View in EDS

Temperature effects on water retention behaviour and structural evolution of GMZ bentonite pellet mixtures.

Saved in:
Bibliographic Details
Title: Temperature effects on water retention behaviour and structural evolution of GMZ bentonite pellet mixtures.
Authors: Liu, Zhang-Rong1 (AUTHOR), Ye, Wei-Min1,2 (AUTHOR) ye_tju@tongji.edu.cn, Cui, Yu-Jun3 (AUTHOR), Zhu, He-Hua1,2 (AUTHOR), Wang, Qiong1,2 (AUTHOR)
Source: Applied Clay Science. Jun2022, Vol. 222, pN.PAG-N.PAG. 1p.
Subjects: Temperature effect, Radioactive waste disposal, Water temperature, Bentonite, Porosity, Surface tension, High temperatures
Abstract: Mixtures of high-density, multi-sized bentonite pellets are considered as a promising buffer/backfill material for deep geological disposal of high-level radioactive waste (HLW). During the operation of a HLW repository, the pellet mixtures will be subjected to ground water infiltrated from surrounding rock and elevated temperatures induced by nuclide decay heat, leading to a complex hydro-mechanical behaviour. In this paper, water retention tests with suction controlled by vapour equilibrium and osmotic techniques, as well as structural observations by mercury intrusion porosimetry (MIP) were performed on three kinds of specimens of Gaomiaozi (GMZ) bentonite at different temperatures (20, 40, 60 and 80 °C), including constant-volume pellet mixtures (PM) and compacted blocks (CB) with an identical dry density (1.45 Mg/m3) and free-swelling single pellets with the same initial dry density (1.95 Mg/m3) as those involved in the PM specimen. For the three kinds of specimens, the water retention capacity decreased with increasing temperature. From a perspective of thermal dynamics theory, it is concluded that in high suction range (> 10 MPa), increasing temperature inhibited the water adsorption and promoted the water desorption process consequently leading to a decreasing water retention capacity. According to the capillary law (Young – Laplace equation), in the low suction range (< 10 MPa), increasing temperature reduces the capillary water content in terms of decreasing the surface tension, contact angle and density of the capillary water, as well as expanding the entrapped pore air. Meanwhile, the MIP test results illustrate that during hydration, most of the large pores (2000–360,000 nm) were gradually converted into medium pores (100–2000 nm) while the change of small pores (6.4–100 nm) and inaccessible pores (< 6.4 nm and > 360,000 nm) were limited. Compared to the effect of suction, the temperature influence on this structural evolution process was relatively slight. Therefore, the temperature-dependent water retention behaviour was mainly caused by temperature-induced changes of water-clay interactions as well as physical properties of adsorbed and capillary water during hydration, rather than the limited changes of pore structure of the specimen. • Comparative studies were performed on pellet mixtures, single pellets and compacted blocks of GMZ bentonite. • Water retention capacity of the three specimens decreased with increasing temperature. • Water adsorption was exothermic and could be inhibited by increasing temperature. • Capillary water was reduced by thermal alteration of water properties and expansion of entrapped pore air. • Temperature effects on pore structure was limited. [ABSTRACT FROM AUTHOR]
Copyright of Applied Clay Science is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
FullText Text:
  Availability: 0
Header DbId: egs
DbLabel: Engineering Source
An: 156469445
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Temperature effects on water retention behaviour and structural evolution of GMZ bentonite pellet mixtures.
