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Title |
Effect of High-Early-Strength Chemical Admixtures on Early Strength Development and Formwork-Striking-Time Reduction in Concrete
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Authors |
강인규(In-Gyu Kang) ; 김건우(Geon-Woo Kim) ; 안태윤(Tae-Yun An) ; 신상철(Sang-Chul Shin) ; 김진만(Jin-Man Kim) |
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DOI |
https://doi.org/10.4334/JKCI.2026.38.3.321 |
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Keywords |
수직 거푸집; 수평 거푸집; 콘크리트 초기 강도; 조강형 혼화제; Maturity formwork; concrete early strength; accelerating admixtures; maturity |
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Abstract |
The formwork striking time is primarily governed by the early age strength of concrete and directly influences structural safety, construction efficiency, and overall project economics. This study evaluates the early strength development of concrete incorporating high early strength chemical admixtures (poly naphthalene sulfonate (PNS) and polycarboxylate (PC)) and quantitatively assesses their effectiveness in accelerating formwork removal using the maturity method. To reflect the wide temperature fluctuations experienced in Korea, curing temperatures of 5, 10, and 20 °C were adopted, and design strengths of 24, 27, and 30 MPa, commonly used in domestic construction, were examined. The test results indicate that high early strength admixtures substantially accelerate early cement hydration, resulting in improved early age strength development, with PNS exhibiting the greatest enhancement. The maturity based analysis further confirmed that these admixtures significantly reduce the time required to achieve the formwork removal strength thresholds of 5 MPa (vertical) and 14 MPa (horizontal). This reduction effect was particularly pronounced under low temperature curing conditions, demonstrating that high early strength admixtures can serve as an effective method for shortening construction duration and improving economic feasibility during cold or transitional seasons.
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