压汞后水泥基材料的孔隙结构变化

The mercury intrusion porosimetry is one of the most commonly used methods to characterize the pore structure of cement-based materials. However, under high pressure, the pore structure of cement-based materials may change significantly. The changes in the pore structure of cement paste before and after mercury intrusion were studied by using XCT. The results show that the mercury intrusion pore distribution curve of cement paste conforms to the characteristics of mercury intrusion in 5 stages; mercury can significantly increase the X-ray absorption rate of pores, resulting in the gray-scale inversion of XCT images before and after mercury intrusion; the analysis shows that the pore size of cement paste increases and the number decreases after mercury intrusion, indicating that the pore structure of the material changes before and after mercury intrusion. The results directly prove the destructive effect of the mercury intrusion process on the pore structure of cement-based materials.

压汞法是表征水泥基材料孔隙结构最为常用的方法之一,但在高压作用下,水泥基材料的孔隙结构可能发生显著变化。利用XCT研究压汞前后水泥净浆的孔隙结构变化,结果表明:水泥净浆进汞孔隙分布曲线符合5阶段进汞特征;汞能够显著增加孔隙的X射线吸收率,导致压汞前后XCT图像灰度反转;分析显示水泥净浆压汞后孔隙尺寸增加,数量减少,表明材料压汞前后孔隙结构发生改变。结果直接证明了压汞过程对水泥基材料孔隙结构的破坏作用。