硫酸盐侵蚀对水泥基材料物相组成及孔结构的影响

Effects of Sulfate Attack on Phase Composition and Pore Structure of Cement-Based Materials

摘要:

采用X射线衍射、压汞法及热力学模拟等手段，研究了硫酸盐侵蚀对水泥基材料力学性能、物相组成及孔结构的影响。结果表明，侵蚀120 d后，水泥基材料膨胀性侵蚀产物如钙矾石的形成加速，引起其宏观与微观特性的显著变化：抗压耐蚀系数由增长转为下降，质量损失加剧；水灰比越高，侵蚀产物越多，且主要积聚在10~100 nm过渡孔中；侵蚀产物膨胀后造成过渡孔孔隙结构破坏，数量减少，平均孔径增大，即从120 d时的45.31 nm显著增大至180 d时的78.79 nm，并使得水泥基材料在180 d后严重劣化。

Abstract:

The effects of sulfate attack on the mechanical properties， phase compositions， and pore structure of cement-based materials were investigated using X-ray diffraction， mercury intrusion porosimetry， and thermodynamic simulation. The results indicate that after 120 d of sulfate attack， the formation of expansive corrosion products such as ettringite is accelerated， leading to significant changes in both macro- and micro-properties. The compressive strength coefficient under erosion shifts from an increasing trend to a decreasing one， accompanied by aggravated mass loss. A higher water-to-cement ratio results in more corrosion products， primarily accumulating in the 10-100 nm transitional pores. The expansion of these corrosion products damages the pore structure， reducing the number of transitional pores while increasing the average pore size from 45.31 nm at 120 d to 78.79 nm at 180 d， ultimately causing severe deterioration of the cement-based materials after 180 d.