Suitability of Thermocouple Psychrometers for Studying Moisture Movement in Unsaturated Soils

Daniel, David E.; Hamilton, J. J.; Olson, Roy E.

doi:10.1520/stp28318s

Cited by 9 publications

(2 citation statements)

References 27 publications

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“…The filter paper method is a simple, low-cost, experimental test method to indirectly determine VWC in the laboratory. It is an indirect technique used for suction measurement and has been used by geotechnical engineers since the 1980s (Chandler & Gutierrez, 1986;Ching & Fredlund, 1984;Daniel, Hamilton, & Olson, 1981;Kim et al, 2015). The standard test method for measurement of soil suction using filter paper is ASTM D5298, ''Standard Test Method for Measurement of Soil Potential (Suction) Using Filter Paper.''…”

Section: Indirect Methods Of Measuring Soil Suction Using Filter Papementioning

confidence: 99%

Investigating the Need for Drainage Layers in Flexible Pavements

Ghavami¹,

Hosseini²,

Zavattieri³

et al. 2019

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Moisture can significantly affect flexible pavement performance. As such, it is crucial to remove moisture as quickly as possible from the pavements, mainly to avoid allowing moisture into the pavement subgrade. In the 1990s the Indiana Department of Transportation (INDOT) adopted an asphalt pavement drainage system consisting of an open-graded asphalt drainage layer connected to edge drains and collector pipes to remove moisture from the pavement system. However, over the intervening two decades, asphalt pavement materials and designs have dramatically changed in Indiana, and the effectiveness of the pavements drainage system may have changed. Today, in-place field densities achieved during construction make asphalt mixtures less susceptible to moisture intrusion than their 1990s counterparts. Additionally, there are challenges involved in producing and placing open-graded asphalt drainage layers, they can potentially increase costs, and they tend to have lower strength than traditional dense-graded asphalt pavement layers. Given the potential difficulties, the overall objective of this research was to evaluate the effectiveness of INDOT's current flexible pavement drainage systems given the changes to pavement cross-sections and materials that have occurred since the open-graded drainage layer was adopted. Additionally, the effectiveness of the filter layer and edge drains were examined. Laboratory experiments were performed to obtain the hydraulic properties of field-produced asphalt mixture specimens meeting INDOT's current specifications and the results used in finite element modeling of moisture flow through pavement sections. Modeling was also performed to investigate the rutting performance of the drainage layer in flexible pavements under various traffic loads and subgrade moisture conditions in combination with typical Indiana subgrade soils. The results were used to develop design graphs to assist the pavement designer in more accurately assessing the need for a pavement drainage system in any given flexible pavement. In general, the results indicate that drainage layers do effectively lower the subgrade moisture content and act to maintain subgrade moisture contents at native levels, while flexible pavements without drainage layers result in fully saturated subgrades. Also, while the results show that either a dense-graded aggregate or a dense-graded asphalt mixture can be used as a filter layer between the subgrade and the open-graded drainage layer, the subgrade tends to have lower moisture content when a granular filter is used. Moreover, the results indicate that edge drains have a positive effect on flexible pavement performance, especially those that do not contain a drainage layer. As expected, the modeling results showed an increase in pavement rutting whenever high moisture levels are present in the pavement system.

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Section: Indirect Methods Of Measuring Soil Suction Using Filter Papementioning

confidence: 99%

Investigating the Need for Drainage Layers in Flexible Pavements

Ghavami¹,

Hosseini²,

Zavattieri³

et al. 2019

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“…Thermocouple psychrometers have been used for a number of years to measure water potential in partially saturated soil and rock (Wiebe et al, 1977;Daniel et al, 1981;Briscoe, 1984;Thamir and McBride, 1985;Rasmussen and Evans, 1987;Rosseau et al, 1989). Psychrometers measure the relative humidity of air in the pores of the media and relate this to water potential by the Kelvin equation (See Section A.6.4).…”

Section: Psychrometersmentioning

confidence: 99%

Theoretical and experimental investigation of thermohydrologic processes in a partially saturated, fractured porous medium

Green¹,

Manteufel

Dodge³

et al. 1993

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The performance of a geologic repository for high-level nuclear waste will be influencedto a large degree by thermohydrologic phenomena created by the emplacement of heat-generating radioactive waste. The importance of these phenomena is manifest in that they can greatly affect the movement of moisture and the resulting transport of radionuclides from the repository. Thus, these phenomena must be well understood prior to a definitive assessment of a potential repository site. For this reason the Thermohydrology Research Project was initiated, An investigation has been undertaken along three separate avenues of analysis to attain the objectives of the research project: (i) laboratory experiments, (ii) mathematical models, and (iii) similitude analysis. A summary of accomplishments to date is as follows. s A comprehensive review of the literature on the theory of heat and mass transfer in partiallysaturatedporous medium was completed and documented.

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Unsaturated Hydraulic Conductivity of Compacted Sand-Kaolin Mixtures

Chiu¹,

Shackelford

1998

J. Geotech. Geoenviron. Eng.

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Suitability of Thermocouple Psychrometers for Studying Moisture Movement in Unsaturated Soils

Cited by 9 publications

References 27 publications

Investigating the Need for Drainage Layers in Flexible Pavements

Investigating the Need for Drainage Layers in Flexible Pavements

Theoretical and experimental investigation of thermohydrologic processes in a partially saturated, fractured porous medium

Unsaturated Hydraulic Conductivity of Compacted Sand-Kaolin Mixtures

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