CCIL Asphalt and Aggregate 5

Question 1

What is the purpose of the Rolling Thin Film Oven (RTFO) test in asphalt binder evaluation?

Accepted Answer

Simulate short-term aging during mixing and construction

Answer

The RTFO test (AASHTO T240 / ASTM D2872) simulates short-term oxidative aging of asphalt binder that occurs during hot-mix production and placement.

Question 2

Which aggregate test method quantifies the percentage of crushed faces on coarse aggregate particles?

Accepted Answer

ASTM D5821

Answer

ASTM D5821 determines the percentage of fractured particles in coarse aggregate by counting particles with one or more mechanically fractured faces.

Question 3

In field density testing of compacted asphalt, what does the nuclear gauge method measure to determine density?

Accepted Answer

Attenuation of gamma radiation passing through the material

Answer

Nuclear density gauges use a Cesium-137 or Radium-226 source; the attenuation of gamma radiation passing through or backscattered from the material correlates with its density.

Question 4

What is the primary mechanism causing stripping in asphalt pavements?

Accepted Answer

Loss of adhesion between asphalt binder and aggregate in the presence of water

Answer

Stripping occurs when water penetrates the asphalt-aggregate interface and displaces the binder, breaking the adhesive bond and weakening the pavement structure.

Question 5

Which test is used to evaluate moisture susceptibility of compacted asphalt mixtures according to AASHTO T283?

Accepted Answer

Lottman test for tensile strength ratio (TSR)

Answer

AASHTO T283 determines moisture sensitivity by comparing the indirect tensile strength of conditioned (freeze-thaw saturated) specimens to unconditioned specimens as a Tensile Strength Ratio (TSR).

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL Asphalt and Aggregate 5