing material?

What is the maximum PI value allowed for stabilizing material?

• A. Maximum PI is 12
• B. Maximum PI is 9
• C. Maximum PI is 10
• D. Maximum PI is 8

Answer: (C)

Plasticity Index measures how much a soil can behave plastically, which is tied to clay content and its tendency to swell or shrink with moisture changes. For stabilizing material, keeping PI at or below 10 helps ensure the mix can be compacted to a uniform density and will respond predictably to stabilization additives. Higher PI means more plastic clay, greater moisture sensitivity, and larger shrink‑swell potential, making compaction and stabilization less reliable. Therefore, the maximum allowable PI value is 10.

Plasticity Index measures how much a soil can behave plastically, which is tied to clay content and its tendency to swell or shrink with moisture changes. For stabilizing material, keeping PI at or below 10 helps ensure the mix can be compacted to a uniform density and will respond predictably to stabilization additives. Higher PI means more plastic clay, greater moisture sensitivity, and larger shrink‑swell potential, making compaction and stabilization less reliable. Therefore, the maximum allowable PI value is 10.