Condition: Even though the rut filling project and materials were properly selected, the final rut filling application did not correct the depressions in the wheel paths.
Possible Causes:
- Underfilled rut
- Improperly crowned rut
- Application of emulsified asphalt at the higher end of the mix design tolerances
- Improperly operated and maintained rut box
- Premature release to traffic
- Premature application of surface course after rut filling
Prevention:
- Monitor rut filling operations with a straightedge to ensure that the ruts are being filled completely.
- For every inch of rut depth, add a 3.2 mm (0.125 inch) to 6.4 mm (0.25 inch) crown to allow for compaction under traffic.
- Apply the mixture at the lower end of the emulsified asphalt mix design tolerance.
- Adjust the box as the rut depth changes and clean as needed.
- Ensure that the application has cured sufficiently to support return to traffic.
- Require a minimum of 24 hours of traffic for compaction before placing the final surface course.
Designer’s Note: For more information on proper site selection on rut filling, refer to Section VI.E.4, Rut Filling.