In the event of a QC density exceeding the Proctor maximum by 5%, where is the independent verification test performed?

• A. Within 10 ft
• B. Within 5 ft
• C. Within 15 ft
• D. At a distant lab

Answer: (B)

When field density results exceed the Proctor maximum by 5%, an independent verification test is required to confirm the result. This verification is done on the same area and on the same lift, within 5 feet of the original test location. The close proximity ensures the soil conditions, moisture, and compaction effort are essentially the same, so the verification outcome is meaningful and comparable to the QC result. A test conducted farther away or in a distant lab could reflect different conditions and wouldn’t reliably confirm the on-site density.