## 3 Results and Discussion
### Pore Size Distribution  
Figure 8a,b show the pore distribution and cumulative porosity of different w/c ratio formulations. From the diagram, it can be found that the porosity of the 0.4 w/c ratio sample shows a significant increase compared to samples with other w/c ratios, but its cumulative distribution curve does not shift to the right.  
In addition, combined with Table 5, it can be found that with the increase in the w/c ratio, the overall porosity of printing materials shows a pattern of decreasing initially, followed by an increase.  
This may be because when the w/c ratio increases from 0.37 to 0.38, a substantial quantity of Ca(OH)\({}_{2}\) contained in the CSM dissolves into the pore solution with the increased  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Temperature Range (\({}^{\circ}\)C)** & **Mixture** \\ \hline
80–120 & Ettringite and bound water \\ \hline
370–530 & Ca(OH)\({}_{2}\) \\ \hline
600–800 & CaCO\({}_{3}\) \\ \hline
900–1000 & C-A-S-H gel \\ \hline \hline \end{tabular}
\end{table}
Table 4: TG decomposing substance.  
Figure 7: TG and DSC analysis of mixture at 28d.  
w/c ratio, which increases the amount of NaOH formed by the synergistic action of dust ash and EVA rubber powder and promotes the hydrolysis and hydration of cementitious materials. This reduced the number of pores in the YN0.38 samples.  
However, with a further increase in w/c ratio, the pH value of the pore solution decreases, the hydrolytic hydration of GBFS decreases, and the increased water content also increases the porosity of the matrix and the interface transition zone between cementitious material and aggregate, which leads to an increase in porosity of the whole system. However, through Table 5, it can be found that when the w/c ratio is increased to 0.39, the pore distribution of the sample does not change obviously, which is consistent with the previous compressive strength experimental patterns, and this may be due to the formation of more ettrinigite in the system. Filling into the pores, the mechanical properties of printing ink are optimized.  
In addition, by calculating the total porosity of different formulations >50 nm, it can also be found that when the w/c ratio of the printing formula increases from 0.37 to 0.40, the >50 nm porosity of the printing ink increases from 4.71% to 5.32%, and the increased water consumption increases the number of macroscopic pores in the whole system, which is consistent with the phenomenon recorded in the previous literature [20, 21, 22, 23, 24].  
However, by observing the pore distribution of >50 nm in the table, it can also be found that the pore distribution of printing ink > 50 nm is more uniform with an increase in the w/c ratio. Although the porosity of >1000 nm increases with an increase in w/c ratio, the porosity of 50-1000 nm in the samples with an increase in w/c ratio is lower than that of YN0.37 samples.  
This may be consistent with the above reasons: an increase in w/c ratio leads to the formation of more ettrinigite in the system, which fills into the macroscopic pores formed by an increase in w/c ratio, optimizes the pore distribution of the sample, and makes the pore distribution more uniform, thus ensuring that the mechanical properties of the specimen do not decrease too much with an increase in w/c ratio.  
Figure 8: Results of rheological tests on the prepared mixtures.