Is Seal Coating Counterproductive or Not?

Summary:

Researchers confirmed the widely held suspicion that freeze-thaw activity damages the bond between seal coats and pavements, and between the aggregate and binder of the coat itself. As freeze-thaw cycles repeat, damage increases. The research team ran extensive lab testing on samples from eight locations in Minnesota, evaluating bond strength between chip seals and underlying aggregate, as well as internal seal coat and asphalt mixture aggregate-binder bonds under various temperatures, moisture levels and freeze-thaw cycle exposures. With careful selection of seal coat chips and emulsions, as well as use at locations with strong subgrade drainage, seal coats can be effective and offer six to eight years of service, and in perfect conditions 15 years of service or more. Investigators identified optimal seal coat material combinations for low-temperature resistance and for freeze-thaw damage resistance.

Final Deliverables:

• Report #2020-34
• Research Summary

Related Materials:

• Investigating Asphalt Pavement Stripping Under Seal Coats  - (Blog Post)

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