KDOT Asphalt & Concrete Paving Inspection 4 — Questions and Answers
Question 1: During asphalt paving, the inspector measures mat thickness and finds it consistently 1/2 inch thin on the right side of the lane. The most likely cause is:
- The paver is traveling too fast on the right side
- The screed is tilted, causing uneven head of material on one side (Correct answer)
- The aggregate gradation is too coarse on the right side
- The roller is making extra passes on the right side
Correct answer: The screed is tilted, causing uneven head of material on one side
Consistent thickness variation across the mat width typically indicates a tilted or unevenly adjusted screed, causing more or less material on one side.
Question 2: What is 'bleeding' in asphalt pavement and what does it indicate?
- Asphalt binder migrating to the surface, indicating excess binder in the mix or inadequate air voids (Correct answer)
- Water seeping up through cracks, indicating drainage problems
- Aggregate particles pulling out under traffic, indicating poor bond
- Roller marks remaining visible, indicating compaction was inadequate
Correct answer: Asphalt binder migrating to the surface, indicating excess binder in the mix or inadequate air voids
Bleeding occurs when excess asphalt binder migrates to the pavement surface, filling air voids and creating a shiny, slippery film that reduces skid resistance.
Question 3: When should an inspector verify that concrete forms are properly staked, braced, and oiled before a concrete paving pour?
- Immediately after the concrete is placed and struck off
- The morning of the pour, just before concrete arrives
- At least the day before the scheduled pour (Correct answer)
- During the pour when concrete is being placed against the forms
Correct answer: At least the day before the scheduled pour
Forms must be inspected at least the day before placement to allow time for corrections; checking forms only at pour time leaves no margin for fixing alignment or stability issues.
Question 4: What does 'raveling' in asphalt pavement describe, and what are the common causes?
- Longitudinal cracking from shrinkage of the binder
- Progressive loss of aggregate particles from the surface, caused by insufficient binder, poor aggregate bond, or early traffic loading (Correct answer)
- Deformation of the surface from excessive roller compaction
- Disintegration of the base course beneath the asphalt
Correct answer: Progressive loss of aggregate particles from the surface, caused by insufficient binder, poor aggregate bond, or early traffic loading
Raveling is the loss of aggregate from the pavement surface, resulting from inadequate binder content, poor coating of aggregate, construction during cold/wet conditions, or traffic before sufficient curing.
Question 5: An inspector finds that a concrete pavement joint was sawed too late. What is the likely consequence?
- The saw cut will be too deep, weakening the slab
- Uncontrolled random transverse cracking may have already occurred before sawing (Correct answer)
- The joint will not bond properly when sealed
- Aggregate interlock across the joint will be eliminated
Correct answer: Uncontrolled random transverse cracking may have already occurred before sawing
If joints are not sawed within the required time window (typically 4–24 hours after placement depending on conditions), uncontrolled cracks may develop ahead of the saw.
Question 6: What minimum compaction temperature is generally required before static steel-wheel finishing passes are made on HMA pavement?
- Above 280°F
- Above 200°F (Correct answer)
- Above 185°F
- There is no minimum — finish rolling can occur at any temperature
Correct answer: Above 200°F
Finish rolling typically occurs while the mat is still above approximately 200°F to remove roller marks without cracking the asphalt surface.
Question 7: On a KDOT project, the contractor wishes to pave during a rain shower. The inspector's appropriate response is:
- Allow paving if the rain is light and temperature is above 60°F
- Stop paving immediately; asphalt must not be placed on a wet surface (Correct answer)
- Allow paving but require two additional roller passes
- Allow paving if a curing compound is applied immediately
Correct answer: Stop paving immediately; asphalt must not be placed on a wet surface
Asphalt must not be placed on a wet or water-covered surface because moisture prevents proper bonding and can cause steam pockets, leading to delamination and accelerated pavement failure.
KDOT Asphalt & Concrete Paving Inspection 4
During asphalt paving, the inspector measures mat thickness and finds it consistently 1/2 inch thin on the right side of the lane.
The most likely cause is: