Oppgavenr: MSA11
Tilknyttede emner: TBA4171 - Bygnings- og materialteknikk, videregående kurs
Bakgrunn:
In Norway, a considerable part of future infrastructure projects will be carried out in areas where soft soil deposits such as peats or quick clays are encountered, including InterCity Sandbukta-Moss-Såstad and E6 Kvithammar-Åsen. The most common ground improvement method for these challenging soils is dry deep mixing in which lime, cement or a mixture of both is added to the soil to improve its strength and deformation properties. These stabilisation works can significantly contribute to the environmental impact of infrastructure projects. For instance, at the E6 Klett project 26% of the overall carbon dioxide (CO2) emissions can be related to ground improvement works (Juvik et al. 2019). Nowadays, there is an increasing focus on reducing greenhouse gas emissions during the development of construction and infrastructure projects. For example, Statens vegvesen and Bane NOR aim to reduce the greenhouse gas emissions of their construction projects by 40% in 2030. This implies that there is an urgent need to develop more sustainable alternative methods to stabilise typical Norwegian soils.
While most research aimed at optimising the content of typical binders such as lime and cement, there is a lack of studies that investigated alternative materials. The purpose of this project and master studies will be to investigate the feasibility of using more sustainable materials such as biochar, zinc slag, ladle furnace slug and biomass ashes, for example, to improve the geotechnical properties of sensitive clays and peat.
Kort beskrivelse av oppgaven:
The main tasks of this project will be to conduct a laboratory study to understand the effects of mixing these alternative materials into soils and binder/soil mixtures. First, this will involve characterising the chemical and physical properties of these alternative materials. Second, different mixtures of the alternative materials, binder and soil will be prepared and typical geotechnical properties (e.g. shrinkage limit tests, plasticity limit tests, pH and unconfined compressive strength (UCS) tests) will be quantified. Third, different performances of these mixtures will be analysed by studying their microstructure and chemical composition using scanning electron microscopy (SEM) and X-ray powder diffraction tests. Finally, a LCA-analysis will be carried out to evaluate the sustainability of using these alternative materials to improve soils.
Soil samples, binders and alternative materials will be provided. The laboratory work will be carried out at NTNU Geotechnics Laboratory and other relevant laboratories in Gløshaugen campus might be also suggested.
Antall studenter på oppgaven: 1-4
Kontaktperson ved IBAT: rolf.bohne@ntnu.no
Eksterne samarbeidspartnere:
NGI, Priscilla Paniagua and Stefan Ritter