Automation of Pavement Sublayer Moisture Content Determination Using Long-Term Pavement Performance Time Domain Reflectometry Data and Micromechanics

2009 ◽  
Vol 2116 (1) ◽  
pp. 16-25
Author(s):  
Sang Ick Lee ◽  
Dan G. Zollinger ◽  
Robert L. Lytton ◽  
Newton C. Jackson
Keyword(s):  
Moisture Content ◽  
Time Domain ◽  
Time Domain Reflectometry ◽  
Pavement Performance ◽  
Performance Time ◽  
Content Determination ◽  
Moisture Content Determination

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

2017 ◽  
Vol 2655 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Habibullah Bhuyan ◽  
Alexander Scheuermann ◽  
Didier Bodin ◽  
Rolf Becker
Keyword(s):  
Moisture Content ◽  
Bulk Density ◽  
Time Domain ◽  
Voltage Drop ◽  
Base Material ◽  
Field Investigation ◽  
Time Domain Reflectometry ◽  
Pavement Performance ◽  
Dry Density ◽  
Volumetric Moisture Content

Soil moisture content and dry density of unbound granular pavement materials are important properties for compaction control that influence pavement performance under cyclic loading. Under these loading conditions, increasing moisture content can accelerate significant changes in density. Time domain reflectometry (TDR) is a method for measuring the moisture content and density of soils with rod probe sensors. This paper introduces new calibration functions for TDR measurements using these rod probe sensors embedded in the soil. TDR measurements were taken in the laboratory for a typical road base material at two basically different conditions: at constant moisture content with different dry densities and at constant dry density with different moisture contents. In this study, a relationship was developed between the voltage drop occurring for the passage of an electromagnetic wave through the soil and the bulk density. The permittivity of the soil sample obtained from the travel time of TDR signals was used to calculate the volumetric moisture content. Finally, the gravimetric moisture content was obtained from the volumetric moisture content and bulk density relationship. For the validation of the calibration functions, rod probe sensors were installed in a road to obtain in situ moisture content and density under field conditions. Laboratory results indicate that the calibration functions are independent of moisture and density, and the field test shows the applicability of the method. The newly developed calibration functions allow for the monitoring of the long-term pavement performance, leading to a better understanding of the time-dependent evolution of, for example, rutting of roads.

Examination of moisture content variation within an operational wet deck

TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 45-50 ◽  
Author(s):  
LAURENCE SCHIMLECK ◽  
KIM LOVE-MYERS ◽  
JOE SANDERS ◽  
HEATH RAYBON ◽  
RICHARD DANIELS ◽  
...  
Keyword(s):  
Moisture Content ◽  
Southeastern United States ◽  
Forest Products ◽  
Time Domain Reflectometry ◽  
Water Application ◽  
Wood Moisture ◽  
International Paper ◽  
Content Variation ◽  
Moisture Variation

Many forest products companies in the southeastern United States store large volumes of roundwood under wet storage. Log quality depends on maintaining a high and constant wood moisture content; however, limited knowledge exists regarding moisture variation within individual logs, and within wet decks as a whole, making it impossible to recommend appropriate water application strategies. To better understand moisture variation within a wet deck, time domain reflectometry (TDR) was used to monitor the moisture variation of 30 southern pine logs over an 11-week period for a wet deck at the International Paper McBean woodyard. Three 125 mm long TDR probes were inserted into each log (before the deck was built) at 3, 4.5, and 7.5 m from the butt. The position of each log within the stack was also recorded. Mixed-effects analysis of variance (ANOVA) was used to examine moisture variation over the study period. Moisture content varied within the log, while position within the stack was generally not significant. The performance of the TDR probes was consistent throughout the study, indicating that they would be suitable for long term (e.g., 12 months) monitoring.

Determination of readiness for laying based on material moisture, corresponding relative humidity, and water release

2020 ◽  
Vol 62 (10) ◽  
pp. 1033-1040
Author(s):  
Christoph Strangfeld ◽  
Sabine Kruschwitz
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Embedded Sensors ◽  
Residual Water ◽  
Floor Covering ◽  
Water Release ◽  
Content Determination ◽  
Two Samples ◽  
Moisture Content Determination

Abstract The moisture content of the subfloor has to be determined before installation to avoid damage to the floor covering. Only if readiness for layering is reached, can an installation without damage be expected in all cases. In general, three approaches exist to measure residual water content: determination of moisture content, determination of water release, or determination of the corresponding relative humidity. All three approaches are tested under laboratory conditions at eight screed types including two samples thicknesses in each case. Moisture content and water release are measured by sample weighing, the corresponding relative humidity is measured by embedded sensors. All three approaches are compared and correlated. The evaluations show only a weak correlation and, in several cases, contradicting results. Samples are considered ready for layering and not ready for layering at the same time, depending on the chosen approach. Due to these contradicting results, a general threshold for a risk of damage cannot be derived based on these measurements. Furthermore, the experiment demonstrates that the measurement of corresponding relative humidity is independent of the screed type or screed composition considered. This makes humidity measurement a potentially very promising approach for the installation of material moisture monitoring systems.

Moisture Content Determination for Potatoes

1989 ◽  
Vol 32 (5) ◽  
pp. 1744-1746 ◽  
Author(s):  
A. D. Ghadge ◽  
M. G. Britton ◽  
D. S. Jayas
Keyword(s):  
Moisture Content ◽  
Content Determination ◽  
Moisture Content Determination

scholarly journals Measurement of density and wetness in snow using time-domain reflectometry

1998 ◽  
Vol 26 ◽  
pp. 69-72 ◽  
Author(s):  
Martin Schneebeli ◽  
Cécile Coléou ◽  
François Touvier ◽  
Bernard Lesaffre
Keyword(s):  
Time Domain ◽  
High Surface ◽  
High Surface Area ◽  
Weight Ratio ◽  
Time Domain Reflectometry ◽  
Soil Physics ◽  
Snow Density ◽  
Intense Solar Radiation ◽  
Air Pockets

Time-domain reflectometry (TDR) is widely used in soil physics to determine water content. Existing equipment and methods ran be adapted to measurements of snow wetness. The main advantages compared to other methods are flexibility in constructing sensors, minimal influence on snow cover during measurements and sensors can be multiplexed. We developed sensors suitable for continuous and non-continuous measurements of snow wetness and density, measured the apparent permittivity in different snow densities and snow types, and compared the measurements to existing mixing formulas for mixtures of snow and air. In dry snow, density was measured from 110 to 470 kg m−3. The residual error is 14 kg m −3 and the 95% confidence interval of our model is 3 kg m−3. To measure snow density and wetness continuously suitable sensors have been constructed. Their small size and high surface area to weight ratio minimizes their movement in the snowpack, except when they are exposed to intense solar radiation. Results show that changes in dry-snow density of less than 5 kgm−3 can be detected. Infiltration of even small amounts of water clearly shows up in the permittivity. At the surface of the snowpack, problems occur due to the formation of air pockets around the sensors during long-term measurements.

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