# Laboratory Evaluation of Rejuvenating Agent on Reclaimed SBS Modified Asphalt Pavement
## 3 Results and Analyses
### Dynamic Modulus Test Results  
The dynamic modulus master curve model parameters (Equation (4)), developed for different recycled mixtures, are presented in Table 12.  
From Table 12 and based on the nonlinear fitting statistics, it is evident that the dynamic modulus models used for developing the master curves are highly related. The temperature shift factors for a reference temperature 20 \({}^{\circ}\)C  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**RSMAP Content**} & \multicolumn{3}{c}{1\(E^{*}\)1 **Master Curve Parameters**} & \multicolumn{3}{c}{**Correlation Coefficient**} \\ \cline{2-7}  & \(\delta\) & \(\alpha\) & \(\beta\) & \(\gamma\) & \(\epsilon\) & \(R^{2}\) \\ \hline
0\% & 2.074 & 2.311 & \(-\)0.986 & \(-\)0.689 & 8516.5 & 0.99 \\
30\% & 1.573 & 2.935 & \(-\)1.109 & \(-\)0.487 & 8356.7 & 0.99 \\
30\% * & 1.901 & 2.609 & \(-\)0.809 & \(-\)0.515 & 7249.7 & 0.99 \\
50\% & 1.116 & 3.458 & \(-\)1.360 & \(-\)0.389 & 7943.0 & 0.99 \\
50\% * & 1.717 & 2.809 & \(-\)1.094 & \(-\)0.452 & 8084.1 & 0.99 \\
70\% & 0.338 & 4.223 & \(-\)1.603 & \(-\)0.339 & 8728.1 & 0.99 \\
70\% * & 1.358 & 3.107 & \(-\)1.229 & \(-\)0.39 & 8218.9 & 0.99 \\ \hline \hline \end{tabular}
*: the addition of rejuvenating agent.  
\end{table}
Table 12: Dynamic modulus master curve model parameters of recycled mixtures.  
Figure 5: SCB test results of recycled mixtures. (**a**) Fracture energy; (**b**) Fracture toughness.  
The dynamic modulus master curves of recycled mixtures with different RSMAP contents are provided in Figure 6. To facilitate comparison, the master curve of control mixture is also provided in Figure 6.  
From Figure 6a-c, it's observed that dynamic modulus of all mixtures tested increases with the increase of the loading frequency. In general, the dynamic modulus values of recycled mixtures are significantly higher than control mixture, and the difference is greater with higher RSMAP content. By adding rejuvenating agent, the dynamic modulus decreases slightly. Figure 6d shows that at higher loading frequency, there is no notable difference between the dynamic modulus of the recycled mixtures and control mixture. The results indicate that the rejuvenating agent has an effect on the stiffness of the recycled mixtures generally, but the effect is not obvious. In addition, when the loading frequency reaches a greater value, the difference of recycled mixtures and control mixture tend to be consistent, and include high RSMAP content.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**RSMAP Content**} & \multicolumn{3}{c}{**Temperature Shift Factors (log\(a\)(T))**} \\ \cline{2-4}  & **4 °C** & **20 °C** & **40 °C** \\ \hline
0\% & 1.678 & 0 & \(-1.857\) \\
30\% & 1.647 & 0 & \(-1.822\) \\
30\% \({}^{*}\) & 1.429 & 0 & \(-1.581\) \\
50\% & 1.566 & 0 & \(-1.732\) \\
50\% \({}^{*}\) & 1.594 & 0 & \(-1.763\) \\
70\% \({}^{*}\) & 1.721 & 0 & \(-1.903\) \\
70\% \({}^{*}\) & 1.620 & 0 & \(-1.792\) \\ \hline \hline \end{tabular}  
*: the addition of rejuvenating agent.  
\end{table}
Table 13: Temperature shift factors (log\(a\)(\(T\))) of recycled mixtures.  
Figure 6: (a) Master curves of recycled mixtures with 30% RSMAP; (b) Master curves of recycled mixtures with 50% RSMAP; (c) Master curves of recycled mixtures with 70% RSMAP; (d) Master curves of recycled mixtures with all RSMAP contents.