# Preparation and Characterization of Polymer-Modified Sulphoaluminate-Cement-Based Materials
## 3 Results and Discussion
### Analysis of Orthogonal Experimental Results
#### 3.1.1 Range Analysis  
Range analysis was utilized to evaluate the influence of various factors at different levels on the indicators. The ki value represented the average value of the corresponding experimental results, while R indicated the range, which was calculated as the maximum minus the minimum for each level. A larger R value signifies a greater influence of that particular factor on the test results.  
According to Table 3, the effects of various factors on the flexural strength of cement-based materials at 7 days were different, with the order of influence being monomer > crosslinking agent > initiator. The dosage of monomer had the greatest impact on the flexural strength of modified cement-based materials, while the effects of the initiator and crosslinking agent were similar. Similarly, for the compressive strength of cement-based materials at 7 days, the order of influence was as follows: monomer > initiator > crosslinking agent. The dosage of monomer had the greatest impact on the compressive strength of modified cement-based materials, while the crosslinking agent dosage had a minimal effect on strength. This indicated that the monomer was a significant influencing factor on the properties of modified cement-based materials, whereas initiators and crosslinking agents had similar effects.  
According to the range analysis, Figures 1 and 2 illustrate corresponding index influence effect curves for each factor. Factor A represented the monomer, B represented the initiator, and C represented the crosslinking agent. There was a positive correlation between the monomer dosage and flexural strength, while there was the opposite trend for the initiator and crosslinking agent's influence on flexural strength. The optimal combination for this experiment was A5B4C5. As the monomer content increased, the compressive strength gradually decreased. With an increasing initiator content, the compressive strength identically decreased and then increased before decreasing again. With an increasing crosslinking agent content, the compressive strength showed a pattern where it first decreased and then increased. The optimal combination for this experiment was A1B4C5, which suggested that there were different correlations between monomers' impact on flexural and compressive strengths. In conclusion, only an appropriate amount of crosslinking agent and initiator can effectively enhance performance in modified materials (acrylamide in situ-polymerization-modified cement-based materials).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Index** & & **Monomer A** & **Initiators B** & **Crosslinkers C** \\ \hline \multirow{8}{*}{Flexural strength} & k1 & 4.2 & 4.33 & 4.89 \\  & k2 & 4.07 & 4.23 & 4.45 \\  & k3 & 4.54 & 4.93 & 5 \\  & k4 & 4.95 & 5.6 & 4.4 \\  & k5 & 6.85 & 5.51 & 5.88 \\  & R & 2.78 & 1.37 & 1.48 \\ \hline \multirow{8}{*}{Compressive strength} & k1 & 35.15 & 33.91 & 34.22 \\  & k2 & 34.77 & 32.85 & 33.62 \\ \cline{1-1}  & k3 & 34.94 & 34.7 & 33 \\ \cline{1-1}  & k4 & 33.47 & 35 & 32.56 \\ \cline{1-1}  & k5 & 30.21 & 32.08 & 35.14 \\ \cline{1-1}  & R & 4.94 & 2.92 & 2.58 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Range analysis results.