Triboluminescent Optical Nerves for Smart Concrete Structures

Abstract

In-situ and real time structural health monitoring is critical for ensuring the safety of users and for extending the useful life of our aged and overloaded 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 flexural loading. Real time failure detection was demonstrated in mortar beams while real time damage monitoring was demonstrated in reinforced concrete (RC) beams. For all samples tested, significant and distinctive jump in the triboluminescent (TL) signal values were detected at the instance of failure in mortar beams and cracking in RC beams. Analysis of the TL signal profiles from the brittle failure of the mortar beams revealed multiple peaks indicative of multiple TL emissions that provided evidence of the sensor’s ability to sense rapidly propagating crack during mortar failure. TL signals were observed at the instance of crack formation (damage) in the tested RC beams that provided early warning of system’s degradation before failure.