## 2 Material and Method
### Method  
This study involved preparing ceramic fiber geopolymer concrete (CFGC) specimens with varying quantities of slag, silica fume, and fly ash, as well as a control specimen with PCC. These preliminary study specimens underwent testing through UPV, water absorption, freeze-thaw, compressive strength, SEM, and EDS scanning, as well as high-temperature tests. The geopolymer concrete specimen with the highest compressive strength and lowest void ratio (GS90) was chosen for high-temperature testing. Subsequently, ceramic fiber was added to the concrete at varying volumes of 2%, 5%, and 10%, and high-temperature tests were conducted at 100, 300, 600, and 900 \({}^{\circ}\)C. The geopolymer concretes have been named 0% CFGC, 2% CFGC, 5% CFGC, and 10% CFGC, based on the amount of ceramic fiber they contain. The mixing ratios for the geopolymer concrete are displayed in Table 8. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Symbol** & **Coarse Aggregate** & **Fine Aggregate** \\ \hline Dry specific gravity (gr/cm\({}^{3}\)) & \(\delta_{\rm k}\) & 1.61 & 2.02 \\ \hline Saturated-surface dry weight (gr/cm\({}^{3}\)) & \(\delta_{\rm ydk}\) & 1.64 & 2.37 \\ \hline Apparent specific gravity (gr/cm\({}^{3}\)) & \(\delta_{\rm g}\) & 1.66 & 2.65 \\ \hline Water absorption capacity (\%) & \(\rm S_{\rm a}\) & 1.72 & 2.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Water absorption and specific gravity results. Figure 5: The ceramic fiber soluble in NaOH. Figure 6: Aggregate granulometry curve. For more details on the tests performed, see Table 9.  
Initially,the flow diameters of each casting specimen were also examined to determine the workability of the concrete. According to Figure 7, it can be observed that the G100 specimen, which had 100% slag content, exhibited the lowest workability. As the slag ratio increased in the specimens, the fluidity of the concrete mix decreased [31]. Additionally, the setting time of the concrete was shortened with an increase in slag content [32], leading to a low spreading diameter for the G100 specimen with 100% slag content. Moreover, it was observed that the S100 specimen contained fine-grained silica fume, which absorbed the liquid in the mixture, leading to a decrease in workability. In contrast, the GSF50 specimen demonstrated the most favorable workability. Additionally, the workability of the GF90 specimen, where the slag rate was reduced to 90% and 10% fly ash was used as a substitute, showed an increase of 8.43% when compared to the G100 specimen. The workability of the GS90 specimen, which contains 90% slag and 10% silica fume, increased by 24.10% compared to G100, and this specimen also performed better in high temperature tests. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Specimen** & **Fine** & **Coarse** & \multicolumn{3}{c}{**Binders**} & \multicolumn{3}{c}{**Activators**} & **Super** \\ \cline{3-8}
**Name** & **Aggregate** & **Aggregate** & **Silica Fume** & **Slag** & **Fly Ash** & **Na\({}_{\text{2}}\)SiO\({}_{\text{3}}\)** & **NaOH** & **Plasticizer** \\ \hline G100 & 1209 & 651 & 0 & 400 & 0 & 115 & 46 & 4 \\ \hline GF90 & 1209 & 651 & 0 & 360 & 40 & 115 & 46 & 4 \\ \hline GF80 & 1209 & 651 & 0 & 320 & 80 & 115 & 46 & 4 \\ \hline GF70 & 1209 & 651 & 0 & 280 & 120 & 115 & 46 & 4 \\ \hline GS90 & 1209 & 651 & 40 & 360 & 0 & 115 & 46 & 4 \\ \hline GS80 & 1209 & 651 & 80 & 320 & 0 & 115 & 46 & 4 \\ \hline GS70 & 1209 & 651 & 120 & 280 & 0 & 115 & 46 & 4 \\ \hline GS50 & 1209 & 651 & 200 & 200 & 0 & 115 & 46 & 4 \\ \hline S100 & 1209 & 651 & 400 & 0 & 0 & 115 & 46 & 4 \\ \hline GSF50 & 1209 & 651 & 200 & 100 & 100 & 115 & 46 & 4 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Geopolymer concrete mixing ratios (kg/m\({}^{3}\)).