Mechanical and damage sensing properties of smart high-performance fibre-reinforced concrete beams under bending

Self-sensing high-performance fibre-reinforced concrete (SS-HPFRC) is a promising smart construction material that potentially replaces traditional sensors in structural health monitoring systems for infrastructure. This study investigated the mechanical and damage detection properties of SS-HPFRC beams containing different short smooth steel fibre contents under bending. The research simultaneously measured electrical resistance at tensile and compressive sections using wired and wireless measurements and captured video of crack propagation. The test results indicated that the damage of SS-HPFRCs could be observed in real-time by evaluating the fractional change in electrical resistance (FCR) under bending. The FCR response at the tensile section indicated that major cracks had opened and propagated, regardless of the fibre content. Additionally, increased FCR in the compressive section suggested cracks propagating from the tensile to the compressive sections. Besides, the embedded electrode direction influenced the FCR of SS-HPFRCs before a peak flexural stress. A model of a conductive network in SS-HPFRC under bending was developed to explain the FCR response. Integrating SS-HPFRCs with wireless electrical resistance measurement systems would be utilised in the SHM system to detect abnormal phenomena in structures early and provide timely repair and maintenance to prevent catastrophic collapse.