The evolution of cement paste hydration process by impedance spectroscopy

Impedance spectroscopy (I.S.) measurements were carried out on ordinary por tland cement paste, cured in 100% relative humidity environment, at differe nt temperatures. The results collected during 28 d show that the electrical conductivity decreases to an almost constant value. The higher the curing temperature the shorter is the time necessary to obtain the quasi-steady-st ate conditions. A thermally activated conduction mechanism in cement paste was observed. The possibility of using I.S. (a non-destructive and in-situ technique) to follow the evolution of the cement paste hydration process wa s validated by traditional techniques (X-ray diffraction and thermogravimet ry). Very good agreement was obtained. (C) 2001 Elsevier Science B.V. All r ights reserved.