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Technical University of Crete
Technical University of Crete
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| URI: | http://purl.tuc.gr/dl/dias/CC051563-8906-494F-A68E-B11C17C57E41 | ||
| Year | 2023 | ||
| Type of Item | Master Thesis | ||
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| Bibliographic Citation | Dimitra Vathi, "Stabilization and improvement of geotechnical properties of marly soils through alkali activation", Master Thesis, School of Mineral Resources Engineering, Technical University of Crete, Chania, Greece, 2023 https://doi.org/10.26233/heallink.tuc.96367 | ||
| Appears in Collections |
The most commonly used binders for soil stabilization are Portland cement and lime. However, due to the high carbon footprint of the cement production recent research efforts focus on the use of other more environmentally friendly binders. The present MSc thesis aims to assess the alkali activation potential of marly soils, also after mixing them with slag or metakaolin at various ratios. The marly soils were obtained from the area of Ptolemais in NW Greece. The slag used in the present study derived from an electric arc furnace during the production of ferronickel (FeNi) at 1450 oC. Metakaolin was produced from the calcination of kaolin at 750 oC. The activating solution used was a mixture of NaOH or KOH and Na2SiO3 solutions at 1:1 ratio.The effect of various operating parameters, including the molarity of NaOH / KOH (2 to 8 moĿL-1), curing temperature (25 to 80 oC), curing period 24 hours and ageing period (7 or 28 days) on the compressive strength of the produced alkali activated materials (AAMs) was explored.The experimental results indicate that alkali activation of mixtures of marly soil with slag or metakaolin at ratios 70:30 is a feasible option for the stabilization of clayey soils and the produced specimens acquire compressive strength that exceeds 14.5 MPa. When the ratio of marly soil:slag is 50:50 the compressive strength of the produced specimens obtains its max. value, 23 MPa. Similar results were obtained from the alkali activation of mixtures of marly soils and metakaolin. The max. compressive strength in this case was 18.5 MPa.Χ-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to elucidate the mineralogy and the microstructural characteristics of the produced specimens that took place during AAM synthesis.
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