Alternative bio-binders for road pavement based on cross-linking of oils

In the road paving sector, the reliance on fossil-derived bitumen is an issue. Here we developed bio-based substitutes of bitumen derived from vegetable oils, such as waste cooking oil (WCO) and epoxidized soybean oil (ESO), engineered to replicate the viscoelastic properties of bitumen through functionalisation and chemical cross-linking processes. Reaction of WCO unsaturated double bonds with molten elemental sulphur (inverse vulcanization) and reaction of ESO with phosphoric acid via its epoxy groups (cross-linking) proved to give final materials with adequate rheological properties. Evidence that the proposed approach is a sustainable alternative for the development of road binders based on renewable resources was given. • Waste cooking oil and epoxidised soybean oil were chemically cross-linked for use in bitumen field. • Reaction times were optimized to obtain final formulations with bitumen-like mechanical properties. • Optimal formulations allowed reduction in the use of bitumen of more than 50%.