CTQP Asphalt Paving Inspection 5 — Questions and Answers
Question 1: What is 'raveling' in an asphalt pavement surface?
- Upward displacement of the pavement under traffic loads
- Progressive loss of aggregate particles from the pavement surface (Correct answer)
- Formation of parallel ruts in wheel paths
- Widening of existing cracks over time
Correct answer: Progressive loss of aggregate particles from the pavement surface
Raveling is the progressive disintegration of the asphalt surface caused by loss of bond between aggregate particles and the binder.
Question 2: The Performance Grade (PG) binder specification system is based primarily on:
- Aggregate gradation and angularity requirements
- Pavement expected service temperature range and traffic loading (Correct answer)
- Mix design air void content and VMA
- Asphalt plant production capacity
Correct answer: Pavement expected service temperature range and traffic loading
The PG system selects binder based on the high and low pavement design temperatures and traffic loading conditions at the project location.
Question 3: What action should an inspector take if asphalt mix arrives at the paver with visible segregation in the truck?
- Accept the load but note it in the inspection report
- Instruct the operator to increase paving speed
- Reject the load and document the rejection (Correct answer)
- Allow the load but reduce roller passes on that section
Correct answer: Reject the load and document the rejection
Segregated loads should be rejected because they result in non-uniform mix placement that cannot be corrected by rolling.
Question 4: During hot weather paving, what problem is most likely to occur with the asphalt mix?
- Mix cools too quickly and becomes unworkable before placement
- Compaction window is reduced due to faster cooling of the mat (Correct answer)
- Excess binder drains to the bottom of the mix during transport
- Aggregate absorption of binder increases significantly
Correct answer: Compaction window is reduced due to faster cooling of the mat
Although hot ambient temperatures slow cooling, very high pavement temperatures in combination with thin lifts can still narrow the compaction window unpredictably.
Question 5: What is the purpose of the breakdown roller in the asphalt compaction sequence?
- To achieve the final density and surface texture of the mat
- To provide the initial primary compaction immediately behind the paver (Correct answer)
- To smooth minor surface irregularities left by previous rollers
- To seat the aggregate into the binder after the mat has cooled
Correct answer: To provide the initial primary compaction immediately behind the paver
The breakdown (or primary) roller follows closely behind the paver to achieve the initial densification of the hot mat while it is still workable.
Question 6: What does VMA stand for in asphalt mix design, and why is it important?
- Voids in Mineral Aggregate — it ensures enough space for binder and air voids (Correct answer)
- Volume of Mix Asphalt — it measures total binder content by weight
- Vertical Mix Analysis — it determines the stiffness of the compacted mixture
- Variable Matrix Additive — it accounts for polymer modifier dosage
Correct answer: Voids in Mineral Aggregate — it ensures enough space for binder and air voids
VMA (Voids in Mineral Aggregate) is the total void space between aggregate particles, which must be large enough to accommodate the asphalt binder and design air voids.
Question 7: When should an asphalt inspector verify the temperature of the mix delivered to the job site?
- Only at the beginning of the day's operations
- At the plant before loading and again upon arrival at the paver (Correct answer)
- Only after the mat has been placed and before rolling begins
- Once per hour regardless of the number of trucks arriving
Correct answer: At the plant before loading and again upon arrival at the paver
Mix temperature should be verified at the plant and again at delivery to ensure it has not cooled excessively during transport and is within specification.
CTQP Asphalt Paving Inspection 5
What is 'raveling' in an asphalt pavement surface?