– Name: Author
  Label: Authors
  Group: Au
  Data: &lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Liu%2C+Zhang-Rong%22&quot;&gt;Liu, Zhang-Rong&lt;/searchLink&gt;&lt;relatesTo&gt;1&lt;/relatesTo&gt; (AUTHOR)&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Ye%2C+Wei-Min%22&quot;&gt;Ye, Wei-Min&lt;/searchLink&gt;&lt;relatesTo&gt;1,2&lt;/relatesTo&gt; (AUTHOR)&lt;i&gt; ye_tju@tongji.edu.cn&lt;/i&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Cui%2C+Yu-Jun%22&quot;&gt;Cui, Yu-Jun&lt;/searchLink&gt;&lt;relatesTo&gt;3&lt;/relatesTo&gt; (AUTHOR)&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Zhu%2C+He-Hua%22&quot;&gt;Zhu, He-Hua&lt;/searchLink&gt;&lt;relatesTo&gt;1,2&lt;/relatesTo&gt; (AUTHOR)&lt;br /&gt;&lt;searchLink fieldCode=&quot;AR&quot; term=&quot;%22Wang%2C+Qiong%22&quot;&gt;Wang, Qiong&lt;/searchLink&gt;&lt;relatesTo&gt;1,2&lt;/relatesTo&gt; (AUTHOR)
– Name: TitleSource
  Label: Source
  Group: Src
  Data: &lt;searchLink fieldCode=&quot;JN&quot; term=&quot;%22Applied+Clay+Science%22&quot;&gt;Applied Clay Science&lt;/searchLink&gt;. Jun2022, Vol. 222, pN.PAG-N.PAG. 1p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: &lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Temperature+effect%22&quot;&gt;Temperature effect&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Radioactive+waste+disposal%22&quot;&gt;Radioactive waste disposal&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Water+temperature%22&quot;&gt;Water temperature&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Bentonite%22&quot;&gt;Bentonite&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Porosity%22&quot;&gt;Porosity&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22Surface+tension%22&quot;&gt;Surface tension&lt;/searchLink&gt;&lt;br /&gt;&lt;searchLink fieldCode=&quot;DE&quot; term=&quot;%22High+temperatures%22&quot;&gt;High temperatures&lt;/searchLink&gt;
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Mixtures of high-density, multi-sized bentonite pellets are considered as a promising buffer/backfill material for deep geological disposal of high-level radioactive waste (HLW). During the operation of a HLW repository, the pellet mixtures will be subjected to ground water infiltrated from surrounding rock and elevated temperatures induced by nuclide decay heat, leading to a complex hydro-mechanical behaviour. In this paper, water retention tests with suction controlled by vapour equilibrium and osmotic techniques, as well as structural observations by mercury intrusion porosimetry (MIP) were performed on three kinds of specimens of Gaomiaozi (GMZ) bentonite at different temperatures (20, 40, 60 and 80 &#176;C), including constant-volume pellet mixtures (PM) and compacted blocks (CB) with an identical dry density (1.45 Mg/m3) and free-swelling single pellets with the same initial dry density (1.95 Mg/m3) as those involved in the PM specimen. For the three kinds of specimens, the water retention capacity decreased with increasing temperature. From a perspective of thermal dynamics theory, it is concluded that in high suction range (&gt; 10 MPa), increasing temperature inhibited the water adsorption and promoted the water desorption process consequently leading to a decreasing water retention capacity. According to the capillary law (Young – Laplace equation), in the low suction range (&lt; 10 MPa), increasing temperature reduces the capillary water content in terms of decreasing the surface tension, contact angle and density of the capillary water, as well as expanding the entrapped pore air. Meanwhile, the MIP test results illustrate that during hydration, most of the large pores (2000–360,000 nm) were gradually converted into medium pores (100–2000 nm) while the change of small pores (6.4–100 nm) and inaccessible pores (&lt; 6.4 nm and &gt; 360,000 nm) were limited. Compared to the effect of suction, the temperature influence on this structural evolution process was relatively slight. Therefore, the temperature-dependent water retention behaviour was mainly caused by temperature-induced changes of water-clay interactions as well as physical properties of adsorbed and capillary water during hydration, rather than the limited changes of pore structure of the specimen. • Comparative studies were performed on pellet mixtures, single pellets and compacted blocks of GMZ bentonite. • Water retention capacity of the three specimens decreased with increasing temperature. • Water adsorption was exothermic and could be inhibited by increasing temperature. • Capillary water was reduced by thermal alteration of water properties and expansion of entrapped pore air. • Temperature effects on pore structure was limited. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: &lt;i&gt;Copyright of Applied Clay Science is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder&#39;s express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.&lt;/i&gt; (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=156469445
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1016/j.clay.2022.106492
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 1
        StartPage: N.PAG
    Subjects:
      – SubjectFull: Temperature effect
        Type: general
      – SubjectFull: Radioactive waste disposal
        Type: general
      – SubjectFull: Water temperature
        Type: general
      – SubjectFull: Bentonite
        Type: general
      – SubjectFull: Porosity
        Type: general
      – SubjectFull: Surface tension
        Type: general
      – SubjectFull: High temperatures
        Type: general
    Titles:
      – TitleFull: Temperature effects on water retention behaviour and structural evolution of GMZ bentonite pellet mixtures.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Liu, Zhang-Rong
      – PersonEntity:
          Name:
            NameFull: Ye, Wei-Min
      – PersonEntity:
          Name:
            NameFull: Cui, Yu-Jun
      – PersonEntity:
          Name:
            NameFull: Zhu, He-Hua
      – PersonEntity:
          Name:
            NameFull: Wang, Qiong
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 06
              Text: Jun2022
              Type: published
              Y: 2022
          Identifiers:
            – Type: issn-print
              Value: 01691317
          Numbering:
            – Type: volume
              Value: 222
          Titles:
            – TitleFull: Applied Clay Science
              Type: main
ResultId 1