Testing methods of various materials for development of cement composites with low electrical resistance

Abstract

Our entire planet is filled by communication routes, and as a result of the evolving information technologies, their numbers will continue to grow in the future. Demand for their reliability and hence the importance of protecting related technologies from all kinds of interference is increasing as well. Therefore, it is necessary to develop new materials in order to protect these routes against negative influences of the environment such as the atmospheric discharge. The main aim of the research is to develop and verify the properties of the cement composite that can be applied in systems of protection of building structures against lightning strike and overvoltage. The first step in the development of this material was the selection of suitable feedstocks, which by their presence in the newly developed material will increase its electrical conductivity respectively reduce its electrical impedance. For this purpose, a spectrum of potential raw materials with a high content of metals and organic carbon was chosen. By means of a suitably selected set of laboratory methods which consisted of determination of specific surface, impedance and total organic carbon content (TOC), materials with the most suitable properties were selected and their parameters determined also in a cement matrix. In order to realize this goal specimens with each conducive material as filler were created with incorporated copper electrodes. Impedance has been significantly reduced compared to the reference samples. The lowest values in the tens of ohms were obtained from samples containing carbon grit 0.5–4.0. This fact proves that the tested fillers can be used in order to produce electrically conductive cement composites.