Reuse of Secondary Materials

Abstract

Over the years, the extraction and consumption of raw materials have increased radically, with a 60% increase since 1980. About one-fifth of the material extracted worldwide ends up as waste, corresponding to 12 billion tonnes (Gt) of waste per year. To tackle the increasing consumption and waste in the economy, the Netherlands government introduced the ‘Circular Netherlands in 2050’ plan in 2016, aiming to reduce 50% consumption of primary resources by 2030 and 100% by 2050. As a result, 95% of the secondary materials from the end-of-service-life demolition process of commercial and non-residential buildings in the Netherlands are recycled. However, comparing different R-option on an R-hierarchy model shows a gradual decrease in value retention of the material with recycling. The research focuses on shifting the facade industry from recycling to reuse by moving up the ladder to retain a higher material value. The thesis explores the research question through design research to support the strategic design and development for reusing secondary materials.

Two cases, ODS Jansen and Buurman, are analyzed for their secondary material flow of steel and timber, respectively, through interviews and inventory analysis. A reuse process is systemized and further elaborated on stakeholders’ role (what, how, and when) to support it. A set of design explorations for facades is done to identify potential scenarios for reuse, considering the functional and technical factors that define office building facades in the Netherlands. The proposed hybrid system using the primary and secondary material stream is compared to an alternate non-reuse scenario. The assessment presented a 60% restorative material flow with the MCI score and a saving of 91% for embodied energy (renewable and non-renewable) and 93% for Global Warming Potential with LCIA with reuse of steel mullions in the curtain wall facade.

The research concludes that the reuse of materials for the same function is feasible through R-strategies of direct reuse, repair, refurbish, and remanufacture as long as the embodied value of the material does not change. Furthermore, it is essential to match the demand and supply of secondary materials for establishing the reuse practice at an industrial scale. For this, original material suppliers must take up the role of material resellers in the market. At the same time, manufacturers and architects need to shift their mindset from the use of abundant to ‘scarce’ resources by altering the design process with the three stages of material sourcing, material processing, and material reuse. Sufficient safety margins in design, material inspectors to overcome lack of information, working with the form of supply, changing design habits, and using materials differently are proposed as design solutions to organize the reuse of materials for facades. Lastly, when the existing materials decline, reuse will happen through materials entering the market now. It is essential to consider their design for future reuse to ensure this flow does not face the same set of challenges.