Journal of the Korea institute for structural maintenance and inspection (한국구조물진단유지관리공학회 논문집)

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
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The Buildability and Strength Properties of 3D Printed Concrete in the Air and Underwater Environment

수중과 기중환경에서 출력된 3D 프린팅 콘크리트의 적층성능 및 강도 특성 분석

  • 서은아 (한국건설기술연구원 구조연구본부) ;
  • 이호재 (한국건설기술연구원 구조연구본부)
  • Received : 2024.02.28
  • Accepted : 2024.03.12
  • Published : 2024.04.30
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Abstract

This study evaluated the buildability and mechanical properties of 3DP concrete printed in air and underwater environments. Buildability was evaluated by green strength test on fresh concrete and height and deflection immediately and 1 hour after printing. The green compressive strength of the concrete was 5.0 kPa after 30 minutes and 7.9 kPa after 3 hours, an increase of 1.6 times the initial strength. The total height of the laminated parts met the design height regardless of the printing environment. The amount of deflection in air and under water 1 hour after printing was 1 mm and 0.2 mm, respectively, indicating a small amount of deflection under water. The apparent density of the sample appeared in the order of A-M > A-P > UW-P. This is believed to be because a large amount of air is mixed into the concrete during the printing process, and water infiltrates during the underwater printing process. The compressive strength ratio of UW-P/A-P was 0.86 at 1 day, but the compressive strength of the underwater printed concrete was high from 7 days.

이 연구에서는 기중 및 수중환경에서 출력한 3DP 콘크리트에 대하여 적층성능과 역학적 특성평가를 수행하였다. 적층성능은 굳지 않은 콘크리트에서의 Green strength test와 적층 직후와 1시간에서의 높이와 처짐량으로 평가하였다. 배합 30분 후 콘크리트 압축강도는 5.0 kPa이며, 3시간 후의 압축강도는 7.9 kPa로 초기 강도 대비 1.6배 높았다. 적층 부재의 총 높이는 출력환경과 관계없이 설계 높이를 만족하였다. 적층 1 시간 후의 기중과 수중환경에서의 처짐량은 각각 1 mm와 0.2mm로 수중환경에서 처짐량이 작게 발생하였다. 겉보기 밀도는 A-M>A-P>UW-P 시험체 순으로 나타났으며, 이는 적층 콘크리트 출력과정 중에 콘크리트와 함께 혼합된 공기의 양이 많고 수중출력 시에는 콘크리트 내부로 물이 침투되어 밀도가 낮아진 것으로 판단된다. UW-P/A-P의 압축강도 비는 재령 1일에서는 0.86이었지만, 재령 7일을 기점으로 수중 제작 콘크리트의 압축강도가 높게 나타났다.

Keywords

Acknowledgement

본연구는 한국건설기술연구원 구조연구본부 목적형 R&R "국민 안전과 건전한 인프라 환경을 위한 지속가능한 인프라구조 기술 연구(과제번호: 20240156)"의 시드과제 "순환자원활용 건설 3D 프린팅 기반 저비용 변단면 거푸집 기술 개발"의 일환으로 수행된 연구임.

