Institute of Geological Sciences

Team

Curriculum

Curriculum

2016 - Scientific Staff, Rock-Water Interaction Group, Institute of Geological Sciences, University of Bern, Switzerland
2009 - 2015 Research associate, Rock-Water Interaction Group, Institute of Geological Sciences, University of Bern, Switzerland
2007 - 2009 Post-doctoral research associate, Immobilisation Science Laboratory, University of Sheffield, United Kingdom
in collaboration with National Nuclear Laboratory, former Nexia Solutions Ltd
Plutonium immobilisation in ceramics, Interaction of zeolitic materials and cement
2004 - 2006 Post-doctoral research associate, Laboratory of Construction Materials, Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland
in collaboration with W.R. Grace
Influence of admixtures on concrete strength, kinetics, and microstructure
2003 Post-doc, University of Bern, Switzerland
Internet presentation of PhD results as marketing and training tool in R&Ds of National Starch & Chemicals
2003 PhD in Material Science, Institute of Geological Sciences, University of Bern, Switzerland
in collaboration with Elotex AG
Microstructural evolution and physical properties of polymer-modified mortars
1999 Master in Earth Sciences (lic. phil. nat.), Institute of Geological Sciences, University of Bern, Switzerland
Geology of the Doldenhorn-nappe and the landslide at the Gspaltenhorn-Spitzhorn

Research

Research Interest: Interactions in the near-field of waste repositories

Repository concepts comprise fundamentally different materials, e.g.: host rock, concrete, clay-based backfill, metallic waste containment, and the waste itself. After saturation of the nearfield with surrounding groundwater, the different materials lead to gradients in the porewaters, followed by solute transport, and subsequent phase reactions. Neoformations or dissolution of minerals might compromise the barrier functionality.

Experiments and analytics

Research in this field requires an interdisciplinary approach containing chemical, mineralogical, physical, material science, and engineering aspects. Field experiments in underground rock laboratories involve long-term compatible designs and a profound knowledge of the geological setting. Confining pressures are in the range of the clay swelling pressures (Mega-Pascals range) and have to be taken into account in lab experiments. Standard water and clay-specific geochemical analytics, as well as spatially resolved chemical-mineralogical characterisation methods are needed in the setting-up, running, and post-mortem phase of such experiments. We develop novel analytical approaches to characterise reaction fronts in the µm scale in clay and cement, where solid-solutions, amorphous phases, and cation exchangers are frequent.

Conceptual understanding and numerical modelling

The negatively charged surface of the clay layers fractionates the aqueous species mainly according to their charge. Anions are depleted, cations strongly enriched in the porewater close to the clay sheets. Numerical modelling of solute transport in such media has to account for this effect combined with the porosity distribution. Some of the constraints needed for modelling are not yet known and certain mechanisms still under debate. We are trying to close these gaps with specific experiments. We implement derived mechanisms into reactive transport codes in order to understand and predict experimental data.

Key topics and current projects

1. Bentonite under different geochemical conditions

If bentonite is exposed to host-rock porewater, glacial melt water, cementitious porewater, to heat, or corroding canister surfaces, phase reactions occur, swelling pressure might change, and the porosity distribution is altered. We conduct core infiltration experiments, participate in large-scale rock lab experiments, and implement dual porosity transport or chemo-mechanical coupling into reactive transport codes.

2. Opalinus Clay – cement interaction

Deep geological waste repositories require concrete fortifications, and cementitious waste matrices are planned for low/intermediate level waste. Possibly malicious scenarios include clay mineral alterations, pore clogging at the interface, or concrete deterioration during the waste emplacement phase. Experiments and numerical modelling help to understand the complex interaction processes.

