The evaluation of the content of fibers in steel fiber reinforced structures and image analysis
Abstract
The distribution of fiber orientation is an important factor in determining the mechanical properties of fiber-reinforced concrete. This study proposes a new image analysis technique for improving the evaluation accuracy of fiber orientation distribution in the sectional image of fibers reinforced concrete. The article is devoted to research the systematic evaluation of fiber-cuts through the image processing software. Mathematical representation of the final dispersal of fibers in steel fiber-reinforced concrete is incorporated into a programmed evaluation software. The software detects fibers and classified according to their axes of rotation angle and size of the identified ellipse detection area. Image processing algorithm and detecting fibers has been developed only for these research purposes. Detection area is randomly inserted via steel fiber reinforced concrete structure. The results show the average value of uniformity in the fiber-samples produced in the laboratory.
Keyword : fiber reinforced concrete, dispersion, uniformity, digital photography, image processing, beams
How to Cite
Ďubek, M., Makýš, P., Ďubek, S., & Petro, M. (2018). The evaluation of the content of fibers in steel fiber reinforced structures and image analysis. Journal of Civil Engineering and Management, 24(3), 183-192. https://doi.org/10.3846/jcem.2018.1642
This work is licensed under a Creative Commons Attribution 4.0 International License.
References
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Barbier, E. 1860. Note sur le problème de l’aiguille et le jeu du joint couvert, Journal de Mathématiques Pures et Appliquées 2(5): 273–286.
Bradski, G. 2000. The OpenCV library [online], [cited 10 March 2018]. Available from Internet: http://www.drdobbs.com/open-source/the-opencv-library/184404319
Deeb, R.; Karihaloo, B. L.; Kulasegaram, S. 2014. Reorientation of short steel fibres during the flow of self-compacting concrete mix and determination of the fibre orientation factor, Cement and Concrete Research 56: 112–120. https://doi.org/10.1016/j.cemconres.2013.10.002
Dupont, D.; Vandewalle, L. 2005. Distribution of steel fibres in rectangular sections, Cement and Concrete Composites 27(3): 391–398. https://doi.org/10.1016/j.cemconcomp.2004.03.005
Eberhardt, C.; Clarke, A.; Vincent, M.; Giroud, T.; Flouret, S. 2001. Fibre-orientation measurements in short-glass-fibre composites – II: A quantitative error estimate of the 2d image analysis technique, Composites Science and Technology 61(13): 1961–1974. https://doi.org/10.1016/S0266-3538(01)00106-3
Eik, M. 2014. Orientation of short steel fibres in concrete: measuring and modelling: PhD thesis. Faculty of Civil Engineering, Institute of Cybernetics at Tallinn University of Technology, and Aalto University School of Engineering.
Eik, M.; Herrmann, H. 2012. Raytraced images for testing the reconstruction of fibre orientation distributions, Proceedings of the Estonian Academy of Sciences 61(2): 128–136. https://doi.org/10.3176/proc.2012.2.05
EN 14845:2007 Test methods for fibres in concrete – Part 1: Reference concretes. European Standard, 2007.
Ferrara, L.; Bamonte, P.; Caverzan, A.; Musa, A.; Sanal, I. 2012. A comprehensive methodology to test the performance of steel fibre reinforced self-compacting concrete (SFR-SCC), Construction and Building Materials 37: 406–424. https://doi.org/10.1016/j.conbuildmat.2012.07.057
Ferrara, L.; Meda, A. 2006. Relationships between fibre distribution, workability and the mechanical properties of SFRC applied to precast roof elements, Materials and Structures 39(4): 411–420. https://doi.org/10.1617/s11527-005-9017-4
Ferrara, L.; Park, Y. D.; Shah, S. P. 2008. Correlation among fresh state behaviour, fiber dispersion and toughness properties of SFRCs, Journal of Materials in Civil Engineering 20(7). https://doi.org/10.1061/(ASCE)0899-1561(2008)20:7(493)
Gettu, R.; Gardner, D. R.; Saldivar, H.; Barrgán, B. E. 2005. Study of the distribution and orientation of fibers in SFRC specimens, Materials and Structures 38(1): 31–37. https://doi.org/10.1007/BF02480572
Gregorová, V.; Štefunková, Z. 2016. Influence of glass fibres to volume changes in cement composites, Czech Journal of Civil Engineering 2(1): 38–43.
