Performance and mechanism analysis of waste edible oil recycled asphalt

Most existing research uses macroscopic experimental methods to study the rheological properties of waste edible oil modified asphalt It has not accurately revealed the regeneration mechanism of waste cooking oil rejuvenated asphalt by combining macroscopic and microscopic approaches." This study aims to analyze the performance of regenerated asphalt from waste edible oil and reveal its regeneration mechanism. The rheological properties of recycled asphalt from waste edible oil were evaluated through dynamic shear rheology and bending creep stiffness tests. The molecular weight distribution and microstructure of recycled asphalt were compared and analyzed by gel permeation chromatography and atomic force microscopy. The results showed that adding waste edible oil softened the aged asphalt, reduced its resistance to rutting, and restored its viscosity. Under different temperature conditions, the stiffness modulus S value of recycled asphalt decreased by more than 50 % compared to aged asphalt, while the creep rate m value increased by more than 30 % compared to aged asphalt. The results indicate that the high-temperature performance of recycled asphalt can be restored to the level of unaged asphalt, and the crack resistance of old asphalt can be improved. Compared with unaged asphalt, the Mw and Mn of aged asphalt increased by 14.1 % and 11.7 %, respectively. After adding waste cooking oil, compared with aged asphalt, Mw and Mn decrease, which adjusts the composition of aged asphalt and improves its compatibility. Compared with aged asphalt, the root mean square roughness Rq of recycled asphalt increased by 37.8 %, 50.1 %, 78.3 %, and 97.3 %, respectively, and the arithmetic mean roughness Ra increased by 17.9 %, 31.5 %, 34.2 %, and 72.6 %, respectively. The addition of waste edible oil suppressed the surface phase separation of aged asphalt, improved the roughness of aged asphalt, and restored its microstructural properties. Practice has proven that waste edible oil can be used as an asphalt rejuvenator, exerting its softening and regeneration effects.