## 3 Test Results
### Variation Patterns of Various Factors on Surface Texture Characteristics  
The surface texture characteristics of EAC are critical to its SRNR performance. According to the Technical Guidelines for Construction of Highway Cement Concrete Pavements (JTG/T F30-2014) [23] and relevant literature [30], the exposed aggregate depth of EAC should be controlled between 2 and 3 mm, and the exposed aggregate area ratio should be maintained between 65 and 75%. Based on the range analysis results of the orthogonal test shown in Table 4, the variation patterns of the average exposed aggregate depth and area ratio under different factor levels are illustrated in Figure 8. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Test Indicators**} & \multicolumn{5}{c}{**Factors**} \\ \cline{2-6}  & & **A** & **B** & **C** & **D** \\ \hline \multirow{5}{*}{Exposed aggregate depth/mm} & \(k_{1}\) & 2.70 & 2.97 & 2.70 & 2.90 \\  & \(k_{2}\) & 2.90 & 2.71 & 2.92 & 2.89 \\  & \(k_{3}\) & 2.78 & 2.70 & 2.77 & 2.59 \\  & range & 0.20 & 0.27 & 0.22 & 0.31 \\  & \(k_{1}\) & 66.70 & 63.00 & 63.85 & 70.64 \\  & \(k_{2}\) & 67.24 & 66.64 & 64.44 & 66.90 \\  & \(k_{3}\) & 64.72 & 69.02 & 70.37 & 61.11 \\  & range & 2.51 & 6.02 & 6.52 & 9.53 \\  & \(k_{1}\) & 72.56 & 73.56 & 73.11 & 71.44 \\  & \(k_{2}\) & 73.78 & 74.11 & 76.22 & 72.44 \\  & \(k_{3}\) & 74.33 & 73.00 & 71.33 & 76.78 \\  & range & 1.78 & 1.11 & 4.89 & 5.33 \\  & \(k_{1}\) & 83.39 & 81.96 & 82.79 & 82.43 \\  & \(k_{2}\) & 81.84 & 82.89 & 82.34 & 81.87 \\  & \(k_{3}\) & 82.90 & 83.29 & 83.00 & 83.83 \\  & range & 1.55 & 1.33 & 0.66 & 1.96 \\  & \(k_{1}\) & 49.99 & 44.75 & 45.08 & 46.62 \\
28-day compressive strength/MPa & \(k_{2}\) & 47.24 & 45.98 & 46.47 & 47.27 \\  & \(k_{3}\) & 41.80 & 48.29 & 47.47 & 45.13 \\  & range & 8.19 & 3.54 & 2.39 & 2.14 \\  & \(k_{1}\) & 5.45 & 5.05 & 5.31 & 5.12 \\
28-day flexural strength/MPa & \(k_{2}\) & 5.20 & 5.42 & 5.23 & 5.23 \\  & \(k_{3}\) & 5.16 & 5.33 & 5.27 & 5.46 \\  & range & 0.30 & 0.37 & 0.08 & 0.33 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Range analysis of an orthogonal test. Figure 8: The variation patterns of exposed aggregate depth and area ratio. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Test Number**} & **Exposed** & **Exposed** & \multirow{2}{*}{**Pendulum**} & \multirow{2}{*}{**Noise Value/dB**} & **28-day** & **28-day flexural** \\  & **Aggregate** & **Aggregate Area** & & & **Strength/MPa** & **Strength/MPa** \\  & **Depth/mm** & **Ratio/\%** & & & **Strength/MPa** & **Strength/MPa** \\ \hline
1 & 2.88 & 65.53 & 70.00 & 82.44 & 47.42 & 5.13 \\
2 & 2.84 & 66.03 & 74.67 & 82.37 & 50.69 & 5.53 \\
3 & 2.38 & 68.54 & 73.00 & 85.38 & 51.86 & 5.70 \\
4 & 3.00 & 57.13 & 79.67 & 81.84 & 44.57 & 5.13 \\
5 & 2.89 & 76.23 & 70.00 & 82.02 & 48.29 & 5.20 \\
6 & 2.81 & 68.34 & 71.67 & 81.66 & 48.86 & 5.27 \\
7 & 3.03 & 66.33 & 71.00 & 81.59 & 42.27 & 4.90 \\
8 & 2.40 & 57.67 & 77.67 & 84.28 & 38.97 & 5.53 \\
9 & 2.92 & 70.17 & 74.33 & 82.82 & 44.15 & 5.03 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of the orthogonal test. As shown in Figure 8, as the water-binder ratio increases, both the exposed aggregate depth and the exposed aggregate area ratio first increase and then decrease. When the water-binder ratio increases from 0.40 to 0.43, the elevation of the water-binder ratio prolongs the setting time of the surface cement mortar. Under identical brushing timing conditions, the EAC surface with a higher water-binder ratio exhibits greater amounts of unset cement mortar, leading to greater exposed aggregate depth and area ratio after brushing. When the water-binder ratio further increases from 0.43 to 0.46, the enhanced fluidity of the EAC mixture causes internal cement mortar to rise to the surface during vibration, while coarse aggregates sink. This increases the surface mortar layer thickness, making cement mortar the primary component within the influence depth of the exposed aggregate agent, rather than the coarse aggregate.