# A Study of the Bond Strength and Mechanism between Basalt Fibers and Asphalt Binders
## 4 Conclusions  
In this study, the bond strength between basalt fibers (BFs) and asphalt binders was investigated using a pull-out tester. Based on the test results and the discussion above, the following conclusions can be drawn:  
1. Appropriate embedment depths of BFs are beneficial to the bonding strength between basalt fibers and asphalt binders, which can further guide the selection of basalt fiber length. In addition, rubber asphalt has a higher bond strength with basalt fibers than the other two asphalts.
2. The types of asphalt binders suitable for basalt fibers and the appropriate fiber embedding depths for different types of asphalt binders guiding the selection of fiber length were recommended based on the influence of the fiber embedding depth and  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Bond Strengths/kPa** & **Embedment Depth/mm** & **Softening Point** \\ \hline
140.8869 & 6 & 74 \\
93.92458 & 12 & 74 \\
65.32027 & 20 & 74 \\
36.43135 & 30 & 74 \\
187.036 & 6 & 69 \\
110.5952 & 12 & 69 \\
80.01886 & 20 & 69 \\
44.56335 & 30 & 69 \\
205.8412 & 6 & 53.7 \\
125.7918 & 12 & 53.7 \\
80.50678 & 20 & 53.7 \\
46.96229 & 30 & 53.7 \\ \hline \hline \end{tabular}
\end{table}
Table 9: The data obtained using the grey relational method.  
asphal binders on fiber-asphalt bonding strength. The recommended fiber length is 20 mm. The recommended asphalt type is rubber asphalt.
* SEM images revealed the uniform distribution of fibers in the asphalt binders and the spatial networks of basalt fibers in the asphalt binders.
* The surface energy of the asphalt binders and basalt fibers showed that rubber asphalt with BFs had good adhesivity and high homogeneity.
* The results obtained using the gray correlation method showed that bond strength correlates more closely with the type of asphalt binder than embedment depth.
* Finally, further research is required to investigate the distribution of basalt fibers in asphalt binders. In this study, a preliminary analysis of the microscopic mechanism of BFs in asphalt binders was carried out. The microscopic mechanisms of basalt fibers-asphalt binders also need to be further analyzed.  
Conceptualization, C.K. and A.K.; Methodology, C.K., A.K. and P.X.; Formal analysis, Y.L.; Investigation, Y.L.; Resources, Z.W.; Data curation, Y.L.; Writing--original draft, Z.S.; Writing--review & editing, Z.S. and C.K.; Supervision, Z.W. and P.X.; Project administration, C.K., Z.W., A.K. and P.X.; Funding acquisition, C.K., Z.W., A.K. and P.X. All authors have read and agreed to the published version of the manuscript.  
The financial support was provided by the National Natural Science Foundation of China (Grant Number: 52178439), the Natural Science Foundation for Youths of Jiangsu Province (Grant Number: BK20190913), the Yangzhou University High-level Talent Support Program, the Postgraduate Research & Practice Innovation Program of Jiangsu Province (Yangzhou University; SICX22_1746), the Jiangsu Science and Technology Association Promotion Project for the Youths (Grant Number: 2021-090), and the Qing Lan Project of Jiangsu Province.  
Not applicable.  
The data presented in this study are available on request from the corresponding author due to privacy.  
We would like to thank the Testing Center of Yangzhou University for their technical support.  
The authors declare no conflict of interest.