Analysis on early hydration characteristics of cement paste containing NMK based on EIS
To investigate the effect of nano-metakaolin(NMK)on the early hydration characteristics of ce-ment paste,the electrochemical impedance spectroscopy(EIS)test was executed on the cement pastes contai-ning NMK particles at the early hydration stage(within 48 h).Five NMK contents(0,1％,3％,5％,7％)were used to replace ordinary cement.The evolution of electrochemical parameters during the early hydration process of five types of NMK cement paste was compared and analyzed.An equivalent circuit model R1(Q1R2)Q2,based on a capacitance series circuit,was established to consider both the dispersion effect and double capacitance at the electrode/paste interface.In addition,dielectric constant was employed to character-ize the early hydration process of NMK cement paste.The results show that NMK delays the negative capaci-tance loss time,enhances calcium aluminate reaction,and promotes the early hydration of cement paste.The calculated results by the provided equivalent circuit model show in good agreement with the experimental re-sults.The pore resistance obtained by the equivalent circuit model presents a linear relation with standard con-sistency water content,while it takes an exponential relation with fluidity.The dielectric constant curve can be used to identify the early hydration process of NMK cement paste.
万方数据
维普
