PIC PIC Pavement Distress & Failure Analysis 2 — Questions and Answers
Question 1: Edge cracking in flexible pavement typically occurs due to:
- Excess roller passes near the center of the lane
- Lack of lateral support at the pavement edge (Correct answer)
- High binder content causing surface instability
- Reflective cracking from a rigid base layer
Correct answer: Lack of lateral support at the pavement edge
Edge cracking develops along the outer edges of the pavement where lateral support is absent or the base is weak, accelerating under traffic and environmental stress.
Question 2: Delamination in an asphalt pavement refers to:
- Crumbling of the surface aggregate due to freeze-thaw cycles
- Separation of one or more pavement layers from each other (Correct answer)
- Formation of potholes from water infiltration and traffic
- Loss of skid resistance due to polished aggregate
Correct answer: Separation of one or more pavement layers from each other
Delamination is the separation or debonding between pavement layers, often caused by contamination of the tack coat or inadequate bonding between lifts.
Question 3: The primary cause of pothole formation in flexible pavement is:
- Excessive aggregate size in the surface mix
- Water infiltrating cracks, weakening the base, and traffic loading displacing material (Correct answer)
- Over-compaction of the asphalt during placement
- Use of polymer-modified binders in cold climates
Correct answer: Water infiltrating cracks, weakening the base, and traffic loading displacing material
Potholes form when water enters existing cracks, weakens the sub-base through freeze-thaw or saturation, and traffic loads then break out pieces of pavement.
Question 4: Reflection cracking in an overlay is most accurately described as:
- New cracks forming from poor mix design in the overlay
- Cracks propagating upward from joints or cracks in an underlying layer through the new surface (Correct answer)
- Cracking along longitudinal joints due to poor compaction
- Transverse cracks caused by thermal contraction of the new lift
Correct answer: Cracks propagating upward from joints or cracks in an underlying layer through the new surface
Reflection cracking occurs when existing cracks or joints in an underlying layer move or open due to thermal or traffic forces, causing the distress to mirror through the overlay.
Question 5: Which pavement condition rating system is most commonly used by FHWA-funded state DOTs to classify pavement distress?
- Pavement Condition Index (PCI) (Correct answer)
- International Roughness Index (IRI)
- Present Serviceability Rating (PSR)
- Structural Number (SN)
Correct answer: Pavement Condition Index (PCI)
The Pavement Condition Index (PCI) is the standard FHWA-recognized rating scale from 0–100 used to classify the surface condition of road and parking lot pavement.
Question 6: Polished aggregate at a pavement surface is considered a distress because it:
- Increases the rate of thermal cracking in cold climates
- Reduces skid resistance and increases the risk of vehicle crashes (Correct answer)
- Causes water to pond rather than drain across the surface
- Leads to rapid deterioration of the asphalt binder
Correct answer: Reduces skid resistance and increases the risk of vehicle crashes
Polished aggregate is worn smooth by traffic, reducing the texture needed for skid resistance and increasing the risk of skidding, especially on wet pavement.
PIC PIC Pavement Distress & Failure Analysis 2
Edge cracking in flexible pavement typically occurs due to: