Self-Sensing Carbon Fiber and Graphite–Epoxy Composites: Fabrication and Optimization for Strain-Monitoring Applications

Abstract

Pavements are poorly monitored and repaired only after damage becomes apparent. This study focused on the self-sensing behavior of epoxy based conductive composites that allows the measurement of the strain distribution of pavements in real time. To do so, carbon fiber (CF) and graphite (G) filled composites were fabricated and optimally characterized to realize the self-sensing capability. The fabrication process involved the incorporation of CF and G through mechanical blending. Subsequently, a comprehensive evaluation was conducted to assess the electrical, microstructural, and mechanical properties of the resulting composites. It was observed that the composites with 3% CF and 5% G exhibited optimum compositions with a gauge factor of 33. Furthermore, strain sensing occurred as a dynamic process from the initial conditioning stage to achieving a stable electrical resistance baseline upon cyclic fatigue. The alignment of conductive fillers reflected the evolution of microstructure. The balance of reversible microstructural functions and degradation determined the durability of the composite. The outcomes are critical to predicting long-term self-sensing capability and ensuring reliable applications of epoxy composites in pavement health monitoring.