The relatively small wavelengths and large bandwidths associated with microwave signals make them great candidates for inspection of construction materials and structures, and for materials characterization and imaging. Signals at these frequencies readily penetrate inside of dielectric materials and composites and interact with their materials characteristics and inner structures. Water molecule is dipolar and possesses a relatively large complex dielectric constant, which is also highly sensitive to the presence of ions that increase its electrical conductivity. Consequently, chemical and physical changes in construction materials affect their complex dielectric constant. This can be measured, and through analytical and empirical dielectric mixing formulae, correlated to those changes. Examples of applications would be, presence of delamination in a bridge deck and pavement, permeation of moisture behind retaining walls or corrosion of reinforcing steel bars which can be imaged with microwave techniques. One of the critical trade-off issues is between the microwave signal penetration into concrete vs. frequency of operation. Dielectric of concrete, particularly when moist, has a relatively high loss factor. As such, lower microwave frequencies are suitable to achieve reasonable penetration. Image resolution degrades as a function of decrease in operating frequency, therefore, a balance must be reached when using these techniques for imaging cement-based materials. In this webinar, issues related to concrete materials property evaluation and high-resolution imaging will be discussed, and examples will be provided.
Dr. Reza Zoughi Schlumberger Endowed Professor Electrical and Computer Engineering Department Director, Applied Microwave Nondestructive Testing Laboratory (amntl) Missouri University of Science and Technology (Missouri S&T) Email: email@example.com URLs: http://amntl.mst.edu/people/zoughi/zoughi2/, http://amntl.mst.edu/
Dr. Reza Zoughi is the Schlumberger Endowed Professor in the Electrical and Computer Engineering department at Missouri S&T. Dr. Zoughi’s research activities are broad many of them are in the area of civil structure evaluation and imaging involving materials characterization of cement-based materials and structures, detection and evaluation of alkali silica reaction (ASR) and gel formation, and imaging of rebars for detecting corrosion. He had his research team have developed high-resolution, portable 3D microwave camera suitable for a number of critical applications. Dr. Zoughi holds 18 patents in the field of microwave nondestructive testing and imaging.
Zoughi, Reza, "Microwave Materials Characterization and Imaging for Structural Health Monitoring" (2018). Archived Webinars. 3.
Civil, Architectural and Environmental Engineering
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