3. Analytical and code developments

  • Scanning electron microscopy combined with energy dispersive spectroscopy (SEM EDX) is pushed to its limits with respect to sensitivity and sample size: novel approaches allow for detection of weak chemical gradients over centimetres. Sample preparation of soft clay or cement materials involves specific drying and polishing methods (including broad ion beam milling).
  • Synchrotron micro X-ray diffraction (µXRD) allows for mineralogical characterisation in the µm range. Preparation of micro-thin sections on very thin supports is developed.
  • Further spatially resolved methods (µRaman, µFTIR) are applied to the same samples measured by the methods above.
  • For specific bulk methods, interaction layers have to be scratched off and the limited amount of sample is measured (Mössbauer, TGA/DTA, aqueous extracts, cation occupancy, etc.).
  • Dual porosity transport in clay is implemented into CrunchFlowMC (Carl Steefel, BNL) and FLOTRAN.
  • Implementation of chemical-mechanical coupling into reactive transport codes aims for the representation of observed alterations of swelling pressure and porosity caused by the changing porewater composition.

 

Research group Rock-Water Interaction

Publications

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2023

Bernard, Ellina; Jenni, Andreas; Toropovs, Nikolajs; Mäder, Urs (2023). Percolation experiment across a 10-year-old interface between Opalinus Clay and Portland concrete. Cement and concrete research, 170, p. 107180. Elsevier 10.1016/j.cemconres.2023.107180

Wersin, Paul; Hadi, Jebril; Kiczka, Mirjam; Jenni, Andreas; Grenèche, Jean‐Marc; Diomidis, Nikitas; Leupin, Olivier X.; Svensson, Daniel; Sellin, Patrik; Reddy, Bharti; Smart, Nicholas; Zhang, Zhidong (2023). Unravelling the corrosion processes at steel/bentonite nterfaces in in situ tests. Materials and corrosion, 74(11-12), pp. 1716-1727. Wiley 10.1002/maco.202313755

Kiczka, M.; Wersin, P.; Mazurek, M.; Zwahlen, C.; Jenni, A.; Mäder, U.; Traber, D. (2023). Porewater composition in clay rocks explored by advective displacement and squeezing experiments. Applied geochemistry, 159, p. 105838. Elsevier 10.1016/j.apgeochem.2023.105838

2021

Jenni, Andreas; Meeussen, Johannes C.L.; Pakkanen, Tapani A.; Hirvi, Janne T.; Akinwunmi, Bukunmi; Yustres, Ángel; Navarro, Vicente; López-Vizcaíno, Rubén; Muuri, Eveliina; Niskanen, Mika; Wersin, Paul; Mäder, Urs (2021). Coupling of chemical and hydromechanical properties in bentonite: A new reactive transport model. Applied Clay Science, 214(106274), p. 106274. Elsevier 10.1016/j.clay.2021.106274

Pekala, Marek; Wersin, Paul; Pastina, Barbara; Lamminmäki, Ralf; Vuorio, Marja; Jenni, Andreas (2021). Potential impact of cementitious leachates on the buffer porewater chemistry in the Finnish repository for spent nuclear fuel – A reactive transport modelling assessment. Applied geochemistry, 131, p. 105045. Elsevier 10.1016/j.apgeochem.2021.105045

Jenni, Andreas; Mäder, Urs (2021). Reactive Transport Simulation of Low-pH Cement Interacting with Opalinus Clay Using a Dual Porosity Electrostatic Model. Minerals, 11(7), p. 664. MDPI 10.3390/min11070664

Navarro, Vicente; Yustres, Ángel; Jenni, Andreas; De la Morena, Gema; Asensio, Laura; López-Vizcaíno, Rubén; Cabrera, Virginia; Wersin, Paul; Mäder, Urs; Muuri, Eveliina; Niskanen, Mika; Akinwunmi, Bukunmi; Hirvi, Janne T.; Pakkanen, Tapani A. (2021). Molecular dynamics data for modelling the microstructural behaviour of compacted sodium bentonites. Applied Clay Science, 201, p. 105932. Elsevier 10.1016/j.clay.2020.105932

Yokoyama, Shingo; Shimbashi, Misato; Minato, Daisuke; Watanabe, Yasutaka; Jenni, Andreas; Mäder, Urs (2021). Alteration of Bentonite Reacted with Cementitious Materials for 5 and 10 Years in the Mont Terri Rock Laboratory (CI Experiment). Minerals, 11(3), p. 251. MDPI 10.3390/min11030251

