CCIL Asphalt Mix Compliance Testing 5

Question 1

What does the Dynamic Modulus (|E*|) test measure in asphalt mixture characterization?

Accepted Answer

Stiffness of the mix over a range of temperatures and frequencies

Answer

The Dynamic Modulus test (AASHTO T 378) measures the complex modulus of asphalt mixtures across multiple temperatures and loading frequencies.

Question 2

Which method is commonly used to reduce the particle size of an asphalt mix sample to a representative test portion?

Accepted Answer

Mechanical splitter or riffle box

Answer

A mechanical splitter (riffle box) is the preferred method per AASHTO R 47 for reducing HMA samples to avoid segregation bias.

Question 3

In Superpave performance grading, what does the low-temperature binder grade (e.g., -28 in PG 64-28) represent?

Accepted Answer

The lowest pavement temperature at which the binder meets cracking criteria

Answer

The low-temperature grade specifies the lowest pavement design temperature at which the binder satisfies both BBR and DTT (if required) cracking criteria.

Question 4

What standard technique is used to verify the calibration of a Superpave Gyratory Compactor (SGC) for height measurements and angle of gyration?

Accepted Answer

AASHTO PP 60 verification procedure with a calibration fixture

Answer

AASHTO PP 60 provides the procedure for verifying SGC performance including angle of gyration, vertical pressure, and ram speed using calibration fixtures.

Question 5

Which parameter measured by the Bending Beam Rheometer (BBR) at low temperature is most critical for predicting thermal cracking resistance?

Accepted Answer

Stiffness (S) and creep rate (m-value)

Answer

BBR measures stiffness (S ≤ 300 MPa) and creep rate (m ≥ 0.300) at low temperatures, both of which must be met for thermal cracking resistance.

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL Asphalt Mix Compliance Testing 5