PIC Pavement Joints & Longitudinal Seam Construction 2 — Questions and Answers
Question 1: A transverse (butt) joint at the start of a new paving day is properly formed by:
- Feathering the existing mat edge to a gradual taper
- Cutting back the previously placed mat vertically to full compacted depth (Correct answer)
- Applying a cold patch flush with the existing surface
- Milling a keyway groove across the full pavement width
Correct answer: Cutting back the previously placed mat vertically to full compacted depth
Cutting back to a clean, full-depth vertical face ensures the new material bonds at full thickness and achieves proper density at the transverse joint.
Question 2: When ending a paving operation at a transverse joint, the inspector should verify that the mat has been:
- Feathered to a thin edge to blend smoothly with the existing surface
- Cut perpendicular to the paving direction at full compacted depth with a vertical face (Correct answer)
- Raked smooth and left without any cutting
- Sealed immediately with hot joint filler while still above 250°F
Correct answer: Cut perpendicular to the paving direction at full compacted depth with a vertical face
A full-depth perpendicular cut provides a clean vertical face so the next paving operation can butt against it at full mat thickness.
Question 3: What is the primary purpose of applying tack coat to a transverse joint face before resuming paving?
- To prevent the new mat from adhering to the cold joint surface
- To promote adhesion between the new HMA and the existing cured asphalt face (Correct answer)
- To accelerate cooling of the new material at the joint
- To satisfy environmental bonding regulations required by the EPA
Correct answer: To promote adhesion between the new HMA and the existing cured asphalt face
Tack coat creates a bonding interface between the cured existing asphalt and the new HMA, reducing the risk of delamination and water ingress at the transverse joint.
Question 4: What is the recommended rolling direction for achieving proper density at a transverse joint during breakdown compaction?
- Roll parallel to the joint from the hot side toward the cold side
- Roll perpendicular to the joint, beginning on the cold side and moving into the hot mat (Correct answer)
- Roll diagonally at 45 degrees across the joint
- Avoid direct rolling on the transverse joint face
Correct answer: Roll perpendicular to the joint, beginning on the cold side and moving into the hot mat
Rolling perpendicular to the transverse joint, beginning on the cold side, presses material into the joint face rather than pushing it away from the joint.
Question 5: Immediately before paving resumes at a transverse joint, which set of conditions should the inspector verify?
- The joint area is clean and dry, tack coat has been applied, and the face is cut to full compacted depth (Correct answer)
- A prime coat has been applied and the joint area has been trafficked for 30 minutes
- The adjacent lane has been milled to create a smooth entry taper
- Fresh aggregate has been spread over the joint face to improve texture
Correct answer: The joint area is clean and dry, tack coat has been applied, and the face is cut to full compacted depth
A clean, full-depth vertical face with tack coat ensures maximum bond strength and prevents contamination at the transverse joint, which is a common location for early pavement failure.
Question 6: After compaction, the surface elevation at a properly constructed transverse joint should be:
- 0.25 inch (6 mm) higher than the adjacent surface to allow for traffic wear
- Flush with or within the specified smoothness tolerance of the existing surface (Correct answer)
- 0.25 inch (6 mm) lower to allow for a future overlay
- Elevation at transverse joints is not included in smoothness specifications
Correct answer: Flush with or within the specified smoothness tolerance of the existing surface
Transverse joints must be flush with adjacent pavement to prevent bumps that cause ride quality failures and stress concentrations that lead to cracking.
Question 7: Which tool is most commonly used by inspectors to evaluate the surface profile across a completed longitudinal or transverse joint?
- Nuclear density gauge positioned over the joint
- Straightedge or profilograph placed across the joint (Correct answer)
- Marshall stability hammer on a core extracted at the joint
- Solvent extraction equipment to check binder content at the seam
Correct answer: Straightedge or profilograph placed across the joint
A 10- or 16-foot straightedge placed across the joint reveals humps, ridges, or low spots that indicate improper joint construction or compaction.
PIC Pavement Joints & Longitudinal Seam Construction 2
A transverse (butt) joint at the start of a new paving day is properly formed by: