Advanced EMI-Based Evaluation of Structural Damage in Composite Fibre Concrete with Integrated Piezoelectric Sensors

Composite fibre concrete offers enhanced strength, durability, and corrosion resistance, making it an attractive material for modern infrastructure. However, its performance can be compromised by damage such as micro-cracking, delamination, and fiber rupture. This research evaluates performance of the electromechanical impedance (EMI) technique using piezoelectric sensors to detect structural damage in composite fibre concrete. Standard cube specimens were prepared using ordinary Portland cement, Class F fly ash, and polypropylene fibers, and surface-mounted piezoelectric patches were employed for real-time monitoring. The EMI method, a non-destructive testing approach, measures changes in electrical impedance to identify damage. Systematic damage was introduced into the specimens, and impedance signatures were recorded over a frequency range of 30–400 kHz. Analysis indicated a strong relationship between the root mean square deviation (RMSD) index and the severity of cracks, with increased sensitivity observed at shorter sensor to the damage distances. Shifts in conductance signature curves provided additional insights, while a novel damage index scaled from 0 to 1 enabled quantitative assessment of damage evolution. Furthermore, evaluations of equivalent stiffness and damping parameters enhanced understanding of the structural response under degradation. Overall, the study demonstrates that the EMI technique, when integrated with piezoelectric sensors, is a reliable tool for real-time structural health monitoring, offering valuable information for maintenance planning and for extending the service life of composite fibre concrete structures. The results indicate that early detection of damage using the EMI method can improve maintenance planning and reduce risks of failure in composite concrete applications.