The effects of the addition of steel fiber and graphite powder on the electric conductivity of concrete were investigated. The percolation transition zone of the concrete + steel fiber was determined, thus fixing the optimum content of steel fiber at 8.5%. Graphite was added to investigate its influence on the electrical conductivity and mechanical properties of the concrete. The electric current passing through the specimens was measured, setting the electric voltage to 50 V. The surface temperature of the specimens submitted to the electrical current was measured for 20 min. It was observed that the higher the graphite addition, the higher the conductivity was and, therefore, the higher the final temperature, which achieved 58 °C higher than the reference mixture, but the compressive strength decreased from 60 to 30 MPa, although still considered as structural concrete.