## 3 Result and Analysis
### Influence of Each Activator on Compressive Strength of Testing Piece  
To obtain the overall trend of changes in the mechanical strength acquisition of cemented tailings backfill samples under different activator dosages, the average strength values at each level of four activators were calculated, and the polynomial function was fitted. Table 4 shows the strength acquisition of cemented tailings backfill samples under different activator dosages, whereas Figure 7 shows the trend line of the mechanical strength gain of CTB samples containing different excitation agents, such as quicklime, desulfurized ash, glauberite mineral and sodium hydroxide. In this paper, the strength growth factor of the tested backfill samples was defined as follows:  
\[K=\frac{\varepsilon_{i}}{\varepsilon_{0}} \tag{1}\]  
where \(K\) is the strength growth factor of the tested backfill sample; \(\varepsilon_{i}\) is the uniaxial compressive strength acquisition of cemented tailings backfill samples with different activator dosages, MPa; and \(\varepsilon_{0}\) is the uniaxial compressive strength acquisition of cemented tailings backfill samples when OPC 32.5 R cement is used as the main activator, MPa. As shown in Figure 7, the mechanical strength changes of cemented tailings backfill samples under different activator dosages basically followed the function \(y=ax^{3}-bx^{2}+cx-d\). The multiple correlation coefficients of the fitting results exceeded 97%, which indicated that the regression effect for the tested cemented tailings backfill samples was significant and demonstrated a high accuracy. Table 4 and Figure 7 showed clearly that the minimum strength growth factor of the DA formulation samples was 1.45 and the highest was 2.03. Therefore, the formula of DA was better than that of the cement activator. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Activator**} & **14-d** & \multirow{2}{*}{**K \({}^{*}\)**} & **28-d** & \multirow{2}{*}{**Activator\%**} & **14-d** & \multirow{2}{*}{**K \({}^{*}\)**} & **28-d** & \multirow{2}{*}{**K \({}^{*}\)**} \\  & **Stress/MPa** & & & & & & & **Stress/MPa** & \\ \hline
32.5R & 0.619 & - & 1.091 & - & & & & \\ Q-4.5\% & 1.097 & 1.77 & 2.105 & 1.93 & DA-16.0\% & 1.097 & 1.77 & 1.981 & 1.82 \\ Q-5.0\% & 1.024 & 1.65 & 2.142 & 1.96 & DA-17.5\% & 1.074 & 1.74 & 2.093 & 1.92 \\ Q-5.5\% & 1.047 & 1.69 & 1.952 & 1.79 & DA-19.0\% & 0.997 & 1.61 & 2.125 & 1.95 \\ GM-1.5\% & 0.99 & 1.60 & 2.054 & 1.88 & SH-0.0\% & 0.897 & 1.45 & 1.889 & 1.73 \\ GM-2.0\% & 1.057 & 1.71 & 1.934 & 1.77 & SH-0.5\% & 1.162 & 1.88 & 2.123 & 1.95 \\ GM-2.5\% & 1.121 & 1.81 & 2.211 & 2.03 & SH-1.0\% & 1.109 & 1.79 & 2.187 & 2.00 \\ \hline \hline \end{tabular} \({}^{*}\)K stands for the strength growth factor.  
\end{table} 
Table 4: The strength gain of CTB samples under different activator dosages. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Curing Period**} & \multirow{2}{*}{**Activator**} & \multirow{2}{*}{**Range Analysis**} & \multicolumn{4}{c}{**Variance Analysis**} \\ \cline{4-7}  & & & **Sum of** & **Degree of** & **Mean Square** & **Significance** \\ \hline \multirow{4}{*}{14d} & Q & 1 & 0.0083 & 2 & 0.0041 & \multirow{4}{*}{SH \(>\) GM \(>\)} \\  & DA & 1.37 & 0.0164 & 2 & 0.0082 & \\ \cline{1-1}  & GM & 1.79 & 0.0257 & 2 & 0.0129 & \\ \cline{1-1}  & SH & 3.63 & 0.1184 & 2 & 0.0592 & \\ \hline \multirow{4}{*}{28d} & Q & 1.32 & 0.0607 & 2 & 0.0304 & \multirow{4}{*}{SH \(>\) GM \(>\)} \\  & DA & 1 & 0.0343 & 2 & 0.0171 & \\ \cline{1-1}  & GM & 1.92 & 0.1155 & 2 & 0.0577 & \\ \cline{1-1}  & SH & 2.07 & 0.1480 & 2 & 0.0740 & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Statistical results of the range and variance analyses. As Figure 7a shows, when the Q content increased from 4.5 to 5.5%, the strength acquisition of 14-day cured CTB sample was influenced by the hydration reaction sequence of the cementitious material used, showing an initial decrease and subsequent increase.