# Determining the Compaction Temperature of Warm-Mix Anti-Rutting Asphal Mixture
## 5 Conclusions  
Through experimental research on the compaction characteristics of warm-mix anti-rutting asphalt mixtures, the compaction temperatures of the warm-mix anti-rutting asphalt mixtures were determined using the viscosity-temperature curve of asphalt material and the voids-temperature curves of asphalt mixtures through saturated surface-dry and CT scanning and comparatively studied. The main conclusions are as follows:  
1. Based on the softening point and viscosity, the optimal dosage of the anti-rutting agent was determined to be 6% of the asphalt weight. AC-20 dense-graded asphalt mixtures were designed and prepared with 6% anti-rutting agent and four levels of warm-mix-agent contents (0%, 1%, 2%, and 3%).
2. The compaction temperature was determined from the viscosity-temperature curve. When the content of the warm-mix agent increased from 0% to 3%, the mixing and compaction temperatures of the warm-mix anti-rutting composite-modified asphalt mixture only decreased by 7.72% and 7.90%, whereas in the continuous temperature compaction test, as the content of the warm-mix agent increased from 0% to 3%, the compaction temperatures determined by the voids-temperature curves based on saturated surface-dry and CT scanning were fundamentally decreased by 22.7% and 19.2%, respectively, much more significant compared to the viscosity-temperature curve.
3. Based on the compaction temperature determined by the equal voids method from the continuous compaction test, the compaction characteristics of warm-mix anti-rutting asphalt mixture was evaluated via a rutting test and a uniaxial penetration test, and the results showed that when the content of the warm-mix agent increased from 0% to 3%, the dynamic stability was improved by 9%, and the shear strength was increased by 29.1%.
4. The additions of a warm-mix agent and an anti-rutting agent to asphalt lead to a complex and diverse composition, thus causing the viscosity to change abnormally with temperature. Therefore, the viscosity-temperature curve is no longer applicable to determine the compaction temperature of a warm-mix anti-rutting-modified asphalt mixture. It is recommended to use a voids-compaction temperature curve, either from saturated surface-dry or CT scanning, to determine the compaction temperature of the warm-mix anti-rutting composite-modified asphalt mixture.  
In this study, the effect of compaction temperature on voids was visually analyzed using CT scanning. Image processing was performed to identify voids. However, voids smaller than the resolution of the CT scanner and consideration of all cross-sections of the specimen are important and should not be ignored; this will be the focus of our research in future work.  
[PERSON]. ([PERSON]), investigation, formal analysis, methodology, and funding acquisition; [PERSON]. ([PERSON]), laboratory test, investigation, data curation, and writing--original draft; Y.H., conceptualization, supervision, funding acquisition, and writing--review and editing; Y.C.,laboratory test and data curation. All authors have read and agreed to the published version of the manuscript.  
This work was supported by National Natural Science Foundation of China (52278437); Science and Technology Innovation Program of Hunan Provincial Department of Transportation (202236); and Open Fund of Engineering Research Center of Catastrophic Prophylaxis and Treatment of Road & Traffic Safety of Ministry of Education (Changsha University of Science & Technology) (kfj210401).  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
Author [PERSON] was employed by the company China Communications Construction Co., LTD. The remaining authors declare that the re-search was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.