## 3 Results and Analysis
### Controllable Preparation Result of the Shape Memory Hydrogenated Epoxy Resin (SM-HEP)
Figure 7: 45 degrees contour map of the SM-HEP \(T_{\rm g}\). was attributed to the presence of epoxy groups. The disappearance of the absorption peak on the spectra of the SM-HEP-AM was due to the complete reaction of the epoxy groups in AL-3040 and the active hydrogen in IPDA. Meanwhile, it indicated that the SM-HEP-AM had been completely cured. The band at 1092 cm\({}^{-1}\) on the spectra of the JH-230 and SM-HEP-AM corresponded to the C-O stretching vibration band in the raw materials (JH-230). The bands located around 1730 cm\({}^{-1}\) in the JH-230 and SM-HEP-AM were assigned to the C=O stretching vibration band presented in the raw materials (JH-230). They also reflected the differences residing in the spectra, depending on the JH-230 content. These bands, with a very low intensity in specimen JH-230-0.0353, appear very visible on the spectra of specimen JH-230-0.0685 and specimen JH-230-0.0796. This indicated that the intensity of the bands at 1092 and 1730 cm\({}^{-1}\) increased with an increased JH-230 content. It can be explained by the fact that there exists a large amount of C-O and C=O stretching vibration bands in JH-230, and with the increased JH-230 content, the C-O and C=O stretching vibration bands of SM-HEP-AM also increased. The peaks at 2859 and 2932 cm\({}^{-1}\) were associated with the -CH\({}_{3}\) symmetric stretching peak and saturation C-H stretching vibration peak. The Thermo-Mechanical Property of the Shape Memory Hydrogenated Epoxy Resin Used for Asphalt Mixtures (SM-HEP-AM)  
The storage modulus (E\({}^{\prime}\)) values of the SM-HEP-AM are shown in Figure 10a. The changes in the E\({}^{\prime}\) values below and above the \(T_{\rm g}\) are also marked in Figure 10a. Generally speaking, a good SMP should have a change of E\({}^{\prime}\) of more than two to three orders below and above the \(T_{\rm g}\). Figure 10a shows that the E' of all of the SM-HEP-AM decreased by almost three orders of magnitude. The glass/rubber modulus ratio is defined as the elastic ratio, and higher elastic ratios would be beneficial to the SM-HEP-AM shape retention. The SM-HEP-AM with a larger glass/rubber modulus ratio below and above \(T_{\rm g}\) is in favour of improving the shape fixity ratio [30]. Figure 10a also revealed that the glass modulus increased with the decreased JH-230 content. The molecular weight of the JH-230 is large (2500 g/mol), and there exist lots of -C-O- single bonds. The molecular chain rotates about a single bond, and the chain is very flexible, which decreased the intermolecular force and increased the mobility of the chain segment, thus leading to the decrease in the glass modulus of the SM-HEP-AM. According to different standards, \(T_{\rm g}\) can be determined in several ways. In this study, the peak of the loss modulus versus temperature curve was defined as \(T_{\rm g}\). The \(T_{\rm g}\) values obtained from the loss modulus versus temperature curve are shown in Figure 10b. According to this definition, dynamic mechanical analysis (DMA) \(T_{\rm g}\) gradually increased with a decreased JH-230 content. For a clearer illustration, the \(T_{\rm g}\) values obtained from DSC and DMA are summarized in Figure 11.  
Figure 9: FT-IR Spectra of IPDA, JH-230, AL-3040, and the SM-HEP-AM. The \(T_{\rm g}\) values obtained from DSC were almost consistent with those obtained from DMA. This difference can be explained by the frequency effect in the DMA test. It can be concluded that the formulations of the SM-HEP-AM obtained by the preparation method are reasonable. The Shape-Memory Performance of the Shape Memory Hydrogenated Epoxy Resin Used for Asphalt Mixtures (SM-HEP-AM)  
To investigate the shape-memory performance of the SM-HEP-AM, the specimens were tested at \(T_{\rm g}-10\), \(T_{\rm g}\), \(T_{\rm g}+10\), and \(T_{\rm g}+20\)\({}^{\circ}\)C using the tensile-recovery shape memory test. The \(T_{\rm g}\) values were obtained from DSC. According to the results, the shape fixity ratio of the SM-HEP-AM could reach 98.5%.