What is the minimum density requirement for QC testing expressed as a percentage of the Standard Proctor maximum density?

What is the minimum density requirement for QC testing expressed as a percentage of the Standard Proctor maximum density?

• A. 95%
• B. 100%
• C. 105%
• D. 90%

Answer: (B)

The essential idea is that quality control testing for compacted fill targets the full compacted density determined in the lab. The Standard Proctor test gives the maximum dry density achievable for the material under standard compaction effort. For QC, the density requirement is that the field density reaches that maximum value, expressed as 100% of the Standard Proctor maximum density. If the field density meets this 100% benchmark, it indicates the material has been compacted to its full tested potential and should perform well in terms strength and settlement. The other percentages don’t fit this exact QC criterion: 105% would exceed the lab-determined maximum, which isn’t achievable under the standard test, and 95% or 90% reflect lower acceptance criteria used in some projects but not the strict QC standard tied to the lab maximum.

The essential idea is that quality control testing for compacted fill targets the full compacted density determined in the lab. The Standard Proctor test gives the maximum dry density achievable for the material under standard compaction effort. For QC, the density requirement is that the field density reaches that maximum value, expressed as 100% of the Standard Proctor maximum density. If the field density meets this 100% benchmark, it indicates the material has been compacted to its full tested potential and should perform well in terms strength and settlement. The other percentages don’t fit this exact QC criterion: 105% would exceed the lab-determined maximum, which isn’t achievable under the standard test, and 95% or 90% reflect lower acceptance criteria used in some projects but not the strict QC standard tied to the lab maximum.