한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

한국지반공학회 (Korean Geotechnical Society)
권호 표지
DOI QR코드

DOI QR Code

커피박을 이용한 순환골재의 pH 저감 및 파쇄성 연구

A Study on pH Reduction of Recycled Aggregates Using Coffee Waste and Its Crushability

  • 이영재 (경북대학교 공과대학 토목공학과) ;
  • 이동윤 (경북대학교 공과대학 건축토목공학부) ;
  • 천커챵 (경북대학교 공과대학 건축토목공학부) ;
  • 김문기 (경북대학교 공과대학 건축토목공학부) ;
  • 박성식 (경북대학교 공과대학 건설환경에너지공학부)
  • 투고 : 2016.08.01
  • 심사 : 2016.10.13
  • 발행 : 2016.11.30
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

본 연구에서는 각종 구조물 철거 시 발생하는 폐콘크리트를 파쇄 처리하여 생산된 순환골재의 크기를 세 종류(10-13mm, 13-20mm, 20-25mm)로 나눈 다음, 순환골재의 pH 저감방법과 순환골재 처리방법에 따른 파쇄값을 실험 분석하였다. 순환골재 침출수의 pH는 골재 크기에 관계없이 약 11 정도로 일정하였으며, 이를 1000ml 증류수에 넣고 pH가 약 5 정도인 커피박을 10, 30, 또는 50g 혼합하여 시간에 따른 pH 변화를 측정하였다. 커피박을 50g 넣은 경우 24시간 후 pH가 최대 6.2까지 떨어지는 결과를 얻었다. 또한 마이크로웨이브(microwave)를 쪼여 가열하는 방법이나, pH가 2인 식초에 순환골재를 1일 침지시켜 중성화시키는 화학적인 방법을 이용하여 순환골재의 파쇄값을 비교 분석하였다. 무처리한 경우보다 마이크로웨이브를 쪼인 경우 평균 3.3% 정도 파쇄값이 증가하였으며, 중성화시키는 방법은 6.2% 정도 파쇄값이 증가하여 상대적으로 파쇄효과가 더 높았다. 순환골재 파쇄시험에서 표준 시료 높이 100mm 보다 높은 120mm로 시험한 경우 파쇄값이 6.3% 증가하였으며, 400kN을 연속으로 재하하는 경우보다 100kN씩 4단계로 재하한 경우 파쇄값이 7.1% 더 증가하였다.

In this study, recycled aggregates crushed from waste concrete were sorted into three groups, 10-13 mm, 13-20 mm, and 20-25 mm. They were treated in different ways and then their crushability was evaluated for each treatment. Coffee waste was used for reducing their pH level. The pH of recycled aggregate was almost 11, regardless of aggregate sizes. The pH of coffee waste was nearly 5 and 10, 30, or 50 g of coffee waste was mixed with 1000 ml of distilled water and recycled aggregates. The lowest pH was about 6.2 when 50 g of coffee waste was mixed. Aggregates were treated with microwave or soaked for 1 day in vinegar (pH = 2) for neutralization reaction. Microwave treated and neutralized aggregates showed 3.3% and 6.2% higher crushing values compared to non-treated one, respectively. Neutralized treatment was more effective for crushing. In crushing tests, a sample height of 120 mm was tried, which gave 6.3% higher crushing value. A four stepped loading with each 100 kN gave 7.1% higher crushing value, compared to standard 100 mm height and 400 kN continuous loading.

