Doctoral Dissertations

Yizheng Chen

Abstract

"This study aims to: (1) explore, develop, calibrate and validate Fe-C coated, long period fiber grating (LPFG) sensors for short-term mass loss measurement of the Fe-C coating; (2) develop, calibrate, and validate steel tube-encapsulated, fiber optic probes and LPFG sensors for long-term mass loss detection of the steel tube; (3) correlate the corrosion process of packaging metal materials with that of steel bars in direct contact with the packaged probe or sensor except for a thin insulation tape; and (4) apply both types of corrosion sensors into reinforced concrete (RC) structures for reinforcing bar corrosion monitoring and structural condition assessment. For short-term monitoring, the corrosion mechanism of the Fe-C coating and the corrosion sensitivity of the Fe-C coated LPFG were investigated and characterized in 3.5 wt. % NaCl solution. For long-term detection, the probe or sensor was used to measure the pitting corrosion growth of steel tubes in simulated concrete pore solution. To validate them in an application setting, two types of LPFG corrosion sensors were embedded in three RC beams under accelerated corrosion test. The resonant wavelength of a Fe-C coated LPFG sensor can be linearly related to the mass loss of Fe-C coating up to 60~90%. When tested in 3.5wt. % NaCl solution, the LPFG sensor coated with an 8~20 μm thick Fe-C layer has a sensitivity of 0.15~0.23 nm/1% Fe-C mass loss. This sensitivity is translated into approximately 1300 nm/g in mass loss of reinforcing steel bars. In RC beam applications, the resonant wavelength of an Fe-C coated LPFG sensor is reduced by 0.49 nm/hour when installed along a steel bar under accelerated corrosion conditions and 0.95 nm/day when installed near the bottom surface of a beam under natural corrosion condition. The corrosion penetration rate through the wall of a steel tube is approximately 8.6 μm/day"--Abstract, page iii.

Advisor(s)

Chen, Genda

Committee Member(s)

Yan, Guirong Grace
Sneed, Lesley
ElGawady, Mohamed
Huang, Jie

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

Ph. D. in Civil Engineering

Sponsor(s)

National Science Foundation (U.S.)

Comments

Financial support for this study was provided by the U.S. National Science Foundation under Award No. CMMI-1235202.

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2017

Pagination

xii, 108 pages

Note about bibliography

Includes bibliographic references (pages 96-107).

Rights

© 2017 Yizheng Chen, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11475

Electronic OCLC #

1104294130

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