Grunewald, S.; Walraven, J. C.; Obladen, B.; Zegwaard, J. W.; Langbroek, M.; Nemegeer, D. 2003. Tunnel segments of selfcompacting steel fibre reinforced concrete, in International RILEM Symposium on Selfcompacting Concrete. RILEM Publications SARL, Paris, France, 715–724.
Henry, M.; Darma, I. S.; Sugiyama, T. 2014. Analysis of the effect of heating and recurring on the microstructure of high-strength concrete using X-ray CT, Construction and Building Materials 67(Part A): 37–46.
Kang, S. T.; Lee, B. Y.; Kim, J-K.; Kim, Y. Y. 2011. The effect of fibre distribution characteristics on the flexural strength of steel fibre-reinforced ultra high strength concrete, Construction and Building Materials 25: 2450–2457. https://doi.org/10.1016/j.conbuildmat.2010.11.057
Kang, S-T.; Kim, J.-K. 2012. Numerical simulation of the variation of fiber orientation distribution during flow molding of ultra high performance cementitious composites (UHPCC), Cement and Concrete Composites 34: 208–217. https://doi.org/10.1016/j.cemconcomp.2011.09.015
Katzer, J.; Domski, J. 2012. Quality and mechanical properties of engineered steel fibres used as reinforcement for concrete, Construction and Building Materials 34: 243–248. https://doi.org/10.1016/j.conbuildmat.2012.02.058
Kim, K. Y.; Yun, T. S.; Choo, J.; Kang, D. H.; Shin, H. S. 2012. Determination of air-void parameters of hardened cement-based materials using X-ray computed tomography, Construction and Building Materials 37: 93–101. https://doi.org/10.1016/j.conbuildmat.2012.07.012
Komárková, T. 2016. Design of methodology for non-destructive testing of steel-reinforced-fiber-concrete, Key Engineering Materials 714: 179–185. https://doi.org/10.4028/www.scientific.net/KEM.714.179
Kwon, S. H.; Kang, S.-T.; Lee, B. Y.; Kim, J.-K. 2012. The variation of flow-dependent tensile behavior in radial flow dominant placing of ultra high performance fiber reinforced cementitious composites (UHPFRCC), Construction and Building Materials 33: 109–121. https://doi.org/10.1016/j.conbuildmat.2012.01.006
Lee, B. Y.; Kang, S.-T.; Yun, H.-B.; Kim, Y. Y. 2016. Improved sectional image analysis technique for evaluating fiber orientations in fiber-reinforced cement-based materials, Materials 9(1): 42. https://doi.org/10.3390/ma9010042
Lee, B. Y.; Kim, J. K.; Kim, J. S.; Kim, Y. Y. 2009. Quantitative evaluation technique of Polyvinyl Alcohol (PVA) fiber dispersion in engineered cementitious composites, Cement and Concrete Composites 31: 408–417. https://doi.org/10.1016/j.cemconcomp.2009.04.002
Lee, J.-H.; Cho, B.; Choi, E. 2017. Flexural capacity of fiber reinforced concrete with a consideration of concrete strength and fiber content, Construction and Building Materials 138: 222–231. http://dx.doi.org/10.1016/j.conbuildmat.2017.01.096
Leone, M.; Centonze, G.; Colonna, D.; Micelli, F.; Aiello, M. A. 2018. Fiber-reinforced concrete with low content of recycled steel fiber: Shear behavior, Construction and Building Materials 161(10): 141–155. https://doi.org/10.1016/j.conbuildmat.2017.11.101
Liu, J. P.; Li, C. F.; Liu, J. Z.; Cui, G.; Yang, Z. 2013. Study on 3D spatial distribution of steel fibers in fiber reinforced cementitious composites through micro-CT technique, Construction and Building Materials 48: 656–666. https://doi.org/10.1016/j.conbuildmat.2013.07.052
Martinie, L.; Roussel, N. 2011. Simple tools for fiber orientation prediction in industrial practice, Cement and Concrete Research 41(10): 993–1000. https://doi.org/10.1016/j.cemconres.2011.05.00
