Graphene-Based Sensing for Structural Health Monitoring

Abstract

The integration of graphene nanoplatelets (GnPs) into cementitious construction yields a multifunctional real-time structural health monitoring (SHM) material for self-sensing. Above a percolation threshold of 3.2 wt% GnP, a conductive network forms in the cementitious material, leading to a sharp decrease in electrical resistance (∼ 4 orders of magnitude) and a sensitive and stable sensory response under cyclic compressive loading. The values of fractional change in resistance (FCR) upon compression were found to be linearly correlated with stress, reaching 40% at a maximum stress of 11 MPa. The correlation between stress and resistance was calibrated using the stress sensitivity factor (SF = ((FCR)/( σ))·100). The obtained SF was 3.6%/MPa, which is a significant improvement over previously reported studies (twice as high). The reproducible response was independent of the load direction with respect to orientation of the electrodes (parallel or perpendicular to the force direction). Currently used sensors mostly provide global information on large structures and are based on complex, fragile external devices such as cameras, lasers, or ultrasound sensors, which require extensive data analysis and operational overhead. In contrast, the findings of this study highlight the potential of the cementitious composite itself as a scalable, durable, and local sensor for SHM applications in concrete elements.