콘크리트학회논문집 (Journal of the Korea Concrete Institute)

  • 제26권3호
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  • Pages.307-313
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  • 2014
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  • 1229-5515(pISSN)
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  • 2234-2842(eISSN)
한국콘크리트학회 (Korea Concrete Institute)
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콘크리트 원형단면에서의 섬유분포계수

Fiber Orientation Factor on a Circular Cross-Section in Concrete Members

  • 이성철 (국제원자력대학원대학교 원자력산업학과) ;
  • 오정환 (에너지기술평가원 해상풍력추진단) ;
  • 조재열 (서울대학교 건설환경공학부)
  • 투고 : 2014.02.10
  • 심사 : 2014.03.26
  • 발행 : 2014.06.30
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초록

섬유보강 콘크리트의 균열 후 인장 거동을 예측하기 위해서는 균열면에 걸쳐 있는 섬유의 개수를 산정하는 섬유분포계수를 합리적으로 예측하는 것이 필요하다. 이 논문에서는 원형단면에서의 섬유분포계수를 분석하기 위해, 콘크리트 압축강도, 단면 크기, 섬유 종류 및 섬유혼입률 등을 변수로 강섬유보강 콘크리트 공시체를 제작하였으며, 제작한 공시체들을 타설 방향에 수직인 방향으로 절단한 후, 절단된 원형 단면에서의 섬유 개수로부터 섬유분포계수를 측정하였다. 측정 결과, 섬유가 타설면에 평행하게 분포할 확률이 증가함에 따라 실제 원형단면에서의 섬유분포계수가 일반적으로 알려진 0.5보다 작은 것으로 나타났다. 또한, 단위 면적 당 섬유 개수가 증가할수록 섬유분포계수가 감소하는 것으로 나타났다. 이 논문에서는 원형단면에서의 섬유분포계수를 합리적으로 예측하기 위해 섬유가 분포할 수 있는 각을 기하학적으로 분석하고, 이로부터 상세 모델과 단순화한 식을 유도하였다. 제안된 모델과 실험에서 측정된 섬유분포계수를 비교한 결과, 제안된 모델이 실제 원형단면에서의 섬유분포계수를 잘 예측하는 것으로 나타났다. 이 연구로부터 확보된 실험 결과 및 제안 모델은 향후 원형단면을 지닌 섬유보강 콘크리트 기둥 부재 등의 구조적 거동 연구에 매우 유용할 것으로 사료된다.

In order to predict the post-cracking tensile behavior of fiber reinforced concrete, it is necessary to evaluate the fiber orientation factor which indicates the number of fibers bridging a crack. For investigation of fiber orientation factor on a circular cross-section, in this paper, cylindrical steel fiber reinforced concrete specimens were casted with the variables of concrete compressive strength, circular cross-section size, fiber type, and fiber volumetric ratio. The specimens were cut perpendicularly to the casting direction so that the fiber orientation factor could be evaluated through counting the number of fibers on the circular cross-section. From the test results, it was investigated that the fiber orientation factor on a circular cross-section was lower than 0.5 generally adopted, as fibers tended to be perpendicular to the casting direction. In addition, it was observed that the fiber orientation factor decreased with an increase of the number of fibers per unit cross-section area. For rational prediction of the fiber orientation factor on a circular section, a rigorous model and a simplified equation were derived through taking account of a possible fiber inclination angle considering the circular boundary surface. From the comparison of the measured data and the predicted values, it was found that the fiber orientation factor was well predicted by the proposed model. The test results and the proposed model can be useful for researches on structural behavior of steel fiber reinforced columns with a circular cross-section.

