Multiobjective optimization design of ternary cementitious materials containing cement, blast furnace slag, and oyster shell powder: A study on mechanical performance, durability, and sustainability

초록

Most existing low-carbon concrete design strategies concentrate on optimizing compressive strength and reducing carbon emissions, yet they commonly overlook durability indicators and broader sustainability considerations. Such omissions may increase the likelihood of steel corrosion and ultimately hinder the development of a truly comprehensive sustainability-driven design. To address these gaps, this study proposes a systematic framework for optimizing the design of supplementary cementitious material (SCM) systems to achieve the optimal mix proportion for low-carbon concrete, in which blast furnace slag (BFS) and waste oyster shell powder (OSP) are used to partially replace ordinary Portland cement (OPC). For the first time, the simplex centroid method (SCMd) was integrated with life cycle assessment (LCA). Based on the SCMd, preliminary mixture proportions were developed and experimentally verified through both macro-scale and micro-scale tests. In parallel, a full LCA was conducted to quantify key environmental impact indicators, including global warming potential (GWP), abiotic depletion (AD), acidification potential (AP), eutrophication potential (EP), photochemical ozone creation potential (POCP), and ozone depletion potential (ODP). Subsequently, Design-Expert software was employed to carry out multi-objective optimization and statistical analysis on the preliminary mix proportions, with the goal of identifying an optimal formulation that balances mechanical performance, durability, and environmental impact. Finally, experimental validation showed that the deviation between the optimized mixture obtained from laboratory tests and the simulated results was less than 5%, confirming the accuracy and practicality of the proposed method. Overall, the study demonstrates that integrating SCMd with LCA enables a robust multi-objective optimization of low-carbon concrete and provides a scientific foundation and practical pathway for its regionalized design and large-scale implementation.

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