Mishurova, T.; Rachmatulin, N.; Fontana, P.; Oesch, T.; Sevostianov, I. 2018. Evaluation of the probability density of inhomogeneous fiber orientations by computed tomography and its application to the calculation of the effective properties of a fiber-reinforced composite, International Journal of Engineering Science 122: 14–29. https://doi.org/10.1016/j.ijengsci.2017.10.002
Mobasher, B.; Stang, H.; Shah, S. 1990. Microcracking in fiber reinforced concrete, Cement and Concrete Research 20(5): 665–676. https://doi.org/10.1016/0008-8846(90)90001-E
Nunes, S.; Pimentel, M.; Carvalho, A. 2016. Non-destructive assessment of fibre content and orientation in UHPFRC layers based on a magnetic method, Cement and Concrete Composites 72: 66–79. https://doi.org/10.1016/j.cemconcomp.2016.05.024
Nunes, S.; Pimentel, M.; Ribeiro, F.; Milheiro-Oliveira, P.; Carvalho, A. 2017. Estimation of the tensile strength of UHPFRC layers based on non-destructive assessment of the fibre content and orientation, Cement and Concrete Composites 83: 222–238. http://dx.doi.org/10.1016/j.cemconcomp.2017.07.019
Poitou, A.; Chinesta, F.; Bernier, G. 2001. Orienting fibers by extrusion in reinforced reactive powder concrete, Journal of Engineering Mechanics 127(6). https://doi.org/10.1061/(ASCE)0733-9399(2001)127:6(593)
Ponikiewski, T.; Golaszewski, J. 2012. The new approach to the study of random distribution of fibres in high performance self-compacting concrete, Cement Wapno Beton 17(3): 165.
Ponikiewski, T.; Gołaszewski, J. 2015. X-ray investigation and modelling of steel fibres In self-compacting concrete, Transactions of the VŠB – Technical University of Ostrava, Civil Engineering Series 15(2). https://doi.org/10.1515/tvsb-2015-0020
Ponikiewski, T.; Gołaszewski, J.; Rudzki, M.; Bugdol, M. 2015. Determination of steel fibres distribution in self-compacting concrete beams using X-ray computed tomography, Archives of Civil and Mechanical Engineering 15(2): 558–568. https://doi.org/10.1016/j.acme.2014.08.008
Ponikiewski, T.; Katzer, J.; Bugdol, M.; Rudzki, M. 2015. X-ray computed tomography harnessed to determine 3D spacing of steel fibres in self compacting concrete (SCC) slabs, Construction and Building Materials 74: 102–108. https://doi.org/10.1016/j.conbuildmat.2014.10.024
Roussel, N.; Geiker, M. R.; Dufour, F.; Thrane, L. N.; Szabo, P. 2007. Computational modeling of concrete flow: general overview, Cement and Concrete Research 37: 1298–1307. https://doi.org/10.1016/j.cemconres.2007.06.007
Rudzki, M.; Bugdol, M.; Ponikiewski, T. 2013. Determination of steel fibers orientation in SCC using computed tomography and digital image analysis methods, Cement Wapno Beton 80: 257–263.
Şanal, İ.; Ozyurt, N. 2013. To what extent does the fiber orientation affect mechanical performance?, Construction and Building Materials 44: 671–681. https://doi.org/10.1016/j.conbuildmat.2013.03.079
Špak, M.; Kozlovská, M.; Struková, Z.; Bašková, R. 2016. Comparison of conventional and advanced concrete technologies in terms of construction efficiency, Advances in Materials Science and Engineering. Article ID 1903729. https://doi.org/10.1155/2016/1903729
Stähli, P. 2008. Ultra-fluid oriented hybrid-fibre-concrete: Dissertation thesis. Swiss Federal Institute of Technology Zurich, Switzerland.
Stähli, P.; van Mier, J. G. M. 2007. Manufacturing, fibre anisotropy and fracture of hybrid fibre concrete, Engineering Fracture Mechanics 74(1–2): 223–242. https://doi.org/10.1016/j.engfracmech.2006.01.028
Stroeven, P.; Guo, Z. 2008. Distribution and orientation of fibers in the perspective of concrete’s mechanical properties, fibre reinforced concrete: Design and applications, in Proceedings of the 7th RILEM International Symposium, Paris, France, 145–154.