키워드

참고문헌

  1. Parra-Montesinos, G. J., "High-Performance Fiber-Reinforced Cement Composites: An Alternative for Seismic Design of Structures," ACI Structural Journal, Vol. 102, No. 5, 2005, pp. 668-675. (doi: http://dx.doi.org/10.14359/14662)
  2. Minelli, F. and Vechcio, F. J., "Compression Field Modeling of Fiber-Reinforced Concrete Members Under Shear Loading," ACI Structural Journal, Vol. 103, No. 2, 2006, pp. 244-252. (doi: http://dx.doi.org/10.14359/15182)
  3. Kim, W. S., Kwak, Y. K., and Kim J. B., "Prediction of Flexural Capacities of Steel-Fiber Reinforced Concrete Beams," Journal of the Korea Concrete Institute, Vol. 18, No. 3, 2006, pp. 361-370. https://doi.org/10.4334/JKCI.2006.18.3.361
  4. Oh, Y. H. and Kim, J. H., "Estimation of Flexural and Shear Strength for Steel Fiber Reinforced Flexural Members without Shear Reinforcements," Journal of the Korea Concrete Institute, Vol. 20, No. 2, 2008, pp. 257-267. https://doi.org/10.4334/JKCI.2008.20.2.257
  5. Yang, I. H., Joh, C. B., Kang, S. T., and Kim, B. S., "An Experimental Study on Flexural Behavior of Steel Fiber Reinforced Ultra High Performance Concrete," Journal of the Korea Concrete Institute, Vol. 21, No. 6, 2009, pp. 737-744. (doi: http://dx.doi.org/10.4334/JKCI. 2009.21.6.737)
  6. Lee, S. C., Kim, J. H., Cho, J. Y., and Shin, K. J., "Tension Stiffening of Reinforced High Performance Fiber Reinforced Cementitious Composites (HPFRCC)," Journal of the Korea Concrete Institute, Vol. 22, No. 6, 2010, pp. 859-866. (doi: http://dx.doi.org/10.4334/JKCI. 2010.22.6.859)
  7. Shin, K. J., Kim, J. H., Cho, J. Y., and Lee, S. C., "Flexural Behavior of High Performance Fiber Reinforced Cementitious Composites (HPFRCC) Beam with a Reinforcing Bar," Journal of the Korea Concrete Institute, Vol. 23, No. 2, 2011, pp. 169-176. https://doi.org/10.4334/JKCI.2011.23.2.169
  8. Dinh, H. H., Parra-Montesinos, G. J., and Wight, J. K., "Shear Behavior of Steel Fiber-Reinforced Concrete Beams without Stirrup Reinforcement," ACI Structural Journal, Vol. 107, No. 5, 2010, pp. 597-606. (doi: http:// dx.doi.org/10.14359/51663913)
  9. Susetyo, J., Gauvreau, P., and Vecchio, F. J., "Effectiveness of Steel Fiber as Minimum Shear Reinforcement," ACI Structural Journal, Vol. 108, No. 4, 2011, pp. 488-496. (doi: http://dx.doi.org/10.14359/51682990)
  10. Marti, P., Pfyl, T., Sigrist, V., and Ulaga, T., "Harmonized Test Procedures for Steel Fiber-Reinforced Concrete," ACI Structural Journal, Vol. 96, No. 6, 1999, pp. 676-686. (doi: http://dx.doi.org/10.14359/794)
  11. Voo, J. Y. L. and Foster, S. J., "Variable Engagement Model for Fibre Reinforced Concrete in Tension," Uniciv Report No. R-420, School of Civil and Environmental Engineering, The University of New South Wales, 2003, 86 pp.
  12. Leutbecher, T. and Fehling E., "Crack Width Control for Combined Reinforcement of Rebars and Fibers Exemplified by Ultra-High-Performance Concrete," fib Task Group 8.6, Ultra High Performance Fiber Reinforced Concrete-UHPFRC, 2008, pp. 1-28.
  13. Stroeven, P., "Stereological Principles of Spatial Modeling Applied to Steel Fiber-Reinforced Concrete in Tension," ACI Materials Journal, Vol. 106, No. 3, 2009, pp. 213-222. (doi: http://dx.doi.org/10.14359/56545)
  14. Lee, S.-C., Cho, J.-Y., and Vecchio, F. J., "Diverse Embedment Model for Fiber Reinforced Concrete in Tension: Model Development," ACI Materials Journal, Vol. 108, No. 5, 2011, pp. 516-525. (doi: http://dx.doi.org/10.14359/51683261)
  15. Lee, S.-C., Cho, J.-Y., and Vecchio, F. J., "Diverse Embedment Model for Fiber Reinforced Concrete in Tension: Model Verification," ACI Materials Journal, Vol. 108, No. 5, 2011, pp. 526-535. (doi: http://dx.doi.org/10.14359/51683262)
  16. Lee, S.-C., Cho, J.-Y., and Vecchio, F. J., "Simplified Diverse Embedment Model for Steel Fiber-Reinforced Concrete Elements in Tension," ACI Materials Journal, Vol. 110, No. 4, 2013, pp. 403-412. (doi: http://dx.doi.org/10.14359/51685787)
  17. Aveston, J. and Kelly, A., "Theory of Multiple Fracture of Fibrous Composites," Journal of Materials Science, Vol. 8, No. 3, 1973, pp. 352-362. (doi: http://dx.doi.org/10.1007/BF00550155)
  18. Soroushian, P. and Lee, C.-D., "Distribution and Orientation of Fibers in Steel Fiber Reinforced Concrete," ACI Materials Journal, Vol. 87, No. 5, 1990, pp. 433-439. (doi: http://dx.doi.org/10.14359/1803)
  19. Gettu, R., Gardner, D. R., Saldivar, H., and Barrangan, B. E., "Study of the Distribution and Orientation of Fibers in SFRC Specimens," Materials and Structures, Vol. 38, No. 1, 2005, pp. 31-37. (doi: http://dx.doi.org/10.1007/BF02480572)

피인용 문헌

  1. Flexural Behavior of HPFRCC Members with Inhomogeneous Material Properties vol.8, pp.4, 2015, https://doi.org/10.3390/ma8041934