Comprehensive evaluation of the environmental performance and durability of biochar-incorporated concrete

초록

To achieve global carbon neutrality, the construction industry is increasingly focused on reducing the carbon footprint of cement-based materials. However, comprehensive evaluations of biochar-incorporated concrete integrating long-term mechanical performance, freeze-thaw durability, and environmental impact remain limited. To address these issues, this study presents a comprehensive experimental evaluation of wood-based biochar as an alternative supplementary cementitious material (ASCM) in concrete. The physical characteristics of the biochar were analyzed using scanning electron microscopy (SEM), SEM-EDX, and Brunauer-Emmett-Teller (BET) analyses, and the chemical characteristics were evaluated using XPS. Concrete performance was evaluated in terms of mechanical properties (compressive strength, flexural strength, and static modulus), freeze-thaw durability with quantitative image-based surface analysis, and a life cycle assessment (LCA) was performed to quantify global warming potential (GWP). The results indicate that concrete containing 5% biochar achieved the target design strength of 24 MPa, whereas 7% replacement resulted in a compressive strength reduction of up to 35.5% compared to the plain mix. After 300 freeze-thaw cycles, the 5% biochar mixture maintained a durability factor of 96.8% and reduced the increase in surface scaling and increase in void count by approximately 74 and 72%, respectively, compared with the plain specimen. LCA results revealed that increasing the biochar replacement ratio reduced GWP, with up to a 27.7% reduction at 7% replacement. Considering both mechanical performance and environmental impact, a biochar replacement range of 3-5% was identified as optimal. These findings demonstrate that wood-based biochar is a viable ASCM for sustainable and low-carbon concrete construction.

키워드