Supply chain mapping for concrete recycling

Abstract

Concrete is the most widely used artificial material, and shapes the largest area of the built environment in the Netherlands. Its waste stream is responsible for the highest percentage of construction and demolition waste and fundamental knowledge for affordable high-grade applications from old concrete has already been introduced. More precisely, the development of technologies that can separate End-of-life (EoL) concrete into its constituents, facilitates its recycling and reuse into new building materials and not in low-quality applications. However, in terms of concrete recycling, there is insufficient communication of the novel technologies in the construction sector and supply chain systems are not introduced in real-world problems. The current research focuses on a closed-loop approach concerning the production of conventional concrete based on a supply chain design. Specifically, the conventional and closed-loop supply chain of the production of concrete are designed in accordance with the SCOR Model. The main differences are identified and a ‘Concrete-to-concrete Recycling Plant’ is proposed as a solution to the EoL problem. It argues to change completely the conventional supply chain of concrete, and therefore recommendations for its future location in an urban environment are given. Additionally, a calculation tool regarding the recycling plant is developed in order to evaluate the suggested solution. The present study demonstrates that for each category of concrete, either prefabricated or site-cast, a recycling plant should be located next to the prefabricated or mortar industry in order to diminish transportation and inventory costs, as well as take advantage of the operating speeds of the novel technologies that compose the plant. Results indicate that a recycling plant is in accordance with the current market conditions and constitutes an efficient solution to the EoL concrete treatment by making concrete a circular material. Further research is required on a laboratory scale in order to collect quantitative data, communicate the results, and consequently, increase the awareness and acceptance of recycled aggregates in the construction sector.