## 3 Results and Discussion
### Stability Analysis  
According to Mohr-Coulomb theory, the strength composition of the cold mixtures is essentially identical to that of hot asphalt mixtures. The strength composition depends on the cohesion from binder and the internal friction from the gradation and angularity of aggregates [30]. However, the strength formation of the cold mixtures has delay and hysteresis characteristics, as compared with the traditional hot asphalt mixtures. This is due to the existence of the dilute [3; 31]. As seen in Table 3, it can be observed that the initial stability of the PADG mixtures was significantly greater than the DG mixtures and OG mixtures due to the reinforcement of the modifier and adhesive from the catalysis of the plasticizer from the break of the microcapsules during the compaction. However, DG mixtures and OG mixtures were added relatively more diluent to maintain an adequate workability. Moreover, there is not enough time for the diluent in the samples to volatilize fully at the low temperature of 5 \({}^{\circ}\)C, in the short fabrication process. Molded stability was tested when most diluent was volatilized. Namely the binder cohesion was utilized to maximize the effect. As shown in Table 4, the PADG mixtures had the highest molded stability of 6.03 kN, which was slightly higher than that of the DG mixtures of 5.54 kN, but was 49.8% more than that of the OG mixtures. This problem could originate in the gap-graded gradation and bounding voids of the OG mixtures, which have a negative effect on the internal friction of the mixtures, creating poor interlocking structure. In Table 3, it can be found that the stability of the PADG mixtures in low temperatures was larger than DG mixtures and OG mixtures by 19.4% and 7.5% in low temperature. This indicates that the PADG materials have a sufficient strength needed to withstand the failure or deformability during the winter. This attributed to the reinforcement of the soft segments from the modifier and continuous dense gradation of the PADG mixtures. Low-temperature deformation resistance and high temperature strength of mixtures can be effectively improved by the controlling ratio of the two segment contents. Table 3 also presents two kinds of stability during dry and immersed conditions. It can be found that the PADG mixtures had the highest immersed residual stability ratio of 83.0%; however, the ratio of the DG mixtures and OG mixtures was only 71.4% and 61.7%. The modifier of the new polymer modified binder seems to improve the bonding of the PADG mixtures considerably even when in immersed conditions. However, the effects of the water on the other two mixtures are appreciable, due to the existence of more diluent in cold mixtures added to improve the workability. Furthermore, the gap-grade gradation of the OG mixtures contributes to numerous voids in the specimens, which exacerbates the seepage problems and is averse to the stripping resistance of the binder. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Mixtures Type** & **Dry Tensile Strength** & **Freezing-Thawing** & **Tensile Strength Ratio** \\  & **(MPa)** & **Tensile Strength (MPa)** & **(TSR) (\%)** \\ \hline DG mixtures & 0.59 & 0.37 & 62.71 \\ OG mixtures & 0.43 & 0.25 & 58.14 \\ PADG mixtures & 0.62 & 0.50 & 80.65 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results of freeze-thaw tensile strength tests. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Mixtures Type**} & \multicolumn{5}{c}{**Stability in Different Conditions (kN)**} \\ \cline{2-6}  & **Initial** & **Modeled** & **Low Temperature** & **Dry** & **Immersed** \\ \hline DG mixtures & 0.30 & 5.54 & 4.40 & 5.32 & 3.80 \\ OG mixtures & 0.55 & 3.03 & 5.05 & 4.52 & 2.79 \\ PADG mixtures & 3.44 & 6.03 & 5.46 & 6.00 & 4.98 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of Marshall stability test in different conditions. The time requirement for complete strength forming varies with the differences in grading and additives.