A method for characterising RAP degree of binder activity

Abstract

Most transportation agencies in the United States continue to assume reclaimed asphalt pavement (RAP) contributes 100% of its binder to a new asphalt concrete (AC) mixture despite mounting evidence to the contrary, leading to mixtures with insufficient binder and resulting in workability and durability issues. This research assessed the practicality of estimating a realistic reduced RAP binder activity for consideration in AC mixture design based on indirect tensile (IDT) strength testing of 100% RAP mixtures. The concept and methodology of the Degree of Binder Activity (DoA) was reviewed, modified, and estimated for RAP materials from six states with varying climates in the United States. Pending further validation, the DoA methodology was determined to be practical for inclusion in existing mixture design methods.

KEYWORDS:

• Reclaimed asphalt pavement (RAP)
• degree of activity (DoA)
• binder blending
• indirect tensile (IDT) strength

Acknowledgements

The authors want to acknowledge the hardworking technicians at the Texas A&M Transportation Institute Center for Infrastructure Renewal for their assistance with the laboratory work in this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).