Towards Circular Economy through Industrial Symbiosis in the Dutch Construction Industry: A Case of Recycled Concrete Aggregates

Keeping concrete at construction value

In this article, we looked at a persistent contradiction in Dutch construction. Most construction and demolition waste is recycled, yet a large share of old concrete is still down-cycled into road foundations instead of returning to new concrete products. That avoids landfill, but it does not retain the material’s full value or reduce demand for newly extracted aggregates as much as it could. We wanted to understand what would make recycled concrete aggregates a reliable part of a more circular construction economy.

Our case is Twente, where we examined how primary aggregates might be replaced in new concrete at scale. We approached this through industrial symbiosis: collaboration in which one actor’s waste or by-product becomes another actor’s resource. In construction, that means demolition firms, recyclers, concrete producers, contractors and clients all have to coordinate. Materials need to arrive at the right place, at the right time, with the required quality and a price that makes cooperation worthwhile for everyone involved.

Making a dispersed chain visible

To understand those relationships, we combined Geographic Information Systems with agent-based modelling. GIS helped us map material flows, facilities and demand across the region. The agent-based model represented the supply-chain actors as independent decision-makers negotiating under different economic conditions. This let us examine the changing relationship between supply and demand rather than relying on a static annual waste figure.

We found what we call an implicit form of industrial symbiosis. Recycled concrete does not move between two neighbouring factories in the classic industrial-symbiosis model. Demolition, processing and new construction can be separated by time and distance, while the recycling facility becomes a crucial intermediary. The cooperation may be happening in practice without being recognised, organised or supported as a shared system.

For us, that observation has practical consequences. Technical feasibility is only one part of circular construction. If the economic benefits are unclear, logistics are difficult or value is not shared fairly, recycled aggregates will remain hard to use even when their environmental case is strong. Our modelling offers businesses and policymakers a way to explore those conditions. More broadly, we hope it shifts the focus from recycling rates alone to the coordination needed to keep concrete in circulation at its highest possible value.