PIC Roller Pattern & Compaction Equipment 4

Question 1

Which type of roller is typically AVOIDED when compacting open-graded friction courses (OGFC)?

Accepted Answer

Pneumatic tire roller

Answer

Pneumatic tire rollers are not used on OGFC because their kneading action can clog the open-graded voids with binder, destroying the drainage characteristics of the mix.

Question 2

What is the recommended direction for beginning the first breakdown roller pass on a newly paved lane?

Accepted Answer

From the high side of the mat toward the low side

Answer

Beginning on the high side (or centerline on a crowned road) and rolling toward the low side prevents the mix from being displaced downhill and ensures the mat is confined laterally.

Question 3

What is 'tenderness' in an asphalt mix, and how should a roller operator respond to it?

Accepted Answer

A mix that is workable but prone to shoving; operator should reduce compactive effort and allow cooling

Answer

A tender mix is temporarily unstable and prone to shoving or rutting under roller load; the operator should reduce roller weight, turn off vibration, or wait for the mix to cool slightly.

Question 4

A 3-axle tandem steel roller is used for finish rolling. Which statement about its operation is CORRECT?

Accepted Answer

It should operate in static mode to remove roller marks without displacing the mix

Answer

During finish rolling, static mode removes surface irregularities without risk of displacing the already-densified mix that is approaching its stiffness threshold.

Question 5

How does increasing the number of passes on a nearly cooled mat (below 175°F) typically affect the compaction result?

Accepted Answer

Has little effect on density and may cause surface damage

Answer

Once HMA cools below approximately 175°F the binder is too stiff to be re-worked, so additional passes add minimal density while risking surface cracking or aggregate fracture.

(PIC) Paving Inspector Certification Practice Test

(PIC) Paving Inspector Certification Practice Test

PIC Roller Pattern & Compaction Equipment 4