Membrane behavior of bentonite-amended compacted clay

Tang, Qiang; Tanaka, Katsumi; Inui, Tomoyuki; Li, Zhenze

doi:10.1016/j.sandf.2014.04.019

Cited by 82 publications

(29 citation statements)

References 44 publications

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“…Except for the 5 mmol/L KCl stage for specimen RW-2, the difference between ave and o , ⌬, was generally ≤0.033, and tended to decrease with increasing C ot . The closeness in values between o and ave for both tests for all values of C ot likely is due, in part, to the circulation of TW across the bottom boundary of the specimens in this study relative to previous studies, where DIW generally has been circulated across the bottom boundary of the specimen (e.g., Malusis and Shackelford 2002;Shackelford and Lee 2003;Yeo et al 2005;Kang and Shackelford 2010;Mazzieri et al 2010;Bohnhoff 2012;Dominijanni et al 2013;Meier et al 2014;Tang et al 2014aTang et al , 2014bTang et al , 2015Di Emidio et al 2015). The use of TW as the bottom circulation liquid resulted in values of −⌬C o and −⌬C ave that were closer in magnitude relative to the differences in these values based on the use of DIW as the bottom circulation liquid.…”

Section: Membrane Efficiency Coefficientssupporting

confidence: 50%

“…The o values measured in this study for compacted SB specimens are compared with o reported in the literature for bentoniteamended CCLs (Kang and Shackelford 2010;Tang et al 2014a) in Fig. 12b.…”

Section: Comparisons With Other Bentonite-based Barriersmentioning

confidence: 85%

“…In addition to low k, the existence of semi-permeable membrane behavior, or the ability to restrict the migration of aqueous miscible chemical species (solutes), has been demonstrated extensively for many bentonite-based barriers, including GCLs, compacted natural clay amended with bentonite, and soil-bentonite backfills for in situ vertical cutoff walls (Kemper and Rollins 1966;Barbour and Fredlund 1989;Malusis et al 2001;Malusis and Shackelford 2002;Shackelford and Lee 2003;Yeo et al 2005;Henning et al 2006;Dominijanni and Manassero 2008;Evans et al 2008;Shackelford 2009, 2011;Shackelford 2011Shackelford , 2012Bohnhoff and Shackelford 2013;Dominijanni et al 2013;Meier et al 2014;Tang et al 2014aTang et al , 2014bTang et al , 2015Shackelford and Scalia 2016). Solute (e.g., contaminant) restriction results in reduced solute mass flux and leads to chemico-osmosis, or the movement of liquid from high to low solvent (H 2 O) chemical potential (low to high solute concentration), such that the containment function of bentonite-based barriers that exhibit semi-permeable membrane behavior is enhanced Malusis et al 2003;Manassero and Dominijanni 2003;Malusis et al 2014;Shackelford , 2014.…”

Section: Introductionmentioning

confidence: 99%

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Membrane behavior of compacted sand–bentonite mixture

Meier

Shackelford

2017

Can. Geotech. J.

