2. Theoretical Frameworks of Closed-Loop Material Flows
Theoretical conceptualisations of circular construction diverge fundamentally between architectural preservation models and systemic supply-chain frameworks. On the one hand, building-level strategies prioritize the retention of embodied energy and historical assets through adaptive reuse, arguing that extending the operational lifespan of existing structures constitutes the most effective barrier against raw material extraction (Foster, 2019). This perspective conceptualises circularity through physical permanence and localised architectural adaptation, treating existing buildings as static material reservoirs. In contrast, broader waste-management syntheses conceptualise circularity as a systemic flow problem, highlighting the structural breakdown between end-of-life deconstruction, secondary processing, and regulatory acceptance across industrial networks (Ababneh et al., 2023). Under this systemic paradigm, the bottleneck does not reside in architectural longevity alone, but rather in the fragmented logistics and lack of standardization governing secondary material exchanges. Furthermore, logistical frameworks emphasize that closed-loop models remain theoretically incomplete without accounting for material transport dynamics, as the environmental costs of spatial relocation can offset the ecological gains of material recycling (Kiani et al., 2025). Synthesizing these perspectives reveals that whereas architectural approaches focus on micro-level structural preservation, industrial ecology models demand macro-level transport optimization and supply-chain integration to realize viable closed-loop systems.