PIC Subbase Compaction Verification 5

Question 1

Which ASTM standard covers the sand cone method for field density testing of soil?

Accepted Answer

ASTM D1556

Answer

ASTM D1556 is the standard test method for density and unit weight of soil in place by the sand-cone method.

Question 2

During a rubber balloon density test, the technician pumps water into the excavated hole. The test measures volume by:

Accepted Answer

Tracking the volume of water required to fill the hole via a calibrated cylinder

Answer

The balloon apparatus uses a graduated cylinder to measure exactly how much water fills the hole, giving the precise volume for density calculation.

Question 3

Intelligent Compaction (IC) rollers equipped with GPS and accelerometers provide real-time data primarily for:

Accepted Answer

Mapping compaction uniformity across the entire subbase area

Answer

IC rollers generate color-coded stiffness maps showing where the subbase is uniformly compacted or where weak spots require additional passes.

Question 4

What is the purpose of the 'check strip' or 'test strip' at the start of subbase compaction operations?

Accepted Answer

To determine the required number of roller passes to achieve specification density with the actual equipment and material

Answer

A test strip establishes the roller pattern (number of passes) needed to reach target density under actual field conditions before full production begins.

Question 5

When compacting subbase material near a structure or retaining wall where a roller cannot operate, the preferred method is:

Accepted Answer

Plate compactor or jumping jack rammer in thin lifts

Answer

Plate compactors and jumping jack rammers achieve adequate compaction in confined areas that rollers cannot access, using reduced lift thicknesses for full depth effectiveness.

(PIC) Paving Inspector Certification Practice Test

(PIC) Paving Inspector Certification Practice Test

PIC Subbase Compaction Verification 5