Towards Circular Economy through Industrial Symbiosis in the Dutch construction industry: A case of recycled concrete aggregates

Since 95% of the Construction and Demolition Waste (CDW) is down-cycled and the material value is not effectively recovered, the Dutch construction industry strives for implementing Circular Economy (CE). From the recycling/reusing perspective, a key enabler towards CE is Industrial Symbiosis (IS). Although IS has been widely applied in manufacturing industries, its implementation is unclear in the construction industry. Particularly, the potential IS economic convenience is hard to predict in the highly fragmented construction supply chain. This study explores the IS based on the Recycled Concrete Aggregates (RCA) in the context of a concrete waste supply chain in the Twente region of the Netherlands. The research tackles with the CE challenge of lacking economic incentives by investigating the Industrial Symbiosis Network (ISN) emerged by replacing Primary Concrete Aggregates (PCA) with RCA. An Agent-Based Modelling (ABM) approach is proposed by integrating Geographic Information Systems (GIS) to present the dynamic supply-demand of RCA. Besides, supply chain actors are simulated as negotiable agents in a platform model to reveal the IS collaboration dynamics under different economic scenarios. It is found that the IS exists in the construction industry but only in an implicit manner because the RCA treatment requires the collaboration of multiple actors across substantial temporal and spatial differences. The study enriches the IS taxonomy by defining Implicit IS and provides instruments to support the decision-making of business collaborations and policy-making for a circular construction industry.