Crack Detection Sensor for Concrete


This sensor is used for easy and accurate detection of cracks developed on the surface of concrete structures due to deterioration. The sensor is bonded onto a concrete structure, and the optical fiber cable is connected to a visible light source. When a crack occurs, the optical fiber is disconnected, and the light leaks from the disconnected part. This light leakage enable you to know the occurrence and position of the crack as a light emission from the sensor.


  • Easy to find out cracks - No special knowledge about management and control of structures is required for the checker.
  • The light emission of the sensor indicates the generation of cracks even in a location where usual visual check is difficult, in cluding an elevated and/or dark place.
  • Detection accuracy of crack widths can be selected from approx. 0.05 / 0.1 / 0.2 / 0.3 mm, allowing use for detection of cracks at the initial stage or repaired cracks.
  • Applicable to concrete structures

Measuring Method

The sensors are previously bonded onto a concrete structure and the wirings are finished. At the time of regular check, the light source is connected to one optical fiber cable connector after another to perform visual observation of multiple points in order. No power supply is needed on the site. The light source itself is very small and light, and the checking job can be securely performed.



Application image of crack detection sensor


Cracks due to deterioration of PC or RC bridges
Cracks of secondary lining concrete in tunnel
Cracks of rigid frame in tunnel connection section
Cracks due to deterioration of box culvert structure
Cracks due to dry shrinkage of concrete structure
Cracks of sprayed concrete in large deep pile
Cracks of temporary beam and support beam in underpinning