# Effect of Polycarboxylate Admixture on the Performance of Fluorogypsum-Based Self-Leveling Material
## 3 Results and Discussion
### Mip  
MIP pore structure analysis was performed on the FSLM 28 d hardened body with various PCE doping to investigate its effect on the material's porosity and pore size distribution. The results are shown in Figure 7.  
The differential curves of the pore structure in Figure 7a reveal interesting trends regarding the effect of PCE doping on FSLM. When the PCE doping amount is 0.14%, there is a noticeable shift of the peak to the left, indicating a reduction in the most available pore size and an increase in the content of small pores in FSLM. This suggests that PCE at 0.14% dosage can effectively modify the pore structure of the material. Additionally, the peak value corresponding to the most available apertures initially increases and then decreases with the increase in PCE doping, indicating that PCE has the ability to increase the number of small pores in the material. However, there is a limit to this effect, as the degree to which PCE increases the number of small pores reaches a maximum and then starts to decrease. Figure 6: Effect of PCE on TG-DSC: (**a**) 0.14% PCE 28d; (**b**) 0.2% PCE 28d; (**c**) 0.14% PCE 3d; (**d**) 0.2% PCE 3d; (**e**) 0.14% PCE 1d; (**f**) 0.2% PCE 1d. In Figure 7b, the cumulative mercury intrusion curve provides further insights into the pore structure of FSLM. It shows that the cumulative mercury intrusion increases to some extent with the increase in PCE dosage. Specifically, when the PCE dosage is increased from 0.08% to 0.2%, the cumulative mercury intrusion increases by 18.4%, 10.2%, 28.2%, and 18.1%, respectively. This indicates that PCE influences the pore size distribution in FSLM, and the cumulative mercury intrusion data are consistent with the porosity data in Figure 7d. It can be inferred that the pore size distribution and porosity collectively affect the strength of FSLM. To further understand the effect of different pore sizes on strength, Figure 7c classifies the pores into four categories: harmless pores (less than 20 nm), less harmful pores (20-50 nm), harmful pores (50-200 nm), and multiple harmful pores (greater than 200 nm) [51]. At 0.14% PCE doping, the number of multiple harmful pores is noticeably reduced, resulting in the lowest total ratio of harmful pores to multiple harmful pores. Additionally, the number of small pores less than 50 nm is the largest in this case. Conversely, at 0.2% PCE doping, the total ratio of harmful pores to multiple harmful pores is the highest, and there are almost no harmless pores. This indicates that excessive PCE doping can negatively impact the pore structure of FSLM, leading to an increase in the number of large pores and a significant coarsening of pore size, thereby affecting the material's strength. Figure 7d provides additional information on porosity and average pore size. It demonstrates that the porosity fluctuates with increasing PCE doping, and the average pore size initially decreases and then increases. Interestingly, both porosity and average pore size reach their minimum values at 0.14% PCE doping. This suggests that the optimal amount of PCE can effectively optimize the pore structure of FSLM and refine the pore size. Figure 7: Influence of PCE on the pore structure of FSLM for 28 days: (**a**,**c**) Pore size distribution, (**b**) Cumulative pore volume, (**d**) Porosity and average pore diameter. Therefore, with an increase in PCE dosing, the strength of FSLM tends to initially increase and then decrease. This trend can be attributed to the effective reduction in porosity and the prevention of excessive coarsening of the pore size at lower dosing, which positively impacts the material's strength. On the other hand, at higher dosing levels, the pore structure of FSLM begins to deteriorate, resulting in an increase in the number of large pores and the coarsening of pore size. This negative effect on strength is influenced by factors such as air-entrainment and the hydration process.