Journal of the Korean Recycled Construction Resources Institute (한국건설순환자원학회논문집)

Korean Recycled Construction Resources Institute (한국건설순환자원학회)
권호 표지
DOI QR코드

DOI QR Code

Carbonation Properties of Recycled Aggregate Concrete by Specified Concrete Strength

설계기준 강도별 순환골재 콘크리트의 탄산화 특성

  • Lee, Jun (Daejeo & Chungnam Branch, Korea Conformity Laboratories) ;
  • Lee, Bong-Chun (Daejeo & Chungnam Branch, Korea Conformity Laboratories) ;
  • Cho, Young-Keun (High-tech Construction Materials Center, Korea Conformity Laboratories) ;
  • Park, Kwang-Min (High-tech Construction Materials Center, Korea Conformity Laboratories) ;
  • Jung, Sang-Hwa (High-tech Construction Materials Center, Korea Conformity Laboratories)
  • 이준 (한국건설생활환경시험연구원 대전.충남지원) ;
  • 이봉춘 (한국건설생활환경시험연구원 대전.충남지원) ;
  • 조영근 (한국건설생활환경시험연구원 첨단건설재료센터) ;
  • 박광민 (한국건설생활환경시험연구원 첨단건설재료센터) ;
  • 정상화 (한국건설생활환경시험연구원 첨단건설재료센터)
  • Received : 2017.03.09
  • Accepted : 2017.03.16
  • Published : 2017.03.30
Download PDF
⟨ Previous Next ⟩

Abstract

This paper presents mechanical properties and carbonation behavior of the recycled aggregate concretes(RAC) in which natural aggregate was replaced by recycled coarse aggregate and fine aggregate by specified concrete strength levels(21, 35, 50MPa). A total of 18 RAC were produced and classified into six series, each of which included three mixes designed with three specified concrete strength levels of 21MPa, 35MPa and 50MPa and three recycled aggregate replacement ratios of 0, 50 and 100%. Physical and mechanical properties of RAC were tested for slump test, compressive strength, and carbonation depth. The test results indicated that the slump of RAC could be improved or same by recycled coarse aggregate replacement ratios, when compared with natural aggregate. But slump of RAC was decreased as the recycled fine aggregate replacement ratios increase. Also, the test results showed that the compressive strength was decreased as the recycled aggregate replacement ratios increased and it had a conspicuous tendency to decrease when the content of the recycled aggregate exceeded 50%. Furthermore, the result indicated that the measured carbonation depth increases by 40% with the increase of the recycled aggregate replacement. In the case of the concrete having low level compressive strength, the increase of carbonation depth tends to be higher when using the RCA. However, the trend of carbonation resistivity in high level compressive strength concrete is similar to that obtained in natural aggregate concrete. Therefore, an advance on the admixture application and mix ratio control are required to improve the carbonation resistivity when using the recycled aggregate in large scale.

본 연구에서는 국내에서 생산되고 있는 콘크리트용 순환 굵은골재 및 순환잔골재를 사용하여 콘크리트의 설계기준 강도(21, 35, 50MPa) 및 순환골재의 혼입조건 변화가 콘크리트의 탄산화 거동에 미치는 영향을 분석하였다. 실험결과 순환 굵은골재의 혼입률 변화에 따른 콘크리트의 슬럼프는 순환골재를 혼입하지 않은 경우에 비해 동등하거나 양호한 유동성을 나타내는 것으로 나타났으며, 순환 잔골재를 혼입한 경우는 혼입률이 증가함에 따라 슬럼프가 감소되는 결과를 나타냈다. 또한, 순환 굵은골재 및 순환 잔골재의 혼입률이 증가할수록 콘크리트의 압축강도는 감소하는 것으로 나타났으며, 순환골재 혼입률이 50%를 초과할 경우 급격한 강도 감소 경향을 나타냈다. 그리고 탄산화 깊이는 모든 순환골재 종류에서 혼입률이 증가함에 따라 최대 40%까지 증가하는 결과를 나타냈으며 낮은 강도 수준의 콘크리트 일수록 순환골재 활용에 따른 탄산화 저항성 저하 정도가 큰 것으로 나타났다. 그리고 콘크리트의 압축강도가 증가할수록 순환골재 혼입에 따른 영향은 감소되어, 고강도 영역에서는 일반 콘크리트와 유사한 탄산화 특성을 발현하는 것으로 분석되었다. 따라서 순환골재를 콘크리트용 재료로 대량 활용하기 위해서는 콘크리트의 탄산화 저항성의 개선 위한 혼화재료의 적용 또는 배합설계상 조정을 통한 강도의 개선 등이 필요할 것으로 판단된다.

