PIC Subbase Compaction Verification 3

Question 1

What does the 'D' value represent in a Dynamic Cone Penetrometer (DCP) test?

Accepted Answer

Penetration rate in mm per blow

Answer

The DCP penetration index (mm/blow) indicates the rate of penetration per hammer blow, correlating inversely with soil strength.

Question 2

A Proctor curve shows the relationship between:

Accepted Answer

Dry density and moisture content at a fixed compaction energy

Answer

The Proctor curve plots dry density versus moisture content at a constant compactive effort, identifying the optimum moisture content for maximum density.

Question 3

Which factor most significantly reduces compaction efficiency in granular subbase material?

Accepted Answer

Excessive moisture content well above optimum

Answer

Excess moisture creates pore pressure that reduces effective stress, causing the material to pump rather than compact efficiently.

Question 4

The AASHTO T 310 standard governs:

Accepted Answer

In-place density of soil and soil-aggregate by nuclear methods

Answer

AASHTO T 310 covers the nuclear gauge method for determining in-place density and moisture content of compacted materials.

Question 5

When testing compaction with a nuclear gauge in backscatter mode versus direct transmission mode, which statement is correct?

Accepted Answer

Direct transmission provides greater depth of measurement and more accurate density readings

Answer

Direct transmission mode inserts a probe rod into the material for a more accurate, deeper density measurement compared to surface backscatter.

(PIC) Paving Inspector Certification Practice Test

(PIC) Paving Inspector Certification Practice Test

PIC Subbase Compaction Verification 3