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Title |
Evaluation of Material Properties of Ultra-High-Strength Cementless Concrete According to the Ca(OH)2 ?CaO Ratio
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Authors |
박기준(Gi-Joon Park) ; 홍세희(Se-Hee Hong) ; 문훈(Hoon Moon) ; 이남곤(Nam-Kon Lee) ; 박정준(Jung-Jun Park) |
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DOI |
https://doi.org/10.11112/jksmi.2026.30.5.34 |
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Keywords |
초고강도 무시멘트 콘크리트; 수산화칼슘; 산화칼슘; 유동성; 역학적 특성 Ultra-high-strength cementless concrete; Calcium hydroxide; Calcium oxide; Flowability; Mechanical properties |
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Abstract |
This study evaluated the effects of the Ca(OH)2-CaO ratio on the flowability, passing ability, setting behavior, mechanical properties, and thermal decomposition characteristics of ultra-high-strength cementless concrete. Ground granulated blast-furnace slag and silica fume were used as binders, while the total amount of Ca-based activator was fixed and only the mass ratio of Ca(OH)2 to CaO was varied. As the CaO replacement ratio increased, the slump flow increased from 655 mm to 746 mm, whereas the air content slightly decreased from 2.77% to 2.40%. In the L-Box test, mixtures containing 40% or more CaO showed a PL value of 0.93, and T500 decreased from 7.97 s to 3.93 s. The initial and final setting times were shortened from 27.3 h and 28.2 h to 11.8 h and 12.0 h, respectively. The compressive strength remained above 127 MPa up to 70% CaO replacement but decreased to 94.8 MPa in the CO100 mixture. The CH60-CO40 mixture exhibited the best flexural performance. TG/DTG results indicated thermal decomposition characteristics related to residual Ca(OH)2 in CaO-rich mixtures. The integrated performance index was highest for CH30-CO70, suggesting that the combined use of Ca(OH)2 and CaO provided the most balanced performance under the conditions of this study.
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