An operator is compacting a trench backfill using a trench roller. The specification calls for 95% Standard Proctor density. If the field density test results show 92% of Standard Proctor, what operational adjustment is most likely required?

Question: An operator is compacting a trench backfill using a trench roller. The specification calls for 95% Standard Proctor density. If the field density test results show 92% of Standard Proctor, what operational adjustment is most likely required?

Answer options: ✅ Increase the number of passes over the material.

• Reduce the lift thickness for subsequent layers.
• Increase the roller's travel speed.
• Decrease the vibratory frequency.

Correct answer: Increase the number of passes over the material.

Explanation: If the required compaction (95%) is not met, the most common and effective initial adjustment is to increase the number of passes over the material, ensuring each pass overlaps, to impart more compactive effort until the desired density is achieved. Reducing lift thickness is also valid, but increasing passes is a more direct operational adjustment on the current lift.