Environmental Life Cycle Analysis of Concrete Utilizing Oyster Shells as Fine Aggregates

초록

The global consumption of seafood has steadily increased owing to rises in income and improved dietary habits, resulting in an increase in seafood byproducts. The recycling rate of shellfish byproducts has remained low, at 19%. To address the issues associated with the disposal of oyster shells, studies have explored the use of oyster shells in concrete blocks, demonstrating that up to 20% of fine aggregates are replaceable. However, most studies have focused on strength analysis, while quantitative evaluations of environmental impacts are scarce. This study conducted a life cycle assessment (LCA) to quantify the environmental benefits of oyster-shell-incorporated concrete blocks, which were compared to those of conventional blocks. Substituting 10% and 20% of fine aggregates with oyster shells reduced the ozone depletion potential (ODP) and photochemical ozone creation potential (POCP) by less than 1%, indicating minor effects. However, it should be noted that oyster shells are predominantly landfilled, and their use as fine aggregate causes landfill-avoidance effects. When these effects were accounted for, reductions were observed across six environmental impact categories. The ODP, eutrophication potential (EP), and POCP were significantly reduced, with 10% substitution achieving reductions of 2.70%, 4.15%, and 2.76%, respectively, and 20% substitution achieving reductions of 5.39%, 8.32%, and 5.52%, respectively. This study emphasizes the feasibility of using untreated oyster shells as substitutes for fine aggregates in concrete blocks and provides a quantitative analysis of the reductions in their environmental impacts. The results serve as an important data reference for promoting the sustainable management and practical utilization of oyster shells. © 2024, Korea Society of Waste Management. All rights reserved.

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