Electrical conductive mortar based on expanded graphite for auxiliary anode

Abstract

The use of cement-based conductive mortar is an effective way to enhance the long-term operation of impressed current cathodic protection (ICCP) system. However, its widespread use is limited by the challenges of dispersing nano-fillers and the associated cost. To overcome these challenges, this study proposes the use of expanded graphite (EG) as a conductive material due to its strong conductivity, easy dispersion, and low cost. Additionally, multilayer EG flakes can promote cement hydration due to their high specific surface area, thereby improving the mechanical properties of mortar. This study examines the effects of EG content on the mechanical properties and electrical conductivity of the conductive mortar. Results reveal an exponential relation between EG content and mechanical strength, with 1.5% EG content producing the maximum mechanical properties. The resistivity of EG cement mortar decreases as the EG content increases, reaching its minimum at the percolation threshold. At this threshold, the resistivity of conductive mortar is 46.4% of the optimal content for mechanical properties (EG content is 1.5%). The incorporation of EG in cement-based conductive mortar is a viable alternative to traditional materials that can improve both conductivity and mechanical properties. This approach has great potential for enhancing the performance of ICCP systems.

Keywords

• Cement-based conductive mortar
• Expanded graphite
• Mechanical property
• Resistivity
• Hydration product