chrissae

• Hov, Sølve; Lopez, Ana Priscilla Paniagua; Sætre, Christian; Long, Michael; Cornelissen, Gerard & Ritter, Stefan (2023). Stabilisation of Soft Clay, Quick Clay and Peat by Industrial By-Products and Biochars. Applied Sciences. 13(16). doi: 10.3390/app13169048. Fulltekst i vitenarkiv Vis sammendrag

  The stabilisation of soft soils using the traditional binders cement and quicklime are known to emit large amounts of carbon dioxide. To reduce this carbon footprint, substitutes such as industrial by-products have been thoroughly tested as viable alternatives for soil stabilisation. However, recent research has also shown that biochar from biomass pyrolysis can in some instances have a positive stabilisation effect and even result in a carbon-negative footprint. This paper presents a laboratory study to investigate the stabilisation effect of five industrial by-products and four types of biochar on three natural Norwegian soils: two clays with low and high water contents and one peat with a very high water content. The soils and binders were characterised by their mineralogical and chemical compositions. The biochars had varying stabilisation effects on the clays when combined with cement, with some negative stabilisation effects, whilst the effect was very beneficial in the peat, with a strength increase of up to 80%. The industrial by-products showed opposite results, with beneficial effects in the clays and a strength increase of up to 150%, but negative stabilisation effects in the peat. Correlating the mineralogical and chemical compositions to stabilisation effects was found to be challenging.

• Hov, Sølve; Lopez, Ana Priscilla Paniagua; Sætre, Christian; Rueslåtten, Håkon; Størdal, Ingvild & Mengede, Martin [Vis alle 7 forfattere av denne artikkelen] (2022). Lime-cement stabilisation of Trondheim clays and its impact on carbon dioxide emissions. Soils and Foundations. ISSN 0038-0806. 62(3). doi: 10.1016/j.sandf.2022.101162. Fulltekst i vitenarkiv
• Helle, Tonje Eide; Kvennås, Marianne; Hamel, Bob; Strand, Stein-Are; Svanø, Geir & Bache, Bjørn Kristian Fiskvik [Vis alle 11 forfattere av denne artikkelen] (2022). Potassium chloride wells used as quick-clay landslide mitigation: installation procedures, cost–benefit analysis, and recommendations for design. Canadian geotechnical journal (Print). ISSN 0008-3674. 59(9), s. 1660–1678. doi: 10.1139/cgj-2021-0230. Fulltekst i vitenarkiv
• Adli, Gabrielle Dublet; Pabst, Thomas; Okkenhaug, Gudny; Sætre, Christian; Vårheim, Anna Merete & Tvedten, Mari Katrine [Vis alle 10 forfattere av denne artikkelen] (2021). Valorisation of partially oxidized tailings in a cover system to reclaim an old acid generating mine site. Minerals. 11(9). doi: 10.3390/min11090987. Fulltekst i vitenarkiv Vis sammendrag

  The reclamation of acid-generating mine tailings typically involves building cover systems to limit interactions with water or oxygen. The choice of cover materials is critical to ensure long-term performance, and partly determines the environmental footprint of the reclamation strategy. The objective of this research was to evaluate if tailings pre-oxidized on-site could be used in cover systems. Column experiments were performed to assess the effectiveness of a cover with capillary barrier effects (CCBE), where the moisture retention layer (MRL) was made of pre-oxidized tailings with little to no remaining sulfides (LS tailings). The columns were submitted to regular wetting and drying cycles, and their hydrological and geochemical behaviour was monitored for 510 days. The LS tailings showed satisfying hydrological properties as an MRL and remained saturated throughout the test. The concentrations of Cu in the drainage decreased by more than two orders of magnitude compared to non-covered tailings. In addition, the pH increased by nearly one unit compared to the control column, and Fe and S concentrations decreased by around 50%. Despite these improvements, the leachate water remained acidic and contaminated, indicating that acid drainage continued to be generated despite a hydrologically efficient CCBE.

• Sætre, Christian; Hellevang, Helge; Dennehy, C. & Dypvik, Henning (2021). Reactive transport modelling of an intra-basalt sandstone reservoir, Rosebank, UK. Scientific Reports. 11(1). doi: 10.1038/s41598-021-86421-w. Fulltekst i vitenarkiv Vis sammendrag

  Abstract The Rosebank field, located in the Faroe-Shetland Basin, contains producible hydrocarbons in intra-basaltic siliciclastic reservoirs. The volcanic-reservoir interface is poorly studied and the geochemical system, as a function of distance from the basalt, is largely unknown. The current paper applies a geochemical model coupling mineral dissolution and precipitation with element diffusion to investigate the geochemical system in time and space from the basalt-sandstone interface. Earlier studies indicate few negative effects on reservoir properties despite the proximity to a reactive volcanic lithology. The causes of this minimal impact have not been studied. The numerical simulations in this study expand on the knowledge demonstrating that precipitation of authigenic phases at the basalt-sandstone interface buffer the formation water solution for key elements, which hamper the transport of solutes and subsequent precipitation of secondary minerals within the reservoir. Saturation index values over the simulated period indicate that precipitation of authigenic phases should not extend beyond the basalt-sandstone interface. This shows that diffusion alone is not enough to reduce the reservoir quality due to increased precipitation of secondary phases. The basalt dissolution rate varies according to the silica concentration. The combined effects on silica concentration by diffusional fluxes, mineral precipitation and dissolution, control the basalt dissolution rate, and there are no differences in the results between high and low basalt reactive surface area.

