矿物掺和料-水泥浆体电学特性与其微结构的关系

采用循环伏安法和交流阻抗法系统研究了粉煤灰、矿渣粉和石灰石粉水泥浆体的电学特性，通过等效电路对电学测试结果进行拟合，并将拟合所得浆体电学参数与浆体化学结合水和压汞所测孔结构之间的相关性进行比较。结果表明：浆体的化学结合水与其电阻率具有较好的正相关性，即化学结合水越多，水化程度越大，浆体电阻率越高；粉煤灰和矿渣粉可以提高浆体电阻率，而石灰石粉在5%掺量下对浆体电阻率无影响；随着水化龄期的延长，浆体孔溶液电阻增大，其变化规律与浆体电阻率一致；浆体凝胶电容和凝胶电阻与C-S-H凝胶含量有关，二者有很好的负相关性；随着水化龄期的延长，浆体孔结构曲折程度提高，交流阻抗法所测得常相角指数减小，压汞测得的分形维数增大。

Relationship Between Electrical Property and Microstructure of Mineral Admixtures-Cement Paste

The electrical properties of fly ash, slag and limestone powder-cement paste were studied by the methods of Cyclic Voltammetry and AC Impedance Spectroscopy. The results of electrical test were fitted by equivalent circuit. The correlations between electrical parameters of paste and unevaporable water content, pore structure by mercury porosimetry were compared. The results show that there is a positive relation between the unevaporable water content and the electrical resistivity of paste. If the unevaporable water content is higher, the hydration degree is higher and the electrical resistivity of paste is higher. The electrical resistivity of paste is increased with fly ash and slag, and it is unaffected with limestone powder of 5% dosage. The resistance Rs of pore solution of paste is increased with the prolongation of hydration, and the changes of resistance Rs and the electrical resistivity are unanimous. The resistance Rp and electrical capacitance C of gel are related to C-S-H content, and there is a negative relation between the resistance Rp and electrical capacitance C of gel. The complexity of pore structure of paste is increased with the prolongation of hydration. The constant phase angle exponent P by AC Impedance Spectroscopy is decreased and the value of fractal dimension by mercury porosimetry is increased.