Abstract

Corrosion of reinforcing steel is a major cause of damage and deterioration in reinforced concrete structures. Therefore, as the presence of a sufficient concentration of chloride ions can lead to the onset of corrosion in embedded steel, it is of utmost importance to be able to determine the free salt content and its distribution in these materials. Moreover, it is important to obtain this information nondestructively. Previous investigations have shown the capability of near-field microwave nondestructive evaluation methods, using open-ended rectangular waveguide probes, to evaluate many important properties of cement-based materials. In this Investigation, the temporal microwave reflection properties of a mortar cube, subjected to cycles of wetting in a saltwater bath with a salinity of 2.8% and drying were measured at 3 GHz and 10 GHz using open-ended rectangular waveguides for several cycles, each lasting about 35 days. A semi-empirical electromagnetic model was then developed, representing the cube as a stratified structure with a dielectric constant profile to simulate the measured reflection properties. The issue of representing a continuous media as a stratified structure was also explored. The simulated and the measured results at both frequencies, and for all cycles were In good agreement. Subsequently, the volumetric free salt distribution, left In the cube, was also calculated. This paper presents a brief description of the model and its results at 3 GHz for the first cycle.

Meeting Name

20th IEEE Instrumentation and Measurement Technology Conference (2003: May 20-22, Vail, CO)

Department(s)

Electrical and Computer Engineering

Keywords and Phrases

Computer Simulation; Electromagnetism; Frequencies; Microwaves; Mortar; Nondestructive Examination; Permittivity; Rectangular Waveguides; Reinforced Concrete; Salinity Measurement; Steel Corrosion; Computational Electromagnetics; Concretes; Corrosion; Geometry; Microwave Frequencies; Microwave Measurement; Steel; Waveguides; Saline Water; Cement Based Material; Electromagnetic Measurement; Electromagnetic Modeling; Electromagnetic Reflection; Frequency Measurements; Microwave Reflection Properties; Non-Destructive Evaluation Methods; Reflection Properties

International Standard Serial Number (ISSN)

1091-5281

Document Type

Article - Conference proceedings

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2003 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

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