Investigations on the mechanical, electrical and piezoresistive properties of concrete with graphene nanoplatelets

Cementitious composites with conductive additives, such as graphene nanoplatelets (GNPs) , show great promise for various civil engineering applications, particularly in structural health monitoring due to their piezoresistive effect . However, several challenges remain, such as the influence of moisture, the calibration of measurements and the determination of the beneficial GNPs content . To address these issues, samples with four different GNPs contents were prepared: 0% (reference), 0.05%, 0.25% and 0.45%. The influence of GNPs on the mechanical properties of smart concrete was determined. The addition of GNPs significantly increased the bending strength , while also reducing the compressive strength . The highest bending strength was achieved in the sample with 0.05% GNP , showing 25.9% increase , while the sample with 0.45% GNP exhibited the greatest reduction in compressive strength , with a decrease of 19.2% . The electrical properties of the specimens were measured both before and after drying . After drying, the resistivity of all samples increased significantly, by more than 50% for the GNP-containing samples and almost 70% for the reference sample. Although the influence of the addition of GNPs on the resistivity was less pronounced, it still led to a noticeable decrease in the resistivity of the samples. The piezoresistive response was evaluated through cyclic bending and compression tests , using the fractural change in resistivity (FCR) as a measure. The sample with 0.25% GNP exhibited satisfactory self-sensing properties in both the bending and compression tests, demonstrating its potential for practical applications in structural health monitoring (SHM). These findings highlight the feasibility of integrating GNP-enhanced cementitious composites into real-time monitoring frameworks. • Cementitious composites reinforced with GNPs are evaluated for self-sensing • The influence of moisture on the electrical resistivity of composites is examined • The duration and persistence of the polarization effect are analysed • Self-sensing capabilities are tested under cyclic compression and bending • GNP-enhanced composites show promise for structural health monitoring