Švec, O.; Žirgulis, G.; Bolander, J. E.; Stang, H. 2014. Influence of formwork surface on the orientation of steel fibres within self-compacting concrete and on the mechanical properties of cast structural elements, Cement and Concrete Composites 50: 60–72. https://doi.org/10.1016/j.cemconcomp.2013.12.002
Svoboda, P.; Doležal, J. 2008. Výroba a kladenie čerstvého drôtikového betónu na priemyselné podlahy, Stavebné materiály 4(5): 46–48.
The fib model code for concrete structures. Ernst & Sohn, 2013.
Tosun-Felekoğlu, K.; Felekoğlu, B.; Ranade, R.; Lee, B. Y.; Li, V. C. 2014. The role of flaw size and fiber distribution on tensile ductility of PVA-ECC, Composites Part B: Engineering 56: 536–545. https://doi.org/10.1016/j.compositesb.2013.08.089
Wang, R.; Gao, X.; Zhang, J.; Han, G. 2018. Spatial distribution of steel fibers and air bubbles in UHPC cylinder determined by X-ray CT method, Construction and Building Materials 160: 39–47. https://doi.org/10.1016/j.conbuildmat.2017.11.030
Wang, R; Gao, X.; Huang, H. 2017. Influence of rheological properties of cement mortar on steel fiber distribution in UHPC, Construction and Building Materials 144: 65–73. https://doi.org/10.1016/j.conbuildmat.2017.03.173
Wong, R. C. K.; Chau, K. T. 2005. Estimation of air void and aggregate spatial distributions in concrete under uniaxial compression using computer tomography scanning, Cement and Concrete Research 35(8): 1566–1576. https://doi.org/10.1016/j.cemconres.2004.08.016
Yang, C. J.; Jin, L. B.; Chen, D. C.; Qi, J. P. 2013. Practical measurement for steel fiber distribution of the SFRC beams, Applied Mechanics and Materials 256–259: 840–843. https://doi.org/10.4028/www.scientific.net/AMM.256-259.840
Yong-zhi, L. 2000. Deutscher Ausschuss für Stahlbeton im DIN Deutsches Institut für Normung e.V. 494DAfStb-Heft 494. Tragverhalten von Stahlfaserbeton. Beuth Verlag GmbH, Berlin.
Zhu, Y. T.; Blumenthal, W. R.; Lowe, T. C. 1997. Determination of non-symmetric 3-D fiber orientation distribution and average fiber length in short-fiber composites, Journal of Composite Materials 31(13): 1287–1301. https://doi.org/10.1177/002199839703101302
Žirgulis, G.; Švec, O.; Sarmiento, E. V.; Geiker, M. R.; Cwirzen, A.; Kanstad, T. 2016. Importance of quantification of steel fibre orientation for residual flexural tensile strength in FRC, Materials and Structures 49: 3861–3877. https://doi.org/10.1617/s11527-015-0759-3
Barbier, E. 1860. Note sur le problème de l’aiguille et le jeu du joint couvert, Journal de Mathématiques Pures et Appliquées 2(5): 273–286.
Bradski, G. 2000. The OpenCV library [online], [cited 10 March 2018]. Available from Internet: http://www.drdobbs.com/open-source/the-opencv-library/184404319
Deeb, R.; Karihaloo, B. L.; Kulasegaram, S. 2014. Reorientation of short steel fibres during the flow of self-compacting concrete mix and determination of the fibre orientation factor, Cement and Concrete Research 56: 112–120. https://doi.org/10.1016/j.cemconres.2013.10.002
Dupont, D.; Vandewalle, L. 2005. Distribution of steel fibres in rectangular sections, Cement and Concrete Composites 27(3): 391–398. https://doi.org/10.1016/j.cemconcomp.2004.03.005
Eberhardt, C.; Clarke, A.; Vincent, M.; Giroud, T.; Flouret, S. 2001. Fibre-orientation measurements in short-glass-fibre composites – II: A quantitative error estimate of the 2d image analysis technique, Composites Science and Technology 61(13): 1961–1974. https://doi.org/10.1016/S0266-3538(01)00106-3
Eik, M. 2014. Orientation of short steel fibres in concrete: measuring and modelling: PhD thesis. Faculty of Civil Engineering, Institute of Cybernetics at Tallinn University of Technology, and Aalto University School of Engineering.
