Prediction of interface conductivity of cement slurry during early hydration considering the effect of curing temperature and pressure

Abstract

Electrical conductivity measurements have been widely used in characterizing the cementitious materials. In mature stages, the influence of interface conductivity to the overall conduction was relatively small. However, its contribution during early hydration is still questionable. This paper calculated the interface conductivity during the first 24 hrs of hydration at elevated temperature and pressure up to 65°C and 3000 psi. The effect of elevated temperature to conductivity measurement is successfully corrected. Johnson equation is employed to predict the interface conductivity of pore-solid particles. The microstructural parameters that are used in the equation are estimated from the proposed particle expansion model. These calculation outcomes have a good agreement compared to the MIP measurements. The results showed that the interface conductivity grew slightly with the progress of drying. Its contribution to the bulk conductivity is relatively very small of about factor 6 in orders of magnitude. Hence, the influence of interface conductivity to the overall conduction might be disregarded during cement's early hydration.