Assessing the impact of technical innovation on circular economy in the built environment by using cMFA-based system dynamics approach

The built environment plays a significant role in material consumption and CO2 emissions, necessitating a proactive shift towards a circular economy (CE). Technical innovations (TIs) are recognized as one of the key drivers in advancing the circularity of the built environment. However, the comprehensive understanding of TIs' influence on the lifecycle and metabolism of construction materials is yet to be explored. Concrete, being a vital construction material, holds particular significance in assessing the effectiveness of CE strategies in the built environment. Hence, this study develops a continuous material flow analysis-based system dynamics model to analyze the impact of TIs in concrete components and construction processes on the CE, adopting a perspective that aligns with real-world logic, thereby reducing the complexity of the dMFA method. Our findings demonstrate that the adoption of different TIs can enhance circularity and resource efficiency within the system by influencing the four circular flows (4Rs). Under stable stock conditions, the combined application of these TIs can yield a maximum reduction of 71 % in inflows and prevent 65 % of natural stock resource losses attributable to their influences on circular flows, as compared to the reference scenario devoid of TIs. Nevertheless, it is important to note that the scenario contributing the highest circular flows does not necessarily optimize resource savings. Therefore, when devising CE strategies, careful consideration should be given to the underlying impacts of circular flows rather than solely focusing on maximizing the flows themselves. These results, in conjunction with geographical spatial features, can guide the design of appropriate technological interventions tailored to the local built environment, thereby enhancing the efficiency of CE strategies. However, as the data utilized in this paper are derived from literature, we believe that further case studies are warranted to refine these general findings and mitigate the limitations in both quantity and quality of data, thereby enhancing their contextual relevance.