Linking hydraulic conductivity and tortuosity parameters to pore space geometry and pore-size distribution

2003 ◽  
Vol 272 (1-4) ◽  
pp. 36-49 ◽  
Author(s):  
R.W. Vervoort ◽  
S.R. Cattle
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Pore Space ◽  
Space Geometry

scholarly journals Investigation on the Deterioration Mechanism of Tuff Stones Used for the Exteriors at the Former Koshien Hotel

2020 ◽  
Vol 172 ◽  
pp. 20008
Author(s):  
Koki Yamada ◽  
Chiemi Iba ◽  
Tomoko Uno ◽  
Kazuma Fukui ◽  
Daisuke Ogura
Keyword(s):  
Hydraulic Conductivity ◽  
Physical Properties ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Vapor Permeability ◽  
Cultural Significance ◽  
Water Permeation ◽  
Deterioration Mechanism ◽  
Main Factor

The former Koshien Hotel is an historic Japanese architectural structure, where two different tuffs called Nikkaseki and Tatsuyamaishi were used to build the exterior. Despite its cultural significance, the building’s exterior is deteriorating in many ways, with water permeation being the main factor. In this study, the hygrothermal properties of both Nikkaseki and Tatsuyamaishi were measured in order to examine the correlation between deterioration mechanisms and the tuff characteristics in detail. The basic physical properties, pore size distribution, vapor permeability, hydraulic conductivity, and sorption isotherm were measured. The results of a comparison of two tuffs led us to hypothesize that the main reason behind Nikkaseki’s deterioration is expansive freezing, while that of Tatsuyamaishi is caused by repeating dehydration or dry-wet cycles.

scholarly journals POROSIMETRY BY RANDOM NODE STRUCTURING IN VIRTUAL CONCRETE

2012 ◽  
Vol 31 (2) ◽  
pp. 79 ◽  
Author(s):  
Piet Stroeven ◽  
Nghi L.B. Le ◽  
Lambertus J Sluys ◽  
Huan He
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Pore Space ◽  
Cementitious Materials ◽  
Discrete Element Modeling ◽  
Concurrent Algorithm ◽  
Random Node ◽  
Volume Measurements ◽  
3D Information

Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT) approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of the aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. However, aggregate grain surfaces lead to anisotropy in porosity. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements. In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS), introduced earlier in IA&S (Stroeven et al., 2011b) and random node structuring (RaNoS) provide such information.

Hydraulic conductivity of clay mixed with nanomaterials

2015 ◽  
Vol 52 (6) ◽  
pp. 808-811 ◽  
Author(s):  
C.W.W. Ng ◽  
J.L. Coo
Keyword(s):  
Hydraulic Conductivity ◽  
Aluminum Oxide ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Mercury Intrusion Porosimetry ◽  
Flow Paths ◽  
Mercury Intrusion ◽  
Flexible Wall ◽  
Conductivity Behavior

The focus of this note is to investigate the hydraulic conductivity behavior of clay mixed with nanomaterials. Two different nanomaterials — namely, gamma-aluminum oxide powder (γ-Al2O3) and nano-copper oxide (CuO) — were selected and mixed with clay at different percentages (i.e., 2%, 4%, and 6%). Hydraulic conductivity tests were carried out in a flexible wall permeameter following the ASTM D5084 standard. Mercury intrusion porosimetry (MIP) tests were also carried out to determine the pore-size distribution. At 2% of γ-Al2O3 and nano-CuO, the hydraulic conductivity of clay decreased 30% and 45%, respectively. As the proportion of the nanomaterial increases, the reduction of hydraulic conductivity becomes less prominent as flow paths devoid of nanomaterials are unlikely. Reduction of hydraulic conductivity is due to the pores of clay being clogged by the nanomaterial. Pore-size distribution curves show that the largest pore size reduced by 20% when clay was mixed with 4% nano-CuO.

scholarly journals The impacts of freeze–thaw cycles on saturated hydraulic conductivity and microstructure of saline–alkali soils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenshuo Xu ◽  
Kesheng Li ◽  
Longxiao Chen ◽  
Weihang Kong ◽  
Chuanxiao Liu
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Water Content ◽  
Size Distribution ◽  
Saturated Hydraulic Conductivity ◽  
High Water Content ◽  
Soil Permeability ◽  
Freeze Thaw ◽  
Alkali Soil

AbstractStudy on the microscopic structure of saline–alkali soil can reveal the change of its permeability more deeply. In this paper, the relationship between permeability and microstructure of saline–alkali soil with different dry densities and water content in the floodplain of southwestern Shandong Province was studied through freeze–thaw cycles. A comprehensive analysis of soil samples was conducted using particle-size distribution, X-ray diffraction, freeze–thaw cycles test, saturated hydraulic conductivity test and mercury intrusion porosimetry. The poor microstructure of soil is the main factor that leads to the category of micro-permeable soil. The porosity of the local soil was only 6.19–11.51%, and ultra-micropores (< 0.05 μm) and micropores (0.05–2 μm) dominated the pore size distribution. Soil saturated water conductivity was closely related to its microscopic pore size distribution. As the F–T cycles progressed, soil permeability became stronger, with the reason the pore size distribution curve began to shift to the small pores (2–10 μm) and mesopores (10–20 μm), and this effect was the most severe when the freeze–thaw cycle was 15 times. High water content could promote the effects of freeze–thaw cycles on soil permeability and pore size distribution, while the increase of dry density could inhibit these effects. The results of this study provide a theoretical basis for the remediation of saline–alkali soil in the flooded area of Southwest Shandong.

