CTQP Asphalt Paving Inspection 2 — Questions and Answers
Question 1: What instrument is used to measure the thickness of an asphalt core sample in the field?
- Digital caliper (Correct answer)
- Nuclear gauge
- Profilograph
- Falling weight deflectometer
Correct answer: Digital caliper
A digital or vernier caliper is used to measure the thickness of asphalt core samples taken from the compacted mat to verify thickness compliance.
Question 2: What is 'ride quality' or 'smoothness' measured with on FDOT asphalt projects?
- A nuclear density gauge
- An inertial profiler or profilograph (Correct answer)
- A straightedge and feeler gauge
- A rolling wheel deflectometer
Correct answer: An inertial profiler or profilograph
Inertial profilers or profilographs are used to measure pavement smoothness and produce an International Roughness Index (IRI) or Profile Index (PI) value.
Question 3: What is the maximum allowable deviation from design elevation for a finished asphalt surface per typical FDOT specifications?
- 1/8 inch
- 1/4 inch (Correct answer)
- 3/8 inch
- 1/2 inch
Correct answer: 1/4 inch
FDOT typically allows a maximum deviation of ±1/4 inch from design grade for finished asphalt pavement surfaces.
Question 4: What does 'joint density' refer to in asphalt paving?
- The bond strength between tack coat and asphalt
- The density of the asphalt at longitudinal or transverse construction joints (Correct answer)
- The number of roller passes required per lift
- The concentration of aggregates at the center of the mat
Correct answer: The density of the asphalt at longitudinal or transverse construction joints
Joint density refers to the compacted density achieved at longitudinal or transverse construction joints, which are typically the weakest areas of a pavement mat.
Question 5: What is a 'string line' used for during asphalt paving operations?
- Marking lane lines before paving
- Controlling the elevation and alignment of the paver screed (Correct answer)
- Measuring the width of the paving pass
- Indicating areas where tack coat has been applied
Correct answer: Controlling the elevation and alignment of the paver screed
A string line or wire reference is used to guide the paver's automatic grade and slope controls, ensuring the finished mat meets design elevation and cross-slope requirements.
Question 6: What condition requires the inspector to stop paving operations immediately?
- Ambient temperature drops below 50°F during paving (Correct answer)
- A brief light rain shower passes over the site
- The paver hopper drops to half full
- The roller makes fewer than the specified number of passes
Correct answer: Ambient temperature drops below 50°F during paving
FDOT specifications prohibit paving when the ambient temperature is below 50°F (or the pavement surface temperature is below 50°F) because cold temperatures prevent adequate compaction.
CTQP Asphalt Paving Inspection 2
What instrument is used to measure the thickness of an asphalt core sample in the field?