Resources Recycling (자원리싸이클링)

The Korean Institute of Resources Recycling (한국자원리싸이클링학회)
권호 표지
DOI QR코드

DOI QR Code

The Fundamental Properties of Foamed Concrete as the Eco-friendly Ground Repair System for Cast in Site Using the CSA

CSA를 사용한 친환경 지반보수용 현장 기포콘크리트의 기초 특성 검토

  • Received : 2019.12.11
  • Accepted : 2020.02.14
  • Published : 2020.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

This study aimed to develop a foam concrete material for a ground repair system that has low strength and low fluidity by using an eco-friendly binder, which substitutes industrial by-products for more than 90% of cement. Basic properties were evaluated after substituting a small amount of calcium sulfo aluminate (CSA) for the binder to improve the sinking depth rate and volume change, commonly found when it had a large amount of industrial by-products. The substitution rates of CSA for the eco-friendly binder used for the foam concrete were 2.5, 5, and 10%. Fresh properties, hardened properties, pore structure, and hydrates were analyzed. Experimental results showed that using only 2.5% of CSA could improve the deep sinking depth which occurred when using an eco-friendly binder. As a result, the weight difference between the upper, middle, and lower parts of cast specimens was improved even after being hardened. The addition of CSA also contributed to the formation of small, uniformly sized closed pores and improved initial strength. However, when the proportion of CSA increased, the long-term strength decreased. However, it satisfied the target strength when 5% or less of CSA was used. The results of this study revealed that it was possible to manufacture foam concrete with low strength and high fluidity for repairing ground satisfying target qualities by adding 2.5% of CSA to the eco-friendly binder containing a large amount of industrial by-products.

본 연구는 시멘트 대비 산업부산물을 90% 이상 대체한 친환경 결합재를 이용하여 저강도·고유동을 갖는 지반보수용 기포콘크리트 소재를 개발하기 위한 연구로서, 산업부산물을 다량 활용시 발생하는 기포콘크리트의 초기 침하율 및 체적변화를 개선하기 위하여 CSA(Calcium sulfo aluminate)를 소량 대체하여 기초특성을 평가하였다. 기포콘크리트용 친환경 결합재 대비 CSA의 대체율은 2.5, 5, 10%로, 굳지않은 특성, 경화특성, 공극구조 및 수화물을 분석하였다. 실험결과 친환경 결합재 사용시의 높은 침하깊이를 CSA 2.5% 사용만으로도 개선할 수 있었으며, 그로인해 경화 후에도 타설된 시험체의 상중하의 중량편차도 개선되었다. CSA 첨가에 따라 공극구조도 작고 균일한 사이즈의 독립기포 형성에 기여하였으며, 초기강도는 개선되었다. 그러나 CSA의 혼입률의 증가에 따라 장기강도는 감소하였으나, 5% 이하를 사용할 경우 목표강도를 만족하였다. 이로써 산업부산물을 다량 활용한 친환경 결합재에 CSA의 2.5% 첨가만으로도 목표성능의 저강도 고유동을 갖는 지반 보수용 기포콘크리트 제조가 가능한 것을 확인하였다.

Keywords

References

  1. Korea Waste Association, 2017 : The Present Status of Waste Emission and Treatment in Korea.
  2. Seunghyun, Lee, 2011 : Importance of the environment and recycling, www.ywca.or.kr >magicboard>labray.
  3. ReSEAT Analysis Report, 2005 : Application of CLSM in Japan.
  4. Yang-yi, Woo, Keun-bae, Park, 2019 : Study on optimum mixture of industrial by-products for lightweight foamed filler production by mixture experimental design, Journal of the Korean Recycled Construction Resources Institute, 7(1), pp.37-43. https://doi.org/10.14190/JRCR.2019.7.1.37
  5. Jinman, Kim, Eungu, Kwank, Kwangchin, Oh, et al., 2011 : Properties of Bubble According to Types and Concentrations of Concrete Foaming Agent, Journal of the Korea Concrete Institute, 23(2), pp.151-158. https://doi.org/10.4334/JKCI.2011.23.2.151
  6. Sunmi, Choi, Jinman, Kim, Dongyeop, Han, et al., 2016 : Hydration properties of ladle furnace slag powder rapidly cooled by air, Construction and Building Materials, 113, pp.682-690. https://doi.org/10.1016/j.conbuildmat.2016.03.089
  7. L, Coppola, D, Coffetti, E, Crotti, et al., 2018 : CSA-based Portland-free binders to manufacture sustainable concretes for jointless slabs on ground, Construction and Building Materials, 187, pp.691-698. https://doi.org/10.1016/j.conbuildmat.2018.07.221
  8. Xiaolu Guo, Huisheng Shi, Wenpei Hu, Kai Wu, 2014 : Durability and microstructure of CSA cement-based materials from MSWI fly ash, Cement and Concrete Composites, 46, pp.26-31. https://doi.org/10.1016/j.cemconcomp.2013.10.015
  9. Hayashido, Yasushi, Shinohara, Masaki, Yoshitake, Hideki, 2013 : Development of filler for underground cavities "SMART GROUT" using granulated blast furnace slag, JFE Research Journal 31, p.58.
  10. Jeong-Ryol, Shin. Jae-Im, Park, An-Ho, Lee, et al., 2015 : Characteristics of light weight mixed soil using eco-friendly solidification material, Autumn Conference of the Korean Society of Railway.
  11. Yong-Sun, Ryu, Jin-Gyu, Han, Woo-Ri, Chae, et al., 2016 : Development of rapid hardening backfill material for reducing ground subsidence, J. Korean Geosynthetics Society, 14(3), pp.13-20. https://doi.org/10.12814/jkgss.2015.14.3.013
  12. Guanghong, Sheng, Qin, Li, Jianping. Zhai, 2012 : Investigation on the hydration of CFBC fly ash, Fuel, 98, pp.61-66. https://doi.org/10.1016/j.fuel.2012.02.008