# Effect of Waste Engine Oil and Waste Cooking Oil on Performance Improvement of Aged Asphalt
## 4 Results and Discussion
### Rheological Properties
#### 4.6.3 Putting Resistance Factor (G*/sin\(\delta\))  
The test results of rutting resistance factor of rejuvenated asphalt with WEO and WCO at 5 h and 15 h are presented in Figures 15 and 16, respectively. WCO and WEO affect the rutting resistance of the rejuvenated asphalt by improving its viscosity. As shown in Figures 15 and 16, the rutting resistance factor decreased with increasing temperature. With the same temperature, the rejuvenated asphalt of aging 15 h had smaller rutting resistance than that of aging 5 h, which proved that longer aging time had a negative influence on the high-temperature property. At the same aging time, the rutting resistance factor decreased notably with the content and temperature increasing.  
When the temperature was up to 70 \({}^{\circ}\)C, the rutting resistance factor reduced notably and it decreased sharply with a temperature higher than 76 \({}^{\circ}\)C. Therefore, the increase in waste oil content did not lead to a larger rutting resistance factor. Though the WCO and WEO were much more important for property recovery of aged asphalt and high-temperature performance of rejuvenated asphalt,  
Figure 14: Effects of WCO on complex modulus of rejuvenated asphalt (different aging time of VA).  
Figure 13: Effects of WEO on complex modulus of rejuvenated asphalt (different aging time of VA).  
there should be reasonable choice according to the asphalt performance requirements and maximum temperature in the construction region.  
There were different reductions for rejuvenated asphalt in rutting resistance factor. At the same temperature, aging time and waste oil dosage, rejuvenated asphalt with WEO had much smaller rutting resistance factor than that with WCO. With temperature increasing, the decreasing extent of rejuvenated asphalt with WCO was lower than that with WEO, especially when the temperature was higher than 76 \({}^{\circ}\)C (this was similar with the conclusions of softening point and viscosity). Meanwhile, this illustrated that the WCO and WEO could both recover part of the performance of aged asphalt, but WCO could achieve the same results with less content. The conclusions confirmed the previous analysis which WCO had better regeneration effect than WEO with different aged asphalts.  
In addition, rutting resistance factor reflected unrecoverable deformation of asphalt during the loading process. At high temperature, bitumen with higher G*/sin8 but smaller flow deformation would have much higher rutting resistance. All these facts indicated that the rutting resistance had satisfactory improvement with waste oil content range of 1 to 3%. When the dosage was more than 3% and the temperature was higher 76 \({}^{\circ}\)C, the WCO could keep better high temperature property. Therefore, the range of 1 to 3% was a more suitable dosage with WEO and WCO for better high temperature performance, which depended on the aged asphalt condition and actual construction requirements.  
Figure 16: Influences of WCO on rutting resistance factor of rejuvenated asphalt (different aging time of VA).  
Figure 15: Influences of WEO on rutting resistance factor of rejuvenated asphalt (different aging time of VA).