Civil and Environmental Engineering
First Advisor
Hamzeh F. Haghshenas
Second Advisor
Jamilla Teixeira
Third Advisor
Mehrdad Negahban
Date of this Version
Summer 5-2023
Citation
Ahmad, M. (2023). Sustainable Revitalization of Asphalt Pavements: An In-Depth Analysis of Enhancing the Performance of Asphalt Binder Through the Application of Rheological and Molecular Dynamics Simulation Techniques. Master's Thesis. University of Nebraska-Lincoln.
Abstract
Vegetable-based oils such as corn and soybean oil have triglycerides and fatty acids that allow them to be considered sustainable and effective recycling agents (RAs) for aged asphalt binder. However, there are concerns about their effect on the recycled asphalt binder's long-term performance, moisture damage resistance, and self-healing characteristics restoration. In this study, crude corn oil (CO) and crude soybean oil (SO) were used as RAs to restore the performance of a reclaimed asphalt binder (RAB) extracted from reclaimed asphalt pavement. The binder extracted from RAB was modified with a neat binder PG64-28 and RAs to restore the high-end performance grade. To address concerns about the long-term performance of the RAs, the modified binders were further modified with either dilauryl thiodipropionate (DLTDP) or zinc diethyldithiocarbamate(ZnDEC) as antioxidants (AO) and rheological, chemical, and moisture susceptibility analyses were conducted. Adding ZnDEC improved the binder’s rheological efficacy at resisting long-term aging but reduced the binder’s moisture resistance while adding DLTDP did not improve efficacy and resulted in inferior binders. The binders modified with RA and AO were tested for damage susceptibility and self-healing (H%) using simplified viscoelastic continuum damage theory (S-VECD) to observe whether the addition of CO restored the self-healing properties of the binder. The use of CO improved the damage resistance and H%. Later, molecular models were prepared for the studied modified binders using molecular dynamics simulation to test the capability of CO to restore rheological properties, damage resistance, and H%. The simulation showed that CO improved the modified binder model's density, viscosity, glass transition temperature, and self-healing ability. The study recommends using natural bio-oils and organic antioxidants to improve the performance of recycled binders and exploring their usefulness and their relation to life‑cycle analysis and cost analysis.
Advisor: Hamzeh Haghshenas Fatmehsari
Comments
A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfilment of Requirements For the Degree of Master of Science, Major: Civil Engineering, Under the Supervision of Professor Hamzeh F. Haghshenas. Lincoln, Nebraska: May 2023
Copyright © 2023 Muhammad Ahmad
Published as https://journals.sagepub.com/doi/10.1177/03611981231161607