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Semi-permeable membrane behavior contributes to the containment function of engineered barriers used for waste containment by restricting the migration of dissolved chemical species (solutes) such as aqueous-phase contaminants. The existence of membrane behavior has been demonstrated extensively for virtually all categories of bentonite-based containment barriers except compacted sand-bentonite mixtures. Accordingly, membrane tests were conducted on two specimens of a compacted sand-bentonite mixture comprising 15% bentonite (dry weight) with sufficiently low hydraulic conductivity (i.e., ≤1.0 × 10 −9 m/s) to be suitable for use as a waste containment barrier. Despite the imposition of relatively complex chemical conditions, including the use of tap water versus de-ionized water as a circulating liquid and incomplete flushing (leaching) of soluble salts from the specimens prior to membrane testing, the results were in good agreement with those previously reported for other bentonite-based engineered barriers when exposed to similar or the same types of salts and salt concentrations. Also, both compacted soil-bentonite specimens exhibited similar magnitudes of membrane behavior, with measured membrane efficiencies ranging from 0.395 ± 0.053 to 0.063 ± 0.012 when exposed to source KCl solutions with concentrations ranging from 5 to 80 mmol/L, respectively. Thus, compacted sand-bentonite mixtures suitable for use as engineered containment barriers can exhibit semi-permeable membrane behavior, thereby potentially enhancing the containment function of the barriers.Key words: containment barrier, hydraulic conductivity, membrane behavior, sand-bentonite mixture, waste containment.Résumé : Le comportement de la membrane semi-perméable contribue à la fonction de confinement des barrières artificielles utilisées pour le confinement des déchets par la limitation de la migration des espèces chimiques dissoutes (solutés) telles que les contaminants en phase aqueuse. L'existence d'un comportement de la membrane a été démontrée de façon intensive pour pratiquement toutes les catégories de barrières de confinement à base de bentonite à l'exception des mélanges sable-bentonite compactés. En conséquence, les tests ont été effectués sur deux spécimens d'un mélange sable bentonite compactée de 15 % de bentonite (poids sec) avec une suffisamment faible conductivité hydraulique (c.-à -d. ≤1,0 × 10 −9 m/s) à servir de barrière de confinement de déchets. Malgré l'imposition de conditions chimiques relativement complexes, y compris l'utilisation de l'eau du robinet plutôt que de l'eau désionisée comme un liquide circulant et un rinçage incomplet (lessivage) de sels solubles de la membrane des spécimens avant les essais, les résultats sont en bon accord avec ceux rapportés antérieurement pour d'autres barrières artificielles à base de bentonite lorsqu'ils sont exposés à de similaires ou mêmes types de sels et de concentrations de sel. De plus, les spécimens de sol-bentonite compactée ont montré des comportements de membrane à ...

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Section: Membrane Efficiency Coefficientssupporting

confidence: 50%

Section: Comparisons With Other Bentonite-based Barriersmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Membrane behavior of compacted sand–bentonite mixture

Meier

Shackelford

2017

Can. Geotech. J.

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“…Considering the existence of Na(I) and Fe shown by ICP results, the characteristic peaks at 2θ � 26.73 and 20.43°indicate the presence of sodium phosphate hydrate (Na 6 P 6 O 18 ·6H 2 O) and iron silicon carbide (Fe-Si-C). 2 , pyromorphite has a much lower solubility and a greater capacity to resist acid or alkaline attack [52,53]. In addition, the solubility of Zn 3 (PO 4 ) 2 ·4H 2 O or CaZn 2 (PO 4 ) 2 ·2H 2 O is much lower than zinc hydroxide (Zn(OH) 2 ), which is the main product involved in the immobilization of Zn(II) with Portland cement [54].…”

Section: Characterization Of the Materialsmentioning

confidence: 99%

“…e development of industry and urbanization was accompanied with soil pollution, which attracts great attention in the recent years [1][2][3][4]. Heavy metal pollution in soils in various countries is summarized in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Carbonation Effects on Cement-Solidified Contaminated Soil Used in Road Subgrade

Zhou

Pan

Tang

et al. 2018

Advances in Materials Science and Engineering

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Cement solidification/stabilization is widely used towards contaminated soil since it has a low price and significant improvement for the structural capacity of soil. To increase the usage of the solidified matrix, cement-solidified contaminated soil was used as road subgrade material. In this study, carbonation effect that reflected the durability on strength characteristics of cementsolidified contaminated soil and the settlement of pavement were evaluated through experimental and numerical analysis, respectively. According to results, compressive strengths of specimens with 1% Pb(II) under carbonation and standard curing range from 0.44 MPa to 1.17 MPa and 0.14 MPa to 2.67 MPa, respectively. e relatively low strengths were attributed to immobilization of heavy metal, which consumed part of SiO 2 , Al 2 O 3 , and CaO components in the cement or kaolin and reduced the hydration and pozzolanic reaction materials. is phenomenon further decreased the strength of solidified soils. e carbonation depth of 1% Cu(II) or Zn(II) contaminated soils was 18 mm, which significantly increased with the increase of curing time and contamination concentration. Furthermore, the finite element calculation results showed that surface settlements decreased with the increase of modulus of subgrade and the distance away from the center. At the center, the pavement settlement was proportional to the level of traffic load.

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