A Digital Twin Framework for Standardized Production of Bio-Based Composites in the Circular Built Environment

The building and construction sector accounts for approximately 37% of global CO2 emissions and nearly 50% of material extraction, driving urgent demand for sustainable material alternatives. Bio-based composites derived from recycled waste and biomass offer a promising pathway toward a circular built environment, yet their production remains hampered by biomass batch variability, the absence of standardized process protocols, and sensitivity to environmental conditions. Digital twin (DT) technology, with its capacity for real-time monitoring, predictive simulation, and closed-loop optimization, has been widely applied in building operation and maintenance but has received scant attention at the material production end. This paper addresses this cross-disciplinary gap by proposing a five-layer DT conceptual framework for the standardized production of bio-based composites, developed using the Design Science Research paradigm. The framework comprises a physical layer, a data acquisition layer, a virtual model layer, a decision and control layer, and a lifecycle-circularity layer, mapped onto five production stages from raw material to recovery. An observe–simulate–decide–adjust (OSDA) closed-loop mechanism runs across all stages. A synthetic-data simulation of the OSDA closed-loop mechanism across 200 virtual production batches illustrates a 48.5% reduction in performance variability (95% CI: 42.9–53.7%) and a 99.0% reduction in the reject rate (95% CI: 96.9–100.0%) in a biochar–recycled-HDPE panel scenario; sensitivity analysis confirms robustness across a range of moisture penalty assumptions. These results are derived from a simplified regression model and constitute numerical proof-of-concept rather than empirical validation. The study contributes a structured, standards-aligned architecture that bridges digital twins and circular building materials, providing a methodological reference and conceptual justification for industry stakeholders.