Electrical behaviour of carbon fibre-reinforced concrete with increasing loading in varying and constant frequencies

Concrete is not a good conductive structural material. The addition of the conductive short carbon fibre to conventional concrete increases its conductivity and this concrete is called ‘smart concrete’. The carbon fibre-reinforced concrete (CFRC) that acquired smartness quality by adding carbon fibre (CF) can sense elastic and inelastic deformation and fracture. In this paper, the microstructural change of CFRC under compression was interpreted depending on the change on its electrical conductivity. The loading was performed by a compression machine and the sample's conductivity was measured before, after and during the loading. A two-probe method was used to measure the conductivity. The frequency range of applied current was chosen between 1 Hz and 100 kHz. An alternating current (AC) was adopted in the experiments. The experiments showed that adding carbon fibre to the concrete increased the electrical conductivity of the conventional concrete; the conductivity values versus the changing load indicated the formation phases of the microcracks in the material.