Betonggrund kontra Koljern-grund : en analys av kostnader och miljöpåverkan på en förskola i två våningar

Concrete is widely used in modern construction, particularly for building foundations. However, the materials included in concrete constructions have a significant negative impact on the environment. To mitigate this, the construction industry must explore more environmentally friendly alternatives. This study focuses on a relatively new technique called the Koljern foundation, which replaces traditional reinforced concrete slabs with a combination of cellular glass and lightweight steel beams. The cellular glass used in this technique is made up of approximately 60% recycled glass and possesses excellent insulation and strength properties. The report compares the cost and environmental impact of the traditional concrete slab with the Koljern foundation. Other factors considered in this study includes construction time, waste, and potential for reuse. A case study was conducted on a preschool building in Gunsta, serving as a reference for the analysis. Climate and cost calculations were performed using Bidcon software, along with manual calculations. The Gunsta preschool utilized green concrete for its foundation slab, and this is also included in the comparison to provide a broader perspective. The results demonstrate that opting for a Koljern foundation reduces environmental impact by 50% compared to a traditional concrete foundation, although costs increase by 103%. When compared to green concrete, the Koljern foundation has a nearly 42% lower carbon footprint but incurs a cost increase of 101%. Green concrete has a nearly 13% lower carbon footprint compared to traditional concrete. The price difference between green and traditional concrete is only 1%, with green concrete being the more expensive option. Furthermore, the Koljern foundation generates minimal waste due to the prefabrication of Koljern elements by Evia AB. In conclusion, the result of the study shows that a slab-on-grade foundation using the Koljern technique can be a possible alternative to the traditional concrete solution, depending on the specific project's objectives and goals. Despite higher costs, the Koljern foundation greatly reduces environmental impact, construction time, and enables high reusability.