NICET Highway Construction Materials Testing 2 — Questions and Answers
Question 1: What test determines the structural adequacy of a compacted subgrade or base course for highway construction?
- Proctor Test
- California Bearing Ratio (CBR) Test (Correct answer)
- Hveem Stability Test
- Marshall Test
Correct answer: California Bearing Ratio (CBR) Test
The CBR Test measures the load-bearing capacity of subgrade and base course materials, providing data used to design pavement thickness.
Question 2: What is the significance of the 95% compaction specification commonly used in highway construction?
- Aggregate moisture content limit
- Required degree of compaction relative to laboratory maximum dry density (Correct answer)
- Minimum passing percentage on a gradation test
- Air void content in asphalt mixes
Correct answer: Required degree of compaction relative to laboratory maximum dry density
A 95% compaction specification requires the field-compacted density to be at least 95% of the maximum dry density determined in the laboratory Proctor test.
Question 3: Which test measures the consistency of freshly mixed Portland cement concrete?
- Air content test
- Compressive strength test
- Slump test (Correct answer)
- Unit weight test
Correct answer: Slump test
The slump test measures the consistency and workability of fresh concrete by measuring the vertical drop of a truncated cone of concrete after the mold is removed.
Question 4: At what age is the standard compressive strength of concrete cylinders typically tested per ASTM C39?
- 7 days
- 14 days
- 28 days (Correct answer)
- 56 days
Correct answer: 28 days
The standard compressive strength of concrete is determined at 28 days, which represents the design strength used for most structural applications.
Question 5: What NICET HCMT work element covers asphalt concrete (hot mix asphalt) testing?
- Soils
- Portland Cement Concrete
- Asphalt Concrete (Correct answer)
- Aggregates
Correct answer: Asphalt Concrete
The Asphalt Concrete work element within NICET HCMT covers testing procedures for hot mix asphalt (HMA) including Marshall and Superpave mix design.
Question 6: What is the purpose of the extraction test for hot mix asphalt?
- Determine aggregate gradation of recovered aggregate and asphalt binder content (Correct answer)
- Measure pavement thickness
- Test the adhesion between asphalt and aggregate
- Determine the softening point of the binder
Correct answer: Determine aggregate gradation of recovered aggregate and asphalt binder content
The extraction test (AASHTO T 164) separates the asphalt binder from the aggregate mixture, allowing determination of binder content and recovered aggregate gradation.
NICET Highway Construction Materials Testing 2
What test determines the structural adequacy of a compacted subgrade or base course for highway construction?