Impacts of field and laboratory long-term aging on asphalt binders

Authors: SINGHVI, PUNIT - University Of Illinois; GARCIA MAINIERI, JAVIER - University Of Illinois; OZER, HASAN - Arizona State University; Sharma, Brajendra - Bk; AL-QADI, IMAD - University Of Illinois

Submitted to: Transportation Research Board
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2022
Publication Date: 5/11/2022
Citation: Singhvi, P., Garcia Mainieri, J.J., Ozer, H., Sharma, B.K., Al-Qadi, I.L. 2022. Impacts of field and laboratory long-term aging on asphalt binders. Transportation Research Board. https://doi.org/10.1177%2F03611981221083614.
DOI: https://doi.org/10.1177%2F03611981221083614

Interpretive Summary: Cracking in asphalt pavements is caused by deterioration of the asphalt binder due to environmental exposure over time. This is often referred to as aging in asphalt binders. To better select and formulate these binders knowing the realistic idea of aging extent is of utmost importance. This study aims to determine the realistic aging potential of asphalt binder exposed to field conditions for extended aging conditions of up to 31 years in Illinois region. The realistic aging correlated to laboratory aging methods using mechanical and chemical indicators for asphalt binders. The study also provided recommended thresholds for some of these indicators that will allow for better selection and formulation of these asphalt binders. This information will help in selecting biobased modifiers like vegetable oils, bio-oils for improving the aging. This work will improve the economic value of waste cooking/vegetable oils and bio-oils derived from biomass, thereby increasing utilization of farm products/waste biomass. This will also help farmers by increasing the value of waste biomass generated on the farms.

Technical Abstract: Asphalt binder aging accelerates flexible pavement cracking. Quantifying the extent of binder aging allows the formulation and selection of appropriate binders for flexible pavement applications. Asphalt binder aging depends on climatic exposure, asphalt concrete (AC) field surface density, and binder chemistry. The objective of this study was to select a laboratory aging protocol to represent realistic field aging in Illinois. Binders were extracted from field cores; which were aged eight to thirty-one years. Extracted binders were tested for rheology and chemical characteristics. Small- and large-strain rheological parameters were determined. In addition, chemical functional groups and molecular weight distribution of extracted binders were evaluated. Effect of aging across pavement depth was also investigated. This study identified double PAV as a suitable laboratory long-term, 8-12 years, aging protocol for Illinois flexible pavements. Thresholds were proposed for selected small- and large- strain rheological parameters representing realistic field aging. These thresholds may be used for binder selection and procurement to ensure binder’s long-term performance. Furthermore, chemical analysis on extracted binders showed that only specific carbonyl functional groups are affected by field aging.