# Effects of Cement-Mineral Filler on Asphalt Mixture Performance under Different Aging Procedures
## 3 Results and Discussion
### Immersion Marshall Test Results  
To comprehensively investigate the influence of the cement filler on the volumetric parameters of the asphalt mixture, this study measured the index and corresponding stability from asphalt mixture specimens for different cement/mineral ratios by the Marshall test [10; 32]. The results are summarized in Table 7.  
Figure 3: High-temperature stability test at 70 \({}^{\circ}\)C.  
From the volume index of the Marshall test piece, as the cement replacement ratio increased, the measured relative density of the asphalt mixture increased gradually, the void ratio and mineral gap ratio decreased gradually, and the asphalt saturation increased gradually. Because Portland cement has a higher density compared to limestone ore powder, incrementally increasing the cement content will inevitably lead to an increase in the density of the asphalt mixture. Because the filler accounts for a relatively small proportion of the total mass of the mixture, the change in the proportion of cement blending had little effect on the relative density of the overall mixture. From the test results, changing \(\text{M}_{\text{PC}}\)/\(\text{M}_{\text{MP}}\) did not significantly change the void ratio, mineral gap ratio, and asphalt saturation of the molded specimens, and the variation range was also small. This proves that the cement, when substituted for mineral powder, had no significant effect on the volumetric parameters of the asphalt mixture after compaction.  
For the design of the asphalt mixture proportion, the Chinese standard uses the water-immersed Marshall test to evaluate the water stability of the asphalt mixture, and the residual stability ratio \(\text{MS}_{0}\) is used as the evaluation index. The results of the residual stability test of the asphalt mixture for different aging degrees in this study are summarized in Table 8.  
With the addition of cement, the residual stability of the asphalt mixture was improved; however, when the cement blending ratio was in the range of 50%-75%, the residual stability reached a maximum. To compare and analyze the improvement effect of the cement filler on the water stability of the asphalt mixture for different aging degrees, the difference \(\Delta\text{MS}_{0}\) between the maximum and minimum values of residual stability in the same test group was calculated. By comparing the three aging levels of \(\Delta\text{MS}_{0}\), we found that after aging, the improvement in water stability due to the cement filler decreased. The improvement effect of the cement filler on water stability was 42% lower than that for the non-aging condition. To more clearly analyze the variation of residual stability for different aging degrees, the test results are plotted in Figure 4.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{\(\text{M}_{\text{PC}}\)/\(\text{M}_{\text{MP}}\)} & **Bulk Relative** & **Void** & **Voids in Mineral** & **Voids Filled** & **Marshall** & **Flow Value** \\  & **Density** & **Volume (\%)** & **Aggregate (\%)** & **with Asphalt (\%)** & **Stability (k N)** & **(0.1 mm)** \\ \hline
0:4 & 2.545 & 4.3 & 13.5 & 68.5 & 16.28 & 49 \\
1:3 & 2.549 & 4.5 & 14.1 & 68.6 & 15.11 & 41 \\
2:2 & 2.552 & 4.9 & 14.7 & 66.7 & 13.80 & 41 \\
3:1 & 2.558 & 4.8 & 13.9 & 65.5 & 15.96 & 48 \\
4:0 & 2.577 & 4.8 & 14.2 & 66.1 & 13.78 & 41 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Volumetric parameter and Marshall test results.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \(\text{M}_{\text{PC}}\)/\(\text{M}_{\text{MP}}\) & **Unaged (\%)** & **Requirement (\%)** & **Short-Term Aged (\%)** & **Long-Term Aged (\%)** \\ \hline
0:4 & 87.8 & & 81.3 & 78.3 \\
1:3 & 94.1 & & 87.4 & 80.3 \\
2:2 & 97.4 & \(\
ot\sim\)85 & 90.7 & 82.6 \\
3:1 & 95.3 & & 87.9 & 83.8 \\
4:0 & 96.0 & & 85.9 & 82.1 \\ \hline \hline \(\Delta\text{MS}_{0}\) & 9.6 & & 9.4 & 5.5 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Residual stability ratio (\(\text{MS}_{0}\)) in immersed Marshall test for different aging degrees (%).