Asphalt Rubber Chip Seal Evaluation in California



The California Department of Transportation (Caltrans) has successfully used asphalt rubber chip seals for over a decade. Over the last five years, there have been approximately forty projects completed. However, five of these have been reported as not performing as expected. The major complaint was that the chip seals were bleeding. Other
reported pavement distress included shoving and rutting. However, this evaluation was limited to the probable cause of the bleeding. Also, a series of test sections were evaluated to determine what effects that various changes to binder application rate, binder type, and aggregate gradation had on the performance of the chip seals. The findings were; high truck traffic volumes, highway geometry, high binder application rate, and non-uniformly graded
aggregates contributed to the bleeding.

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