Quantifying environmental impacts of circular economy approaches through life cycle assessments: A case study in materials science on ceramic matrix composites

The circular economy and the use of lightweight composites are two promising concepts for reducing resource consumption in future products. While circular economy approaches close loops and minimize resource loss, the application-specific design of composites reduces material demand. This study combines these concepts by discussing circular economy approaches for the lightweight material class of ceramic matrix composites. Suitable approaches were identified and compared using life cycle assessments to determine the environmental impact reductions. Twenty-two circular economy approaches were identified for the primary processing routes on four different life-cycle stages (circular inputs, external and internal loops, and end-of-life (EoL)). The most significant reduction is achieved by alternative input materials and EoL options, especially by using recycled carbon fibers, followed by various EoL options, such as recycling and repair processes. Combining several circular economy approaches reduces the current global warming potential of processing routes for CMC by up to 94%.