## 3 Results and Discussions
### Failure Process and Failure Mode of the Specimens  
In order to compare the failure mode of NCRPB with and without FAC, the control group was prepared and tested by using the \(L_{4}\) mix ratio as standard and only removed FAC. As shown in Figure 6a,b, the compressive damage process of NCRPB with and without FAC addition was basically identical. At the early stage of loading, no cracks were found on the surface of the specimens. When the load increased, cracks started to appear on the surface of one side of the specimen, and the cracks expanded thereafter. In the middle position of the specimen height, the cracks developed vertically upward and downward and gradually turned to the corner, which formed a positive-inverse connected V-shaped crack. With further increase in load, V-shaped cracks gradually formed on the other side of the surface, new cracks gradually developed inward, and the surface concrete bulged and cracked. The observations of the damage shows that the specimens containing FAC can produce more cracks during the failure process to absorb the damage energy. The damage of the specimen section without FAC is mainly in the form of cement shedding, while the damage surface of the specimen with FAC also contains the fragmentation of ceramic particles, as shown in Figure 6c,d.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Factor**} & \multicolumn{4}{c}{\(R_{p}\)/**Mpa**} & \multicolumn{4}{c}{\(W\)/\%} & \multicolumn{4}{c}{\(K\)/\%} & \multicolumn{4}{c}{\(\rho\)/**kg\(\cdot\)m\({}^{-3}\)**} \\ \cline{2-13}  & **1** & **12** & **13** & **\(r\)** & **11** & **12** & **13** & **\(r\)** & **11** & **12** & **13** & \(r\)** & **11** & **12** & **13** & \(r\) \\ \hline A & 9.50 & 9.74 & 9.65 & 0.24 & 15.43 & 15.80 & 14.96 & 0.83 & 86.86 & 86.74 & 88.06 & 1.32 & 1578 & 1574 & 1579 & 5.12 \\ B & 10.40 & 9.66 & 8.80 & 1.63 & 11.80 & 15.03 & 19.36 & 7.56 & 91.77 & 88.50 & 81.38 & 10.39 & 1540 & 1582 & 1609 & 68.94 \\ C & 9.49 & 9.55 & 9.84 & 0.35 & 16.70 & 15.00 & 14.50 & 2.20 & 86.48 & 87.63 & 87.53 & 1.15 & 1580 & 1574 & 1577 & 6.73 \\ D & 9.41 & 9.59 & 9.89 & 0.49 & 16.30 & 16.13 & 13.70 & 2.66 & 86.58 & 86.66 & 88.42 & 1.84 & 1681 & 1571 & 1479 & 202.02 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Range analysis of the orthogonal test.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Factor**} & \multicolumn{4}{c}{\(R_{p}\)/**Mpa**} & \multicolumn{4}{c}{\(W\)/\%} & \multicolumn{4}{c}{\(K\)/\%} & \multicolumn{4}{c}{\(\rho\)/**kg\(\cdot\)m\({}^{-3}\)**} \\ \cline{2-13}  & **1** & **12** & **13** & **\(r\)** & **11** & **12** & **13** & **\(r\)** & **11** & **12** & **13** & \(r\)** & **11** & **12** & **13** & \(r\) \\ \hline A & 9.50 & 9.74 & 9.65 & 0.24 & 15.43 & 15.80 & 14.96 & 0.83 & 86.86 & 86.74 & 88.06 & 1.32 & 1578 & 1574 & 1579 & 5.12 \\ B & 10.40 & 9.66 & 8.80 & 1.63 & 11.80 & 15.03 & 19.36 & 7.56 & 91.77 & 88.50 & 81.38 & 10.39 & 1540 & 1582 & 1609 & 68.94 \\ C & 9.49 & 9.55 & 9.84 & 0.35 & 16.70 & 15.00 & 14.50 & 2.20 & 86.48 & 87.63 & 87.53 & 1.15 & 1580 & 1574 & 1577 & 6.73 \\ D & 9.41 & 9.59 & 9.89 & 0.49 & 16.30 & 16.13 & 13.70 & 2.66 & 86.58 & 86.66 & 88.42 & 1.84 & 1681 & 1571 & 1479 & 202.02 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Variance analysis of the orthogonal test.