## 3 Results and Discussion
### Analysis of Orthogonal Test Results
#### 3.1.2 Variance Analysis  
A variance analysis for the orthogonal experiment was conducted. The significance levels of \(F_{0.01}\) (2,2) and \(F_{0.05}\) (2,2) were used to evaluate the significance of factors. The variance analysis results  
Figure 3: Relationships between various property indices and K values: (**a**) between compressive strength and K; (**b**) between flexural strength and K; (**c**) between permeability coefficient and K; (**d**) between freeze-thaw cycles and K.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Index**} & \multicolumn{3}{c}{**f\({}_{\textbf{c}}\) (MPa)**} & \multicolumn{3}{c}{**f\({}_{\textbf{f}}\) (MPa)**} & \multicolumn{3}{c}{**k (mm/s)**} & \multicolumn{3}{c}{**Freeze-Thaw Cycles**} \\ \cline{2-13}  & **A** & **W/B** & **P** & **A** & **W/B** & **P** & **A** & **W/B** & **P** & **A** & **W/B** & **P** \\ \hline K1 & 20.99 & 19.74 & 21.93 & 4.16 & 3.83 & 4.36 & 5.95 & 6.36 & 3.83 & 73.3 & 60.0 & 70.0 \\ K2 & 19.18 & 18.79 & 19.43 & 3.71 & 3.84 & 3.70 & 6.19 & 5.95 & 5.95 & 60.0 & 60.0 & 60.0 \\ K3 & 17.70 & 19.33 & 16.50 & 3.44 & 3.63 & 3.25 & 6.24 & 6.07 & 8.60 & 50.0 & 63.3 & 53.3 \\ R & 3.29 & 0.96 & 5.43 & 0.72 & 0.21 & 1.11 & 0.29 & 0.41 & 4.77 & 23.3 & 3.3 & 16.7 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Range analysis results; A: aggregate size; W/B: water-binder ratio; P: porosity are listed in Table 6. From Table 6, following conclusions can be drawn: (a) \(F\)-values of porosity for flexural strength and permeability coefficient are larger than \(F_{0.01}\) (2,2), which means there is a 99% probability that porosity has a significant influence on flexural strength and the permeability coefficient. \(F\)-value for the permeability coefficient is larger than that for flexural strength, which means the influence of porosity on the permeability coefficient is larger than that on flexural strength. \(F\)-values of porosity for compressive strength and the freeze-thaw cycles are between \(F_{0.01}\) (2,2) and \(F_{0.05}\) (2,2), which means there is a 95% probability that porosity has a significant influence on compressive strength and the freeze-thaw cycles. The \(F\)-value for compressive strength is larger than that for the freeze-thaw cycles, which means the influence of porosity on compressive strength is larger than that on the freeze-thaw cycles. (b) \(F\)-values of aggregate size for compressive strength, flexural strength, and the freeze-thaw cycles are between \(F_{0.01}\) (2,2) and \(F_{0.05}\) (2,2), which means there is a 95% probability that aggregate size has a significant influence on compressive strength, flexural strength, and the freeze-thaw cycles. \(F\)-value for flexural strength is larger than that for compressive strength and the freeze-thaw cycles, which means the influence of aggregate size on flexural strength is larger than that on compressive strength and the freeze-thaw cycles. \(F\)-value of aggregate size for the permeability coefficient is smaller than \(F_{0.05}\) (2,2), which means the influence of aggregate size on the permeability coefficient is not significant. (c) \(F\)-values of the water-binder ratio for PC properties (compressive strength, flexural strength, permeability coefficient, and freeze-thaw cycles) are smaller than \(F_{0.05}\) (2,2), which means the influence of the water-binder ratio on PC properties is not significant. The reason may be that the addition of superplasticizer weakens the influence of the water-binder ratio.