(304h) Lifecycle Assessment of Bio-Based Rejuvenators for Asphalt: Seso and Biomag

Field trials conducted on low-volume roads in Minnesota—including MnROAD test tracks and public infrastructure—demonstrated the practical effectiveness of both materials. Both treatments reduced pavement stiffness and improved binder flexibility, with BioMag-treated sections showing statistically significant stiffness reductions compared to untreated controls. Utilizing domestically produced soybean oil, SESO and BioMag enable localized supply chains and support circular economy models within agriculture and materials processing. Their rapid curing times, preserved skid resistance, and compatibility with standard maintenance operations further support practical implementation.

To evaluate environmental performance, a cradle-to-gate life cycle assessment (LCA) was conducted using pilot-scale production data. System boundaries included soybean cultivation, oil extraction, epoxidation (for SESO), and additional polymer synthesis and blending (for BioMag). The LCA quantified environmental burdens associated with raw material cultivation, chemical processing, and product formulation, using impact categories such as global warming potential (GWP), human toxicity, etc. SESO, produced via partial epoxidation, exhibited a lower overall environmental footprint due to its simpler synthesis and higher yield. BioMag, though more complex to produce, offers enhanced durability and longer service life, potentially reducing lifecycle emissions associated with frequent pavement treatments.

Preliminary results suggest SESO may offer economic advantages due to its straightforward processing, while BioMag may deliver greater long-term performance and reduce reliance on fossil-derived polymers. Using SESO in mixtures with 40% reclaimed asphalt pavement (RAP) reduces the total carbon footprint from approximately 63 kg CO₂-eq per ton of mix to 47 kg CO₂-eq per ton, a 25% reduction in greenhouse gas emissions. Total energy use is also reduced by up to 33%, due to lower demand for virgin binder and aggregate. At high RAP content, the rejuvenator contributes roughly 5–6 kg CO₂-eq per ton, underscoring the importance of selecting low-impact alternatives like SESO to maximize net environmental benefit.

Sensitivity analyses revealed that soybean oil pricing, catalyst efficiency, and solvent recovery are key factors influencing environmental impacts. Although neither rejuvenator is currently produced at commercial scale, this work highlights the trade-offs between performance, environmental sustainability, and scalability. It offers a framework for the future deployment of bio-based rejuvenators in asphalt infrastructure and underscores the potential for soybean-derived materials to improve pavement resilience while lowering environmental burden.