Journal of the Korea Institute of Building Construction (한국건축시공학회지)

The Korean Institute of Building Construction (한국건축시공학회)
권호 표지
DOI QR코드

DOI QR Code

Properties of Cement Paste Containing High Volume γ-C2S and MgO Subjected to CO2 Curing

γ-C2S 및 MgO를 다량 혼입한 시멘트 페이스트의 CO2 양생유무에 따른 특성변화

  • Sung, Myung-Jin (Department of Architectural System Engineering, Hanyang University) ;
  • Cho, Hyeong-Kyu (Department of Sustainable Architectural Engineering, Hanyang University) ;
  • Lee, Han-Seung (School of Architecture, Hanyang University)
  • Received : 2015.03.04
  • Accepted : 2015.04.29
  • Published : 2015.06.20
Download PDF
⟨ Previous Next ⟩

Abstract

Carbonation of concrete causes reduction of pH and subsequently causes steel corrosion for reinforced concrete structure. However, for plain concrete structure or PC product, it can lead to a decrease in porosity, high density, improvement of concrete, shrinkage-compensation. Recently, based on this theory, research of $CO_2$ curing effect has been performed, but it was mainly focused on its effects on compressive strength using only ordinary portland cement. Researches on $CO_2$ curing effect for concrete containing $CO_2$ reactive materials such as ${\gamma}-C_2S$, MgO haven't been investigated. Therefore, this study has performed experiments under water-binder ratio 40%, and the replacement ratios of ${\gamma}-C_2S$ and MgO were 90%. Micro-chemical analysis, measurement of compressive strength according to admixtures and $CO_2$ curing were investigated. Results from this study revealed that higher strength was measured in case of $CO_2$ curing compared with none $CO_2$ curing for plain specimen indicating difference between 1.08 and 1.26 times, in case of ${\gamma}-C_2S$ 90, MgO 90 specimen, incorporating high volume replaced as much as 90%, it was proven that when applying $CO_2$ curing, higher strength which has difference between 14.56 and 45.7 times, and between 6.5 and 10.37 times was measured for each specimen compared to none $CO_2$ curing. Through micro-chemical analysis, massive amount of $CaCO_3$, $MgCO_3$ and decrease of porosity were appeared.

본 연구에서는 $CO_2$ 양생 효과를 극대화 할 수 있는 ${\gamma}-C_2S$와 MgO와 같은 $CO_2$ 흡수 물질을 혼입한 시멘트 페이스트의 $CO_2$ 양생 효과에 관한 연구를 위하여 W/B를 40%로 설정하고 혼화재료 ${\gamma}-C_2S$와 MgO를 90% 다량 치환하여 혼화재료, $CO_2$ 양생 유무에 따른 압축강도 측정, 미세 화학분석을 실시하였다. 그 결과 $CO_2$ 양생으로 인해 Plain의 경우 약 1.08배~1.26배의 압축강도 증가 효과가 나타났으며 ${\gamma}-C_2S$와 MgO를 90% 치환한 ${\gamma}-C_2S$, MgO 실험체의 경우, 각각 14.56배~45.7배, 6.5배~10.37배 향상 효과가 나타났다. 이에 따라 미세 화학분석을 실시하여 다량의 $CaCO_3$, $MgCO_3$가 생성된 것을 확인하고 공극 감소의 효과를 확인하였다. 따라서 $CO_2$ 흡수물질 ${\gamma}-C_2S$, MgO를 다량 혼입한 시멘트 페이스트의 $CO_2$ 양생에 의한 압축강도 발현효과가 검증됨을 확인할 수 있었다.

