## 4 Asphalt Binder Test Results Analysis
### Binder MSCR Test Results  
Figure 2a,b show the ten cycles of creep and data from recovery and test cycle number nine of MSCR testing at 25\({}^{\circ}\)C using TFOT/PAV aged base asphalt, respectively. As shown, the curves are fairly smooth with no jagged edges observed, indicating that the application of the MSCR test on fatigue resistance of asphalt binder is technically feasible without sacrificing data accuracy. Figure 2c compares the MSCR \(R_{3,2}\) among all the asphalt types based on the short-term TFOT aged binders. Error bars representing standard deviation of the results are also presented. It can be observed that the error bars are all in small values, representing good repetition of the test.  
Additionally, the binders with 15% rubber and SBS hold high \(R_{3,2}\) values and were minorly affected by aging condition and temperature change. Although the asphalt property was very sensitive to the climatic condition, such sensitivity was diminished when SBS or a high content of rubber were applied to reform the base asphalt. In contrast, the Evotherm M1 and Evotherm 3G binders have the lowest \(R_{3,2}\) values and the results are greatly influenced by temperature alternation. The MSCR \(R_{3,2}\) values under TFOT/PAV aging showed exactly the same trend compared to TFOT aged binder with a slight increase of \(R_{3,2}\) values.  
Figure 3a,b show the sensitivity of MSCR \(R_{3,2}\) to asphalt binder type and additive content at a testing temperature of 25 \({}^{\circ}\)C. By visual observation, the MSCR \(R_{3,2}\) was sensitive enough to distinguish different binder types and additive contents. A statistical t-test was conducted with a significance level of 0.05 between any two binder types in Figure 3a, or between any two additive contents in Figure 3b. Results indicate that except for the rubber-SBS pair (as shown in Figure 3a) and 5% rubber \(-10\)% rubber pair (as shown in Figure 3b), all the other pairs were statistically different.  
Additionally, Figure 3a shows that the MSCR \(R_{3,2}\) values between TFOT aging and TFOT/PAV aging are almost overlapping except for the Evotherm 3G binder. Such a finding indicates the potential that the Evotherm 3G could experience a fast aging rate, as specified elsewhere [17].  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Modification** & **\% of Additive** & **Containes PG**, \({}^{\circ}\)**C TFOT** & **Containes PG**, \({}^{\circ}\)**C TFOT/PAV** & **Viscosity, MPa-s** & **Viscosity, MPa-s** \\  & & & \({}^{\circ}\)**C TFOT/PAV** & **Original** & **TFOT** \\ \hline Base & 0 & 78.8–25.6 & 87.3–25.6 & 497.5 & 706.2 \\ Sasobit & 1 & 82.9–23.2 & 85.8–23.2 & 474.3 & 590.8 \\ Sasobit & 2 & 86.7–24.3 & 88.4–24.3 & 434.2 & 553.5 \\ Sasobit & 3 & 90.8–25.7 & 92.0–25.7 & 349.2 & 495.8 \\ Evotherm M1 & 0.6 & 79.2–25.6 & 85.3–25.6 & 446.7 & 557.5 \\ Evotherm 3G & 0.6 & 75.4–25.3 & 83.6–25.3 & 427.3 & 533.8 \\ SBS & 4.5 & 92.1–28.5 & 92.0–28.5 & 1446.0 & 1911.3 \\ Rubber & 5 & 85.9–26.8 & 95.8–26.8 & 991.8 & 1166.3 \\ Rubber & 10 & 87.2–27.5 & 96.5–27.5 & 1191.7 & 1554.7 \\ Rubber & 15 & 91.5–27.8 & 98.3–27.8 & 1930.0 & 2297.3 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Test Results of Binder PG and Viscosity under Thin-Film Oven Test (TFOT) and Pressure Aging Vessel (PAV) Aging.  
Figure 3: Sensitivity of MSCR \(R_{3.2}\) to (**a**) Binder Type, and (**b**) Additive Content.  
Figure 2: MSCR Test Results (**a**) Typical 10 Cycles of Creep and Recovery; (**b**) Test Cycle No. 9 Data Plot Showing Creep and Recovery, and (**c**) \(R_{3.2}\) Comparison of TFOT Aged Binders.