Infrared Thermography for Crack Depth Assessment in Concrete Subjected to Fire Exposure

Simultaneous monitoring of concrete temperature and overflowing water and steam temperature within concrete cracks was performed using infrared thermography. The migration of high-temperature water and vapor through cracks to the low-temperature area was driven by steam pressure in the high-temperature region. By combining the temperature field distribution in the concrete with the temperature of water and vapor in the crack, the depth of the crack can be inferred. After 95 minutes of fire exposure, cracks on the unexposed ceiling surface extended to the exposed surface with a depth exceeding 150 mm.