基于电化学阻抗谱的偏高岭土水泥性能研究

利用电化学阻抗谱、压汞法和抗压强度试验研究了偏高岭土(MK)水泥净浆从早期水化到养护28d的性能发展规律,分析了MK水泥净浆的电化学参数随养护龄期的变化规律,提出了1种同时考虑弥散效应和水泥净浆/电极界面扩散过程的等效电路模型,分析了电化学参数与抗压强度、孔结构参数的关系.结果表明:MK能够促进水泥净浆的水化进程;利用等效电路模型得到的MK水泥净浆电荷转移电阻R_(ct1)能够很好地反映MK水泥净浆的抗压性能;MK水泥净浆的孔隙率与电荷转移电阻R_(ct1)、高频区阻抗模数|Z|_1呈负相关关系.

Performance of Cement Paste with Metakaolin Based on Electrochemical Impedance Spectroscopy

The performance development of metakaolin(MK) cement paste was examined from early hydration stage to curing for 28d by electrochemical impedance spectroscopy, mercury intrusion porosimetry and compressive strength test. The variation of electrochemical parameters of MK cement paste with curing age was analyzed. A new equivalent circuit model was provided, which can take both the dispersion effect and the diffusion process at cement paste/electrode interface into consideration. The relationship between electrochemical parameters, compressive strength and pore structure parameters were discussed. The results show that MK can promote the hydration process of cement paste. The charge transfer resistance(Rct1) of MK cement paste obtained by the equivalent circuit model can well reflect the compressive behavior of MK cement paste. Porosity of MK cement paste shows a negative correlation with charge transfer resistance Rct1 and high frequency impedance modulus |Z|1 of MK cement paste.