A micro sensor based on a V-shaped resonator (VSR) is implemented for the purpose of determining fiber content and ratio in construction materials as a nondestructive method. Concrete is investigated as the construction material in the study. First, electrical properties of concretes reinforced by different fiber types and ratios are investigated using the Nicolson-Ross-Weir technique. These values are used to design a nondestructive sensor based on microwave transmission line methods. At the resonance frequency, the VSR has a dense electric field. Construction material which is positioned within range of the VSR can change the distribution of the electric field, thus affecting the resonance response and transmission magnitude in the operating frequency. Since construction materials having various contents have different complex dielectric permittivity and loss tangent values, the resonance frequency, transmission magnitude and bandwidth of VSR shift correspondingly. Alterations in the resonance frequency and magnitude of transmission values which are related to the permittivity of the construction materials enable us to detect characteristics of the content in construction materials. The proposed technique is not only capable of sensing the type of content in the construction material which is positioned within range of the VSR, but it is also capable of determining the percentage of this content. Results show that the proposed microwave-based VSR sensor provides a cost-efficient and nondestructive solution for sensing the type and percentage of the contents in fiber-reinforced concretes.
Nondestructive readout resonators computation theory
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