Circular economy by upgraded aggregates and soil

Purpose and goal

The project aim and objective were to investigate how upgraded excavated soils may replace aggregates in constructions and propose suitable methods for pilot studies. Wet separation may extract 50 % of excavated soils to aggregates and, in theory, cover the whole demand at a construction site. Increased circularity decreases transport and costs but requires a change in mindset with the building industry and environmental authorities to accept recycled materials.

Expected results and effects

The proportions excavated soil to aggregetes at a site is 2:1 and about 50 % the soils can be used as aggregates. Wet separation has good potential to refine mixed materials but the end product needs to meet quality standards. A site at Malmö has been picked for a pilot study and sites in northern Stockholm and Sundsvall will be investigated further. Circular ekonomy demands circular flows of materials but also a change from linear value chains to a network approach where indirect actors are involved. Gender specific norms in industry and authorities were identified.

Planned approach and implementation

Methods for refining soils were identified and assessed. Wet separation was deemed promising. Analyses of input and output material were compared to technical and environmental standards. The flux of aggregates and soil in Skåne, northern Stockholm area and Sundsvall were assessed and nodes for upgrading sites were identified. Researchers in equality held a workshop with the project. A dialogue was held through the project with Trafikverket och Vallentuna municipality, representing end user and authorities.