Eco-friendly modification of bitumen: The effects of rubber wastes and castor oil on the microstructure, processability and properties

The bitumen industry in the European Union is facing several difficulties, including rising demand, unstable oil supply, rising prices for synthetic polymer modifiers, and a focus on lowering carbon footprint. Bitumen modification with crumb rubber (CR) is one of the most promising solution to these challenges. However, CRmodified bitumen have poor processability and low storage stability. To overcome these flaws we are introducing a sustainable approach for ecological modification of bitumen taking advantage of renewable resources. For this reason, unmodified castor oil was selected as a green modifier of reclaimed rubber dust. The ecologically modified bitumen underwent visco-elastic behavior analysis based on rheological tests varying the temperature. The modification with rubber -oil improved the longevity of typical pavement, featured by an exceptional deformation resistance at elevated temperatures (well above 70(degrees)C, the maximum pavement temperature reported in the region). The Cole -Cole graphs and black space diagrams unraveled the enhanced elasticity of bitumen. Technically, in comparison to plain bitumen, the compatibility ratio of modified bitumen to aggregates showed an uplift by 258%. The environmentally friendly bitumen modified ecologically herein revealed potential for performance window enlargement. Nevertheless, future investigations should focus on optimization of the bitumen formulation, along with examination of other sustainable moieties for the sake of commercialization of the developed binders in pavement construction.