Study on Heating Performance and Flexural Strength Properties of Electrically Conductive Mortar

Abstract

The use of electrically conductive mortar (ECM) is a relatively new construction material technology developed to obtain high conductivity and mechanical strength. This study presents an experimental investigation on the heating performance and flexural strength properties of ECM mixed with carbon fiber (CF) and steel fiber (SF), which are conductive fibers. Furthermore, the internal microstructure of the ECM was analyzed with a scanning electron microscope (SEM) and thermogravimetric analysis was carried out using a thermogravimetric analyzer (TGA) device. The results of the experiment showed that the incorporation of SF had little effect on heating performance. In the case of CF, however, it was found that as the fiber contents and applied voltages increased, the heating performance increased. In particular, the maximum heating temperature of the ECM-CF125 specimen was 145.1 °C at an applied voltage of 30 V and an electrode spacing of 40 mm, which was about 7.3 times higher than the initial temperature (20 °C). In addition, the flexural strength of ECM mixed with SF was higher than that of plain mortar (PM), whereas the ECM-CF125 specimen showed a greater tendency to significantly decrease. It was confirmed that the hydration products and internal microstructures of the specimens were unaffected by repetitive electrical heating, and the ECM maintained stable electrical conductivity.