Analysis of Aggregates and Binders Used for the ODOT Chip Seal Program

Chip seals are widely used for preventative maintenance of pavements. While there has been extensive research on the various parts of the surface treatment, there is little research on how the various materials and methods are brought together. Hence, chip sealing continues to be considered an art rather than a rationally engineered composite system. In most cases Oklahoma Department of Transportation (ODOT) maintenance engineers use empirical design based on trial and error. Additional technical information is needed that defines binder selection based on environment and local traffic conditions. This information must be integrated with locally available aggregate properties to permit ODOT engineers to calculate appropriate emulsion/binder and aggregate application rates during chip seal placement based on local conditions. This information can then be used to revise ODOT chip seal specifications and update ODOT chip design methods. The major products of this project will be recommendations for revising ODOT chip seal specifications, fine-tuning division-specific chip seal design procedures, and training for ODOT maintenance engineers in each division.