The utilization of fiber Bragg grating sensors to monitor high performance concrete at elevated temperature

Embedded optical fiber Bragg grating (FBG) sensors are used to evaluate the properties of high performance concrete (HPC), subjected to high thermal strain. HPC is composed of polypropylene fibers and steel fibers, as additives, in a cylindrical concrete filled steel tube (CFT). A good agreement response between the FBG temperature sensor and a thermocouple was obtained. In addition, experimental results indicate that a CFT behaves differently from unconfined concrete in the center of a specimen, at a furnace temperature of 250 °C and that polypropylene fibers potentially have a higher capability to restrain spalling than do steel fibers.