# Properties and Preparation of a New High-Permeability Emulsified Asphalt and Its Modification
## 4 Results and Discussion
### Tensile Strength  
When ordinary (traditional) emulsified asphalt, high-permeability emulsified asphalt, and modified high-permeability emulsified asphalt were used as bonding materials, the pull-off strength results under different spraying rates are shown in Table 13.  
\begin{table}
\begin{tabular}{c} **Standard** \\ **Deviation** \\ \end{tabular} \\ \hline
0 h & 0.7 & 0.034 & 4.8 & 0.275 & 2.3 & 0.101 \\
10 h & 2.4 & 0.105 & 15.0 & 0.344 & 8.8 & 0.297 \\
1 d & 3.4 & 0.031 & 23.1 & 0.281 & 14.6 & 0.251 \\
3 d & 4.2 & 0.033 & 27.7 & 0.234 & 18.1 & 0.132 \\
7 d & 4.7 & 0.021 & 30.0 & 0.104 & 19.9 & 0.091 \\
14 d & 4.9 & 0.011 & 31.0 & 0.042 & 20.7 & 0.023 \\ \hline \hline \end{tabular}
\end{table}
Table 12: Penetration depth of emulsified asphalt on bases in different conditioning periods.  
As can be seen from Figure 13, the tensile strength of the three kinds of emulsified asphalt increased first and then decreased with the increase of spraying amount. The optimal spraying amount of traditional emulsified asphalt and modified high-permeability emulsified asphalt is 1.1 L/m\({}^{2}\), while the optimal spraying amount of high-permeability emulsified asphalt is 1.3 L/m\({}^{2}\).  
It can be seen from Table 13 that at the optimal spreading rate, the tensile strength of modified high-permeability emulsified asphalt is the highest (0.53 Mpa), followed by traditional emulsified asphalt (0.32 Mpa), and the worst is high-permeability emulsified asphalt (0.27 Mpa). Obviously, traditional emulsified asphalt and modified high-permeability emulsified asphalt have higher viscosity and better tensile strength. From the bonding point of view of the base and surface, the increase of viscosity is beneficial to the bonding. However, the increase in viscosity inevitably leads to difficulty in penetration. The penetration depth of traditional emulsified asphalt is very small, only asphalt oil film is formed on the surface of the base, and the bonding force is poor. Compared with traditional emulsified asphalt and modified high-permeability emulsified asphalt, high-permeability emulsified asphalt has the best permeability. Although the modified high-permeability emulsified asphalt with waterborne epoxy resin and curing agent is not as good as the high-permeability emulsified asphalt in the penetration effect, it can also meet the specification requirements, and its tensile strength is better than that of the high-permeability emulsified asphalt.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Spraying Volume (L/m\({}^{2}\))**} & \multicolumn{3}{c}{**Pull-Off Strength (MPa)**} \\ \cline{2-4}  & **Traditional** & **High-Permeability** & **Modified** \\  & **Emulsified Asphal** & **Emulsified Asphal** & **High-Permeability** \\  & & & **Emulsified Asphal** \\ \hline
0.7 & 0.20 & 0.17 & 0.45 \\
0.9 & 0.23 & 0.19 & 0.48 \\
1.1 & 0.32 & 0.20 & 0.53 \\
1.3 & 0.28 & 0.27 & 0.50 \\
1.5 & 0.24 & 0.23 & 0.46 \\ \hline \hline \end{tabular}
\end{table}
Table 13: Tensile strength of different emulsified asphalts at different sprinkling rates.  
Figure 13: Effect of material type and spraying volume on the interlayer pull-off strength.