CCIL - Canadian Council of Independent Laboratories Pavement Construction and Inspection Questions and Answers Flashcards

What pavement condition survey method assigns a numerical rating from 0 to 100 to quantify overall pavement surface condition?

Answer: Pavement Condition Index (PCI) per ASTM D6433

PCI per ASTM D6433 rates pavement condition from 0 (failed) to 100 (excellent) by cataloguing distress types, severities, and quantities across defined survey sections.

What is the purpose of a geotextile fabric placed between the subgrade and granular base course in pavement construction?

Answer: Separation and filtration to prevent subgrade fines from migrating into the base

A separation geotextile prevents subgrade clay or silt from pumping upward into the granular base under traffic loading, maintaining the design thickness and drainage capacity of the base.

What does 'reflection cracking' in an asphalt overlay refer to?

Answer: Cracks in the existing pavement reflecting upward through the new overlay above

Reflection cracking occurs when cracks or joints in the underlying pavement layer propagate upward through a new asphalt overlay due to differential movement at those discontinuities.

Which specification document governs the performance grading (PG) of asphalt binders used in pavement construction across North America?

Answer: AASHTO M 320

AASHTO M 320 specifies Performance Graded (PG) asphalt binder requirements based on the high and low temperature performance grades relevant to the project climate zone.

During pavement thickness measurement using ground-penetrating radar (GPR) on an in-service highway, what property allows GPR to distinguish layer interfaces?

Answer: Differences in dielectric constant between pavement layers and underlying materials

GPR detects layer interfaces because different materials (asphalt, base, subgrade) have distinct dielectric constants, causing partial reflection of the radar wave at each boundary.

What compaction pattern is recommended for achieving uniform density across the full width of an asphalt mat during final rolling operations?

Answer: Overlapping parallel passes from the low side to the high side of the mat

Rolling from the low to high side of the mat with overlapping passes prevents shoving of the unconfined edge and ensures uniform compactive effort across the mat width.