Keywords

References

  1. Seo CH, Lee HS. Mechanism and effect factors of carbonation in concrete. Proceeding of Korean Concrete Institute; 2002 May 11; Seoul, Korea. Seoul (Korea): Korean Concrete Institute; 2002. p. 3-12.
  2. Tatsuhiko S, Kouichi Y, Shigeyoshi N. Change in strength of mortar due to carbonation. Journal of Japan Society of Civil Engineers. 1992 Aug;17(451):69-78.
  3. Lee JC, A basic study for $CO_2$ gas curing application to cementitious product. Journal of architectural institute of Korea. 2014 May;30(5):81-8.
  4. Sormeh KH, Yixin S, Subhasis G. Mathematical modeling of $CO_2$ uptake by concrete during accelerated carbonation curing. Cement and Concrete Research. 2015 Jan;67:1-10. https://doi.org/10.1016/j.cemconres.2014.07.020
  5. Vahid R, Yixin S, Andrew J.B. Carbonation curing versus steam curing for precast concrete production. Journal of Materials in Civil Engineering. 2012 Sep;24(9):1221-9. https://doi.org/10.1061/(ASCE)MT.1943-5533.0000462
  6. Daman KP, Liwu Mo. Properties of binary and ternary reactive MgO mortar blends subjected to $CO_2$ curing. Cement and Concrete Composites. 2013 Apr;38:40-9. https://doi.org/10.1016/j.cemconcomp.2013.03.009
  7. Vahid R, Yixin S, Andrew J.B, Zhen H. Microstructure of cement paste subject to early carbonation curing. Cement and Concrete Research. 2012 Jan;42(1):186-93. https://doi.org/10.1016/j.cemconres.2011.09.010
  8. Lee JC, Choi YS. Property of early $CO_2$ curing of cement mortar with admixture. Proceeding of Architectural Institute of Korea; 2014 Oct 23-25; Busan, Korea. Seoul (Korea): Architectural Institute of Korea; 2014. p. 601-2.
  9. Kenzo W, Kosuke Y, Noboru S, Etsuo S. The mechanism of pore reduction due to carbonation reaction of ${\gamma}-2CaO{\cdot}SiO_2$ and pozzolanic admixtures with low-heat-portland-cement. Journal of Japan Society of Civil Engineers. 2012 Mar;68(1):83-92.
  10. Liwu Mo, Daman KP. Effects of accelerated carbonation on the microstructure of Portland cement pastes containing reactive MgO. Cement and Concrete Research. 2012 June;42(6):769-77. https://doi.org/10.1016/j.cemconres.2012.02.017
  11. Tsuyoshi S, Etsuo S, Minoru M, Nobuaki O. Carbonation of ${\gamma}$-Ca2SiO4 and the mechanism of vaterite formation, Journal of Advanced Concrete Technology. 2010 Oct;8(3):273-80. https://doi.org/10.3151/jact.8.273
  12. Liwu Mo, Daman KP. Accelerated carbonation-A potential approach to sequester $CO_2$ in cement paste containing slag and reactive MgO, Cement and Concrete Composites, 2013 Oct;43:69-77. https://doi.org/10.1016/j.cemconcomp.2013.07.001
  13. Takeshi T, Kosuke Y, Minoru M, Kenji Y. Reduction of the environmental impact using carbonated cementitious materials with ${\gamma}-2CaO{\cdot}SiO_2$. Cement Science and Concrete Technology. 2009;63(1):161-7. https://doi.org/10.14250/cement.63.161
  14. Kim HS, KIM SB. Mineral properties of clinker and hydration products. Journal of Mineral Logical Society of Korea. 2008 Dec;21(2):65-81.
  15. Watanabe K, Yokozeki K, Torichigai T, Sakata K. High Durability Concrete using Mineral Admixtures cured with $CO_2$ Gas. Journal of Japan Concrete Institute. 2007 Jul;45(7):31-7.
  16. Tsuyoshi S, Nobuaki O, Tatsuya Y, Saphouvong K. Permeability of Sulfate Ions in Cementitious Materials with Autoclave Curing and Accelerated Carbonation Curing Using ${\gamma}-2CaO{\cdot}SiO_2$. Journal of the Society of Materials Science. 2011 Apr;60(4):332-8. https://doi.org/10.2472/jsms.60.332
  17. Jang BS, Kwon YG, Choi SW, Lee KM. Fundamental properties of cement composites containing lightly burnt MgO powders. Journal of the Korea Concrete Institute. 2011 Apr;23(2):225-33. https://doi.org/10.4334/JKCI.2011.23.2.225
  18. C.Unluer, A.Al-Tabbaa. Impact of hydrated magnesium carbonate additives on the carbonation of reactive MgO cements. Cement and Concrete Research. 2013 Dec;54:87-97. https://doi.org/10.1016/j.cemconres.2013.08.009