Electrically Conductive Cement-Based Materials: A New Approach using Metal-Organic Frameworks

Concrete resistivity lies at the border between insulators and poor semiconductors. Studies have investigated the feasibility of improving and stabilizing the conductivity of concrete by adding well-dispersed electrically conductive components. These components were typically in the form of conductive fillers, particles, or fibers. Several applications were proposed for electrically conductive concrete, including overlay snow melting systems, cathodic protection systems, structural health monitoring systems, self-sensing for smart structures, and grounding systems. Recently, electrically conductive concrete was proposed for electrochemical extraction of chloride ions from concrete structures and in developing low-cost cement-based batteries for low power operations. However, its application has been limited because the produced mixtures did not meet the structural requirements. Also, concrete incorporating electrically conductive additives simply utilized the newly added components without having the cement matrix being conductive. To attain this conductive matrix characteristic, the integration of novel materials is needed. Of these newly developed materials, metal-organic frameworks (MOFs) emerged as a powerful tool for producing porous crystalline materials and precisely designing their interior structure to acquire different properties, including electrical conductivity, which works as a solid-state electrolyte. With such capability, it is possible to integrate electrically conductive MOFs into cement-based mixes to modify the cement matrix to be conductive itself. Yet, such an investigation has not been carried out. This research aims to develop concrete that incorporates MOFs in the mixture proportions to produce an electrically conductive matrix structure. Different dosages of MOFs will replace the cement or fine aggregates, depending on its particle size. The physical, rheological, mechanical, durability, electrical, and thermal properties of MOF-embedded concrete will be assessed at different ages. A multi-criteria performance index approach will be employed to evaluate and select optimized mixtures for multifunctional applications. This research is expected to alleviate the capabilities and expand the applications of electrically conductive concrete.

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Contributors:

• Amr S. El-Dieb, Professor & Chair, Civil & Environmental Engineering Dept., COE.
• Hilal El-Hassan, Associate Prof., Civil & Environmental Engineering Dept., COE