Swelling pressures of MX-80 bentonite in solutions of different ionic strength

Herbert, Horst-Juergen; Kasbohm, Joern; Sprenger, H.; Fernández, Ana María; Reichelt, Christian

doi:10.1016/j.pce.2008.10.005

Cited by 120 publications

(61 citation statements)

References 23 publications

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“…At a given temperature, increasing pH of NaOH solution induced a decrease in the swelling pressure, and its rate was controlled basically by pH for high temperatures. Similar results were found in different studies using Azraq Green clay ( [72]) and MX-80 bentonite ( [73]). Also, as in some other studies ( [74]), it was noticed that the increase in temperature for a constant pH value caused a decrease in the swelling pressure as well (also appreciable in Fig.…”

Section: Influences Of Alkaline Solutionssupporting

confidence: 91%

Investigation on chemical effects on GMZ bentonite used as buffer materials

2016

E3S Web Conf.

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Abstract. GMZ bentonite has been selected as a buffer/backfill material for the design of Chinese HLW repository due to its suitable properties. Investigations have been conducted on this material to have a better understanding of its engineering behavior. In this paper, a review of the studies on the chemical effects in GMZ bentonite is presented. The adsorption of radionuclides Ni(II), Cr(III) and Eu(III) etc. on GMZ bentonite is investigated and the influences of external chemical agents are assessed. Some modifications on GMZ bentonite have been implemented to improve its adsorption properties. In the meantime, the influences of NaOH solutions with variations in concentration and pH values on hydraulic conductivity, mechanical behavior and mineralogy of GMZ bentonite are investigated with consideration of temperature. Effects of salt solutions are also assessed in different studies using solutions of Na + and Ca 2+ , which are the predominant cations in the groundwater of Beishan area. It is observed that both cations influence the buffering behavior of bentonite at a different degree. Further investigations should be done for better understanding the influences of coupling factors and time on the chemical behavior of material.

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Section: Influences Of Alkaline Solutionssupporting

confidence: 91%

Investigation on chemical effects on GMZ bentonite used as buffer materials

2016

E3S Web Conf.

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“…Precisions on the chemo-mechanical coupling δ n π g During a saturation process, bentonite develops a larger swelling pressure when the saturation fluid has a smaller ion concentration (Cariou, 2010;Herbert et al, 2008). Bentonite is essentially impure clay consisting mostly of montmorillonite, a member of the smectite family.…”

Section: Determination Of the Coupling Termsmentioning

confidence: 99%

An original constitutive law for Callovo-Oxfordian argillite, a two-scale double-porosity material

Cariou

Dormieux

Skoczylas

2013

Applied Clay Science

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“…It is also well established that bentonite displays a high swelling characteristic that is a function of the aforesaid physicochemical properties related to the montmorillonite mineral [3,[11][12][13][14]. The high swelling capacity provides an effective mechanism for the barrier to retard and adsorb radionuclides as well as the ability to self-heal to ensure fissure closure.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical and Geotechnical Alterations to MX-80 Bentonite at the Waste Canister Interface in an Engineered Barrier System

Davies¹,

Davie

Edward

et al. 2017

Geosciences

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Abstract:The study investigated the basic geomechanical and mineralogical evolution of the bentonite barrier under various experimental boundary conditions which replicated the near-field Thermo-Hydro-Chemico (THC) conditions in a repository. The relationships between the physicochemical alterations and changes in the geotechnical properties have seldom been studied, especially on a consistent dataset. This paper attempts to link the physicochemical properties of Na-bentonite (MX-80) to the macro-scale engineering functionality of the bentonite post THC exposure. Experiments investigated the impact of THC variables on the engineering and physicochemical functionality of the bentonite with respect to its application within a High-Level Waste (HLW) engineered barrier system. Intrinsic alterations to the MX-80 bentonite under relatively short-term exposure to hydrothermal and chemical conditions were measured. Additionally, two long-term tests were conducted under ambient conditions to consider the impact of exposure duration. The intrinsic measurements were then related to the overall performance of the bentonite as a candidate barrier material for application in a UK geological disposal facility. Findings indicate that exposure to thermo-saline-corrosion conditions (i.e., corrosion products derived from structural grade 275 carbon steel) inhibits the free swell capacity and plasticity of the bentonite. However, the measured values remained above the design limits set out for the Swedish multi-barrier concept, from which the UK concept may take a lead. Corrosion alone does not appear to significantly affect the geotechnical measurements compared with the influence of thermal loading and high saline pore water after relatively short-term exposure. Thermal and corrosion exposure displayed no impact on the intrinsic swelling of the smectite component, indicating that no significant structural alteration had occurred. However, when exploring more complex saline solutions i.e., mixed Na, K and Ca, rather than the reference NaCl, divalent cation replacement was observed within the interlayer exchange site. This was accelerated in higher thermal loading conditions.

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Swelling pressures of MX-80 bentonite in solutions of different ionic strength

Cited by 120 publications

References 23 publications

Investigation on chemical effects on GMZ bentonite used as buffer materials

Investigation on chemical effects on GMZ bentonite used as buffer materials

An original constitutive law for Callovo-Oxfordian argillite, a two-scale double-porosity material

Physicochemical and Geotechnical Alterations to MX-80 Bentonite at the Waste Canister Interface in an Engineered Barrier System

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