Relationship between electrical resistance and rheological parameters of fresh cement slurry

Abstract Conductive parameters (electrical resistivity and electrochemical impedance spectroscopy) and profound mechanism of fresh cement slurry with water to cement (w/c) ratios of 0.35, 0.4, and 0.45 and samples whose w/c ratio is 0.4 containing 90% cement and 10% silica fume (or 10% blast furnace slag) are studied in this paper. Furthermore, fresh cement slurry with various dosages of superplasticizer is prepared to explore different rheological properties of the fresh paste. Results indicate that the evaluation function for electrical resistance and slump flow or apparent viscosity fits well with one dimensional Gauss function equation. Silica fume can improve the conductivity of fresh cement slurry, while blast furnace slag shows a contrary effect. The conductivity of fresh cement slurry can be simplified as an equivalent circuit which consists of the contact resistance between embedded electrodes and fresh cement slurry and three following series-connected electrical components (three resistor elements and three capacitance elements). Both the rheological and electrical properties of fresh cement slurry are closely related to the content of free water which highlights the possibility of monitoring the rheological parameters of fresh cement slurry through electrical testing ways.