Unsaturated hydraulic conductivity of vineyard soils with high rock fragment content in the Mosel area, Germany

2021 ◽  
Author(s):  
Selina Walle ◽  
Thomas Iserloh ◽  
Manuel Seeger
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Unsaturated Soils ◽  
Hydrological Cycle ◽  
Calculated Data ◽  
Rock Fragment ◽  
Unsaturated Hydraulic Conductivity ◽  
Significant Difference

&lt;p&gt;The study deals with the unsaturated hydraulic conductivity of soils within the scope of the Diverfarming-Project, funded by the EU commission (Horizon 2020 grant agreement no 728003). For this reason, the field work took place in the examined vineyard of the Wawerner Jesuitenberg near Kanzem in the Saar-Mosel valley (Rhineland-Palatinate, Germany). The mentioned parameter is one of the most important specific factors of the hydrological cycle to characterize soil hydraulic properties in the unsaturated soil zone. A mini disc infiltrometer was used to measure the conductivity values at different suctions. The purpose of this study is to determine the plausibility of the fundamentals and the analytical expression of the unsaturated conductivity models in a nearly skeletal soil of schist. In this regard, the mathematical expressions of Mualem (1976), van Genuchten (1980) and Zhang (1997) are focused on calculating the unsaturated hydraulic conductivity. The two variables &amp;#945; and n are analysed in order to better compare between literature specifications and the explicit calculated data of the vineyard&amp;#8217;s soil. As a result, the various developments of &amp;#945; are similar thus the significant difference is based on the value of n. Nevertheless, in consideration of these frame conditions the models represent a suitable mathematical expression of the unsaturated hydraulic conductivity. Furthermore, a range of parameters affecting this conductivity is analysed, particularly with regard to the applied variable soil and cultivation management under the grapevines in the vineyard. Also, the rock fragment cover and the pore size distribution are taken into account. In this context the soil compaction and modified pore size distribution in the wheel tracks stand out due to salient unsaturated hydraulic conductivities at higher tensions. In particular, the stone cover of the contact surface influence the characteristics of the analysed conductivity. Additionally, the connection of stone cover, management and pore size distribution creates a mixture of affected parameters of the unsaturated hydraulic conductivity.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Mualem, Y.: A new model for predicting the hydraulic conductivity of unsaturated porous media, Water Resour. Res, 12, 513&amp;#8211;522, https://doi.org/10.1029/WR012i003p00513, 1976.&lt;/p&gt;&lt;p&gt;Van Genuchten, M.T.: A Closed-form Equation for Predicting the Hydraulic Conductivity of Unsaturated Soils, Soil Sci. Soc. Am. J., 44, 892&amp;#8211;898, https://doi.org/10.2136/sssaj1980.03615995004400050002x, 1980.&lt;/p&gt;&lt;p&gt;Zhang, R.: Determination of Soil Sorptivity and Hydraulic Conductivity from the Disk Infiltrometer, Soil Sci. Soc. Am. J., 61, 1024&amp;#8211;1030, https://doi.org/10.2136/sssaj1997.03615995006100040005x, 1997.&lt;/p&gt;

Salinity dependence of the complex surface conductivity of the Portland sandstone

Geophysics ◽  
2016 ◽  
Vol 81 (2) ◽  
pp. D125-D140 ◽  
Author(s):  
Qifei Niu ◽  
André Revil ◽  
Milad Saidian
Keyword(s):  
Relaxation Time ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Pore Space ◽  
Complex Surface ◽  
Surface Conductivity ◽  
Formation Factor ◽  
Polarization Model ◽  
Fluid Conductivity

Induced polarization can be used to estimate surface conductivity by assuming a universal linear relationship between the surface and quadrature conductivities of porous media. However, this assumption has not yet been justified for conditions covering a broad range of fluid conductivities. We have performed complex conductivity measurements on Portland sandstone, an illite- and kaolinite-rich sandstone, at 13 different water salinities (NaCl) over the frequency range of 0.1 Hz to 45 kHz. The conductivity of the pore water [Formula: see text] affected the complex surface conductivity mainly by changing the tortuosity of the conduction paths in the pore network from high to low salinities. As the fluid conductivity decreases, the magnitude of the surface conductivity and quadrature conductivity was observed to decrease. At relatively high salinities ([Formula: see text]), the ratio between the surface conductivity and quadrature conductivity was roughly constant. At low salinities ([Formula: see text]), the ratio decreased slightly with the decrease of the salinity. A Stern layer polarization model was combined with the differential effective medium (DEM) theory to describe this behavior. The tortuosity entering the complex surface conductivity was salinity dependent following the prediction of the DEM theory. At high salinity, it reached the value of the bulk tortuosity of the pore space given by the product of the intrinsic formation factor and the connected porosity. The relaxation time distributions were also obtained at different salinities by inverting the measured spectra using a Warburg decomposition. The mode of the relaxation time probability distribution found a small but clear dependence on the salinity. This salinity dependence can be explained by considering the ions exchange between Stern and diffuse layers during polarization of the former. The pore-size distribution obtained from the distribution of the relaxation time agreed with the pore-size distribution from nuclear magnetic resonance measurements.

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