# Effect of an Organic Rectorite on the Properties of a Waste Engine Oil-Modified Asphalt
## 4 Conclusions  
The OREC + WEO composite-modified asphalt was prepared by adding four different OREC content levels to the WEO-modified asphalt. A series of tests were conducted to investigate the impact of OREC on the chemical structure, storage stability, rheological properties, and self-healing property of the composite-modified asphalt. The main conclusions are as follows:  
1. Compared to WEO-modified asphalt, OREC + WEO composite-modified asphalt did not show any new peaks related to chemical reactions, indicating that OREC and WEO-modified asphalt are only physically mixed. Therefore, the influence of OREC on the macroscopic properties of WEO-modified asphalt mainly manifests in the physical form.
2. Adding OREC improves the storage stability of WEO-modified asphalt. Compared to WEO-modified asphalt, the 48-h softening point difference of the composite-modified asphalt with 2% OREC content decreased from 2.8 \({}^{\circ}\)C to 1.8 \({}^{\circ}\)C, meeting the requirements of \"Technical Specifications for Highway Asphal Pavement Construction\" for polymer-modified asphalt storage stability (\(\leq\)2.5 \({}^{\circ}\)C).
3. Adding OREC can enhance the stiffness, elasticity, and resistance to putting of WEO-modified asphalt at high temperatures, but it has a negative impact on low-temperature crack resistance and the self-healing property. However, only when the OREC content reaches 2% does the corresponding composite-modified asphalt exhibit better high- and low-temperature performance and self-healing property than the base asphalt. Therefore, the introduction of OREC can fully compensate for the performance loss caused by WEO in asphalt, and the OREC content is recommended to be 2%.
4. The findings of this research shed light on the potential benefits of using an organic recrotite as an additive in waste engine oil-modified asphalt and could be valuable for paving material engineers and researchers seeking sustainable and high-performance asphalt solutions. However, it is essential to further evaluate the impact of OREC on the aging resistance of WEO-modified asphalt, and we note that further research  
Figure 8: Test results of healing index of base asphalt and WEO/OREC-modified asphalt.  
and field tests may be required in order to validate the practical application and long-term performance of this modified asphalt mixture. Additionally, it is essential to compare the effects of OREC with other types of nanoclays on the performance of WEO-modified asphalt.  
Conceptualization and investigation, M.J. and D.W.; methodology and resources, X.L.; software and validation, D.Y. and X.L.; formal analysis and data curation, S.Y.; writing--original draft preparation, D.Y.; writing--review and editing, M.J.; visualization and supervision, A.C.F. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Guangxi Transportation Science and Technology Demonstration Project (Grant number 2023-0002).  
Not applicable.  
Access to any other materials can be requested by writing to the corresponding authors.  
The authors declare no conflict of interest.