Wersin, Paul; Hadi, Jebril; Jenni, Andreas; Svensson, Daniel; Greneche, Jean-Marc; Sellin, Patrik; Leupin, Olivier (2021). Interaction of Corroding Iron with Eight Bentonites in the Alternative Buffer Materials Field Experiment (ABM2). Minerals, 11(8), p. 907. MDPI 10.3390/min11080907

2020

Gaboreau, Stephane; Rodríguez-Cañas, Enrique; Maeder, Urs; Jenni, Andreas; Turrero, Maria Jesús; Cuevas, Jaime (2020). Concrete perturbation in a 13-year in situ concrete/bentonite interaction from FEBEX experiments. New insight of 2:1 Mg phyllosilicate precipitation at the interface. Applied geochemistry, 118, p. 104624. Elsevier 10.1016/j.apgeochem.2020.104624

Bernard, Ellina; Jenni, Andreas; Fisch, Martin; Grolimund, Daniel; Mäder, Urs (2020). Micro-X-ray diffraction and chemical mapping of aged interfaces between cement pastes and Opalinus Clay. Applied geochemistry, 115, p. 104538. Elsevier 10.1016/j.apgeochem.2020.104538

Wersin, P.; Pekala, M.; Mazurek, M.; Gimmi, T.; Mäder, U.; Jenni, A.; Rufer, D.; Aschwanden, L. (2020). Porewater Chemistry of Opalinus Clay: Methods, Data, Modelling & Buffering Capacity (Technical Report, Nagra 18-01). NAGRA, National Cooperative for the Disposal of Radioactive Waste

2019

Jenni, Andreas; Wersin, Paul; Thoenen, T.; Baeyens, B.; Ferrari, A.; Gimmi, Thomas; Mäder, Urs; Marschall, P.; Hummel, W.; Leupin, O. (2019). Bentonite backfill performance in a high-level waste repository: a geochemical perspective (Technical Report, Nagra NTB 19-03). Wettingen, Switzerland: NAGRA, National Cooperative for the Disposal of Radioactive Waste

2018

Alt-Epping, Peter; Gimmi, Thomas; Wersin, Paul; Jenni, Andreas (2018). Incorporating electrical double layers into reactive-transport simulations of processes in clays by using the Nernst-Planck equation: A benchmark revisited. Applied geochemistry, 89, pp. 1-10. Elsevier 10.1016/j.apgeochem.2017.10.018

Jenni, Andreas; Mäder, Urs (2018). Coupling of chemical and hydromechanical properties in bentonite. Applied geochemistry, 97, pp. 147-156. Elsevier 10.1016/j.apgeochem.2018.08.013

2017

Hadi, J.; Wersin, P.; Jenni, A.; Greneche, J. M. (2017). Redox evolution and Fe-bentonite interaction in the ABM2 experiment, Äspö Hard Rock Laboratory (Technical Report NTB 2017-10). Nagra

Mäder, Urs; Jenni, Andreas; Lerouge, Cathérine; Gaboreau, Stephane; Miyoshi, Satoru; Kimura, Yukinobu; Cloet, Veerle; Fukaya, Masaaki; Claret, Francis; Otake, Tsubasa; Shibata, Masahito; Lothenbach, Babara (2017). 5-year chemico-physical evolution of concrete–claystone interfaces, Mont Terri rock laboratory (Switzerland). Swiss journal of geosciences, 110(1), pp. 307-327. Springer 10.1007/s00015-016-0240-5

Yustres, A.; Jenni, Andreas; Asensio, L.; Pintado, X.; Koskinen, K.; Navarro, V.; Wersin, Paul (2017). Comparison of the hydrogeochemical and mechanical behaviours of compacted bentonite using different conceptual approaches. Applied Clay Science, 141, pp. 280-291. Elsevier 10.1016/j.clay.2017.03.006

