An Experimental and Numerical Investigation on the Bending Behavior of Fiber Reinforced Concrete Beams

Abstract

The effects of hooked end steel and polypropylene (PP) fibers on the behavior of large-scale doubly reinforced concrete beams under flexure were investigated using experimental and numeric methods. For this purpose, a total of eight beam specimens consisting in two groups were produced in the laboratory and three-point bending tests were conducted under monotonically increasing load. The beams in the groups were designed to have 0.86 and 1.30% tensile reinforcement ratios leading to either flexural or shear critical sections. Three out of eight were produced to be control samples and did not have any fiber additive while remaining five had 0, 0.5 and 1.0% steel or PP fibers by volume. Experimental results showed that the existence of 0.5% either type of fiber in densely reinforced specimens contributed to shear strength and allowed flexural capacities to be fully used instead of an improvement in the capacity. However, when the steel fiber ratio increased to 1.0% flexural capacity was enhanced by 10% for both type of beams. After the experimental study, the beams numerically modeled using nonlinear finite element method and flexural stiffness before yielding as well as yield strength with load carrying capacities were found to be consistent with that of experiments specifically for the beams having stirrup and steel fibers.

Keywords

• Fiber-reinforced concrete (FRC)
• bending behavior of FRC beams
• polypropylene and hooked end steel fibers
• nonlinear finite element analysis

References

1. Saatçi, S., ve Batarlar, B., Çelik fiber katkılı etriyesiz betonarme kirişlerin davranışı. Journal of the Faculty of Engineering and Architecture of Gazi University, 32:4, 1143-1154, 2017
2. Folino, P., et. al., Comprehensive analysis of fiber reinforced concrete beams with conventional reinforcement. Engineering Structures, 202, 2020
3. Amin, A. and Foster, S. J., Shear strength of steel fibre reinforced concrete beams with stirrups. Engineering Structures, 111, 323-332, 2016
4. Arslan, G., et al. An experimental study on the shear strength of SFRC beams without stirrups. Journal of Theoretical and Applied Mechanics, 55:4, 1205-1217, 2017
5. Lee, S.,-G., et al. Analysis of steel fiber-reinforced concrete elements subjected to shear. ACI Structural Journal, 113:2, 275-285, 2016
6. Mahmood, S., M., F., et al. Flexural performance of steel fibre reinforced concrete beams designed for moment redistribution. Engineering Structures, 177, 695-706, 2018
7. Xu, C., et al. Experimental investigation of the behavior composite steel-concrete composite beams containing different amounts of steel fibres and conventional reinforcement. Construction and Building Materials, 202, 23-36, 2019
8. Dwarakanath, H., V., and Nagaraj, T., S., Deformational Behavior of Reinforced Fiber Reinforced Concrete Beams in Bending. Journal of Structural Engineering, ASCE, 118:10, 2691-2698, 1992.

