Triboluminescent optical nerves for smart concrete structures

In-situ and real time structural health monitoring is critical for ensu ring the safety of users and for extending the useful life of our aged and overlo aded civil infrastructure systems like concrete bridges and dams. The development of the insitu triboluminescent optical fiber (ITOF) sensor may provide concrete structures with these capabilities. Two types of cement-based composites with integrated ITOF sensors were fabricated and tested under flex ural loading. Real time fail u re detection was demonstrated in mortar beams while real time damage m onitoring was demonstrated in reinforced concrete (RC) beams. For all sample s tested, significant and distinctive jump in the triboluminescent (TL) signal values were detected at the instance of failure in mortar beams and crackin g in RC beams. Analysis of the TL si gnal profiles from the brittle failure of the mortar beams revealed multiple peaks indicative of multiple TL emissions that provided evidence of the sensor\u27s ability to sense rapidly propagating crack during mortar failure. TL signals were observed at the instance of crack for mation (damage) in the t ested RC beams that provided early warning of system\u27s degradation before failure