Jenni, Andreas; Gimmi, Thomas; Alt-Epping, Peter; Mäder, Urs; Cloet, V (2017). Interaction of ordinary Portland cement and Opalinus Clay: Dual porosity modelling compared to experimental data. Physics and chemistry of the earth, 99, pp. 22-37. Elsevier 10.1016/j.pce.2017.01.004

Lerouge, Catherine; Gaboreau, Stéphane; Grangeon, Sylvain; Claret, Francis; Warmont, Fabienne; Jenni, Andreas; Cloet, Veerle; Mäder, Urs (2017). In situ interactions between Opalinus Clay and Low Alkali Concrete. Physics and chemistry of the earth, 99, pp. 3-21. Elsevier 10.1016/j.pce.2017.01.005

Mäder, Urs; Jenni, Andreas; Naumann, B.; Reichenwallner, Simon; Cloet, V. (2017). CI Experiment: 4th Sampling Campaign (2017) for 10-year-old interfaces of OPA with OPC/LAC/ESDRED concrete, MX-80 bentonite with OPC/LAC, and 2-year-old interfaces of OPA with Belgian super container concrete and Japanese HFSC St. Ursanne, Switzerland: Mont Terri Project

Fisch, Martin; Jenni, Andreas; Mäder, Urs; Grolimund, D.; Cloet, V. (2017). CI Experiment: Micro-XRD studies on 3.2-year-old interfaces between Opalinus Clay and OPC and ESDRED mortar (3rd sampling campaign 2015) St. Ursanne, Switzerland: Mont Terri Project

2016

Dolder, Florian Dominik; Mäder, Urs; Jenni, Andreas; Münch, B. (2016). Alteration of MX-80 bentonite backfill material by high-pH cementitious fluids under lithostatic conditions – an experimental approach using core infiltration techniques. Geological Society Special Publications, 443(1), pp. 281-305. Geological Society 10.1144/sp443.10

2015

Dolder, Florian Dominik; Mäder, Urs; Jenni, Andreas (2015). Experimental Characterization and Quantification of Cement-Bentonite Interaction using Core Infiltration Techniques Coupled with X-ray Tomography (In Press). (Dissertation, Institut für Geologie, Philosophischen-naturwissenschaftlichen Fakultät)

Dolder, Florian Dominik; Mäder, Urs; Jenni, Andreas; Münch, Beat (23 March 2015). Stability of bentonite under high-pH conditions: An experimental approach including modeling (Unpublished). In: 6th international conference on Clays in Natural and Engineered Barriers for Radioactive Waste Confinement. Brüssel. 23.-26.03.2015.

Wersin, Paul; Jenni, Andreas; Mäder, Urs (2015). Interaction of corroding iron with bentonite in the ABM1 experiment at Äspö, Sweden: A microscopic approach. Clays and clay minerals, 63(1), pp. 51-68. Clay Minerals Society 10.1346/ccmn.2015.0630105

Jenni, Andreas; Mäder, Urs; Wieland, E.; Lerouge, C.; Gaboreau, S. (2015). Concrete-clay interaction: give-and-take without a loser? (Unpublished). In: 6th Meeting on Clays in Natural and Engineered Barrier for Radioactive Waste Confinement. Brussels, Belgium.

Jenni, Andreas; Mäder, Urs (2015). FE-C Experiment: Investigation of the interface between Opalinus Clay and the shotcrete used in the FE tunnel (Arbeitsbericht). St. Ursanne, Switzerland: Mont Terri Project

2014

Dolder, Florian Dominik; Mäder, Urs; Jenni, Andreas (21 November 2014). Stability of bentonite under high-pH conditions (Unpublished). In: 12th Swiss Geoscience Meeting. Fribourg. 21.-22.11.2014.

