Evolutionary trace for early hydration of cement paste using electrical resistivity method

• Early hydration of cement paste is traced by electrodeless electrical resistivity method.
• Linear relationship explored between setting time with the electrical resistivity parameters.
• Compressive strength of cement pastes is predicted by electrical resistivity results.

Setting time and early strength of cement are two key parameters to the early hydration of cementitious materials. The two indexes are qualified via traditional electrical method in the past, but several defects still remain in traditional electrical methods, electrical resistivity measurement is put forward to study the two key parameters in this paper. A relationship between setting times (including initial and final setting time) and the electrodeless resistivity has been discussed, aiming to establish a rapid testing method which could predict setting time of cementitious materials. Furthermore, electrical resistivity measurement and standard compressive strength test has been studied and the experimental results show that the cement paste matrices with higher water cement ratio present the lower electrical resistivity value. A linear relation is established between the standard compressive strength of cements at 1 d and the resistivity of the pastes at 24 h, which can demonstrate the resistivity and the standard compressive strength have a close corresponding relationship, and the resistivity curve of cement and the strength development curve has the same trend. So the standard compressive strength of cements could be predicted by electrical resistivity curve.