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A recently developed microwave dual waveguide sensor is applied for the measurement of gap in concrete-based composites in this paper. The sensor includes two waveguide sections embedded in a metal plate and opened in the structure under test. A transceiver that generates, transmits, and receives microwave signals, and a measurement unit that measures reflection and transmission coefficients is the...
A microwave dual waveguide sensor system has been proposed and applied for the measurement of gap between concrete and metal surfaces. The system includes two rectangular waveguides embedded in a metal plate and opened in a concrete member to create a dual waveguide sensor arrangement, transceiver that generates, transmits and receives microwave signals using the dual sensor, and a measurement unit...
This paper presents the results of a cross-disciplinary research project work, where microwave near-field noninvasive technique was used for the prediction of compressive strength of the state-of-the-art cementitious material, known as Engineered Cementitious Composites (ECCs). We mixed and cast specimens with water-to-binder ratios of 0.20, 0.255 and 0.30 for both the microwave noninvasive tests...
In this paper a modified antipodal Vivaldi antenna with frequency range of 0.65 GHz - 2.6 GHz is presented to be used for Infrastructure Health Monitoring (IHM) techniques. The proposed antenna offers high gain and directive radiation patterns at operating bandwidth. The feasibility of the designed antenna for IHM is investigated by modeling a 500-mm cubic concrete block with an air gap representing...
The reflection properties of early-age concrete specimens have been investigated with an open-ended waveguide radiator at R-band (frequency range of 1.7 GHz – 2.6 GHz). The complex dielectric permittivity of a concrete specimen is determined using measured reflection coefficient and simulation with CST Microwave studio. The numerical investigation into sensitivity of the reflection coefficient to...
Measurement and monitoring results on reflection properties of concrete and mortar cubic specimens are presented in this paper. The results were obtained by using a sweeping microwave frequency over entire X-band (8.2 – 12.4 GHz). Dependencies of the reflection coefficient and conductance on water-to-cement ratio and effect of coarse aggregates in the specimens are demonstrated. It is shown that the...
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