Steel Bar Corrosion Monitoring with Long-Period Fiber Grating Sensors Coated with Nano Iron/Silica Particles and Polyurethane


In this article, a recently proposed long-period fiber grating sensor coated with a thin layer of polyurethane and nano iron/silica particles is further developed and applied to monitor the corrosion process of deformed steel bars. Once calibrated, one coated long-period fiber grating sensor and one uncoated long-period fiber grating sensor for environmental compensation were attached to each of three steel bar samples that were tested in 3.5 wt% NaCl solution for 512 h. The resonant wavelength in long-period fiber grating spectra increased exponentially with immersion time due to corrosion of iron particles and thus reduction in coating thickness. The mass loss rate of steel bar #1 at the completion of corrosion tests (512 h of corrosion time) was correlated with that of sparse iron particles on long-period fiber grating sensor #1 after 130.5 h of immersion. The corrosion rates of long-period fiber grating sensors #2 and #3 were evaluated at 130.5 h and then used as a prediction of the corrosion rates of steel bars #2 and #3. The predicted corrosion rates by the long-period fiber grating sensors #2 and #3 were finally compared with those by potentiodynamic tests. The maximum mass loss prediction error by the long-period fiber grating sensors #2 and #3 is 26%. The coefficients of variation of three corrosion rate measurements are 0.049 by the long-period fiber grating sensors and 0.115 by the potentiodynamic tests, indicating more consistent and reliable measurements with the proposed technology.


Civil, Architectural and Environmental Engineering

Second Department

Electrical and Computer Engineering

Keywords and Phrases

Long-Period Fiber Gratings; Nano Iron Particles; Polyurethane; Steel Corrosion; Bars (Metal); Diffraction Gratings; Fibers; Nanosensors; Steel Fibers; Thickness Measurement; 3.5 Wt% NaCl Solution; Coefficients Of Variations; Corrosion Rate Measurements; Environmental Compensation; Long Period Fiber Grating; Nanoiron; Potentiodynamic Tests; Resonant Wavelengths

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


File Type





© 2015 SAGE Publications Ltd, All rights reserved.

Publication Date

01 Mar 2015