In this study, a home-built Rayleigh scattering based optical frequency domain reflectometry (OFDR) technique is used for the measurement of strain distribution in a loaded cement paste. The system offers a spatially-continuous strain measurement on an optical fiber with a spatial resolution of 1 cm, dynamic range of 1 km, measurement accuracy of ±2 microstrain, and an update rate of 10 Hz. The feasibility and performance of this technique for detection of uneven strain distribution are studied and evaluated. The distributed optical fiber sensors are embedded in a cement paste cantilever. A controlled deflection is applied at the free end of it, and the strain is measured. The results are compared with the values obtained from theoretical analysis using Euler-Bernoulli beam theory and a finite element simulation. The comparison shows a reasonable consistence in overall deformation, demonstrating that the proposed technique can be used for real time strain monitoring in cement based materials; while this technique can reflect the uneven distribution of local strains due to the material heterogeneity with a controllable, high spatial resolution.
- Cement Paste,
- Distributed Sensing,
- Optical Fiber,
- Uneven Strain Distribution
Available at: http://works.bepress.com/hongyan-ma/69/
The authors gratefully acknowledge the financial and technical support from the Center for Infrastructure Engineering Studies (through Advanced Materials for Sustainable Infrastructure seed funding program) and the Materials Research Center at Missouri University of Science and Technology.