Multiphase modelling of electrical conductivity of concrete with conductive inclusions

Electrical conductivity (EC) of concrete can be effectively improved by incorporating conductive materials such as carbon nanotubes in the mix design. However, mechanism for the EC enhancement to which the addition of conductive materials contributes has not yet been well understood. Besides, either sand or coarse aggregate in concrete also affects the EC of concrete, which complicates understanding of the mechanism. This paper presents a multiphase analytical model to investigate the effect of constituents on the effective EC of concrete. This multi-phase model was developed based on Maxwell model which was modified in this research to consider the effects of electrical conductivities and volume fractions of sand, cement and/or binder paste, coarse aggregate, and conductive inclusions on the effective EC of concrete. The model developed is validated against published experimental data. To highlight the features of the model, parametric analysis is further performed. • A multiphase model is proposed for electrical conductivity of concrete with conductive materials. • Analytical formulas are derived for calculation of electrical conductivity of concrete. • Effects of cement paste, sand and aggregate on electrical conductivity of concrete are examined. • Effects of sand and aggregate on percolation threshold of conductive inclusions in concrete are examined. • The proposed model is validated by using published experimental data.