Effect of catalytic esterification of waste cooking oil on the rejuvenation performance of aged asphalt

To mitigate the environmental impact of reclaimed asphalt pavement (RAP) and waste cooking oil (WCO), and enhancing the utilization efficiency of WCO in asphalt rejuvenation. This study employed catalytic esterification to reduce the fatty acid (FFA) content of WCO before incorporating it to aged asphalt to prepare rejuvenated asphalt. Rutting resistance, low-temperature deformation resistance and fatigue resistance properties of rejuvenated asphalt binders were assessed through rheological tests, while the microscopic morphology and functional group characteristics were analyzed using atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). Results from Dynamic shear rheometer (DSR) tests revealed that rejuvenated asphalt containing 6 % catalytically esterified WCO (C6) exhibited superior resilience to high-temperature deformation compared to virgin asphalt, yet retained comparable creep recovery efficacy. Additionally, the fatigue life at 5 % strain increased by 71.63 % compared to virgin asphalt. In contrast, 6 % original WCO rejuvenated asphalt (O6) exhibited inferior high-temperature and fatigue properties compared to the C6. Moreover, bending beam rheometer test (BBR) results demonstrated the creep rate of C6 at −24℃ is 4.15 % and 17.84 % higher than that of virgin asphalt and O6 respectively, revealing superior low-temperature flexibility. AFM images revealed that the microscopic morphology of both C6 and virgin asphalt displays a ‘honeycomb’ structure and continuous-phase composite structure. Additionally, the arithmetic average roughness (R a ) and root mean square roughness (S q ) for C6 decreased by 29.05 % and 12.72 %, respectively, relative to those of O6. These results indicated that the catalytic esterification of the WCO rejuvenator provides superior rheological properties for aged asphalt. FTIR spectra suggested that no chemical reaction occurred when the catalytically esterified WCO rejuvenator was added to the aged asphalt. Overall, the incorporation of catalytic esterification WCO into aged asphalt, markedly rejuvenating the aged asphalt's characteristics and showing enhanced stability at high temperature and superior performance at low temperature compared to virgin asphalt. • Catalytic esterification was utilized to process waste cooking oil (WCO) to reduce its fatty acid content. • Catalytic esterification of WCO asphalt rejuvenator at an optimum dosage of 6 %. • 6 % catalytically esterified WCO rejuvenated asphalt shows better low temperature properties and fatigue resistance.