This report summarizes the findings and results from a laboratory and field study on the strain distribution and crack development in 3" thick concrete panels cast on top of existing concrete pavements as a rapid rehabilitation strategy for roadways. Both fiber Bragg gratings (FBG) and Brillouin Optical Time Domain Reflectometry/Analysis (BOTDR/A) were applied and tested for their feasibility and effectiveness in distributed strain measurement and crack detection. For laboratory tests, six 6'×6" panels were cast similar to their corresponding field construction. Each was tested under both truck loads and under threepoint loads. The performance of distributed BOTDR/A strain measurements was compared with that of FBG sensors. In field study, the performance of FBG sensors was compared with that from strain gauges when the ambient temperature was measured with thermocouples. Overall, hairline to major cracks can be successfully detected with the distributed BOTDA measurements. The strain distributions measured from the FBG and BOTDR/A sensors are consistent. The FBG readings are in good agreement with those of strain gauges. Both FBG and BOTDR/A technologies are promising for pavement monitoring.


Civil, Architectural and Environmental Engineering


United States. Department of Transportation

Keywords and Phrases

Unbonded Concrete Panel; Optical Fiber Sensors; Crack Detection; Strain Distribution

Report Number


Document Type

Technical Report

Document Version

Final Version

File Type





© 2014 National University Transportation Center at Missouri University of Science and Technology, All rights reserved.

Publication Date

01 Jun 2014