Observation of reinforcing fibers in concrete upon bending failure by X-ray computed tomographic imaging

Seok Yong Lim, Kwang Soo Youm, Kwang Yeom Kim, Yong Hoon Byun, Young K. Ju, Tae Sup Yun

Research output: Contribution to journalArticlepeer-review


This study presents the visually observed behavior of fibers embedded in concrete samples that were subjected to a flexural bending test. Three types of fibers such as macro polypropylene, macro polyethylene, and the hybrid of steel and polyvinyl alcohol were mixed with cement by a designated mix ratio to prepare a total of nine specimens of each. The bending test was conducted by following ASTM C1609 with a net deflection of 2, 4, and 7 mm. The X-ray computed tomography (XCT) was carried out for 7 mm-deflection specimens. The original XCT images were post-processed to denoise the beam-hardening effect. Then, fiber, crack, and void were semi-manually segmented. The hybrid specimen showed the highest toughness compared to the other two types. Debonding based on 2D XCT sliced images was commonly observed for all three groups. The cement matrix near the crack surface often involved partially localized breakage in conjunction with debonding. The pullout was predominant for steel fibers that were partially slipped toward the crack. Crack bridging and rupture were not found presumably due to the image resolution and the level of energy dissipation for poly-fibers, while the XCT imaging was advantageous in evaluating the distribution and behavior of various fibers upon bending for fiber-reinforced concrete beam elements.

Original languageEnglish
Pages (from-to)433-442
Number of pages10
JournalComputers and Concrete
Issue number5
Publication statusPublished - 2023 May

Bibliographical note

Funding Information:
The research described in this paper was financially supported in part by the National Research Foundation of Korea (NRF) grant fund by the Korea government(MSIT) (No. NRF-2021R1A5A1032433) and in part by the Ministry of Land, Infrastructure, and Transport of the Korean government through the Railway Technology Research Program (RS-2021-KA163289).

Publisher Copyright:
© 2023 Techno-Press, Ltd.


  • debonding
  • fiber-matrix mechanism
  • fiber-reinforced concrete
  • pullout
  • third-point loading test
  • X-ray computed tomography

ASJC Scopus subject areas

  • Computational Mechanics


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