Research on the Pore Distribution Characteristics and Strength Degradation of Cement-Based Materials under Sulfate Attack

To investigate the influence of sulfate erosion on the performance of cement-based materials, this study designed mortar, concrete, and mortar-aggregate specimens with a water-to-cement ratio of 0.35. The study examined the changes in performance over 30 days, 60 days, 90 days, 120 days, and 150 days of sulfate erosion, and the findings showed that: as the duration of sulfate erosion increased, the mass change and compressive strength of cement-based materials generally showed an increasing trend first and then decreasing trend. The mass change of mortar, concrete, and mortar-aggregate specimens was 0.64%, 0.274%, and 0.16%, respectively, after 150 days of sulfate erosion. The compressive strength of mortar, concrete, and mortar-aggregate specimens decreased by 56.86%, 14.29%, and 19.34%, respectively, after 150 days of sulfate erosion. The porosity of mortar, concrete, and mortar-aggregate specimens showed that the porosity of mortar was greater than that of concrete, which was greater than that of mortar-aggregate specimens. The porosity of mortar-aggregate specimens showed a trend of decreasing first and then increasing after sulfate erosion. The porosity of mortar-aggregate specimens reached 12.57% after 30 days of sulfate erosion and 18.27% after 150 days of sulfate erosion.