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An Experimental Study on the Strength Development of High Strength Concrete in Various Curing Conditions at an Early-age

초기 양생조건에 따른 고강도 콘크리트의 강도발현에 관한 실험적 연구

  • Received : 2016.10.24
  • Accepted : 2017.02.06
  • Published : 2017.04.30

Abstract

This study is experimentally investigated the effects of various steam curing parameters on the early-age compressive strength development of high strength concrete (over 40 MPa) in the precast plant production. High strength concrete are used only ordinary portland cement (type I) and water-cement ratio selected 3cases (25%, 35% and 45%). Also, steam curing parameters are as followings ; (1) Preset period 2cases (3 hours and 6 hours) (2) Maximum curing temperature 3cases ($45^{\circ}C$, $55^{\circ}C$ and $65^{\circ}C$) (3) Maintenance time of curing temperature 3cases (4 hours, 6 hours and 8 hours) (4) Maximum rate of heating and cooling $15^{\circ}C$/hr. Initial setting time and adiabatic temperature rising ratio of these concrete according to water-cement ratio are tested before main tests and examined the compressive strength development for the steam curing parameters. Also compressive strength are compared with optimum steam curing condition and standard curing at test ages. As test results, the optimum steam curing conditions for high strength concrete(over 40 MPa) are as followings. (1) Preset period ; over initial setting time of concrete (2) Maximum curing temperature ; bellow $55^{\circ}C$ (3) Maintenance time of curing temperature ; bellow 6hours. Also strength development of steam curing concrete show in the reversed strength at 28 days. It is to propose an efficient steam curing condition for high strength concrete in the precast method.

본 연구는 PC부재의 공장생산에 있어서 여러 가지 증기양생 조건의 변수에 따른 고강도 콘크리트의 초기 압축강도 발현성상을 실험적으로 검증하고, 최적 양생조건을 확인하기 위한 것이다. 40 MPa 이상의 고강도 콘크리트 제조에는 보통 포틀랜드 시멘트를 사용하였으며, 콘크리트의 배합조건은 물-시멘트비 3종류(W/C 25%, 35% 및 45%)를 대상으로 하였다. 본 연구의 증기양생 변수로 (1) 전치양생 시간 3종류, (2) 최고 양생온도 3종류, (3) 최고온도 유지시간 3종류, (4) 승온 및 강온양생 온도 1종류 등을 대상으로 재령별 압축강도 시험을 실시하였다. 또한, 증기양생 및 표준양생에 따른 재령별 강도발현을 비교하였다. 실험결과, (1) 전치양생은 콘크리트의 초기 응결시간 이상, (2) 최고 양생온도는 $55^{\circ}C$ 이하, (3) 최고온도 유지시간은 6시간 이하로 하는 것이 증기양생 고강도 콘크리트의 강도발현에 적합한 양생조건으로 나타났다. 또한, 재령 28일에서 증기양생과 표준양생의 압축강도 발현성상의 역전현상이 발생하였다. 따라서 이러한 양생조건으로 PC부재의 생산성 및 현장관리를 위한 기초자료로 제시하고자 한다.

Keywords

References

  1. Park, J.S., Kim, Y.J., Cho, J.R., and Jeon, S.J., "Early-Age Strength of Ultra-High Performance Concrete in Various Curing Conditions", Journal of Materials published by MDPI AG, Basel, Switzerland, Vol. 8, 2015, pp.5537-5553.
  2. Nagao, Y., and Suzuki, K., "Basic Properties and Utilization of Steam-Cured Concrete using Ground Granu- lated Blast-Furnace Slag", Nippon Steel & Sumitomo Metal Technical Report, No.109, 2015, pp.125-129.
  3. Hwang, S.D., Khatib, R., Lee, H.K., Lee, S.H., Khayat, K.H., "Optimization of Steam-Curing Regime for High-Strength, Self-Consolidating Concrete for Precast, Prestressed Concrete Application", Journal of Precast/prestressed Concrete Institute (PCI), Vol.57, No.3, 2012, pp.48-62.
  4. Song, Y.W., Yoon, S., Jeong, Y., Jeon, Y.S., Gong, M. H., and Chung, G.T., "A Study for Strength Proper- ties by Temperature Change of Steam Curing of Concrete using Blast-Furnace Slag of High Volume", Proceedings of the Korea Concrete Institute, Vol.24, No.2, 2012, pp.183-184.
  5. Lee, M. K., Kim, K. S., Lee, K. H., and Jung, S. H., "Strength of Recycled Concrete with Furnace Slag cement under Steam Curing Condition", Journal of the Korea Concrete Institute, Vol.17, No.4, 2005, pp.613-620. https://doi.org/10.4334/JKCI.2005.17.4.613
  6. Park, H. L., Kim, S.J., Paik, M.S., Lee, H.K., Park, B.K., and Jung, S.J., "An Experimental Study on Tem- perature Property of High-strength Mass Concrete Cured by Steam", Proceedings of the Korea Concrete Institute, Vol.19, No.2, 2007, pp.593-596.
  7. Yoon, S., Jung, Y.M., Jeong, Y., Lee, S.Y., and Kim, Y.B., "The Effect of Steam Curing on the Compressive Strength and Durability in High Strength Concrete", Proceedings of the Korea Concrete Institute, Vol.19, No.1, 2007, pp.697-700.
  8. Kwon, H.S., Choi, E.K., Lim, N.K., Lee, Y.D., and Jung, S.J., "An Effects of the Strength Development of High Strength Mortar under Temperature History by Steam Curing", Journal of the Korea Institute of Building Construction, Vol.8, No.4, 2008, pp.115-121. https://doi.org/10.5345/JKIC.2008.8.4.115
  9. Park, J.H., Kim, S.J., Paik, M.S., Lee, S.H., Park, B.K., and Jung, S.J., "An Experimental Study on Strength Characteristics of Mass Concrete Cast with High-Strength Concrete for Precast Application", Proceedings of the Korea Concrete Institute, Vol.19, No.2, 2007, pp.49-52.
  10. Kim, M.H., Lee, S.H., Kang, S.P., Khil, B.S., and Joo, J.H., "Development of Early-Strength of High Strength Concrete According to Curing Temperature for Application of System Form", Journal of the Korea Concrete Institute, Vol.13, No.4, 2001, pp.536-543.