References

  1. Ahn, H. J., Lee, D. Y., Ji, W. J., Lee, W. J., and Cho, H. H. (2020), Development of Method for Manufacturing Freeform EPS Forms Using Sloped-LOM Type 3D Printer, Journal of the Korea Institute of Building Construction, 20(2), 171-181 (in Korean).
  2. ASTM Standard C39. (2012), Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens, ASTM Standard International.
  3. Chang, Z., Liang, M., Chen, Y., Schlangen, E., and Savija, B. (2023), Does early age creep influence buildability of 3D printed concrete? Insights from numerical simulations, Additive Manufacturing, 77, 103788.
  4. Jha, K. N. (2012), Formwork for Concrete Structures, Tata Mc Graw Hill Education Private Limited.
  5. KCI-CT115, (2021), Standard Method of Making Compressive Strength Specimens of Underwater Additive Layering Concrete, Standards of the Korean Concrete Society (in Korean).
  6. Khan, M. S., Sanchez, F., and Zhou, H. (2020), 3-D printing of concrete: Beyond horizons, Cement and Concrete Research, 133, 106070.
  7. KS F 2405. (2022), Test method for compressive strength of concrete, Korea Standards Association (in Korean).
  8. KS L 5111. (2022), Flow table use in tests of hydraulic cement. Korea Standards Association (in Korean).
  9. Lee, D. K. (2017), 3D Printing Technology for Building Construction, Journal of Korean Association for Spatial Structures, 17(4), 16-19 (in Korean).
  10. Lee, H. J., Kim, J. H. J., Moon, J. H., Kim, W. W., and Seo, E. A. (2019), Evaluation of the Mechanical Properties of a 3D-Printed Mortar, Materials, 12(24), 4104.
  11. Lee, H. J., Kim, W. W., Seo, E. A., and Moon, J. H. (2020), Effect of Shrinkage Characteristics of Cement-Based Composites by Extrusion and Lamination Process of Construction 3D Printing, Journal of the Korea Institute for Structural Maintenance and Inspection, 24(6), 113-118 (in Korean).
  12. Lee, H. J., Moon, H. J., and Kim, J. J. (2012), An Experimental Study on Pumpability Characteristics of High Strength Concrete Mixed Polymix, Journal of the Korea Concrete Institute, 24(5), 509-516 (in Korean). https://doi.org/10.4334/JKCI.2012.24.5.509
  13. Lee, J. Y., and Lee, T. S. (2020), Using In Situ Resources and 3D Printing for Space Exploration Habitat Construction, Journal of Civil and Environmental Engineering Research, 40(3), 337-343 (in Korean).
  14. Liu, H., Liu, C., Wu, Y., Bai, G., He, C., Yao, Y., Zhang, R., and Wang, Y. (2022), 3D printing concrete with recycled coarse aggregates: The influence of pore structure on interlayer adhesion, Cement and Concrete Composites, 134, 104742.
  15. Mazhoud, B., Perrot, A., Picandet, V., Rangeard, D., and Courteille, E. (2019), Underwater 3D printing of cement-based mortar: Construction and Building Materials, 214, 458-467. https://doi.org/10.1016/j.conbuildmat.2019.04.134
  16. Muthukrishnan, S., Ramakrishnan, S., and Sanjayan, J. (2021), Technologies for improving buildability in 3D concrete printing, Cement and Concrete Composites, 122, 104144.
  17. Seo, E. A., Kim, W. W., Kim, S. W., Kwon, H. K., and Lee, H. J. (2023a), Mechanical properties of 3D printed concrete with coarse aggregates and polypropylene fiber in the air and underwater environment, Construction and Building Materials, 378, 131184.
  18. Seo, E. A., Lee, H. J., and Yang, K. H. (2023b), Strength Characteristics of 3D Printed Composite Materials According to Lamination Patterns, Journal of the Korea Institute for Structural Maintenance and Inspection, 25(6), 193-198 (in Korean).
  19. Seo, E. A., Yang, K. H., and Lee, H. J. (2022), Experimental Study for Evaluating Early Age Shrinkage of Mortar for 3D Printing, Journal of the Korea Institute for Structural Maintenance and Inspection, 26(2), 76-83 (in Korean).
  20. Wang, L., Ye, K., Wan, Q., Li, Z., and Ma, G. (2023), Inclined 3D concrete printing: Build-up prediction and early-age performance optimization, Additive Manufacturing, 71, 103595.
  21. Wangler, T., Roussel, N., Bos, F. P., Salet, T. A. M., and Flatt, R. J. (2019), Digital Concrete: A Review, Cement and Concrete Research, 123, 105780.
  22. Wolfs, R. J. M., Bos, F. P., and Salet, T. A. M. (2018), Early age mechanical behaviour of 3D printed concrete: Numerical modelling and experimental testing, Cement and Concrete Research, 106, 103-116. https://doi.org/10.1016/j.cemconres.2018.02.001
  23. Wolfs, R., Bos, D., and Salet, T. (2023), Lessons learned of project Milestone: The first 3D printed concrete house in the Netherlands, Materials Today Proceedings, 1-6.
  24. Won, H. J. (2021), Strength characteristics of 3D printed concrete according to the stacking direction, Journal of the Korea AcademiaIndustrial Cooperation Society, 22(2), 632-637 (in Korean). https://doi.org/10.5762/KAIS.2021.22.12.632
  25. Woo, S. J., Yang, J. M., Lee, H. J., and Kwon, H. K. (2021), Comparison of Properties of 3D-Printed Mortar in Air vs. Underwater, Materials, 14(19), 5888.
  26. Zhang, J., and Khoshnevis, B. (2013), Optimal machine operation planning for construction by Contour Crafting, Automation in Construction, 29, 50-67. https://doi.org/10.1016/j.autcon.2012.08.006
  27. Zhu, B., Pan, J., Nematollahi, B., Zhou, Z., Zhang, Y., and Sanjayan, J. (2019), Development of 3D printable engineered cementitious composites with ultra-high tensile ductility for digital construction, Materials & Design, 181, 108088.
  28. Zou, M., Liu, C., Zhang, K., Li, W., Cao, Q., Zhang, L., Gu, T., Zhang, G., and Liu, L. (2023), Evaluation and control of printability and rheological properties of 3D-printed rubberized concrete, Journal of Building Engineering, 80, 107988.