Probabilistic circular economy assessment for infrastructures considering time-variant influencing factors

Abstract

Circular economy (CE) is increasingly used to accelerate the transition of infrastructure towards circularity and sustainability. However, a practical and accurate assessment procedure considering the stochasticity of influencing factors for CE implementation in infrastructures has not yet been fully developed. This paper first develops a CE index and models for predicting the CE performance of infrastructure over time based on functional circularity, embodied carbon and embodied energy. Time-dependent reliability theory is then employed to account for the randomness of factors, such as structural degradation rates, embodied impact coefficients, recycling rates and recycling efficiency. The proposed methods are demonstrated through a case study of three concrete structures with design for disassembly (DfD) and different recycled aggregate substitution rates. Results of the case study suggest that the structure with DfD and natural aggregate has a lower probability of unsatisfactory CE performance. The results will guide the future implementation of CE in infrastructures.