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Pavements 2025

Asphalt Binder and Mixture Characterization

POSTER RECEPTION (View list of posters here)

Developing a Long-term Aging Protocol for Asphalt Cracking Evaluation in Virginia

Tuesday, June 10, 2025

4:45 PM – 6:00 PM MT

Co-Author(s)

Elie Hajj, PhD

Professor
University of Nevada, Reno
Reno, Nevada, United States

Presenter(s)

Elie Hajj, PhD

Professor
University of Nevada, Reno
Reno, Nevada, United States

Co-Author(s)

IA

Iftekar Alam, n/a

Graduate Research Assistant
University of Nevada Reno
Reno, Nevada, United States
HE

Habib El Hajj, M.S., EIT

Pavement Engineer
Terracon Consultants, Inc.
Indianapolis, Indiana, United States
Ilker Boz, PhD (he/him/his)

Senior Research Scientist
virginia transportation research council
Charlottesville, VA, United States

Presenter(s)

Ilker Boz, PhD (he/him/his)

Senior Research Scientist
virginia transportation research council
Charlottesville, VA, United States

Primary Author(s)

JH

Jhony Habbouche, n/a

Western US Regional Engineer
Asphalt Institute
Gilbert, Arizona, United States

Co-Author(s)

JH

Jhony Habbouche, n/a

Western US Regional Engineer
Asphalt Institute
Gilbert, Arizona, United States

Presenter(s)

JH

Jhony Habbouche, n/a

Western US Regional Engineer
Asphalt Institute
Gilbert, Arizona, United States

Co-Author(s)

Stacey D. Diefenderfer, Ph.D., P.E.

Associate Principal Research Scientist
Virginia Transportation Research Council
Charlottesville, Virginia, United States

Submitter(s)

JH

Jhony Habbouche, n/a

Western US Regional Engineer
Asphalt Institute
Gilbert, Arizona, United States

Abstract: The Virginia Department of Transportation (VDOT) currently requires the use of the Indirect Tensile Cracking Test (IDT-CT) as per ASTM D8225-19 in its Balanced Mix Design (BMD) specification to assess the cracking susceptibility of its dense-graded asphalt surface mixtures (SM). A minimum cracking tolerance (CT) index of 70 is recommended for laboratory-produced (after loose mix short-term oven aging) and reheated plant-produced asphalt mixtures to mitigate cracking susceptibility.
While the current CT index criteria is indicative of the cracking performance of asphalt mixtures, it does not consider the impact of oxidative aging over time. Therefore, laboratory evaluation of the long-term oxidative aging characteristics of asphalt mixtures is critical to ensure their durability throughout their service life.
This study has two main objectives (I) to develop a practical long-term aging protocol for asphalt SMs that can be used for mix design verification and production quality control and acceptance; and (II) to establish preliminary performance criteria for the CT index based on the developed long-term aging protocol.
The study evaluated ten asphalt mixtures with different reclaimed asphalt pavement (RAP) contents and asphalt binder performance grades. These mixtures underwent laboratory oven-aging at 95°C and 135°C (or higher, as the compaction temperature) to determine suitable aging durations. The CT index of the asphalt mixtures was measured, and the rheological and chemical properties of both virgin and recovered asphalt binders were analyzed. Results indicated a reduced aging duration at 95°C and an equivalent accelerated aging duration at compaction temperatures. Preliminary CT index criteria were developed based on the relationship between the CT index values and their corresponding Glover-Rowe Parameter of the recovered asphalt binders.
Finally, a series of mechanistic pavement simulations were conducted to assess the effect of aging on the performance of the asphalt mixtures within typical pavement structures in Virginia. The findings from these mechanistic simulations contributed to the verification of the performance criteria established for the CT index after long-term oven aging.

Learning Objectives:

Attendees can expect to learn the following from this session:

Upon completion, participants will be able to gain insights on how oxidative aging affects the performance of dense-graded asphalt surface mixtures throughout their service life.
Upon completion, participants will learn to develop/apply practical long-term aging protocols for asphalt surface mixtures that can be utilized in mix design verification and production for quality control and acceptance.
Upon completion, participants will be equipped to understand the relationship between the CT index of asphalt mixtures under various aging conditions and the Glover-Rowe Parameter of recovered asphalt binders.