Electrically conductive mortars based on cement or alkali-activated fly ash: mechanical and electrical characterization

This work presents the study carried out within the SensCrHEAT project (self-SENSing conCretes for HEATing products) funded by the European Union NextGeneration EU within the Proof of Concept (PoC) VALUE program. In this experimentation, mortar compositions have been pre-pared with two different binders, namely ordinary Portland cement (OPC) and alkali-activated fly ash (AAF). Hence, mortars were loaded with commercial graphene nanoplatelets (GNP) at 0.5% by the total volume and a combination of two recycled materials, i.e., biochar (BCH) and recycled carbon fibres (RCF), in amounts of 0.5% and 0.05% by the total volume, respectively. Mortars have been compared in terms of mechanical and electrical properties according to specific test protocols, test machines and sensors. Results show that the combined addition of the two sustain-able materials in both cement-based and alkali-activated fly ash mortars are less impacting on compressive strength and more able to reduce the electrical impedance of the final materials, making them probably better performing in terms of self-sensing/monitoring ability, than the expensive commercial GNP.