If the surface is A-2-7 Soil Groups after removing unsuitable material, compact the surface with a sheepfoot roller exerting a compression of at least what psi on the tamper foot for the full width of the roadbed?

• A. 150 psi
• B. 200 psi
• C. 300 psi
• D. 250 psi

Answer: (D)

The main idea is that the roadbed surface must be densified to a safe, load-bearing level using a sheepfoot roller, with a specific minimum pressure applied on the tamper foot across the full width. Sheepfoot rollers work by kneading and rearranging soil particles, so applying a defined pressure helps achieve the needed density in soils like A-2-7 after unsuitable material has been removed.

A minimum of 250 psi on the tamper foot ensures enough force is transmitted to compact the surface adequately and uniformly across the entire roadbed width. Values lower than this would likely not achieve the required density, while a higher value isn’t the standard specification in this case and isn’t needed to meet the requirement.