PIC Roller Pattern & Compaction Equipment 2

Question 1

When using a vibratory steel drum roller, at what speed should the roller typically operate to achieve effective compaction without causing mix displacement?

Accepted Answer

1–3 mph

Answer

Vibratory rollers should operate at 1–3 mph to allow sufficient dwell time for the vibration to densify the mix without shoving or tearing.

Question 2

Which roller configuration is BEST suited for breakdown rolling immediately behind the paver?

Accepted Answer

Steel tandem vibratory roller

Answer

A steel tandem vibratory roller is typically used for breakdown rolling because it provides high compactive effort closest to the paver while the mix is hottest.

Question 3

What is the primary purpose of the finish (third) pass in a three-stage compaction operation?

Accepted Answer

To remove roller marks and surface blemishes

Answer

The finish pass uses a static roller or smooth-drum pass to remove any marks, tears, or surface irregularities left by previous rolling stages.

Question 4

A roller operator notices the asphalt mat is cracking transversely ahead of the drum. What is the MOST likely cause?

Accepted Answer

Mix temperature is too low

Answer

Transverse cracking ahead of the drum indicates the mix has cooled below the minimum compaction temperature and has become too stiff to compact without fracturing.

Question 5

For a 4-inch compacted lift of dense-graded HMA, how many passes with a vibratory roller are typically required to achieve 92–96% density?

Accepted Answer

3–5 passes

Answer

Typically 3–5 passes of a vibratory roller are needed for standard HMA lifts; exact count depends on mix type, roller weight, and amplitude settings.

(PIC) Paving Inspector Certification Practice Test

(PIC) Paving Inspector Certification Practice Test

PIC Roller Pattern & Compaction Equipment 2