Eik, M.; Herrmann, H. 2012. Raytraced images for testing the reconstruction of fibre orientation distributions, Proceedings of the Estonian Academy of Sciences 61(2): 128–136. https://doi.org/10.3176/proc.2012.2.05
EN 14845:2007 Test methods for fibres in concrete – Part 1: Reference concretes. European Standard, 2007.
Ferrara, L.; Bamonte, P.; Caverzan, A.; Musa, A.; Sanal, I. 2012. A comprehensive methodology to test the performance of steel fibre reinforced self-compacting concrete (SFR-SCC), Construction and Building Materials 37: 406–424. https://doi.org/10.1016/j.conbuildmat.2012.07.057
Ferrara, L.; Meda, A. 2006. Relationships between fibre distribution, workability and the mechanical properties of SFRC applied to precast roof elements, Materials and Structures 39(4): 411–420. https://doi.org/10.1617/s11527-005-9017-4
Ferrara, L.; Park, Y. D.; Shah, S. P. 2008. Correlation among fresh state behaviour, fiber dispersion and toughness properties of SFRCs, Journal of Materials in Civil Engineering 20(7). https://doi.org/10.1061/(ASCE)0899-1561(2008)20:7(493)
Gettu, R.; Gardner, D. R.; Saldivar, H.; Barrgán, B. E. 2005. Study of the distribution and orientation of fibers in SFRC specimens, Materials and Structures 38(1): 31–37. https://doi.org/10.1007/BF02480572
Gregorová, V.; Štefunková, Z. 2016. Influence of glass fibres to volume changes in cement composites, Czech Journal of Civil Engineering 2(1): 38–43.
Grunewald, S.; Walraven, J. C.; Obladen, B.; Zegwaard, J. W.; Langbroek, M.; Nemegeer, D. 2003. Tunnel segments of selfcompacting steel fibre reinforced concrete, in International RILEM Symposium on Selfcompacting Concrete. RILEM Publications SARL, Paris, France, 715–724.
Henry, M.; Darma, I. S.; Sugiyama, T. 2014. Analysis of the effect of heating and recurring on the microstructure of high-strength concrete using X-ray CT, Construction and Building Materials 67(Part A): 37–46.
Kang, S. T.; Lee, B. Y.; Kim, J-K.; Kim, Y. Y. 2011. The effect of fibre distribution characteristics on the flexural strength of steel fibre-reinforced ultra high strength concrete, Construction and Building Materials 25: 2450–2457. https://doi.org/10.1016/j.conbuildmat.2010.11.057
Kang, S-T.; Kim, J.-K. 2012. Numerical simulation of the variation of fiber orientation distribution during flow molding of ultra high performance cementitious composites (UHPCC), Cement and Concrete Composites 34: 208–217. https://doi.org/10.1016/j.cemconcomp.2011.09.015
Katzer, J.; Domski, J. 2012. Quality and mechanical properties of engineered steel fibres used as reinforcement for concrete, Construction and Building Materials 34: 243–248. https://doi.org/10.1016/j.conbuildmat.2012.02.058
Kim, K. Y.; Yun, T. S.; Choo, J.; Kang, D. H.; Shin, H. S. 2012. Determination of air-void parameters of hardened cement-based materials using X-ray computed tomography, Construction and Building Materials 37: 93–101. https://doi.org/10.1016/j.conbuildmat.2012.07.012
Komárková, T. 2016. Design of methodology for non-destructive testing of steel-reinforced-fiber-concrete, Key Engineering Materials 714: 179–185. https://doi.org/10.4028/www.scientific.net/KEM.714.179
Kwon, S. H.; Kang, S.-T.; Lee, B. Y.; Kim, J.-K. 2012. The variation of flow-dependent tensile behavior in radial flow dominant placing of ultra high performance fiber reinforced cementitious composites (UHPFRCC), Construction and Building Materials 33: 109–121. https://doi.org/10.1016/j.conbuildmat.2012.01.006
Lee, B. Y.; Kang, S.-T.; Yun, H.-B.; Kim, Y. Y. 2016. Improved sectional image analysis technique for evaluating fiber orientations in fiber-reinforced cement-based materials, Materials 9(1): 42. https://doi.org/10.3390/ma9010042
