Condition: Longitudinal joints are constructed with one, or more, of the following conditions:
- Crooked
- Excessive overlap
- Excessive build-up
- Unsightly appearance
- Uncovered areas
Figure 65 – Unacceptable Longitudinal Joint
Possible Causes: Although pavement geometry may contribute to difficulty in placing longitudinal joints, these conditions are typically related to poor construction practices.
- Lack of a pilot line to guide driver
- Improper box width
- Improper box operation
- Poor workmanship
- Inadequate box width for pavement
Prevention: Proper planning of the product application process by the contractor will ensure proper joint placement and construction.
- Use pilot lines as a guide for alignment in areas where necessary.
- Place longitudinal joints on lane lines utilizing a box width equal to the lane width, when possible.
- Operate the spreader box so that the joint has no more than 6.4 mm (0.25 inch) difference. in elevation when measured by placing a 3 meter (10 foot) straight edge over the joint and measuring the elevation difference.
- Keep longitudinal joint overlap to less than 76.2 mm (3 inches) unless the width of the pavement requires wider overlaps to keep the spreader box on the pavement surface.
- Eliminate gaps or uncovered areas at the longitudinal joint.
- Apply partial width passes only when necessary and not for the last pass of any paved area.
Inspector’s Note: During application, squeegees or drag mops are effective for eliminating small gaps and slight overlaps between adjacent lanes. If the longitudinal joints are not neat and aligned in a uniform manner, the contractor may be required to repair them with full width slurry surfacing.
Designer’s Note: In certain project situations (freeway ramps, cul-de-sacs, irregular pavement widths/geometries, etc.), specifications may require the use of application equipment with driving controls on both sides of the equipment.