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FRINATEK-Fri prosj.st. mat.,naturv.,tek

Sustainable Stable Ground

Alternative title: Bærekraftig Grunn

Awarded: NOK 12.5 mill.

Soft soil, such as marine clay, gives challenging conditions for infrastructure development in many places in the world. As an example, it is estimated that more than 80 percent of all cultivated land, settlements and infrastructure in Trøndelag and at Østlandet (south of Mjøsa) is located below the marine limit. Thus, large infrastructure development projects in these areas require enormous amounts of ground stabilization. Due to the cost effectiveness, ground improvement by deep-mixing using lime-cement is widely used. However, considering the huge amount of lime and cement used in ground improvement projects and the carbon intensity of lime and cement production, the contribution from these geotechnical works to the carbon inventory of large infrastructure projects in Norway (and in the world in general), is extremely high. Often, it is the largest single contributor. This project will work on developing an alternative effective sustainable ground improvement technology. The project is interdisciplinary across scales from fundamental chemistry, starting at nano-scale, through engineering scale, ending at industrial ecology, to assess life cycle impact.

Soft soil, such as marine clay, gives challenging conditions for infrastructure development in many places in the world, which requires enormous amounts of ground stabilization. In Norway the major challenge is quick-clay (non-swelling illite). Due to the cost effectiveness, ground improvement with lime-cement stabilization using deep-mixing technology is widely used. However, considering the huge amount of lime and cement used in ground improvement projects and the carbon intensity of lime and cement production, the contribution from these geotechnical works, to the carbon inventory of large infrastructure projects in Norway (and in the world in general), is very high. Many times, it is the largest single contributor. At the same time waste from concrete and bricks, and ashes are the largest contributors to the masses being deposited in Norway. These materials have a great potential as additives in the stabilizing technology. We aim to radically change the deep-mixing technology by introducing sustainable alternative stabilizers based on solid wastes and creating a circular economy around this technology. To achieve this goal, we need interdisciplinary research with a bottom-up combined experimental and modelling approach, across the scales and disciplines. At nano and sub-nano scale, we will employ a combination of numerical and experimental work starting with the water and ions interactions at illite-clay particle surfaces. At micro scale, we will combine thermodynamic modelling with experiments to investigate how the interactions between illite-clay and cementitious materials contribute to the microstructure and strength development. At macro scale, representative elements of stabilized clay will be tested and full-scale geotechnical problems simulated. Finally, we will calculate and compare the total environmental impacts of the alternative technologies.

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FRINATEK-Fri prosj.st. mat.,naturv.,tek