Holographical Microwave Imaging of Corroded Steel Bars in Concrete


Corrosion assessment of embedded steel in concrete structures is generally performed by electrochemical methods that are not fully nondestructive because the device requires connection to the steel. For practical applications, the development of a truly nondestructive technique for the detection of corrosion is desirable. This paper presents an experimental study of a wideband microwave three-dimensional synthetic aperture radar imaging technique applied to reinforced concrete specimens subjected to corrosion. Two orthogonal wave polarization directions were used for this purpose. Two-dimensional microwave image slices were analyzed and compared with the actual loss of steel measured during the destructive testing. As expected, the results indicated that higher-frequency images have higher spatial resolution, while the signal penetration became more limited at these frequencies. Though the relatively high moisture content significantly increased the dissipative properties against electromagnetic propagation, the technique was capable of differentiating between corroded and non-corroded steel bars.


Electrical and Computer Engineering

Keywords and Phrases

Corrosion; Nondestructive Evaluation; Reinforcing Steel; Three-Dimensional Microwave Imaging; Bars (Metal); Concretes; Imaging Systems; Imaging Techniques; Radar Imaging; Reinforced Concrete; Synthetic Aperture Radar; Dissipative Properties; ELectrochemical Methods; Electromagnetic Propagation; High Moisture Contents

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


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© 2015 American Concrete Institute (ACS), All rights reserved.

Publication Date

01 Jan 2015