Keywords

References

  1. Berndt, M.L. (2009). Properties of sustainable concrete containing fly ash, slag and recycled concrete aggregate, Journal of Construction and Building Materials, 23(7), 2606-2613. https://doi.org/10.1016/j.conbuildmat.2009.02.011
  2. Dhir R.K, Limbachiya M.C, Leelawat T. (1999). Suitability of recycled concrete aggregate for use in BS 5328 designated mixes, Institute Civil Engineering-Structure Build, 134(3), 257-274. https://doi.org/10.1680/istbu.1999.31568
  3. Iva Despotovic. (2016). The Improvement of recycled concrete aggregate, Contemporary Achievements in Civil Engineering, 22.
  4. Kim, Y.S., Kim, J.J., Seok, W.K., Lee, J.H., Kim, G.Y. (2011). An experimental study on the strength properties and durability performance of recycled concrete with water to cement ratio and unit water content, Journal of the Korean Recycled Construction Resources Institute, 16, 88-93 [in Korean].
  5. Kong, D., Lei, T., Zheng, J., Ma, C., Jiang, J., Jiang, J. (2010). Effect and mechanism of surface-coating pozzolanic materials around aggregate on properties and ITZ microstructure of recycled aggregate concrete. Journal of Construction and Building Materials, 24(5), 701-708. https://doi.org/10.1016/j.conbuildmat.2009.10.038
  6. Korea Institute of Civil Engineering and Building Technology. (2014). Study on the Application of Recycled Aggregate [in Korean].
  7. Korean Ministry of Environment. (2015). Environmental Statistics Yearbook [in Korean].
  8. Kwan, W.H., Ramli, M., Kam, K.J., Sulieman, M.Z. (2012). Influence of the amount of recycled coarse aggregate in concrete design and durability properties. Journal of Construction and Building Materials, 26(1), 565-573.
  9. Lee, W.K., Choi, J.O., Jung, Y.W. (2015). Effect of the amount of attached mortar of recycled aggregates on the properties of concrete, Journal of the Korean Recycled Construction Resources Institute, 3(2), 132-139 [in Korean]. https://doi.org/10.14190/JRCR.2015.3.2.132
  10. M. Barra de Oliveira, E. Vazquez. (1996). Influence of retained moisture in aggregates from recycling on the properties of new hardened concrete. Journal of Waste Management, 16(1-3), 113-117. https://doi.org/10.1016/S0956-053X(96)00033-5
  11. Montgomery, D., Sturgiss, D. (1996). Properties of concrete incorporating recycled concrete aggregates. Institution of Engineers, 153.
  12. Padmini AK, Ramamurthy K, Mathews MS. (2002). Relative moisture movement through recycled aggregate concrete. Magazine of Concrete Research. 54(5), 377-384. https://doi.org/10.1680/macr.2002.54.5.377
  13. Poon, C. (2007). Influence of fly ash as cement replacement on the properties of recycled aggregate concrete. Journal of Materials in Civil Engineering, 19(2), 709-717. https://doi.org/10.1061/(ASCE)0899-1561(2007)19:9(709)
  14. Silva, R.V., Neves, R., Brito, C. (2015). Carbonation behavior of recycled aggregate concrete. Journal of Cement & Concrete Composites, 62, 22-32. https://doi.org/10.1016/j.cemconcomp.2015.04.017
  15. Sim, J.S., Park, C.W., Moon, I,W., Lee, H.C. (2005). Fundamental performance evaluation of recycled aggregate concrete with varyin amount of fly ash and recycled fine aggregate. Journal of the Korea Concrete Institute, 17(5), 793-801 [in Korean]. https://doi.org/10.4334/JKCI.2005.17.5.793
  16. Xiao, J., Li, J., Zhang, C. (2005). Techanical properties of rcycled aggregate concrete under uniaxial loading, Journal of Cement and Concrete Composites, 35, 1187-1194. https://doi.org/10.1016/j.cemconres.2004.09.020