Electrical effects generated by mechanical loading of hardened Portland cement paste

This work presents results on the effect of applied load on the electrical properties (resistivity and capacitance) of hardened cement paste. Impedance spectroscopy measurements in the high frequency region (100 kHz-15 MHz) show two time constants, one associated to the solid phase, and the other to the liquid filling the pores. The time constant associated with the liquid phase is sensitive to external loads acting on the specimen. The observed variations are explained in terms of electrolyte drag from interlaminar spaces and structure pores and vice versa. The importance of those electrolyte movements concerning structure fatigue and rebars corrosion is also discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.