Life cycle assessment-based multi-dimensional evaluation of embodied carbon in concrete structures and structural scheme optimization

To improve the decision-support capability of embodied carbon assessment for concrete structures, this study proposes a structural-level multidimensional low-carbon evaluation framework based on life cycle assessment (LCA). An embodied carbon accounting model covering the stages of material production, transportation, and concrete manufacturing was established, and a multidimensional comprehensive low-carbon evaluation system at the structural level was developed. A multi-storey public building was selected as the case study for analysis. The results indicate that the carbon emissions of the case project are mainly dominated by reinforcement works, floor systems, and foundation systems, among which reinforcement accounts for 44.72% of the total emissions. The overall low-carbon performance of the project is classified as level III, with a comprehensive evaluation score of 0.546. Among different structural systems, the frame–shear wall structure achieved the highest comprehensive evaluation score (0.603), demonstrating the best low-carbon performance. Optimization scenario analysis shows that low-carbon reinforcement adoption and binder material optimization are the most sensitive emission reduction pathways. Under the synergistic effects of multiple optimization measures, the carbon emissions of the main structural system can be reduced by up to 20.12%, while the comprehensive evaluation score can be improved to 0.691. This study provides a reference for embodied carbon accounting, low-carbon decision-making optimization, and engineering applications of concrete structures.