NCHRP Synthesis 342 - Chip Seal Best Practices


Douglas Gransberg and David M.B. James


This synthesis report provides an overview of successful chip seal practices in the United States, Canada, and overseas. Although not meant to be an exhaustive study, it covers the spectrum of chip seal practice and presents, where possible, the state of the art, as reported in the literature and survey responses. The report presents ways to assist in the development and implementation of pavement preservation programs by identifying the benefits of using chip seal as part of a preventive maintenance program. Innovative and advanced chip seal programs from around the world were identified with respect to critical factors that can be incorporated by other transportation agencies. Approximately 40 best practices were identified in the areas of chip seal design methods, contract administration, equipment practices, construction practices, and performance measures. The increased use of chip seals for maintenance can be a successful, cost-effective way of using preventive maintenance to preserve both low-volume and higher-volume pavements.