## 4 Discussion
\begin{table}
\begin{tabular}{c c c} \hline \hline
**NO.** & **Mixture Composition** & **Effect of Geopolymers** & **Source** \\ \hline
1 & Geopolymer: Mineral powder, fly ash, wet carbide slag, NaOH & When geopolymer is used to replace 20\% cement, the UCS of the base mixture is 7.69 MPa; the freeze-thaw cycle test shows that the mixture with 20\% geopolymer substitution rate has the best frost resistance. & Present study \\
2 & Geopolymer: Calcium carbide residue, Linear alkyl benzene sulfonic acid & When the ratio of Calcium carbide residue to Linear alkyl benzene sulfonic acid is 80\%:20\%, the UCS of the geopolymer is the largest. When the local polymer content is 7.5\%, it is the best geopolymer content of the mixture. & [8] \\
3 & Geopolymer: Rubber wood fly ash, NaOH, Na\({}_{2}\)SiO\({}_{3}\) & When the geopolymer content is 30\% and the ratio of sodium silicate to sodium hydroxide is 70.30, the mixture has the highest UCS and ITS. & [12] \\
4 & Geopolymer: jarofix, NaOH, Na\({}_{2}\)SiO\({}_{3}\) & When the content of geopolymer is 13\%, the UCS of the mixture reaches 2.75 MPa and 6.55 MPa respectively in environmental curing and dry curing. & [15] \\
5 & Geopolymer: Slag, Fly Ash, Na\({}_{2}\)SiO\({}_{3}\) & The freeze-thaw cycle test of geopolymer stabilized materials: Aggregate & [22] \\
6 & Geopolymer: carbide slag, coal gangue, NaOH, Na\({}_{2}\)SiO\({}_{3}\) & When the geopolymer content is 10\%, the 7 d UCS of the mixture reaches 3.68 MPa, and the UCS and frost resistance are better than 4\% cement stabilized mixture. & [23] \\
7 & Geopolymer: Red mud, Mineral powder, alkali activator & When the local polymer content is 8\%, the 7 d UCS of the mixture reaches 7.1 MPa; after freeze-thaw cycles, the strength loss rate of the mixture with 8\% geopolymer content is the smallest. & [24] \\
8 & Geopolymer: Fly ash, metakaolin, NaOH and anhydrous sodium metasilicate & When 14\% geopolymer stabilized mixture is used, the 7 d UCS of the mixture reaches more than 6 MPa, and the frost resistance is significantly better than that of cement & [25] \\
8 & Stabilized materials: Aggregate and domestic waste incineration slag & & [25] \\ \hline \hline \end{tabular}
\end{table} 
Table 14: Compare the results obtained with the literature. will lead to the deterioration of the internal compactness of the mixture [4]. Therefore, too little or too much geopolymer dosage is not recommended. Combined with the previous research conclusions, it can be seen that under the condition of freeze-thaw cycles, the strength of the mixture will decrease with the increase in the number of freeze-thaw cycles [22; 23; 24; 25], which is consistent with the conclusions of this study. According to the mechanism analysis part of this study, this kind of strength damage mainly comes from the increase in porosity and the change in the pore size distribution in the mixture after freeze-thaw cycles. The increase in total porosity leads to a significant decrease in UCS in the mixture, while an increase in more harmful pores and increase in total porosity lead to the damage of ITS in the mixture. In addition, relevant studies have pointed out that after the freeze-thaw cycle, the mixture develops cracks, the internal damage increases and the effective contact area of the particles inside the sample is reduced, which is also the cause of the strength damage in the mixture after the freeze-thaw cycle [22; 24].