• Dypvik, Henning; Hellevang, Helge; Krzesinska, Agata Magdalena; Sætre, Christian; Viennet, Jean-Christophe & Bultel, Benjamin Gabriel Rene [Vis alle 13 forfattere av denne artikkelen] (2021). The Planetary Terrestrial Analogues Library (PTAL) – An exclusive lithological selection of possible martian earth analogues. Planetary and Space Science. ISSN 0032-0633. 208. doi: 10.1016/j.pss.2021.105339. Fulltekst i vitenarkiv Vis sammendrag

  The Planetary Terrestrial Analogues Library (PTAL) is a dedicated lithological collection that currently consists of 102 terrestrial rock samples selected to be possible Mars analogues. The ultimate goal is improving future remote mineralogical and petrological analysis on Mars and other planetary bodies based on selected analysis such as Near- Infrared Reflectance Spectroscopy (NIR), Raman spectroscopy, Laser Induced Breakdown Spectroscopy (LIBS) and X-ray diffraction (XRD). Most international standards applied in the remote martian mineralogical and petrological analysis have so far been based on single, pure mineral analysis, with minimal interferences from other naturally occurring minerals. Here we present detailed lithological sample evaluations based on field appearance along with optical and XRD analysis of key terrestrial rock types. The detailed mineralogical and petrological descriptions give good basis for more complete lithological understanding. In combination with NIR, LIBS and Raman analysis of the very same samples PTAL aims at improving mineralogical and petrographical information from future rovers on Mars e.g. NASA's Mars2020-Perseverance and ESA and Roscosmos's ExoMars - Rosalind Franklin. The PTAL sample collection covers exclusively collected volcanic, magmatic and various sedimentary rocks and regoliths from well-known locations all over the world. These samples have a general composition comparable to what is currently known from Mars. The strength of this sample collection is its origin as common whole rock samples, in which minerals occur in their natural settings. It thereby allows studying possible detection interferences and a comparison of the sensitivity of the different techniques. The collection, in addition, forms the base for various alteration studies to better understand and explain alteration and weathering conditions on Mars. The complete results and sample preparations will be available to all scientists interested.

• Sætre, Christian; Hellevang, Helge; Riu, Lucie; Dypvik, Henning; Pilorget, C & Poulet, Francois [Vis alle 7 forfattere av denne artikkelen] (2019). Experimental hydrothermal alteration of basaltic glass with relevance to Mars. Meteoritics and Planetary Science. ISSN 1086-9379. 54(2), s. 357–378. doi: 10.1111/maps.13214. Fulltekst i vitenarkiv Vis sammendrag

  Phyllosilicates, carbonates, zeolites, and sulfates on Mars give clues about the planet's past environmental conditions, but little is known about the specific conditions in which these minerals formed within the crust and at the surface. The aim of the present study was to gain increased understanding on the formation of secondary phases by hydrothermal alteration of basaltic glass. The reaction processes were studied under varying conditions (temperature, pCO2, water:rock ratio, and fluid composition) with relevance to aqueous hydrothermal alteration in fully and partly saturated Martian basalt deposits. Analyses made on reaction products using X-ray diffraction (XRD) and scanning electron microscope (SEM) were compared with near infrared spectroscopy (NIR) to establish relative detectability and spectral signatures. This study demonstrates that comparable alteration minerals (phyllosilicates, carbonates, zeolites) form from vapor condensing on mineral surfaces in unsaturated sediments and not only in fully water-saturated sediments. In certain environments where water vapor might be present, it can alter the basaltic bedrock to a suite of authigenic phases similar to those observed on the Martian surface. For the detection of the secondary phases, XRD and SEM-EDS were found to be superior to NIR for detecting and characterizing zeolites. The discrepancy in detectability of zeolites between NIR and XRD/SEM-EDS might indicate that zeolites on Mars are more abundant than previously thought.

• Sætre, Christian; Hellevang, Helge; Dennehy, Cleona; Dypvik, Henning & Clark, Samantha (2018). A diagenetic study of intrabasaltic siliciclastics sandstones from the Rosebank field. Marine and Petroleum Geology. ISSN 0264-8172. 98, s. 335–355. doi: 10.1016/j.marpetgeo.2018.08.026. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Sætre, Christian; Dypvik, Henning & Hellevang, Helge (2016). Basaltic glass alteration and its reservoir importance. Fulltekst i vitenarkiv
• Sætre, Christian; Dypvik, Henning; Hellevang, Helge & Werner, Stephanie C. (2016). Earth Mars Analogues - Linking experimental and Martian clays. Fulltekst i vitenarkiv

Se alle arbeider i NVA