Asphalt Technology Flashcards

What does the term 'viscosity' describe in relation to asphalt binders?

Answer: The resistance of asphalt to flow under applied stress

Viscosity measures an asphalt binder's resistance to flow, which directly affects mixing, compaction, and pavement performance.

Which Superpave performance grade parameter addresses rutting resistance at high service temperatures?

Answer: G*/sinδ at high temperature

G*/sinδ (dynamic shear modulus divided by sine of phase angle) measured at high temperature indicates resistance to rutting.

What is the primary purpose of a tack coat applied between pavement layers?

Answer: To promote bonding between existing and new asphalt layers

Tack coats create an adhesive bond between layers, preventing slippage and delamination under traffic loads.

In a Superpave mix design, what does the term 'Ndesign' represent?

Answer: The number of gyrations used to compact the design specimen

Ndesign is the number of gyratory compactor revolutions used to compact specimens to simulate expected traffic-level densification.

Which aggregate property most directly affects the rutting resistance of an asphalt mix?

Answer: Particle shape and angularity

Crushed, angular aggregates interlock more effectively than rounded particles, providing greater resistance to permanent deformation under load.

What pavement distress is characterized by a series of closely spaced transverse cracks resembling alligator skin?

Answer: Fatigue (alligator) cracking

Fatigue cracking, also called alligator cracking, results from repeated traffic loading that exceeds the pavement's structural capacity.

Which test is used to measure the low-temperature cracking susceptibility of an asphalt binder?

Answer: Bending beam rheometer (BBR)

The BBR measures creep stiffness and m-value of aged asphalt binder at low temperatures to predict thermal cracking resistance.