Dolder, Florian; Mäder, Urs; Jenni, Andreas; Schwendener, Nicole (2014). Experimental characterization of cement–bentonite interaction using core infiltration techniques and 4D computed tomography. Physics and chemistry of the earth, 70-71, pp. 104-113. Elsevier 10.1016/j.pce.2013.11.002

Jenni, Andreas; Mäder, Urs; Lerouge, C.; Gaboreau, S.; Schwyn, B. (2014). In-situ interaction between different concretes and Opalinus Clay. Physics and chemistry of the earth, 70-71, pp. 71-83. Elsevier 10.1016/j.pce.2013.11.004

Dähn, Rainer; Popov, Dmitry; Schaub, Philippe; Pattison, Philip; Grolimund, Daniel; Mäder, Urs; Jenni, Andreas; Wieland, Erich (2014). In-situ X-ray micro-diffraction studies of heterogeneous interfaces between cementitious materials and geological formations. Physics and chemistry of the earth, 70-71, pp. 96-103. Elsevier 10.1016/j.pce.2013.10.010

Alt-Epping, Peter; Tournassat, C.; Rasouli, P.; Steefel, C. I.; Mayer, K. U.; Jenni, Andreas; Mäder, Urs; Sengor, S. S.; Fernández, R. (2014). Benchmark reactive transport simulations of a column experiment in compacted bentonite with multispecies diffusion and explicit treatment of electrostatic effects. Computational geosciences, 19(3), pp. 535-550. Baltzer Science Publishers 10.1007/s10596-014-9451-x

Mäder, Urs; Jenni, Andreas; Dolder, Florian Dominik (2014). CI Experiment: Sample preparation and sample inventory of the 2nd sampling campaign (2012) for concrete/Opalinus Clay and concrete/MX-80 bentonite interfaces (Arbeitsbericht). St. Ursanne, Switzerland: Mont Terri Project

Mäder, Urs; Eul, A.; Jenni, Andreas; Frieg, B.; Dolder, Florian Dominik (2014). CI Experiment: Sampling by stabilized overcoring for the 2nd campaign (2012) (Arbeitsbericht). St. Ursanne, Switzerland: Mont Terri Project

Jenni, Andreas; Mäder, Urs; Lerouge, C.; Gaboreau, S. (2014). CI Experiment: Synthesis of in-situ interaction for 2.2 y between different concretes and Opalinus Clay (Arbeitsbericht). St. Ursanne, Switzerland: Mont Terri Project

Jenni, Andreas; Mäder, Urs (2014). CI (Cement Clay Interaction) Experiment: SEM/EDX characterisation of concrete/Opalinus Clay interfaces from 2nd sampling campaign and comparison to state after 1st sampling (Arbeitsbericht). St. Ursanne, Switzerland: Mont Terri Project

Jenni, Andreas; Mäder, Urs (2014). CI (Cement Clay Interaction) Experiment: Set-up and first results for modelling of concrete/Opalinus Clay interfaces (Arbeitsbericht). St. Ursanne, Switzerland: Mont Terri Project

2013

Dolder, Florian Dominik; Mäder, Urs; Jenni, Andreas (25 August 2013). Tracking high-pH reaction fronts in MX-80 bentonite using infiltration techniques and 4D CT (Unpublished). In: Goldschmidt Conference. Florence. 25.-30.08.2013.

2012

Dolder, Florian Dominik; Jenni, Andreas; Mäder, Urs (22 October 2012). Experimental characterization of cement-bentonite interaction using core infiltration techniques coupled with 4D X-ray tomography (Unpublished). In: Physics and Chemistry of the Earth. Montpellier. 22 – 25 October 2012.

