## 3 Results and Analysis  
### Controllable Preparation Result of the Shape Memory Hydrogenated Epoxy Resin (SM-HEP)  
The SM-HEP specimens were named JH-230 N; the \"N\" is the JH-230 molar mass of the specimens. The formulations of specimens JH-230 0.02-JH-230 0.10 are shown in Table 1.  
Figure 2: The testing equipment of the deformation recovery test. To study the relationship between the JH-230 content and \(T_{\rm g}\), the \(T_{\rm g}\) of the specimens with the specifications in Table 1 were tested by the differential scanning calorimeter (DSC). As can be seen in Figure 3, the SM-HEP \(T_{\rm g}\) linearly decreased as the JH-230 content increased, which means that \(T_{\rm g}\) could be changed by adjusting the JH-230 content. The \(T_{\rm g}\) is a key characteristic parameter of the thermo-mechanical behaviour and shape recovery performance of SMPs. The flexible change in the \(T_{\rm g}\) of the SM-HEP is a very useful feature that can expand the applications of the material to meet different demands. The \(T_{\rm g}\) values obtained from the DSC curves are also marked in Figure 3. As shown in Figure 3, all SM-HEP specimens show \(T_{\rm g}\) values ranging from 33.5 to 71.4 \({}^{\circ}\)C. The \(T_{\rm g}\) values gradually decreased with an increased JH-230 content. To further study the relationship of the JH-230 content and \(T_{\rm g}\), the relationship was fitted linearly. Figure 4 shows the linear fit results. The preliminary linear fit equation is presented in Equation (4). \[Y=-4.56163\times X+76.64286 \tag{4}\]  
In Equation (4), \(Y\) is the \(T_{\rm g}\) of SM-HEP and \(X\) is the JH-230 content. As can be seen in Figure 4, the \(T_{\rm g}\) of SM-HEP linearly decreased with the increase in the JH-230 content. The correlation coefficient \(R^{2}\) is 0.9405, which proves that the linear fit degree is high. The formulations of the SM-HEP with different \(T_{\rm g}\) values can be back-calculated using Equation (4). \begin{table}
\begin{tabular}{c c c c} \hline
**Specimen** & **AL-3040 (mol)** & **JH-230 (mol)** & **IPDA (mol)** \\ \hline JH-230 0.02 & 0.98 & 0.02 & 0.5 \\ JH-230 0.04 & 0.96 & 0.04 & 0.5 \\ JH-230 0.05 & 0.95 & 0.05 & 0.5 \\ JH-230 0.06 & 0.94 & 0.06 & 0.5 \\ JH-230 0.08 & 0.92 & 0.08 & 0.5 \\ JH-230 0.10 & 0.90 & 0.10 & 0.5 \\ \hline \end{tabular}
\end{table} 
Table 1: Specimens and their specifications. Figure 3: The second heating DSC curves of the shape-memory hydrogenated epoxy resin (heating flow = 10 \({}^{\circ}\)C/min). The SM-HEP studied in this paper was mainly used to reduce the accumulation of permanent deformation on an asphalt pavement at high temperatures and then improve the rutting resistance of the asphalt pavement. Due to the fact that SM-HEP can correct its temporary deformed shape and restore its original shape upon an external stimulus, the deformation temperature may be below the \(T_{\rm g}\) of the SM-HEP [14]. When the temperature of the asphalt mixture ranges from 30 to 70 \({}^{\circ}\)C, the cracks will start to self-heal [28]. The SM-HEP \(T_{\rm g}\) used for the asphalt mixture was set as 40, 45, 50, 55, and 60 \({}^{\circ}\)C to investigate the improvement effect of the SM-HEP on the rutting resistance of the asphalt pavement. The back-calculated formulations of the SMP-HEP with \(T_{\rm g}\) values of 40, 45, 50, 55, 60 \({}^{\circ}\)C are shown in Table 2. The corresponding measured \(T_{\rm g}\) values tested by DSC are displayed in Figure 5. \begin{table}
\begin{tabular}{c c c c c} \hline
**Specimen** & **AL-3040 (mol)** & **JH-230 (mol)** & **IPDA (mol)** & **Tg-Fitted (\({}^{\circ}\)C)** \\ \hline JH-230-0.0274 & 0.9726 & 0.0274 & 0.5 & 60 \\ JH-230-0.0407 & 0.9593 & 0.0407 & 0.5 & 55 \\ JH-230-0.0540 & 0.9460 & 0.0540 & 0.5 & 50 \\ JH-230-0.0678 & 0.9322 & 0.0678 & 0.5 & 45 \\ JH-230-0.0805 & 0.9805 & 0.0805 & 0.5 & 40 \\ \hline \end{tabular}
\end{table} 
Table 2: Specimens with back-calculated formulations and their \(T_{\rm g}\) values. Figure 4: The linear fit of the JH-230 content and \(T_{\rm g}\).