Insulated electrodes were used to avoid the effect of electrode polarization on the dielectric measurements for the hydrating cement paste. Theoretical examination for the dielectric spectrum due to the relaxation of space charge polarization was performed at two types of interface; one is insulated electrodes/conductive dielectric interface(type I) and the other is insulated electrode/conductive dielectric/partially insulated electrode interface(type II). The change of frequency dependence of complex dielectric permitivity, $\epsilon^*(\omega)=\epsilon'(\omega)-i\epsilon"(\omega)$, during the hydration of ordinary portland cement at the two types of interface was investigated for the frequency range of $10^4-10^6$Hz. The change of $\epsilon"$ at type. 1 interface during the hydration showed sensitive change at 1MHz and good correlation with hydration stages. The water/cement (W/C) ratio dependence of the change of $\epsilon"$ at type I interface was investigated. The change of relaxation time of space charge polarization at the type II interface was obtained from the change of complex permitivity and reflected the hydration mechanism. The W/C ratio and environmental temperature dependence of the relaxation time were determined. The electric conductivity and dielectric permitivity of fresh cement paste were determined in the temperature range between -10°C and -30°C from the temperature dependence of $\epsilon"(\omega)$ and$\epsilon"(\omega)$ at type I interface. Temperature dependence of the conductivity showed that the ionic conduction in fresh cement paste below -10°C is a activation process. The $\epsilon'(\omega)$ and $\epsilon"(\omega)$ for a hardened cement paste showed distribution of relaxation time below 0°C and the relaxation time showed exponential dependence for temperature.
세멘트 수화과정동안 유전성 측정에서 electrode impedance의 영향을 피하기 위해 절연된 전극이 사용되었다. Insulated electrodes/conductive dielectric interface 그리고 insulated electrode/conductive dielectric/partially insulated electrode interface 에서 공간전하 분극의 유전이완으로 인한 복소 유전상수의 주파수의존성을 이론적으로 고찰하였다. 세멘트 수화과정 동안 두 interface 에서 공간전하 분극의 유전이완이 실험적으로 관찰되었다. 수화과정동안 공간전하 분극의 relaxation time의 변화로 인한 복소유전 상수의 민감한 변화가 관측되었으며, 이 변화는 수화 mechanism과 좋은 연관성을 보였다. 수화동안 복소 유전상수 변화에 대한 water/cement ratio 및 주위온도 영향이 연구 되었다. Fresh cement paste에서 dielectric spectrum의 온도 의존성으로 부터 유전상수와 전기전도도 그리고 전기전도도의 activation energy가 -10°C 에서 -30°C 범위에서 결정되었다. Hardened cement paste에서 공간전하 분극은 0°C 아래에서 relaxation time의 분포를 보였으며, relaxation time의 activation energy가 결정되었다.
