Condition: The finished surface has scratches, drag marks, tears, or other surface irregularities.
Figure 64 – Excessive Drag Marks and Scratches
Possible Causes:
- High/Low application rate,
- Oversized aggregate (not using scalping screen),
- Spreader box cleanliness
- Debris on existing pavement surface.
Prevention:
- Ensure the proper application rate for the aggregate gradation used.
- Use a scalping screen (properly sized) to remove oversized aggregate before it enters the application equipment.
- Keep the spreader box and strike-off rubbers free of broken slurry surfacing materials by cleaning as needed each time the application equipment stops.
- Use a secondary strike-off to eliminate drag marks and provide a uniform surface texture.
- Properly clean and prepare the existing surface according to Section VI.B.2, page 39, Surface Cleaning.
Inspector’s Note: An experienced crew can repair small tears, damaged areas, and drag marks before the emulsified asphalt breaks using hand squeegees and drag mops. They can also make hand repairs between double strike-offs so that the marks cannot be seen after the second strike-off passes over it. Small, isolated areas can be addressed provided they are squared off and have an appearance consistent with the rest of the slurry surfacing as excessive repairs may lead to a non-uniform appearance. Larger repairs should be full width and completed using the application equipment and spreader box to match the existing lane width. The repairs need to be long enough to cover the damaged are.