# Characteristics of Moduli Decay for the Asphalt Mixture under Different Loading Conditions
## Materials Preparation and Test Method
### Specimens Preparation  
According to the Chinese Standard Test Methods of Asphalt and Asphalts Mixtures for Highway Engineering (JTG E20-2011) [23], the block samples of 400 mm \(\times\) 300 mm \(\times\) 50 mm were fabricated through the equipment of vibrating compaction. Then, the beam specimens were cut from block samples into the size of 250 mm \(\times\) 50 mm \(\times\) 50 mm for the direct tensile tests, as shown in Figure 2a. During the uniaxial compression test, the Superpave Gyratory Compactor (SGC) was employed, which can control the volume of air voids of asphalt mixture more accurately. The previous studies [24; 25] showed that the stress concentration would be occurred when the height is less than 50 mm. The specimens for uniaxial compression test were manufactured with 100 mm in height and 100 mm in diameter, which was shown in Figure 2b, and the indirect tensile specimens were prepared by cutting the top and the bottom surface of the specimens of uniaxial compression test to the size of 100 mm in height and 60 mm in diameter, which was shown in Figure 2c. All of the specimens were put in an environment chamber at 15 \({}^{\circ}\)C for 24 h before the tests. There were four parallel tests for each type of test.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Test Projects**} & \multicolumn{3}{c}{**Test Standard: JTG F40-2004 (China) [21]**} \\ \cline{2-4}  & \multicolumn{1}{c}{**Technical**} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} \\  & **Requirements** & **Test Results** & **Test Methods** \\ \hline Penetration (25 \({}^{\circ}\)C, 100 g 5 s) (0.1 mm) & 30–60 & 53.9 & T 0604-2000 \\ Penetration index PI & \(\geq\)0 & 0.533 (r = 0.997) & T 0604-2000 \\ Ductility (5 cm/min, 5 \({}^{\circ}\)C) (cm) & \(\geq\)20 & 36.3 & T 0605-1993 \\ Softening point (Ring ball) (\({}^{\circ}\)C) & \(\geq\)60 & 72.5 & T 0606-2000 \\ Flash point (\({}^{\circ}\)C) & \(\geq\)230 & 265 & T 0611-1993 \\ Solubility (\%) & \(\geq\)99 & 99.9 & T 0607-1993 \\
135 \({}^{\circ}\)C kinematic viscosity (Pa.s) & \(<\)3 & 2.37 & T 0620-2000 \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Rolling Thin Film Oven Test \\ (RTFOOT) 163 \({}^{\circ}\)C 85 min} & Mass loss (\%) & \(\leq\)\(\pm\)1.0 & 0.23 & T 0609-1993 \\ Residual penetration ratio (25 \({}^{\circ}\)C) (\%) & \(\geq\)65 & 75.2 & T 0604-2000 \\ Residual ductility (5 \({}^{\circ}\)C) (cm) & \(\geq\)15 & 23.4 & T 0605-1993 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Test result of Styrene-butadiene-styrene (SBS) modified asphalt.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Test Item**} & \multicolumn{1}{c}{**Technical**} & \multicolumn{1}{c}{} \\  & **Requirements** [22] & **Test Results** & **Test Methods** \\ \hline Crushed stone value (\%) & \(\leq\)28 & 15.6 & T 0316-2005 \\ Los Angeles weared stone value (\%) & \(\leq\)30 & 19.7 & T 0317-2005 \\ Apparent relative density (g/cm\({}^{3}\)) & \(\geq\)25 & 2.6 & T 0321-2005 \\ Water absorption (\%) & \(\leq\)2.0 & 1.4 & T 0304-2005 \\ Content of flat and elongated particles in coarse aggregate (\%) & \(\leq\)15 & 8 & T 0312-2005 \\ \(<\)0.075 mm particle content (Washing methods) (\%) & \(\leq\)1 & 0.2 & T 0310-2000 \\ Asphal adhesion/grade & \(\geq\)4 & 6 & T 0616-1993 \\ Firmes (\%) & \(\leq\)12 & 5 & T 0314-2000 \\ Content of soft stone (\%) & \(\leq\)5 & 2.5 & T 0320-2000 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Physical property of aggregates.