Exothermicity and electrical resistivity during cement hydration

The changes of hydration heat and resistivity of pastes during cement hydration were tested, and their hydration and resistivity rates were also compared. The results show that the resistivity at 1 d increases with accumulative hydration heat, and the alterations of resistivity and hydration rate with time can reflect the hydration process independently. Moreover, some remarkable peaks like the dissolution heat peak, the primary hydration heat peak and the peak of ettringite (AFt) transformation to monosulfoaluminate (AFm), have corresponding mutations on the resistivity rate curve in a certain period of time. The hydration rate increases rapidly after having reached its minimum in the induction period, and then it increases slowly. There is a turning point, and a corresponding peak exists on the resistivity rate curve.