Chip seals, used for pavement surfacing, rehabilitation, maintenance, and preservation, cover over 7,000 miles of roadway in Washington state. Chip seals (or bituminous surface treatments) involve the application of emulsified asphalt, followed by the spreading of chips and choke stone, compaction, sweeping, and application of a fog seal. The cost of a chip seal project per lane mile is far less than that of hot mix asphalt. However, an inability to accurately measure and control the percentage of chip embedment contributes to unpredictable variation in the performance of chip seal projects. A laser scanner could be used to determine the percentage of chip embedment both quickly and accurately. The device is portable and smaller than a nuclear gauge. However, even though laser scanners have shown great potential, no one has systematically evaluated this tool for use in chip seal construction. In addition, a specification for the required percentage of chip embedment and a test protocol for the laser scanner are needed. This project will draft a specification for the appropriate percentage of chip embedment and will develop a test protocol for the use of a laser scanner in chip seal construction. The results should help prevent premature failure of chip seals and lower pavement life cycle costs.
Principal Investigator: Haifang Wen, Civil and Environmental Engineering, WSU
Sponsor: WSDOT
WSDOT Technical Monitors:
Kevin Littleton
Kim Schofield
WSDOT Project Manager: Jon Peterson
Scheduled completion: December 2023