This study investigated the influence of nanobubble water generated using carbon dioxide (CO₂) and oxygen (O₂) gases on the physical and chemical performances of cement-based materials, including mortar and concrete. Nanobubbles, defined as gas bubbles with diameters of less than 100 nm, exhibit high surface energy, prolonged stability in aqueous environments, and enhanced chemical reactivity. These properties promote accelerated cement hydration and the development of a refined microstructure. In particular, carbon-dioxide-based nanobubble water facilitates in situ calcium carbonate formation within the cement matrix, contributing to microstructural densification and offering a promising route for permanent carbon dioxide sequestration. Oxygen-based nanobubble water was used as the control because of its stable generation and measurable concentration. Mortar and concrete specimens were prepared using nanobubble water with various gas types and concentrations. The stability of the nanobubble water was evaluated using zeta potential and particle size distribution analyses. The mortar tests included flow and setting time evaluations, whereas the concrete tests consisted of slump, air content, compressive strength at different curing ages (3 and 28 d) and rapid chloride ion penetration resistance measurements. The results showed that carbon-dioxidebased nanobubble water effectively accelerated early hydration, improved early compressive strength, and reduced chloride ion permeability, indicating improved long-term durability. In contrast, oxygen-based nanobubble water resulted in moderate improvements in workability and strength development. These results suggest that the incorporation of nanobubble water, particularly carbon-dioxide-based nanobubble water, into cementitious systems can improve the material performance while supporting carbon-neutral construction through integrated carbon dioxide utilization.

ABSTRACT
1. 서론
2. 이론적 배경
    2.1. 탄소중립 및 CCU기술
    2.2. 나노버블
    2.3. 혼화제
3. 실험계획 및 방법
    3.1. 실험계획
    3.2. 사용재료
    3.3. 배합설계
    3.4. 실험방법
4. 실험결과
    4.1. 나노버블워터 제타전위 및 입도분석 실험
    4.2. 모르타르 응결 실험
    4.3. 모르타르 플로우 실험
    4.4. 콘크리트 슬럼프 및 공기량 실험
    4.5. 콘크리트 압축강도 실험
    4.6. 콘크리트 염소이온 침투저항성 실험
5. 결론
REFERENCES

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• 윤경구(강원대학교 공과대학 토목공학과 교수) | Yun Kyong Ku Corresponding author