Electrical prediction of tortuosity in porous media

Abstract

The fluid transport phenomena in porous materials such as concrete, is one of the main actions involved in the degradation of the structures lying in aggressive areas. This transport is governed by several physical and chemical parameters such as porosity, tortuosity, diffusion coefficient or concentration of chemical species. The main objective of this work is to quantify the tortuosity parameter by a non-destructive method. Tortuosity is a parameter with significant inflluence on the transfer and diffusion of particles in porous media. Indeed it takes account of the irregularity and sinuous transport paths in the pore structure of the material. The experimental program focuses on applying a non-destructive method for measuring the electrical conductivity of materials as glass beads and sand with different classes, saturated with NaCl solution at different concentration. The material is placed in a PVC cell of 50 mm diameter, equipped with two stainless steel electrodes connected to the measuring circuit. The tortuosity values obtained in this work are less than unity. This accords considerably with the values found in the literature, we also note that the variation of this parameter depends on the nature of the medium but also according to its geometrical properties.