## 3 Results and Discussion
### Morphological Analysis  
The curing of epoxy asphalt was further analyzed by tracking the micromorphological changes of epoxy asphalt with different curing times using LSCM. Fluorescence images of the epoxy asphalt samples cured at 60 \({}^{\circ}\)C for different times are shown in Figure 6. The fluorescent and dark phases correspond to the epoxy resin and the base asphalt, respectively. The epoxy resin, the curing agent, and asphalt were mixed and then stirred by shearing to evenly disperse the three components, as shown in Figure 6a. After mixing, the epoxy resin and the curing agent underwent a polymerization reaction, where the homogeneous phase of asphalt microparticles was polymerized into larger particles to form a two-phase system with an island-like structure, with asphalt as the dispersed phase and epoxy resin as the continuous phase, as shown in Figure 6b-e. As the curing reaction proceeded (Figure 6e-h), an epoxy resin crosslinked network gradually formed. The crosslinking density then continuously increased, and the large asphalt particles were gradually divided into small particles by the epoxy resin network. At 72 h, the asphalt particle diameter gradually stabilized at an average particle diameter of approximately 20 \(\upmu\)m (Figure 6h,i). The particles were evenly dispersed in the epoxy resin, forming a stable two-phase 3D network structure. This result is consistent with that observed by [PERSON] et al. (2016),  
Figure 5: Comparison of curing degrees as represented by the tensile strength and conversion rate of epoxy groups: (**a**) increase curves for both curing degrees; (**b**) polynomial fitting curve for conversion rate of epoxy groups, and (**c**) correlation curve between two curing degrees. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Curing Time/h** & **12** & **24** & **36** & **48** & **72** & **96** & **120** \\ \hline \(G_{\alpha}\)**/\%** & 27 & 48 & 65 & 77 & 93 & 99 & 99 \\ \(G_{\delta}\)**/\%** & 17 & 39 & 64 & 76 & 97 & 99 & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Curing degrees at different curing times as characterized by the epoxy group conversion rate and tensile strength. that is, the diameter of asphalt particles first increases and then decreases during the epoxy asphalt curing process. Two definitions are introduced to quantify the dispersion of asphalt particles in the epoxy resin crosslinked network: homogeneity (also known as overall uniformity) and dispersion. Homogeneity refers to the amplitude of concentration fluctuations of the dispersed phase, and dispersion refers to the size distribution range of the particulate phase. The image analysis program ImageJ was used to determine and statistically analyze the asphalt particle sizes in epoxy asphalt [27]. Figure 7 shows the asphalt particle size distribution in epoxy resin for different curing times. In the initial curing stage, the distribution range of the asphalt particle diameters increased from 0-50 \(\upmu\)m to 0-100 \(\upmu\)m. After 12 h, the particle size distribution range gradually decreased and returned to a stable normal distribution in the 0-40 \(\upmu\)m range at 96 h. As the curing reaction proceeded, the diameter distribution changed from narrow to wide, then retracted, and stabilized at 0-40 \(\upmu\)m, indicating that the asphalt particles tended to become evenly distributed in the epoxy resin as the curing time increased. Figure 6: LSCM photographs of epoxy asphalt samples with different curing times (60 \({}^{\circ}\)C): (**a**) 0 h, (**b**) 0.5 h, (**c**) 3 h, (**d**) 5 h, (**e**) 12 h, (**f**) 24 h, (**g**) 48 h, (**h**) 72 h, and (**i**) 96 h.  
According to [PERSON] et al.