Component analysis of bio-asphalt binder using crumb rubber modifier and guayule resin as an innovative asphalt replacer

This research seeks to interpret the component analysis of an innovative bio-asphalt binder using guayule resin at high concentrations and crumb rubber modifier (CRM). Such asphalt modification aims to minimize the dependency on base asphalt and provide new solutions concerning sustainable, flexible pavement industry. Guayule resin is a promising bioresource for asphalt replacement. The provided interpretation could help in understanding the asphalt-rubber-guayule interaction mechanism. Fourier transform infrared spectroscopy (FTIR), supported by thermo-gravimetric analysis (TGA), was used to investigate the component analyses of guayule resin composition, asphalt-guayule interaction, and asphalt-rubber-guayule interaction, followed by oxidative aging behavior. Additionally, the rheological properties at high and intermediate temperatures were provided to link the microscale properties with the final product performance. The study clarified the distinct carbon and hydrogen compositional elements of guayule resin. Asphalt and guayule resin had similarities in component composition and rheological behavior with temperature susceptibility. Asphalt-guayule interaction yielded a physical blending, with no chemical reaction. Rubber seems to dissolve in both asphalt-rubber and asphalt-rubber-guayule interactions evenly. Devulcanization occurred, resulting in a partial migration of CRM polymeric components to the liquid binder. This was reflected in the enhanced performance of asphalt-rubberguayule blends at high temperatures. However, due to the strong oxidation bonding chains attributed to guayule resin, the oxidative aging negatively affected the guayule-based binder performance reflected on the intermediate temperature performance. The mix performance was initiated with the guayule-based binder's successful performance against rutting susceptibility, comparative to the base asphalt.