키워드

참고문헌

  1. Akbarnezhad, A., Ong, K. C. G., Zhang, M. H., Tim C. T., and Foo, T. W. J. (2011), "Microwave-assisted beneficiation of recycled concrete aggregate", Construction and Building Materials, Vol.25, pp.3469-3479. https://doi.org/10.1016/j.conbuildmat.2011.03.038
  2. BS EN 1744-3 (2002), Tests for chemical properties of aggregates - Preparation of eluates by leaching of aggregates.
  3. Byeon, M. W. and Ahn, J. H. (2015), "Determination of adhered mortar content of recycled aggregate using microwave irradiation and mixed solution of HCL and $H_2O_2$", Journal of Korean Society of Waste Management, Vol.32, No.6, pp.566-573. https://doi.org/10.9786/kswm.2015.32.6.566
  4. Choi, H. S., Kitagaki, R., and Noguchi, T. (2014), "Effective recycling of surface modification aggregate using microwave heating", Journal of Advanced Concrete Technology, Vol.12, pp.34-45. https://doi.org/10.3151/jact.12.34
  5. Coffee Cube (2005), www.coffeecube.co.kr.
  6. Figg, J. (1974), "Microwave heating in concrete analysis", Journal of Applied Chemistry and Biotechnology, Vol.24, pp.143-145. https://doi.org/10.1002/jctb.5020240306
  7. Kang, S. C., Kim, G. H., Wi, J. H., Ahn, T. B., Lee, D. S., and Choi, H. S. (2015), "Effect of particle breakage on compaction and thermal resistivity of concrete-based recycled aggregates", Journal of the Korean Geotechnical Society, Vol.31, No.10, pp.17-28.
  8. Kim, B. G., Park, N. Y., and Lee, S. H. (2016), "Quality characteristics and antioxidative activity of muffins added with coffee ground residue water extract and powder", Journal of Korean Society of Food Science and Nutrition, Vol.45, No.1, pp.76-83. https://doi.org/10.3746/jkfn.2016.45.1.076
  9. Kim, J. H. (2016), "Study on the pH of Recycle Aggregates", Master Thesis, Kumoh National Institute of Technology.
  10. Kim, Y. J. (2014), "Quality assessment of recycled aggregate concrete using microscopic studies", Ph.D thesis, Hanyang Univeristy.
  11. KS F 2541 (2002), Testing method for determination of aggregates crushing value.
  12. Kwon, J. H., Kim, S. W., and Park, B. S. (2013), "Study on the reinforced retaining wall using the backfill of recycled aggregate", Journal of Korean Society of Environmental Technology, Vol.14, No.2, pp.128-134.
  13. Lee, W. K., Choi, J. O., and Jung, Y. W. (2015), "Effect of the amount of attached mortar of recycled aggregates on the properties of concrete", Journal of Korean Recycled Construction Resources Institute, Vol.3, No.2, pp.132-139. https://doi.org/10.14190/JRCR.2015.3.2.132
  14. Lee, J., Lee, B. C., Cho, Y. G., and Jung, S. H. (2016), "Chloride diffusivity of concrete using recycled aggregate by strength levels", Journal of the Korea Institute of Structural Maintenance and Inspection, Vol.20, No.2, pp.102-109.
  15. Lee, J. C., Song, T. H., Lee, S. H., and Kim, J. B. (2011), "A study on the optimization of recycled aggregate alkalinity reducing facility in the field", Journal of Korean Recycled Construction Resources Institute, Vol.6, No.3, pp.53-60.
  16. Lee, M. J., Kim, S. E., Kim, J. H., Lee, S. W., and Yeum, D. M. (2013), "A study of coffee bean characteristics and coffee flavors in relation to roasting", Journal of the Korean Society of Food Science and Nutrition, Vol.42, No.2, pp.255-261. https://doi.org/10.3746/jkfn.2013.42.2.255
  17. Ministry of environment (2007), Testing methods for waste pollution.
  18. Ministry of environment (2009), Testing methods for soil pollution.
  19. Ministry of Land, Infrastructrue and Transport (2013), Quality Standards for Recycled Aggregates.
  20. Noguchi, T. (2015), Life cycle perspective of concrete recylcling.
  21. Park, J. W. (2014), "Physical Characteristics of Concrete using Acid Treatment Recycled Aggregate", Master Thesis, Hanyang University.
  22. Park, S. S., Kim, S. J., and Moon, H. D. (2016), "Crushing Characteristics of Single Particle of Recycled Aggregate produced by Wasted Concrete", Journal of the Korean Geotechnical Society (accepted).
  23. Park, B. S., Sim, D. S., Lee, H. K., and Jung, G. S. (2011), "Installation resistance test for the rainforecd materials with compaction of recycled aggregate", Proc. of Korean Society of Hazard Mitigation.
  24. Shin, J. L., Kim, W. S., Baek, S. M., Kang, H. K., and Kwak, Y. K. (2015), "Structural performance evaluation of steel fiberreinforced concrete beams with recycled coarse aggregates", Journal of the Korea concrete institute, Vol.27, No.3, pp.215-227. https://doi.org/10.4334/JKCI.2015.27.3.215
  25. Song, T. H., Lee, J. C., and Lee, S. H. (2011), "A study on the pH characteristic of recycle aggregate according to test methods and elapsed time", Journal of Korean Recycled Construction Resources Institute, Vol.6, No.3, pp.61-68.
  26. Wi, J. H., Hong, S. Y., Lee, D. S., Park, S.W., and Choi, H. S. (2011), "Evaluation of compaction and thermal characteristics of recycled aggregates for backfilling power transmission pipelines", Journal of the Korean Geotechnical Society, Vol.27, No.7, pp. 17-33.