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采用压汞仪、气孔结构分析仪测定了不同含气量水泥砂浆的孔结构参数,通过热力学关系的分形模型计算得到了水泥砂浆不同尺度孔结构分形维数,并分析了水泥砂浆不同尺度孔结构孔体积分形维数与孔隙率、平均孔径、孔比表面积、孔间距系数、孔总体积关系。结果表明:基于热力学关系的分形模型计算得到的不同尺度孔结构分形维数呈现多重性,能够很好地表征水泥砂浆孔结构的复杂程度;含气量的增加,使得102nm以上孔径范围的分形维数呈增大的趋势,而102nm以下孔径范围的分形维数呈减小趋势;龄期的增加,103~104nm孔径范围的分形维数呈减小趋势,其他孔径范围内分形维数呈增大趋势;各孔结构参数中,103~104nm及102~103nm孔径范围内孔体积分形维数与孔隙率、平均孔径、总孔体积具有良好的相关关系,与孔比表面积相关性极差。考虑到102~103nm范围孔径孔在总孔中所占比例较高,因而可将其作为统一的分形维数来表征孔结构参数的变化。
The pore structure parameters of cement mortar with different gas content were determined by mercury intrusion porosimetry and pore structure analyzer. The fractal dimension of cement mortar with different scales was calculated by the fractal model of thermodynamic relationship. The pore structure of different sizes of cement mortar The relationship between volume fractal dimension and porosity, average pore diameter, pore specific surface area, pore spacing coefficient and total pore volume. The results show that fractal dimension of pore structure with different scales calculated based on the fractal model of thermodynamics shows multiplicity, which can well characterize the complexity of pore structure of cement mortar. With the increase of gas content, the fractal dimension of pore size above 102nm The fractal dimension of pore size below 102 nm showed a decreasing trend. With the increase of age, the fractal dimension of pore size in 103 ~ 104 nm showed a decreasing trend while the fractal dimension in other pore sizes increased In the pore structure parameters, pore volume fractal dimension in 103 ~ 104nm and 102 ~ 103nm pore size has a good correlation with porosity, average pore diameter and total pore volume, and has very poor correlation with pore specific surface area. Considering that the pore size in the range of 102 nm to 103 nm occupies a higher proportion of the total pore, it can be used as a uniform fractal dimension to characterize the change of pore structure parameters.