# Experimental Study of Low Temperature Performance of Porous Asphalt Mixture
## 2 Low Temperature Performance Test
### Raw Materials
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{3}{*}{**Materials**} & \multicolumn{6}{c}{**Percentage Passing through the Following Sieve Apertures (\%)**} \\ \cline{2-10}  & & 16 & 13.2 & 9.5 & 4.75 & 2.36 & 1.18 & 0.6 & 0.3 & 0.15 & 0.075 \\  & mm & mm & mm & mm & mm & mm & mm & mm & mm \\ \hline Coarse & S10 & 100 & 91.3 & 35.9 & 0.8 & 0.4 & 0.4 & 0.4 & 0.4 & 0.4 & 0.4 \\ aggregate & S12 & 100 & 100 & 99.1 & 3.3 & 0.6 & 0.6 & 0.5 & 0.5 & 0.5 & 0.5 \\ \hline Fine & & & & & & & & & & & \\ aggregate & S16 & 100 & 100 & 100 & 97.0 & 68.3 & 47.4 & 33.5 & 22.9 & 17.4 & 11.9 \\ \hline Limestone powder & 100 & 100 & 100 & 100 & 100 & 100 & 100 & 99.2 & 95.7 & 77.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Screening results of aggregates and filler material. Currently, the high-viscosity modifiers commonly used in porous asphalt mixture include synthetic polymers such as SBS and proprietary systems such as SINOTPS. [PERSON] [48] found that SINOTPS modifier had certain superiority. For instance, the ductility of SINOTPS modifier at low temperature was significantly better than that of SBS modifier. In view of the desirable performance of SINOTPS modifier, it was adopted in the present work. As confirmed by the experimental trial in this study, SINOTPS had good compatibility with asphalt and could melt to integrate with the asphalt quickly. [PERSON] [48] selected 70# asphalt as matrix asphalt, and tested the properties of modified asphalt with SINOTPS modifier content of 6%, 9%, 12%, and 15% respectively. By comparing the indicators of modified asphalt with different contents of SINOTPS modifier, it was found that at a modifier content of 12% or 15%, all the indicators of modified asphalt could meet the requirements of Chinese Standard JTG F40-2004 [50]. At 15% content of SINOTPS modifier, the viscosity of modified asphalt at 60 \({}^{\circ}\)C and 135 \({}^{\circ}\)C was much higher than that of modified asphalt with 12% content of SINOTPS. However, it should be noted that excessive viscosity of modified asphalt would adversely affect the field construction works. Considering the economic factors and aversion of negative effect on production and construction, the optimum content of SINOTPS in modified asphalt was set to be 12% in this study, and the technical indicators of the modified asphalt per JTG E20-2011 [49] are shown in Table 8. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Test Item** & **Unit** & **Test Result** & **Indicator Requirement** \\ \hline Apparent density & g/cm\({}^{3}\) & 2.699 & \(\geq\)2.50 \\ Water content & \% & 0.43 & \(\leq\)1 \\ Particle size range & \textless{}0.6 mm & \% & 100 & 100 \\ (by washing & \textless{}0.15 mm & \% & 95.7 & 90–100 \\ method) & \textless{}0.075 mm & \% & 77.6 & 75–100 \\ Appearance & — & No agglomeration & No agglomeration \\ Hydrophilic coefficient & — & 0.46 & \textless{}1 \\ Plasticity index & \% & 2.9 & \textless{}4 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Technical indicator requirements and test results of limestone powder. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Test Item** & **Unit** & **Test Result** & **Indicator Requirement** \\ \hline Needle penetration (25 \({}^{\circ}\)C, 5 s, 100 g) & 0.1 mm & 70.5 & 60–80 \\ Softening point (ring and ball method) & \({}^{\circ}\)C & 48.5 & \(\geq\)46 \\ Ductility (10 \({}^{\circ}\)C) & cm & 24.1 & \(\geq\)20 \\ Density & g/cm\({}^{3}\) & 1.031 & Measured value \\ Relative density & — & 1.035 & Measured value \\ Rolling thin film & Quality change & \% & \(-\)0.6 & \(\pm\)0.8 \\  & Residual needle & \% & 69.1 & \(\geq\)61 \\  (RTFOT) & penetration ratio & & \\  & Residual ductility (10 \({}^{\circ}\)C) & cm & 7.8 & \(\geq\)6 \\ \hline \hline \end{tabular} Note: Tests were carried out according to Chinese Standard JTG E20-2011 [49].  
\end{table} 
Table 7: Technical indicator requirements and test results of 70# matrix asphalt.