CCIL Asphalt and Aggregate 4 — Questions and Answers
Question 1: What does the abbreviation 'RAP' stand for in pavement engineering?
- Refined Asphalt Product
- Reclaimed Asphalt Pavement (Correct answer)
- Reactive Aggregate Particle
- Resilient Asphalt Pavement
Correct answer: Reclaimed Asphalt Pavement
RAP (Reclaimed Asphalt Pavement) refers to removed and reprocessed pavement materials containing asphalt binder and aggregate, commonly used in recycled mix designs.
Question 2: Which AASHTO test method is used to determine the dynamic shear rheology of asphalt binder?
- AASHTO T315 (Correct answer)
- AASHTO T313
- AASHTO T316
- AASHTO T240
Correct answer: AASHTO T315
AASHTO T315 uses the Dynamic Shear Rheometer (DSR) to measure the complex shear modulus (G*) and phase angle (δ) of asphalt binder specimens.
Question 3: What is the maximum allowable percent wear by mass loss in the Los Angeles abrasion test for aggregate used in surface course pavement?
- 25% (Correct answer)
- 40%
- 50%
- 10%
Correct answer: 25%
Most specifications limit Los Angeles abrasion loss to 25% or less for aggregate used in wearing course applications to ensure adequate durability.
Question 4: Which test measures the ductility of asphalt binder by pulling a briquette sample apart at a standard rate?
- Penetration test
- Softening point test
- Ductility test (ASTM D113) (Correct answer)
- Viscosity test
Correct answer: Ductility test (ASTM D113)
ASTM D113 measures ductility by elongating a briquette of asphalt binder at 25°C and 5 cm/min until it breaks, recording the distance in centimeters.
Question 5: In Superpave mix design, what is the design number of gyrations (Ndesign) used to simulate?
- Initial construction compaction by rollers
- Traffic compaction over the pavement's design life (Correct answer)
- Laboratory quality control testing cycles
- Aggregate breakdown during mixing
Correct answer: Traffic compaction over the pavement's design life
Ndesign represents the expected traffic compaction over the pavement's design life and is selected based on design ESALs to achieve target air void content.
Question 6: What does a 'tender mix' condition indicate in hot-mix asphalt during paving operations?
- Mix is too stiff and causes screed dragging
- Mix is unstable and shoves under roller action due to excess asphalt or fine content (Correct answer)
- Mix has too many air voids and is permeable
- Mix has cooled below compaction temperature range
Correct answer: Mix is unstable and shoves under roller action due to excess asphalt or fine content
A tender mix exhibits instability under roller loads, causing shoving and rutting, typically due to excess asphalt binder, high fine content, rounded aggregate, or compaction at too high a temperature.
Question 7: Which Canadian standard governs sieve analysis of fine and coarse aggregates?
- CSA A23.2-2A (Correct answer)
- CSA A23.1
- ASTM C136 only
- CAN/CSA-G40.20
Correct answer: CSA A23.2-2A
CSA A23.2-2A is the Canadian standard test method for sieve analysis of fine and coarse aggregates, analogous to ASTM C136.
CCIL Asphalt and Aggregate 4
What does the abbreviation 'RAP' stand for in pavement engineering?