Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
권호 표지
DOI QR코드

DOI QR Code

Engineering Characteristics of Bio-cemented Soil Mixed with PVA Fiber

PVA섬유를 혼합한 미생물 고결토의 공학적 특성

  • Received : 2016.03.15
  • Accepted : 2016.07.08
  • Published : 2016.08.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, Polyvinyl alcohol (PVA) fiber was used to increase strength (unconfined compressive strength and tensile strength) of bio-cemented sand using microorganism. Ottawa sand was mixed with PVA fibers having three fiber contents (0, 0.4, and 0.8%). The fiber mixed sand was treated 14 times by using Microbially Induced Calcite Precipitation (MICP) which included culture (2 times per day) during 7 days to improve its engineering properties. The Bacillus Sporosarcina pasteurrii (Bacillus sp.) was used for urease activity. The specimen was prepared as a cylindrical specimen of 5 cm in diameter and 10 cm in height. Unconfined compressive strength and tensile strength were measured after cementation. Moreover, calcium carbonate content and SEM analyses were performed with a piece of sample. An average value of unconfined compressive strength increased and then slightly decreased but an average value of tensile strength ratio increased with increasing carbonate content the in same condition. Unconfined compressive strength and tensile strength increased about 30% and 160%, respectively. A strength ratio of unconfined compressive strength to tensile strength representing the brittleness decreased from 8 to 4 when fiber content increased from 0.0 to 0.8%. Such bio-cemented sand can be applied into slope area to prevent its shear failure or increase its tensile strength.

본 연구에서는 미생물 고결토의 압축강도 및 인장강도 개선을 위하여 PVA(Polyvinyl alcohol) 섬유를 혼합하는 연구를 수행하였다. 미생물 고결토의 인장강도 특성을 개선하기 위해 모래에 섬유를 혼합한 다음 미생물 배양액을 7일 동안 1일 2회 총14회 반복주입하여 고결을 유도하였다. 모래는 Ottawa모래를 사용하였으며, 섬유는 PVA섬유를 세 종류의 함유량(0, 0.4, 0.8%)으로 혼합하였다. 미생물은 Bacillus sp. 미생물을 사용하였으며, 공시체의 크기는 직경 5cm, 높이 10cm로 제작하였다. 고결이 완료된 다음 일축압축강도, 인장강도시험을 실시하였으며, 시험 후에는 탄산칼슘 석출량과 SEM 분석을 실시하였다. 섬유의 함유량이 증가함에 따라 평균 일축압축강도는 증가하다가 약간 감소하는 경향을 보이지만, 인장강도는 점진적으로 증가하는 경향을 보였다. 탄산칼슘 석출량이 유사하다고 볼 경우, 압축강도는 약 30%의 강도 증가를 발생하였지만, 인장강도는 약 160%의 강도 증가를 보였다. 공시체의 취성도를 나타내는 압축강도와 인장강도의 비는 섬유 함유량이 0%인 경우 약 8 정도에서 섬유 함유량이 0.8%로 증가할 경우 4까지 감소하였으며, 동일한 조건에서 섬유의 함유량이 증가할수록 인장강도의 증가 폭은 커짐을 확인하였다. 이러한 섬유를 혼합한 미생물 고결토는 전단파괴 방지 및 인장강도 증진을 요하는 사면 등의 분야에 적용 가능 할 것으로 판단된다.

