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Title |
Manufacture and Mechanical Properties of Silica Fume-Coated Biochar-Based Lightweight Aggregate
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Authors |
우진석(Jin-Seok Woo) ; 정재용(Jae-Yong Jeong) ; 이진희(Jin-Hui Lee) ; 윤현도(Hyun-Do Yun) ; 박완신(Wan-Shin Park) ; 최원창(Won-Chang Choi) |
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DOI |
https://doi.org/10.4334/JKCI.2026.38.1.071 |
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Keywords |
바이오차; 잔골재; 시멘트 기반 복합체; 실리카흄; 기계적 특성 biochar; fine aggregate; cement-based composite; silica fume; mechanical property |
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Abstract |
The construction industry faces serious environmental challenges, including excessive CO2 emissions and the depletion of natural aggregates, with approximately 39 % of global carbon emissions attributed to construction activities. In this context, biochar?a carbon-rich byproduct with potential for carbon sequestration and structural reinforcement?has emerged as a promising alternative construction material. This study presents the development of a biochar-based lightweight aggregate (BA) utilizing silica fume (SF) as a binding agent. The BA was manufactured through drying and grinding processes in accordance with the KS F 2527 standard. Its physical properties and structural suitability were evaluated, and the mechanical performance of mortar incorporating BA was assessed under 14-day and 28-day curing conditions. The results demonstrated that BA exhibited significantly improved physical strength and a 70~80 % reduction in water absorption compared to uncoated biochar (BC). Notably, the SF30 aggregate achieved a crushing strength of 2.8 MPa, representing around 55 % improvement over commercial lightweight aggregate (LWA), which had a strength of 1.8 MPa. Mortar tests further confirmed the superior performance of BA: mortar incorporating SF30 achieved a compressive strength of 46.2 MPa after 28 days of curing, marking a 204 % increase compared to BC mortar (15.2 MPa) and a 63 % increase compared to LWA mortar (28.2 MPa). Additionally, the specimen recorded a high compressive energy of 205.3 J, indicating excellent energy dissipation capacity, ductile fracture behavior, and favorable microstructural characteristics. Analysis of stress?strain curves revealed that BA mortar exhibited a more stable and gradual failure pattern, suggesting advantages in structural durability and resilience. Overall, this study experimentally demonstrates that biochar can serve not merely as an additive but as a structurally viable lightweight aggregate, highlighting its potential as a high-value, eco-friendly construction material.
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