## 4 Conclusions  
1. The unique natural macroporous/mesoporous structure of DE endows it with excellent water absorption and release properties, which can improve the internal relative humidity of mortar and significantly slow down the decline rate of internal relative humidity. Compared to the benchmark group, when the content of DE is 1%, the saturation duration of the internal humidity of mortar is extended by 3.4%.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Grouping**} & \multirow{2}{*}{**Porosity/\%**} & \multirow{2}{*}{
\begin{tabular}{c} **Average** \\ **Aperture/nm** \\ \end{tabular} } & \multicolumn{4}{c}{**Pore Size Distribution/(mL g\({}^{-1}\))**} \\ \cline{3-6}  & & & **<10 nm** & **10-100 nm** & **100 nm-1 μm** & **>1 μm** \\ \hline A1 (28 d) & 14.05 & 19.01 & 0.0136 & 0.0262 & 0.0028 & 0.0267 \\ \hline A2 (28 d) & 17.44 & 22.19 & 0.0162 & 0.0236 & 0.0024 & 0.0497 \\ \hline A3 (28 d) & 17.88 & 16.47 & 0.0233 & 0.0397 & 0.0034 & 0.0299 \\ \hline A4 (28 d) & 17.49 & 13.69 & 0.0257 & 0.0448 & 0.0037 & 0.0176 \\ \hline A2 (3 d) & 19.02 & 26.13 & 0.0135 & 0.0419 & 0.0051 & 0.0373 \\ \hline A2 (7 d) & 14.38 & 21.52 & 0.0131 & 0.0334 & 0.0033 & 0.0249 \\ \hline \hline \end{tabular}
\end{table}
Table 3: The pore structure parameters and distribution of mortar with different DE doping amounts at 28 d and mortar with 1% DE doping amount at different ages.  
Under the standard of not reducing the 28 d compressive strength of mortar, compared to the reference group, the mortar mix proportion of DE replacing 1% cement mass reduces the 3 d autogenous shrinkage value by 30.9% and the 7 d autogenous shrinkage value by 36.7%. In the ring-constrained crack resistance test, the initial cracking time is delayed by 10.7%, and the crack width is reduced by 28%.
3. The mechanism of DE reducing autogenous shrinkage comprises in three aspects. Firstly, SiO\({}_{2}\) and Al\({}_{2}\)O\({}_{3}\) in DE react with Ca(OH)\({}_{2}\) to produce expansive ettringite, which compensates for part of the shrinkage. Secondly, DE replaces part of the cement, reducing the activity of cementing materials and thus reducing autogenous shrinkage from the source. Thirdly, the slow release of water from its porous structure can increase the internal relative humidity of mortar and reduce the driving force of autogenous shrinkage.  
Conceptualization, S.L. ([PERSON]); methodology, S.L. ([PERSON]); software, S.L. ([PERSON]); validation, S.L. ([PERSON]); formal analysis, S.L. ([PERSON]); investigation, S.L. ([PERSON]); resources, S.L. ([PERSON]); data curation, S.L. ([PERSON]); writing--original draft preparation, S.L. ([PERSON]); writing--review and editing, S.L. ([PERSON]), S.L. ([PERSON]), and C.J.; visualization, C.J.; supervision, S.L. ([PERSON]); project administration, S.L. ([PERSON]); funding acquisition, S.L. ([PERSON]). All authors have read and agreed to the published version of the manuscript.  
Not applicable.  
The data presented in this study are available upon request from the corresponding author. The data are not publicly available due to the fact that dataset production is part of the innovation of this paper, and the dataset will not be open-sourced at this time. We will continue to explore new possibilities in subsequent experimental research, and then the dataset will be made public along with the related code.  
The authors declare no conflicts of interest.