Keywords

References

  1. Ahmed, S. F. U. and Mihashi, H. (2011), "Strain Hardening behavior of Lightweight Hybrid Polyvinyl Alcohol (PVA) Fiber Reinforced Cement Composites", Materials and Structures, Vol.44, No.6, pp. 1179-1191. https://doi.org/10.1617/s11527-010-9691-8
  2. Al Qabany, A. and Soga, K. (2013), "Effect of Chemical Treatment used in MICP on Engineering Properties of Cemented Soils", Geotechnique, Vol.63, No.4, pp.331-339. https://doi.org/10.1680/geot.SIP13.P.022
  3. Burbank, M., Weaver, T., Green, T., Williams, B., and Crawford, R. (2011), "Precipitation of Calcite by Indigenous Microorganisms to Strengthen Liquefiable Soils", Geomicrobiology Journal, Vol.28, No.4, pp.301-312. https://doi.org/10.1080/01490451.2010.499929
  4. Burbank, M.B., Weaver, T.J., Lewis, R., Williams, T., Williams, B., and Crawford, R. (2012), "Geotechnical Tests of Sand Following Bio-induced Calcite Precipitation Catalyzed by Indigenous Bacteria", Journal of Geotechnical and Geoenvironmental Egnineering, Vol. 139, No.6, pp.928-936.
  5. Burbank, M., Weaver, T., Lewis, R., Williams, T., Williams, B., and Crawford, R. (2013), "Geotechnical Tests of Sands Following Bioinduced Calcite Precipitation Catalyzed by Indigenous Bacteria", J. Geotech. Geoenviron. Eng., Vol.139, No.6, pp.928-936. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000781
  6. Chu, J., Ivanov, V., and Stabnikov, V. (2012), "Microbially Induced Calcium Carbonate Precipitation on Surface or in the Bulk of Soil", Geomicrobiol. J., Vol.29, No.6, pp.544-549. https://doi.org/10.1080/01490451.2011.592929
  7. DeJong, J.T., Soga, K.S., Kavazanjian, E., Burns, S., van Paassen, L., Fragaszy, R., Al Qabany, A., Aydilek, A., Bang, S.S., Burbank, M., Caslake, L., Chen, C.Y., Cheng, X., Chu, J., Ciurli, S., Fauriel, S., Filet, A.E., Hamdan, N., Hata, T., Inagaki, Y., Jefferis, S., Kuo, M., Larrahondo, J., Manning, D., Martinez, B., Mortensen, B., Nelson, D., Palomino, A., Renforth, P., Santamarina, J.C., Seagren, E.A., Tanyu, B., Tsesarsky, M., and Weaver, T. (2013), "Biogeochemical Processes and Geotechnical Applications: Progress, Opportunities and Challenges", Geotechnique, Vol.63, No.4, pp. 287-301. https://doi.org/10.1680/geot.SIP13.P.017
  8. Griffith, A. A. (1924), "Theory of rupture", Proc. 1st. Int. Congr. Applied Rock Mechanics, Delft, pp.55-63.
  9. Li, M., Li, L., Ogbonnaya, U., Wen, K., Tian, A., and Amini, F. (2015), "Influence of Fiber Addition on Mechanical Properties of MICP-Treated Sand", J. Mater. Civ. Eng., Vol.28, No.4, pp. 04015166.
  10. Mitchell, J. K. and Santamarina, J. C. (2005), "Biological Considerations in Geotechnical Engineering", J. Geotech. Geoenviron. Eng., Vol.131, No.10, pp.1222-1233. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:10(1222)
  11. Park, S. S. (2011), "Unconfined Compressive Strength and Ductility of Fiber-reinforced Cemented Sand", Construction and Building Materials, Vol.25, No.2, pp.1134-1138. https://doi.org/10.1016/j.conbuildmat.2010.07.017
  12. Park, S., Choi, S., and Nam, I. (2014), "Effect of Plant-Induced Calcite Precipitation on the Strength of Sand", J. Mater. Civ. Eng., Vol.26, No.8, pp.06014017 1-5. https://doi.org/10.1061/(ASCE)MT.1943-5533.0001029
  13. Park, S. S. and Lee, J. W. (2014), "Study on the Direct Tensile Test for Cemented Soils using a Built-in Cylinder", Journal of the Korean Society of Civil Engineers, Vol.34, No.5, pp.1505-1516. https://doi.org/10.12652/Ksce.2014.34.5.1505
  14. van Paassen, L. A. (2009), "Biogrout (ground improvement by microbially induced carbonate precipitation)", PhD thesis, Delft University of Technology, the Netherlands.
  15. van Paassen, L. A., Ghose, R., van der Linden, T. J. M., van der Star, W. R. L., and van Loosdrecht, M. C. M. (2010), "Quantifying Biomediated Ground Improvement by Ureolysis: Large-scale Biogrout Experiment", J. Geotech. Geoenviron. Eng., Vol.136, No.12, pp. 1721-1728. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000382
  16. Whiffin, V. S., van Paassen, L. A., and Harkes, M. P. (2007), "Microbial Carbonate Precipitation as a Soil Improvement Technique", Geomicrobiol. J., Vol.24, No.5, pp.417-423. https://doi.org/10.1080/01490450701436505
  17. Zhang, Y., Guo, H. X., and Cheng, X. H. (2014), "Influences of Calcium Sources on Microbially Induced Carbonate Precipitation in Porous Media", Materials Research Innovations, Vol.18, No.2, pp.79-84.
  18. Zhao, Q., Li, L., Li, C., Li, M., Amini, F., and Zhang, H. (2014), "Factors Affecting Improvement of Engineering Properties of MICPTreated Soil Catalyzed by Bacteria and Urease", J. Mater. Civ. Eng., Vol.26, No.12, pp.04014094 1-10. https://doi.org/10.1061/(ASCE)MT.1943-5533.0001013