混凝土中水泥水化过程的电化学阻抗研究

Study of hydration process of concrete by electrochemical impedance spectroscopy

分析了电化学阻抗谱的基本原理,对水灰比为0.4、0.5、0.6的混凝土进行了电化学阻抗谱试验,研究了混凝土中水泥浆体的水化反应进程,比较了不同水灰比和不同龄期混凝土的电化学阻抗谱图的变化,得到阻抗参数与混凝土细观结构参数的关系。研究表明,随着混凝土水泥水化龄期的增长和水灰比减小,孔溶液电阻R s、水化电子进行电荷传递的电阻R ct和扩散阻抗系数σ不断增加,双电层电容C d基本不变,表明混凝土的总孔隙率、平均孔径不断降低,结构逐渐致密。

The basic principle of electrochemical impedance spectroscopy was analyzed, electrochemical impedance spectroscopy tests were made on concrete specimens with water-cement ratio of 0.4,0.5 and 0.6, and the process of the hydration reaction of the cement slurry in the concrete was studied.Then the discrepancy of the electrochemical impedance spectra for different concrete was compared, and the relationship between the impedance parameters and the concrete meso-structure parameters was obtained.The results showed that the resistance of the pore solution Rs, resistance to transfer the hydrated electron Rct and the coefficient of diffusion impedance σ continually increase with the increase of age of cement hydration and decrease of cement ratio, and the electric double layer capacitor was substantially constant, indicating that the concrete total porosity and average pore diameter continuously decreased and the structure became compact.