Correlating Long-Term Chip Seals Performance and Rheological Properties of Aged Asphalt Binders

Two most common distresses found in chip seals are raveling and bleeding. Although raveling is a process that continues throughout the whole service life of chip seals, current performance tests available for chip seals focus mainly on early raveling and bond maturation. In this study, chip seals binders from the field were extracted and recovered for two consecutive years. Rheological properties of original, field-aged, and laboratory-aged binders were compared. Results showed that pressurized aging vessel (PAV-) aging simulates 3 to 4years of field-aging for hot asphalt and less than 3years for emulsion. Strain tolerance, shear stress at failure, oxidative aging index, and yield energy of the binder were correlated with long term field performance (raveling). Shear stress at failure of field-aged binders showed strong correlation with long-term field performance, exhibiting an R2 value of 0.95. However, yield energy (a product of strain tolerance and shear stress at failure) of original binder, which showed an R2 value of 0.83 with long-term field distress rating (raveling), was recommended as performance parameter for chip seals binder.