Decisions on recycling: Construction stakeholders’ decisions regarding recycled mineral construction materials

Construction and demolition (C&D) waste, being already the largest waste fraction in industrialized coun- tries, is expected to increase in the future. C&D waste recycling has been considered to be a valuable option not only for minimizing C&D waste streams to landfills but also for mitigating primary mineral resource depletion. Even though the use of recycled mineral construction materials (RMCM) is regulated and successful application examples are available, construction stakeholders do not yet broadly apply them. Although various criteria hindering a transition towards a broader application of RMCM have been identified, it is yet unknown how these criteria differ among decisions, stakeholders and applications. We therefore analyze construction stakeholders’ behavior, and decision-making regarding RMCM for the construction material market in Switzerland. Stakeholders’ decision-making was quantified with the ana- lytical hierarchy process (AHP) in a survey in combination with their behavior. The results demonstrate the importance of stakeholder interaction, i.e. most stakeholders decide which material to apply based on interaction with other stakeholders e.g., recommendations and specifications. However, the initial general specification by awarding authorities that construction should be sustainable has little relevance to the subsequent material decisions. On the contrary the role of the recommendation of engineers, have a high impact on the subsequent decisions by the other stakeholders. Results also confirm that RMCM are broadly accepted in civil engineering (CE), whereas in structural engineering (SE) RMCM are still a niche product. The good alignment of the outcome of decision modeling with observed behavior shows the usefulness of analyzing decision-making with AHP