UTC 2022 Funding - Cycle 1 Research Projects

Project No.: CY1-UTEP-02
Title: Investigation of Hot Mix Asphalt Aging Effect on Mechanical Properties of Mixes Based on Their Binder Performance Results
Performing Institution: The University of Texas at El Paso
Principal Investigator: Imad Abdallah and Miguel Montoya, The University of Texas at El Paso
Start and Anticipated Completion Dates: 09/01/2023-08/31/2024
Abstract: As hot mix asphalt (HMA) pavement layers undergo a complex aging process over time that changes their physical and chemical properties, it is important to develop guidelines for designing HMAs with improved resistance to aging. Equally important is to implement such guidelines. This study aims to investigate the effects of HMA aging on the mechanical properties of mixes, including cracking and strength using an overlay tester, indirect tensile test, IDEAL-CT, and performance grades of associated binders. Binders will be extracted and recovered from laboratory-aged HMA specimens prepared as part of a previous University of Texas at El Paso (UTEP) study on HMA aging with varying percentages of reclaimed asphalt pavement (RAP), binder contents, mix types, aggregate sources, and additives. Even though the rutting and cracking performance of these specimens were thoroughly documented in the previous study, no rheological tests were conducted on the binders extracted from them. The present study will help understand the effect of HMA aging on changes in binder performance as a function of RAP percentage, aggregate quality, rejuvenator dosage and type, and asphalt content. The outcome of this project in terms of technology readiness can help with the modification of design guidelines to produce cost-effective and sustainable pavements with longer life. The following tasks will be pursued to accomplish the aforementioned goals: (1) determination of rheology of binders extracted and recovered from laboratory-aged HMA specimens previously prepared and preserved under another study; (2) analysis of impacts of aging on binder performance as a function of mix properties; (3) evaluation of relationships between properties of extracted binders and traditional binders; (4) recommendations for the optimization of hot mix asphalt design. Specifically, the impact of aging on the binders’ performance grades and volumetric properties of asphalt mixes will be evaluated and used in making recommendations for the DOTs for mix design consideration. A final report will be prepared including preliminary guidelines to select appropriate asphalt binders for specific road conditions and environments. The results from this project are expected to help transportation engineers better understand aging asphalt binders over time and the development of durable asphalt mixtures. The research team will integrate Diversity, Equity, and Inclusion (DEI) considerations by engaging students from El Paso Community College and recruiting a female graduate student for this project.
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