Effect of Fly Ash on the Electrical Resistivity of Cement-based Materials During the Hydration Process

The evolution of electrical resistivity, concentration of ions in the pore solution and the pore structure of Portland cement pastes with fly ash in mass fraction of 0%, 20% and 40%, respectively during 72 h were investigated. The results show that the curves of electrical resistivity of cement paste blended with different contents of fly ash will intersect with each other. Before the intersections of the curves of electrical resistivity, the electrical resistivity increases with the increase of fly ash content, while after the intersections, the electrical resistivity is lower when the fly ash content is higher. The incorporation of fly ash leads to the decrease of pH value of the pore solution, the decrease of the ion concentration in the liquid phase and the increase of the total porosity. The ion concentration of the pore solution in the paste with higher content of fly ash is lower than that in the paste with lower content of fly ash, while the porosity is higher, the coupling effect results in the intersection of the curves of electrical resistivity. © 2019, Materials Review Magazine. All right reserved.