## Materials and Methods  
### Materials  
As shown in the Figure 1, the PADG mixtures consisted of 70.1% aggregate, 23.4% mineral fines, 5.5% matrix asphalt, and 1% additive. Among these, the functional components of the additive involved the modifier, adhesive, and a film-forming agent. Thirteen percent Styrene-Butadiene-Styrene (SBS) polymers was used as a modifier and were added to 18% of trichloroethylene evenly, which was from Shandong Agile Road Bridge Engineering Co., Ltd., China. The adhesive was made up of 15% ethylene-vinyl acetate copolymer (EVA), which was supplied by Zhejiang Minghua new material co., Ltd., China, and it was dissolved into 34% 2-Ethoxyethyl Acetate. 10% polystyrene was used as the film-forming agent. The plasticizer was 10% di-n-butyl phthalate, which was provided from Nanjian Chemical Co., Ltd. The chemical formulas for the active component in additive are shown in Figure 2.  
The Fourier infrared spectra of the matrix asphalt and the new polymer modified asphalt are shown in Figure 3. The peak of 1594 cm\({}^{-1}\) represents a conjugated olefinic bond from the film-forming agent, which was used to form a flexible solid film within the spatial network structure of the microcapsules. The microcapsules containing plasticizer were spread into the additive evenly, as shown in Figure 4. This was done to ensure the workability and storability of the cold mixtures by isolating the modifier or adhesive and plasticizer in the microcapsules during the storage period. When a constant and sufficient pressure is loaded on the capsules, the capsules rupture and the plasticizer flow out of the capsules to catalyze the curing of modifiers and adhesive. In order to guarantee the stability of the microcapsules during the storage phase and the breakability of the microcapsules in the use stage, Microcapsules require a specific toughness and density. Therefore, the values of n\({}_{6}\) in Figure 2c are recommended which are between 800 and 1200. The peak in wavenumber 965 cm\({}^{-1}\) was functional groups of polybutadiene from the modifier, which can improve the low temperature performance of the binder. The absorption peaks in the range of 2800-3000 cm\({}^{-1}\) were caused by the C-H stretching vibration of cycloalkanes and alkanes, which is one of most common chemical bond in asphalt [25; 26].  
90# matrix asphalt is produced in Korea, and its main properties were listed in Table 1. Compared with matrix asphalt, the cured polymer modified asphalt has a higher softening point of 55.8 \({}^{\circ}\)C. Both aggregates and fines are made of limestone. The OG mixtures and the DG mixtures, produced in Canada and China, and are widely used as patching materials in pothole repairs. The gradations of mixtures are plotted in Figure 5.  
Figure 1: Compositions of polymer modified asphalt and dense graded (DG) of aggregates (PADG) mixtures.  
Figure 2: The chemical formulas for the active component in additive: (**a**) Styrene–Butadiene-Styrene (SBS) polymers; (**b**) ethylene-vinyl acetate copolymer; (**c**) polystyrene.  
Figure 4: Microscopy images of microcapsules in additive.  
Figure 5: Gradations of DG mixtures, open graded (OG) mixtures and PADG mixtures.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Properties** & **Values** & **Specifications** \\ \hline Penetration (25 \({}^{\circ}\)C,100 g, 5 s) (0.1 mm) & 88.5 & 80–100 \\ Softening point (\({}^{\circ}\)C) & 48.2 & \(\geq\)44 \\ Ductility (15 \({}^{\circ}\)C) (mm) & 138 & \(\geq\)100 \\ Density (g/cm\({}^{3}\)) & 1.022 & - \\ Wax content (\%) & 1.6 & \(\leq\)2.2 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The main properties of 90# matrix asphalt.  
Figure 3: Fourier infrared spectra of matrix asphalt and new polymer modified asphalt.