Lee, B. Y.; Kim, J. K.; Kim, J. S.; Kim, Y. Y. 2009. Quantitative evaluation technique of Polyvinyl Alcohol (PVA) fiber dispersion in engineered cementitious composites, Cement and Concrete Composites 31: 408–417. https://doi.org/10.1016/j.cemconcomp.2009.04.002
Lee, J.-H.; Cho, B.; Choi, E. 2017. Flexural capacity of fiber reinforced concrete with a consideration of concrete strength and fiber content, Construction and Building Materials 138: 222–231. http://dx.doi.org/10.1016/j.conbuildmat.2017.01.096
Leone, M.; Centonze, G.; Colonna, D.; Micelli, F.; Aiello, M. A. 2018. Fiber-reinforced concrete with low content of recycled steel fiber: Shear behavior, Construction and Building Materials 161(10): 141–155. https://doi.org/10.1016/j.conbuildmat.2017.11.101
Liu, J. P.; Li, C. F.; Liu, J. Z.; Cui, G.; Yang, Z. 2013. Study on 3D spatial distribution of steel fibers in fiber reinforced cementitious composites through micro-CT technique, Construction and Building Materials 48: 656–666. https://doi.org/10.1016/j.conbuildmat.2013.07.052
Martinie, L.; Roussel, N. 2011. Simple tools for fiber orientation prediction in industrial practice, Cement and Concrete Research 41(10): 993–1000. https://doi.org/10.1016/j.cemconres.2011.05.00
Mishurova, T.; Rachmatulin, N.; Fontana, P.; Oesch, T.; Sevostianov, I. 2018. Evaluation of the probability density of inhomogeneous fiber orientations by computed tomography and its application to the calculation of the effective properties of a fiber-reinforced composite, International Journal of Engineering Science 122: 14–29. https://doi.org/10.1016/j.ijengsci.2017.10.002
Mobasher, B.; Stang, H.; Shah, S. 1990. Microcracking in fiber reinforced concrete, Cement and Concrete Research 20(5): 665–676. https://doi.org/10.1016/0008-8846(90)90001-E
Nunes, S.; Pimentel, M.; Carvalho, A. 2016. Non-destructive assessment of fibre content and orientation in UHPFRC layers based on a magnetic method, Cement and Concrete Composites 72: 66–79. https://doi.org/10.1016/j.cemconcomp.2016.05.024
Nunes, S.; Pimentel, M.; Ribeiro, F.; Milheiro-Oliveira, P.; Carvalho, A. 2017. Estimation of the tensile strength of UHPFRC layers based on non-destructive assessment of the fibre content and orientation, Cement and Concrete Composites 83: 222–238. http://dx.doi.org/10.1016/j.cemconcomp.2017.07.019
Poitou, A.; Chinesta, F.; Bernier, G. 2001. Orienting fibers by extrusion in reinforced reactive powder concrete, Journal of Engineering Mechanics 127(6). https://doi.org/10.1061/(ASCE)0733-9399(2001)127:6(593)
Ponikiewski, T.; Golaszewski, J. 2012. The new approach to the study of random distribution of fibres in high performance self-compacting concrete, Cement Wapno Beton 17(3): 165.
Ponikiewski, T.; Gołaszewski, J. 2015. X-ray investigation and modelling of steel fibres In self-compacting concrete, Transactions of the VŠB – Technical University of Ostrava, Civil Engineering Series 15(2). https://doi.org/10.1515/tvsb-2015-0020
Ponikiewski, T.; Gołaszewski, J.; Rudzki, M.; Bugdol, M. 2015. Determination of steel fibres distribution in self-compacting concrete beams using X-ray computed tomography, Archives of Civil and Mechanical Engineering 15(2): 558–568. https://doi.org/10.1016/j.acme.2014.08.008
Ponikiewski, T.; Katzer, J.; Bugdol, M.; Rudzki, M. 2015. X-ray computed tomography harnessed to determine 3D spacing of steel fibres in self compacting concrete (SCC) slabs, Construction and Building Materials 74: 102–108. https://doi.org/10.1016/j.conbuildmat.2014.10.024
Roussel, N.; Geiker, M. R.; Dufour, F.; Thrane, L. N.; Szabo, P. 2007. Computational modeling of concrete flow: general overview, Cement and Concrete Research 37: 1298–1307. https://doi.org/10.1016/j.cemconres.2007.06.007
Rudzki, M.; Bugdol, M.; Ponikiewski, T. 2013. Determination of steel fibers orientation in SCC using computed tomography and digital image analysis methods, Cement Wapno Beton 80: 257–263.
