Electrical resistivity of plain cement-based materials based on ionic conductivity: A review of applications and conductive models

As a non-destructive testing technology, the resistivity method can respond quickly to the microstructure and macro-performance of cement-based materials(CBMs). This paper reviews the resistivity test methods as well as the application of resistivity in hydration, compressive strength and ions diffusion. Besides, in order to capture the evolution of the pore structure by resistivity, the multi-phase conductive models are also systematically reviewed. Emphasis is placed on the evolution history, strength/weakness, and prediction accuracy of these models. The precision analysis results show that the process of model parameters changing with the pore structure cannot be ignored. A conductive model with constant model parameters can only evaluate porosity in the short term but fails to estimate the porosity during the whole service life of CBMs. Future works on the testing methods, raw materials, testing environments and conductive models are indicated.