2010

Jenni, Andreas; Hyatt, N. C. (2010). Encapsulation of caesium-loaded Ionsiv in cement. Cement and concrete research, 40(8), pp. 1271-1277. Elsevier 10.1016/j.cemconres.2009.10.015

Hyatt, N. C.; Jenni, Andreas; Stennett, M. C. (2010). Stability of Cs-Ionsiv in Portland cement blends for radioactive waste disposal. Materials Research Society Symposium Proceedings, 1265, pp. 221-226. Materials Research Society

2009

Hyatt, N. C.; Stennett, M.; Jenni, Andreas; Reid, D.; Maddrell, E. R. (2009). Ceramic formulation and processing design for plutonium disposition. Materials Research Society Symposium Proceedings, 1193, pp. 61-66. Materials Research Society

Mäder, Urs; Jenni, Andreas (2009). CI Experiment: First sampling campaign of the in-situ experiment to recover concrete/Opalinus Clay interfaces after 2.2 years (Arbeitsbericht). St. Ursanne, Switzerland: Mont Terri Project

Jenni, Andreas; Stennett, M. C.; Hyatt, N. C. (2009). Strategies for disposition of separated PuO2: Durability benchmarking Nexia Solutions

2008

Jenni, Andreas; Stennett, M. C.; Hyatt, N. C. (2008). Strategies for disposition of separated PuO2: Reduction of Ce (Pu surrogate) Nexia Solutions

Jenni, Andreas; Stennett, M. C.; Hyatt, N. C. (2008). Strategies for disposition of separated PuO2: Effect of pre-treatment of wasteform precursor batch on cold press and sintering of zirconolite Nexia Solutions

Jenni, Andreas; Stennett, M. C.; Hyatt, N. C. (2008). Strategies for disposition of separated PuO2: Effect of milling on sinter and HIP of zirconolite Nexia Solutions

2007

Zurbriggen, R.; Herwegh, Marco; Jenni, Andreas; De Gasparo, Alex; Holzer, L.; Aberle, T. (2007). The influence of organic additives on the microstructural development and properties of mortars. ZKG International, 60(2), pp. 62-73. Bauverlag BV, Gütersloh

Jenni, Andreas; Stennett, M. C.; Hyatt, N. C. (2007). Strategies for disposition of separated PuO2: Am3+ impurities in Pu feedstock Nexia Solutions

2006

Jenni, Andreas; Zurbriggen, Roger; Holzer, Lorenz; Herwegh, Marco (2006). Changes in microstructures and physical properties of polymer-modified mortars during wet storage. Cement and concrete research, 36(1), pp. 79-90. Oxford: Elsevier 10.1016/j.cemconres.2005.06.001

Scheidegger, A. M.; Vespa, M.; Wieland, E.; Harfouche, M.; Grolimund, D.; Dähn, R.; Jenni, Andreas; Scrivener, K. (2006). Micro-scale chemical speciation of highly heterogeneous cementitious materials using synchrotron-based X-ray absorption spectroscopy. CHIMIA, 60(3), p. 149. Schweizerische Chemische Gesellschaft

Herwegh, Marco; Zurbriggen, R.; Scrivener, K.; De Gasparo, Alex; Kighelman, J.; Jenni, Andreas (2006). A comparison between tile adhesive mortars and resulting microstructures in thin-bed mortars. Tagungsband ibausil, 2, pp. 1059-1066.

Jenni, Andreas; Scrivener, Karen (2006). 28 day strength prediction of concrete: Influence of admixtures W.R. Grace confidental report

2005

Jenni, Andreas; Holzer, L.; Zurbriggen, R.; Herwegh, Marco (2005). Influence of polymers on microstructure and adhesive strength of cementitious tile adhesive mortars. Cement and concrete research, 35(1), pp. 35-50. Elsevier 10.1016/j.cemconres.2004.06.039

2003

Jenni, Andreas; Herwegh, Marco; Zurbriggen, R.; Aberle, T.; Holzer, L. (2003). Quantitative microstructure analysis of polymer-modified mortars. Journal of microscopy, 212(2), pp. 186-196. Wiley-Blackwell 10.1046/j.1365-2818.2003.01230.x

Jenni, Andreas (2003). Microstructural Evolution and Physical Properties of Polymer-Modified Mortars (Unpublished). (Dissertation, University of Bern, Institute of Geological Sciences)

2001

Herwegh, Marco; Jenni, Andreas (2001). Granular flow in polymineralic rocks bearing sheet silicates: New evidence from natural examples. Tectonophysics, 332(3), pp. 309-320. Elsevier