Şanal, İ.; Ozyurt, N. 2013. To what extent does the fiber orientation affect mechanical performance?, Construction and Building Materials 44: 671–681. https://doi.org/10.1016/j.conbuildmat.2013.03.079
Špak, M.; Kozlovská, M.; Struková, Z.; Bašková, R. 2016. Comparison of conventional and advanced concrete technologies in terms of construction efficiency, Advances in Materials Science and Engineering. Article ID 1903729. https://doi.org/10.1155/2016/1903729
Stähli, P. 2008. Ultra-fluid oriented hybrid-fibre-concrete: Dissertation thesis. Swiss Federal Institute of Technology Zurich, Switzerland.
Stähli, P.; van Mier, J. G. M. 2007. Manufacturing, fibre anisotropy and fracture of hybrid fibre concrete, Engineering Fracture Mechanics 74(1–2): 223–242. https://doi.org/10.1016/j.engfracmech.2006.01.028
Stroeven, P.; Guo, Z. 2008. Distribution and orientation of fibers in the perspective of concrete’s mechanical properties, fibre reinforced concrete: Design and applications, in Proceedings of the 7th RILEM International Symposium, Paris, France, 145–154.
Švec, O.; Žirgulis, G.; Bolander, J. E.; Stang, H. 2014. Influence of formwork surface on the orientation of steel fibres within self-compacting concrete and on the mechanical properties of cast structural elements, Cement and Concrete Composites 50: 60–72. https://doi.org/10.1016/j.cemconcomp.2013.12.002
Svoboda, P.; Doležal, J. 2008. Výroba a kladenie čerstvého drôtikového betónu na priemyselné podlahy, Stavebné materiály 4(5): 46–48.
The fib model code for concrete structures. Ernst & Sohn, 2013.
Tosun-Felekoğlu, K.; Felekoğlu, B.; Ranade, R.; Lee, B. Y.; Li, V. C. 2014. The role of flaw size and fiber distribution on tensile ductility of PVA-ECC, Composites Part B: Engineering 56: 536–545. https://doi.org/10.1016/j.compositesb.2013.08.089
Wang, R.; Gao, X.; Zhang, J.; Han, G. 2018. Spatial distribution of steel fibers and air bubbles in UHPC cylinder determined by X-ray CT method, Construction and Building Materials 160: 39–47. https://doi.org/10.1016/j.conbuildmat.2017.11.030
Wang, R; Gao, X.; Huang, H. 2017. Influence of rheological properties of cement mortar on steel fiber distribution in UHPC, Construction and Building Materials 144: 65–73. https://doi.org/10.1016/j.conbuildmat.2017.03.173
Wong, R. C. K.; Chau, K. T. 2005. Estimation of air void and aggregate spatial distributions in concrete under uniaxial compression using computer tomography scanning, Cement and Concrete Research 35(8): 1566–1576. https://doi.org/10.1016/j.cemconres.2004.08.016
Yang, C. J.; Jin, L. B.; Chen, D. C.; Qi, J. P. 2013. Practical measurement for steel fiber distribution of the SFRC beams, Applied Mechanics and Materials 256–259: 840–843. https://doi.org/10.4028/www.scientific.net/AMM.256-259.840
Yong-zhi, L. 2000. Deutscher Ausschuss für Stahlbeton im DIN Deutsches Institut für Normung e.V. 494DAfStb-Heft 494. Tragverhalten von Stahlfaserbeton. Beuth Verlag GmbH, Berlin.
Zhu, Y. T.; Blumenthal, W. R.; Lowe, T. C. 1997. Determination of non-symmetric 3-D fiber orientation distribution and average fiber length in short-fiber composites, Journal of Composite Materials 31(13): 1287–1301. https://doi.org/10.1177/002199839703101302
Žirgulis, G.; Švec, O.; Sarmiento, E. V.; Geiker, M. R.; Cwirzen, A.; Kanstad, T. 2016. Importance of quantification of steel fibre orientation for residual flexural tensile strength in FRC, Materials and Structures 49: 3861–3877. https://doi.org/10.1617/s11527-015-0759-3