NETTCP Roadway Design & Maintenance 3 — Questions and Answers
Question 1: When patching a pothole using the throw-and-roll method, what is the MOST critical step to ensure patch durability?
- Applying a tack coat to the pothole walls before filling
- Mounding the patch material 1–2 inches above the surrounding pavement
- Compacting the patch with a roller or vehicle tires (Correct answer)
- Sealing the edges with rubberized crack filler
Correct answer: Compacting the patch with a roller or vehicle tires
Compaction is the most critical step in throw-and-roll patching because it bonds the material and eliminates voids that cause premature failure.
Question 2: In New England, frost heave damage to pavements is primarily caused by which soil mechanism?
- Shrinkage of clay soils during freezing temperatures
- Ice lens formation drawing water upward through capillary action in frost-susceptible soils (Correct answer)
- Expansion of granular base course materials
- Thermal contraction of the asphalt binder
Correct answer: Ice lens formation drawing water upward through capillary action in frost-susceptible soils
Ice lenses form when water migrates upward through capillary action in fine-grained soils and freezes, causing differential heaving of the pavement.
Question 3: What is the design purpose of a clear zone along a rural highway?
- To provide space for future lane additions
- To give errant vehicles a recoverable area free of fixed obstacles (Correct answer)
- To separate opposing traffic flows
- To reduce right-of-way acquisition costs
Correct answer: To give errant vehicles a recoverable area free of fixed obstacles
The clear zone is a traversable, obstacle-free area beyond the edge of the traveled way that allows errant vehicles to recover or safely stop.
Question 4: Which factor MOST directly influences the selection of guardrail end treatment type at a hazardous terminal?
- The design vehicle's fuel type
- The traffic volume and posted speed limit (Correct answer)
- The color of the guardrail system
- The pavement marking layout
Correct answer: The traffic volume and posted speed limit
End treatment selection is governed by the speed of approaching traffic and volume, because crash tests are classified by impact speed requirements under MASH or NCHRP 350.
Question 5: A crew is crack sealing an asphalt pavement. At what minimum crack width should routing be performed before sealing?
- Less than 1/8 inch
- 1/8 inch to 1/4 inch
- Greater than 1/2 inch to 1 inch (Correct answer)
- Greater than 2 inches
Correct answer: Greater than 1/2 inch to 1 inch
Cracks wider than approximately 1/2 inch benefit from routing to create a uniform reservoir that improves sealant adhesion and long-term performance.
Question 6: What is the recommended maximum cross-slope for a paved shoulder on a rural highway to promote drainage?
- 1%
- 2%
- 5% (Correct answer)
- 8%
Correct answer: 5%
AASHTO guidelines recommend paved shoulders have a cross-slope of approximately 4–5% to ensure positive drainage away from the travel lane.
Question 7: During a pavement condition survey, International Roughness Index (IRI) measures which roadway characteristic?
- The depth of rutting in the wheel paths
- The longitudinal profile variation that affects ride quality (Correct answer)
- The pavement surface friction number
- The structural number of the pavement layers
Correct answer: The longitudinal profile variation that affects ride quality
IRI quantifies the vertical deviations of a road surface that affect vehicle response and ride quality, expressed in inches/mile or m/km.
NETTCP Roadway Design & Maintenance 3
When patching a pothole using the throw-and-roll method, what is the MOST critical step to ensure patch durability?