## 3 Results and Discussion
### Mip  
Figure 5 illustrates the graphs depicting the incoming and outgoing tribute pressure for C3 and M3. Under conditions of a constant water-cement ratio, the volume of mercury intake exceeds that of mercury withdrawal. The incorporation of fine aggregates results in a decrease in the amount of incoming mercury, while the addition of coarse aggregates leads to an increase in the incoming mercury; however, this value remains lower than that observed for net slurry. Both the total porosity and effective porosity exhibit an initial upward trend followed by a subsequent decline. During the mercury pressure test, liquid mercury penetrates into the material's pores under applied pressure, and upon cessation of this pressure application, some liquid mercury is retained within these pores. Consequently, the volume of incoming mercury surpasses that of outgoing mercury; this residual portion resembles ink bottle holes [33]. Pores that can freely discharge after unloading are classified as effective pores. Effective pores serve as primary conduits for moisture transport and erosion mediums, which are critical determinants influencing material durability. Figure 3: XRD images of M3 specimen at different erosion durations: (**a**) 0, 30, and 60 d; (**b**) 90, 120, and 150 d.  
Figures 6 and 7 present the pore size distribution curves for C3 and M3 alongside their corresponding cumulative suction curves. In Figure 6, it is observed that within the pore diameter range of 100 nm to 10,000 nm, the pore size distributions of mortar and concrete are essentially comparable. However, when the pore diameter falls below 100 nm or exceeds 10,000 nm, the intrusion volume of concrete surpasses that of mortar. Regardless of pore size, Figure 7 indicates that concrete contributes more significantly than mortar; specifically, this contribution is approximately three to five times greater for concrete in the pore size range of 100 nm to 100,000 nm. Under identical water-cement ratio conditions, both the pore size and mercury intake exhibit a trend where concrete > mortar. This phenomenon can be attributed to increased non-homogeneity as coarse aggregates are incorporated into the mix, resulting in a substantial rise in porosity. Figure 4: SEM images of M3 specimen at different erosion durations: (**a**) 0 d; (**b**) 30 d; (**c**) 60 d; (**d**) 90 d; (**e**) 120 d; and (**f**) 150 d.  
Figure 5: M3 and C3 incoming and outgoing tribute pressure variation. The pore size distribution curves and cumulative contribution curves for M3 withvarious erosion durations of M3 are illustrated in Figures 8 and 9. As depicted in Figure 8, it is apparent that for pore diameters of less than 100 nm, the cumulative distribution of sulfate erosion at 60 days exceeds that observed at 120 days, which in turn surpasses the values recorded for samples without any erosion. For pore diameters ranging from 100 nm to 1000 nm, the cumulative distribution indicates that un-eroded samples exhibit a greater value than those subjected to sulfate erosion for 60 days, but fall short compared to those eroded for a period of 120 days. In the range of pore diameters from 1000 nm to 100,000 nm, the cumulative distribution reveals that sulfate erosion after 120 days is greater than that of both the un-eroded samples at day zero and those eroded for 60 days. In Figure 9, the volume of non-eroded material exceeds that of eroded material at 120 days, and also surpasses the erosion volume observed at 60 days when the pore size ranges from 10 nm to 100 nm. In the range of 100 nm to 1000 nm, the erosion volume at 60 days is greater than that of non-eroded samples, and also exceeds the erosion volume recorded at 120 days. When pore sizes fall within the range of 1000 nm to 100,000 nm, the erosion volume after 120 days is greater than both that of non-eroded samples and that observed after 60 days. Figure 6: M3 and C3 pore size distribution curves. Figure 7: M3 and C3 cumulative tribute intake curves.