5-year chemico-physical evolution of concrete–claystone interfaces, Mont Terri rock laboratory (Switzerland)

Mäder, Urs; Jenni, Andreas; Lerouge, Cathérine; Gaboreau, Stéphane; Miyoshi, Seiji; Kimura, Yukinobu; Cloet, Veerle; Fukaya, Masaaki; Claret, Francis; Otake, Tsubasa; Shibata, Masahito; Lothenbach, Barbara

doi:10.1007/978-3-319-70458-6_16

Cited by 4 publications

(8 citation statements)

References 27 publications

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“…Magnesium was observed near the interface together with silicon only. These simple cell experiments clearly proved that M-S-H formation occurs within a relatively short time and that M-S-H forms from the dissolution of C-S-H, as had been postulated in (Dauzères et al, 2016;Jenni et al, 2014;Lerouge et al, 2017;Mäder et al, 2017) (Bernard et al, submitted).…”

Section: A C C E P T E Dsupporting

confidence: 72%

“…3 Garcia Calvo et al, 2010;Jenni et al, 2014;Lerouge et al, 2017;Mäder et al, 2017). At the interfaces of low pH concretes and Opalinus clayey rock (OPA) a poorly crystalline phase containing magnesium and silicon with a sheet-like structure was observed in association with C-S-H (Dauzères et al, 2016;Lerouge et al, 2017;Mäder et al, 2017).…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

“…This work aims at investigating the formation of M-S-H in similar conditions as in field experiments (Dauzères et al, 2016;Jenni et al, 2014;Lerouge et al, 2017;Mäder et al, 2017) (Bernard et al, submitted;Bernard et al, 2017a;. Recently, it was demonstrated that a low amount of calcium can be taken up by M-S-H, while no magnesium uptake in C-S-H was observed (Bernard et al, submitted).…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

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Magnesium and calcium silicate hydrates, Part II: Mg-exchange at the interface “low-pH” cement and magnesium environment studied in a C-S-H and M-S-H model system

Bernard

Dauzères

Lothenbach

2018

Applied Geochemistry

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Low-pH" cementitious materials have been developed in the context of nuclear wastes encapsulation to reduce the alkaline plume and the early hydration heat causing shrinkage of the Portland cement basedmaterials in contact with clayey rocks. This study follows the evolutions at an interface between calcium silicate hydrate (C-S-H) with a Ca/Si ratio of 0.8 and magnesium silicate hydrate (M-S-H) with a Mg/Si ratio of 0.8, while controlling the pore solution by using reservoirs. In a first step a simplified "low-pH" binder was mimicked by C-S-H with a low Ca/Si in the presence of magnesium. In a second step the impact of calcium on pure M-S-H was studied. Secondary electron microscopy observations show the fast deterioration of the C-S-H and the precipitation of M-S-H in the C-S-H disk and an uptake of calcium in the M-S-H disk together with a change of the reservoir compositions including pH values.The reactive transport modelling is in good agreement with the changes in both the solid phases and the composition of the solution reservoirs.

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Section: A C C E P T E Dsupporting

confidence: 72%

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

See 1 more Smart Citation

Magnesium and calcium silicate hydrates, Part II: Mg-exchange at the interface “low-pH” cement and magnesium environment studied in a C-S-H and M-S-H model system

Bernard

Dauzères

Lothenbach

2018

Applied Geochemistry

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“…Experimental investigations on the cement-clay interfaces often use composite specimens consisting of cement/mortar/concrete and compacted clay (Sugiyama and Tsuji 2008;Dauzeres et al 2010;Shafizadeh et al 2015;Fernández et al 2016;Yamaguchi et al 2016;Balmer et al 2017) same as the first paper. More recently, long-term in-situ experiments in underground research laboratories (URL) on the cement-clay interfaces have also been conducted (Read et al 2001;Gaboreau et al 2012;Mäder et al 2017). Generally, the experimental investigation of cement-clay interactions are limited by the slow evolution of these systems as a result of the slow mass transport across the interface and slow dissolution and precipitation kinetics of clay minerals.…”

Section: Introductionmentioning

confidence: 99%

Calcite Precipitation at Cement–Bentonite Interface. Part 2: Acceleration of Transport by an Electrical Gradient

Nakarai

Watanabe

Koibuchi³

et al. 2021

ACT

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Calcium leaching from cementitious materials in contact with bentonite in nuclear waste repositories can alter the functionality of an engineered barrier system. In this study, we contribute to the fundamental understanding of calcite precipitation at cement-bentonite interfaces by adding carbonate to bentonite. In addition, we accelerate the transport of charged reactants towards the interface using an electrochemical migration method. The carbonate admixture successfully promotes calcite precipitation at the surface of cement paste. The analysis also revealed that the amount of precipitated calcite is not simply correlated to the amount of added carbonate or the applied electrical potential. Experiments in which bentonite pore water contains high initial contents of carbonate exhibit rapid calcite precipitation in a very narrow region at the cement-bentonite interface, resulting in pore clogging.

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“…omitting the chemical and mineralogical evolution of the concrete itself. Previous works have outlined the relative absence of representative experiments in real clay/concrete interfaces (Gaboreau et al , 2011, 2012; Bartier et al , 2013; Mäder et al , 2017) and the difficulty of taking into account the effects of real volumes and the composition of solutions migrating through connected porosities (Cuevas et al , 2016). Moreover, few works have put low-pH cementitious materials in contact with clays (Jenni et al , 2014; Dauzères et al , 2016; Lerouge et al, 2017).…”

mentioning

confidence: 99%

Low-pH cement mortar-bentonite perturbations in a small-scale pilot laboratory experiment

et al. 2018

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A novel method to perform small-scale laboratory experiments that reproduce concrete–bentonite and concrete–groundwater interactions has been developed. Such interfaces will prevail in engineered barrier systems used for isolation of nuclear waste. With the goal of optimizing the experimental method, this work has analysed the geochemical interaction of distilled water, low-pH cement mortar and FEBEX-bentonite for 75 days. Limited but evident reactivity between the materials was observed, mainly decalcification in cement mortar, carbonation at the interface with bentonite and Mg enrichment in bentonite. These results are consistent with the state-of-the-art literature and were used to validate this small-scale pilot laboratory experiment to establish the basis for further studies comparing the behaviour of different buffer and cement materials.

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5-year chemico-physical evolution of concrete–claystone interfaces, Mont Terri rock laboratory (Switzerland)

Cited by 4 publications

References 27 publications

Magnesium and calcium silicate hydrates, Part II: Mg-exchange at the interface “low-pH” cement and magnesium environment studied in a C-S-H and M-S-H model system

Magnesium and calcium silicate hydrates, Part II: Mg-exchange at the interface “low-pH” cement and magnesium environment studied in a C-S-H and M-S-H model system

Calcite Precipitation at Cement–Bentonite Interface. Part 2: Acceleration of Transport by an Electrical Gradient

Low-pH cement mortar-bentonite perturbations in a small-scale pilot laboratory experiment

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