9. Vandewalle, L., Cracking behavior of concrete beams reinforced with a combination of ordinary reinforcement and steel fibers. Materials and Structures, 33, 164-170, 2000.
10. Dinh, H., H., et al. Shear behavior of steel fiber reinforced concrete beams without stirrup reinforcement. ACI Structural Journal, 107:5, 597-606, 2010
11. Yoo, D., -Y., et al. Feasibility of replacing minimum shear reinforcement with steel fibers for suitable high-strength concrete beams. Engineering Structures, 147, 207-222, 2017
12. Abbas, A., A., et al. Shear behavior of steel-fibre-reinforced concrete simply supported beams. Structures and Buildings, 167:SB9, 544-558, 2014
13. Oh, B., H., Flexural Analysis of Reinforced Concrete Beams Containing Steel Fibers. Journal of Structural Engineering, ASCE, 118:10, 2821-2835, 1992.
14. Ashour, S., A., et al., Effect of the concrete compressive strength and tensile reinforcement ratio on the flexural behavior of fibrous concrete beams. Engineering Structures, 22, 1145-1158, 2000.
15. Lim, T-Y., et al., Behavior of Reinforced Steel-Fiber-Concrete Beams in Flexure. Journal of Structural Engineering, ASCE, 113:12, 2439-2458, 1987.
16. Ning, X., et al., Experimental study and prediction model for flexural behavior of reinforced SCC beam containing steel fibers. Construction and Building Materials, 93, 644-653, 2015.
17. Wu, Y., Flexural Strength and Behavior of Polypropylene Fiber Reinforced Concrete Beams. Journal of Wuhan University of Technology- Mater. Sci. Ed., 17:2, 54-57, 2002.
18. Alhozaimy, A., M., et al., Mechanical Properties of Polypropylene Fiber Reinforced Concrete and the Effects of Pozzolanic Materials. Cement and Concrete Composites, 18, 85-92, 1996.
19. Tutanji, H., A., Properties of polypropylene fiber reinforced silica fume expansive-cement concrete. Construction and Building Materials, 13, 171-177, 1999.
20. Banthia, N., and Gupta, R., Influence of polypropylene fiber geometry on plastic shrinkage cracking in concrete. Cement and Concrete Research, 36, 1263-1267, 2006.
21. Sivakumar, A. and Santhanam, M., Mechanical properties of high strength concrete reinforced with metallic and non-metallic fibres. Cement and Concrete Composites, 29, 603-608, 2007.
22. Hsie, M., et al., Mechanical properties of polypropylene hybrid fiber-reinforced concrete. Materials Science and Engineering A, 494, 153-157, 2008.
23. Monteiro, V., M., A., M., et al. On the mechanical behavior of polypropylene, steel and hybrid fiber reinforced self-consolidating concrete. Construction and Building Materials, 188, 290-291, 2018
24. Karimipour, A., and Ghalehnovi, M., Comparison of the effect of the steel and polypropylene fibres on the flexural behavior of recycled aggregate concrete beams. Structures, 29, 129-146, 2021
25. Vecchio, F. J., and Wong, P., S., VecTor2 & FormWorks User’s Manual. 2002
26. TS500, Requirements for design and construction of reinforced concrete structures. Turkish Standard Institutes, Ankara, 2000
27. ACI 211.1, Standard practice for selecting proportions for normal, heavyweight and mass concrete, ACI Manual of Concrete Practice, Part 1, 211.1-1 to 211.1-38, 1994
28. TS802, Design of concrete mixes, Turkish Standard Institute, Ankara, 2016
29. TS EN 206, Concrete – Specification, performance, production and conformity, Turkish Standard Institute, Ankara, 2014
30. ACI318, Building code requirements for structural concrete, American Concrete Institute, 2019
31. TBDY, Türkiye bina deprem yönetmeliği, Afet ve Acil Durum Yönetimi Başkanlığı, Resmî Gazete, 2018
32. Ersoy, U., Betonarme kiriş ve kolonların moment kapasitelerinin saptanması. İMO Teknik Dergi, 9:44, 1781-1798, 1998
33. Akan, Ç., Lif katkılı betonarme kirişlerin deneysel ve sayısal incelenmesi. Yüksek Lisans Tezi, İzmir Kâtip Çelebi Üniversitesi, 2022.
34. Ersoy, U., Özcebe, G. and Tankut, T., Reinforced concrete. METU Press, Ankara, 2016
35. Sahoo, D., R., et al. Influence of steel and polypropylene fibers on flexural behavior of RC beams. Journal of Materials in Civil Engineering, 27:8, 2015
36. Meda, A., et al. Flexural behavior of RC beams in fibre reinforced concrete. Composites: Part B, 43:8, 2930-2937, 2012.
37. Vecchio, F., J., and Collins, M., P., The modified compression-field theory for reinforced concrete elements subjected to shear. ACI Structural Journal, 83:2, 219-231, 1986.