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

Abstract

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 1d and the resistivity of the pastes at 24h, 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.