Fog Sealing Chip Sealed Roads Can Improve Performance

Status:  Complete
Report Date:  10/28/2022


New research produced a best practices manual for local agencies to improve the chip seal experience. While chip sealing is frequently used by some agencies to fill small cracks and generally improve pavement conditions, it can result in loose, small stones that can damage windshields and be tracked back to driveways, yards and homes. Applying an additional product—a fog seal—shortly after chip sealing may alleviate many of these concerns and extend pavement life. In a project sponsored by the Local Road Research Board, investigators interviewed city and county transportation agencies in the state to understand their experiences with chip seal and fog seal. They also analyzed the costs and benefits of using fog seal and found that the additional pavement protection could be achieved at a relatively small cost. The agencies reported a reduction in loose rocks and needed maintenance, including street sweeping. Public comments indicated a fog-sealed road was more aesthetically pleasing, looking like new pavement and improving the visibility of street markings. Though chip seal is only appropriate for certain road types, including residential streets, agencies choosing to use it can add fog seal for improved pavement conditions and public satisfaction. A Best Practices Manual is available in Chapter 3 of the Final Report.

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