Use of a Double Chip Seal to Correct a Flushing Hot Mix Asphalt Pavement in Washington State

A chip seal constructed on an existing flushed roadway has the potential to result in bleeding or flushing of the new chip seal. The excess binder, if not properly accounted for during design and construction, will migrate to the surface of the chip seal and fill the aggregate void spaces leaving a flushed surface. The Washington State Department of Transportation (WSDOT) elected to construct a double chip seal to mitigate a flushing section of pavement on SR 20. This report documents the design and construction of the double chip seal and provides information on its initial performance. The double chip seal will be monitored for up to five years at which a final report will be prepared including conclusions as to its success or failure.