Use of Time Domain Reflectometry to Estimate Moisture and Density of Unbound Road Materials: Laboratory Calibration and Field Investigation

Bhuyan, Habibullah; Scheuermann, Alexander; Bodin, Didier; Becker, Rolf

doi:10.3141/2655-10

Cited by 27 publications

(9 citation statements)

References 11 publications

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“…Previous studies showed the potential of measuring both w and d with TDR (Siddiqui and Drnevich 1995;Lin et al 2000;Siddiqui et al 2000;Yu and Drnevich 2004;Drnevich et al 2005;Thring et al 2014;Jung et al 2013aJung et al , 2013bCurioni et al 2018), but these methods have not been tested in field monitoring applications. Recently, Bhuyan et al (2017) reported an interesting application of the TDR method for monitoring the condition of granular pavement materials. The aim of this paper is to demonstrate the potential use of TDR for soil condition monitoring from the measurement of w and d in a field case study.…”

Section: Introductionmentioning

confidence: 99%

Time domain reflectometry (TDR) potential for soil condition monitoring of geotechnical assets

et al. 2019

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The performance of geotechnical assets is influenced by various external factors including time and changing loading and environmental conditions. These changes could reduce the asset’s ability to maintain its function, potentially resulting in failure, which could be extremely disruptive and expensive to remediate; thus, the ability to monitor the long-term condition of the ground is clearly desirable as this could function as an early-warning system, permitting intervention prior to failure. This study demonstrates, for the first time, the potential of using time domain reflectometry (TDR) for long-term monitoring of the relative health of an asset (via water content and dry density) in a field trial where a clayey sandy silt was exposed to leaking water from a pipe. TDR sensors were able to provide detailed information on the variation in the soil conditions and detect abrupt changes that would relay a prompt for asset inspections or interventions. It is proposed that TDR could be used alone or together with other shallow geophysical techniques for long-term condition monitoring of critical geotechnical assets. Early-warning systems could be based on thresholds defined from the values or the relative change of the measured parameters.

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Section: Introductionmentioning

confidence: 99%

Time domain reflectometry (TDR) potential for soil condition monitoring of geotechnical assets

et al. 2019

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“…For materials with an increase in moisture content, the dielectric permittivity will increase and result in a larger travel time of the pulse propagating along the conducting probes. The use of wave propagation along a three-rod probe has been used for estimating moisture content, metal, or salts in agri-food materials [98] or moisture content and density in unbound road materials [99] from electrical permittivity measurements. Inductive sensors are based on generating and detecting magnetic flux by using inductive coils.…”

Section: Electric and Magnetic Sensorsmentioning

confidence: 99%

Sensor Technology Options for Municipal Solid Waste Characterization for Optimal Operation of Waste-to-Energy Plants

Muri

Hjelme

2022

Energies

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Reuse, refurbishing, and recycling are the most sustainable options for handling waste materials. However, for municipal solid waste (MSW) that is highly heterogenic, crude, contaminated, and decrepit, thermal conversion in waste-to-energy (WtE) plants is an option. In such plants, the fuel quality of MSW is difficult to predict and the substantial changes expected are challenging for incineration stability. Development of new online sensor technologies for monitoring waste properties prior to incineration is therefore needed. Sensors may contribute to increase WtE process stability, as well as reducing the probability of incineration stops or emissions exceeding legal limits. In this work, the operating principles of potential sensor systems for waste monitoring are categorized and assessed to be implemented for providing parameters for process control or indicators for process alarms in the waste incineration process. For transmissive settings, the use of inductance and hard X-ray sensors are most promising, whereas for reflective settings, utilization of photonic, inductive, soft and hard X-ray, as well as low-frequency radiowave sensors, are most promising. The analytic capacity of single-point measurements with inductance, radiowave, photonic, or X-ray sensors are limited to providing indicators for process alarms, whereas spectral imaging with X-ray or photonic techniques are feasible for providing parameters for both process control and indicators for process alarms. The results obtained in this sensor assessment will be important as a first step in guiding the evolution of monitoring waste properties in the WtE industry to increase repeatability, performance of energy production, and manual labor safety in controlling the waste incineration.

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“…Reflection and refraction occur when the electromagnetic wave meets the boundary between two kinds of media in the process of propagation. e propagation velocity of the electromagnetic wave in different media is related to the dielectric constant, as shown in equation ( 2) [28]. In general, the permeability of a nonmagnetic material (μ) is nearly the same as that of a vacuum (μ 0 ).…”

Section: Time-domain Reflectometry and Its Principlementioning

confidence: 99%

Multifactor Analysis of Calibration and Service Quality of the Soil Moisture Sensor Applied in Subgrade Engineering

Xiao¹,

Bai²,

Wang³

2021

Advances in Materials Science and Engineering

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The soil is an important natural resource, and its moisture status plays a key role in the strength and stability of the soil structure. In civil industries including the agriculture engineering and the forestry engineering, moisture sensors are widely used to test and monitor the engineering properties and long-term service performance of soil. The influence of multiple factors on the quality and the accuracy of the soil moisture sensor should be taken into account. Both laboratory and field tests were performed by the time-domain reflectometry (TDR) method. The soil dielectric constant and magnetic permeability under different moisture contents, different temperatures, and different dry densities were comprehensively evaluated. At the same time, the sensitive factors in the service performance of the TDR sensor have been revealed by the real state of tested soil samples. Based on the testing principle of TDR, a calibration calculation model has been developed to evaluate accurately the moisture content of the subgrade slope. The results show that both the moisture content and the dry density had a significant influence on the dielectric constant and the magnetic permeability of soil. The developed calculation model has a good fitting effect and stability. Through the model, the influence of moisture content and temperature on the soil dielectric constant has been analyzed, and the fitting goodness is above 90%. After half a year of settlement, the soil was gradually drained and consolidated, and the moisture content of the subgrade section gradually decreased. It verified that the monitoring method determined by the laboratory calibration test was effective and accurate.

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Use of Time Domain Reflectometry to Estimate Moisture and Density of Unbound Road Materials: Laboratory Calibration and Field Investigation

Cited by 27 publications

References 11 publications

Time domain reflectometry (TDR) potential for soil condition monitoring of geotechnical assets

Time domain reflectometry (TDR) potential for soil condition monitoring of geotechnical assets

Sensor Technology Options for Municipal Solid Waste Characterization for Optimal Operation of Waste-to-Energy Plants

Multifactor Analysis of Calibration and Service Quality of the Soil Moisture Sensor Applied in Subgrade Engineering

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