WAQTC: Asphalt 2 Exam Questions With
Correct Answers (Verified Answers) Plus
Rationales 2025
1. What is the primary purpose of a nuclear gauge in asphalt testing?
A. Check air temperature
B. Determine compaction and moisture
C. Measure density and moisture
D. Identify aggregate shape
The nuclear gauge measures in-place density and moisture content of asphalt
using radioactive isotopes.
2. At what temperature should asphalt be compacted during field testing?
A. Below 175°F
B. Above 325°F
C. As low as possible
D. As specified in the mix design (typically 275–300°F)
Compaction temperature must align with the mix design specifications to ensure
proper density.
, 3. What tool is used to extract a core sample from asphalt?
A. Chisel and hammer
B. Core drill
C. Trowel
D. Moisture gauge
Core drills cut cylindrical samples to check field density and layer thickness.
4. What is the acceptable tolerance for nuclear gauge readings compared to
core density?
A. ±0.1%
B. ±1.0%
C. ±5.0%
D. ±10.0%
Field densities from nuclear gauges must closely correlate with core results,
typically within ±1.0%.
5. What causes asphalt mat segregation?
A. Cold weather
B. Fine grading
C. Improper handling or loading of the mix
D. Overcompaction
, Segregation occurs when coarse and fine particles separate, often from poor
handling during transport or placement.
6. What is the purpose of tack coat in asphalt paving?
A. Moisture protection
B. Bonding between layers
C. Aesthetic finish
D. Acts as insulation
Tack coat improves bonding between existing pavement and new asphalt
layers.
7. What does a high air void content indicate in compacted asphalt?
A. Durable mat
B. Under-compacted mix
C. Over-heated mix
D. Excess binder
Too many air voids can reduce durability and allow moisture infiltration,
indicating under-compaction.
8. When should the nuclear gauge be standardized?
A. After 24 hours
B. At the beginning of each day
Correct Answers (Verified Answers) Plus
Rationales 2025
1. What is the primary purpose of a nuclear gauge in asphalt testing?
A. Check air temperature
B. Determine compaction and moisture
C. Measure density and moisture
D. Identify aggregate shape
The nuclear gauge measures in-place density and moisture content of asphalt
using radioactive isotopes.
2. At what temperature should asphalt be compacted during field testing?
A. Below 175°F
B. Above 325°F
C. As low as possible
D. As specified in the mix design (typically 275–300°F)
Compaction temperature must align with the mix design specifications to ensure
proper density.
, 3. What tool is used to extract a core sample from asphalt?
A. Chisel and hammer
B. Core drill
C. Trowel
D. Moisture gauge
Core drills cut cylindrical samples to check field density and layer thickness.
4. What is the acceptable tolerance for nuclear gauge readings compared to
core density?
A. ±0.1%
B. ±1.0%
C. ±5.0%
D. ±10.0%
Field densities from nuclear gauges must closely correlate with core results,
typically within ±1.0%.
5. What causes asphalt mat segregation?
A. Cold weather
B. Fine grading
C. Improper handling or loading of the mix
D. Overcompaction
, Segregation occurs when coarse and fine particles separate, often from poor
handling during transport or placement.
6. What is the purpose of tack coat in asphalt paving?
A. Moisture protection
B. Bonding between layers
C. Aesthetic finish
D. Acts as insulation
Tack coat improves bonding between existing pavement and new asphalt
layers.
7. What does a high air void content indicate in compacted asphalt?
A. Durable mat
B. Under-compacted mix
C. Over-heated mix
D. Excess binder
Too many air voids can reduce durability and allow moisture infiltration,
indicating under-compaction.
8. When should the nuclear gauge be standardized?
A. After 24 hours
B. At the beginning of each day
