Relationship between fiber orientation/distribution and post-cracking behaviour in ultra-high-performance fiber-reinforced concrete (UHPFRC)

Zhou, Bo; Uchida, Yoshiyuki

doi:10.1016/j.cemconcomp.2017.07.007

Cited by 58 publications

(21 citation statements)

References 17 publications

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“…During casting, the concrete was pumped from a truck mixer to the centre of the formworks to allow a radial flow of the fresh concrete and no vibration was carried out. It has been shown that fibres tend to align perpendicularly to the flow direction in concrete slabs [35][36][37][38] which increases the fibre effectiveness [39]. After casting, all specimens were covered with wet burlaps and kept moist for a couple of days.…”

Section: Specimen Preparationmentioning

confidence: 99%

Biaxial bending of SFRC slabs: Is conventional reinforcement necessary?

2018

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Fibre reinforced concrete shows enhanced performance in statistically redundant bi-dimensional structural elements that undergo biaxial bending. However, the lack of reinforcing rebars in fibre reinforced structural elements may affect the structural ductility which may further affect the overall load bearing capacity of these structures. To investigate the influence of fibres in such elements, six concrete plates of 2000 9 2000 9 150 mm reinforced with steel fibres and/or reinforcing rebars are tested under a central concentrated load. Two of the elements are reinforced with only 35 kg/m 3 of steel fibres, two are reinforced with 2-way conventional reinforcing rebars (35 kg/m 3 , in each direction) and two are reinforced with both steel fibres and rebars. The specimens are simply supported at the middle of each side by means of a bilateral restraint; the deflection response and cracking behaviour of all the specimens are recorded and compared. Moreover, the methodology introduced in the fib Model Code 2010 for design of steel fibre reinforced concrete is implemented to predict the ultimate load bearing capacity of these elements and its reliability is determined in comparison with the experimental values. The comparison of the behaviour of the specimens reinforced only with steel fibres, with those reinforced with steel rebars, shows the higher efficiency of steel fibres in terms of load carrying capacity, but with a lower ductility. The combination of steel fibres and rebars allows for a better exploitation of the capacity of both reinforcement solutions. Finally, the reliability of the approach implemented for the ultimate load prediction is shown and the need of rebars in providing ductility in fibre reinforced concrete members is underlined.

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Section: Specimen Preparationmentioning

confidence: 99%

Biaxial bending of SFRC slabs: Is conventional reinforcement necessary?

2018

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“…Balázs et al [7] studied the distribution and orientation of steel fiber with computed tomography. Zhou and Uchida [8] evaluated steel fiber orientation/distribution throughout the ultra-high performance fiber-reinforced concrete using image analysis and 3D visualization of fiber orientation based on X-ray computed tomography data. Snoeck et al [9] analyzed the self-healing efficiency of cementitious materials promoted by superabsorbent polymers using X-ray CT. Ren et al [10] developed two-dimensional mesoscale finite element models with realistic aggregates, cement paste, and voids of concrete using microscale X-ray computed tomography images.…”

Section: Introductionmentioning

confidence: 99%

“…e previous research mostly focused on dispersion of synthetic fibers [5,11,12], distribution and orientation of metal fibers [6][7][8], oriented fiber [13,14], defect and damage of fiber-reinforced concrete [9,15,16], fabrication of cementitious materials [17,18], or modeling based on CT image [10,19]. However, these studies do not provide much attention to microscopic texture of polypropylene fiberreinforced concrete.…”

Section: Introductionmentioning

confidence: 99%

Microscopic Texture of Polypropylene Fiber‐Reinforced Concrete with X‐Ray Computed Tomography

Qin

Wu²,

Zheng

et al. 2019

Advances in Civil Engineering

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Polypropylene fiber-reinforced concrete (PFRC) is a cement-based composite material with short-cut fibers which has been utilized to provide multidimensional reinforcement and enhance toughness of concrete. However, this improvement is closely related to the microstructural morphology of the concrete. A nondestructive technique using X-ray computed tomography (CT) was therefore used to grasp the microscopic texture of PFRC samples. The results showed that the orientation of microcracks, which appear in the interfacial transition zone, are along the surface of the coarse aggregate. The range of distribution of fibers is proportional to fiber volume fraction. The coarse aggregate influence distribution and orientation of polypropylene fibers whose shape are mainly fold line and curve. The dispersion of pores with small volume is uniform, and the distance between the pores with larger volume is short. The proportion of pores with the diameter in the range 0∼199 μm exceeds 70%, of which the sum of volume exceeds a half of total volume with the amount being about 1% of total amount.

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“…All aforementioned factors largely influence the position and orientation of the fibers in the concrete mass and thus, have an effect on the improvement of the mechanical properties of cementitious materials. Several scientists have shown the importance of uniform spatial fiber distribution, increasing of fiber content and the impact of proper dispersion of fibers on the ultimate flexural strength (Kang, Lee, J. K. Kim, & Y. Y. Kim, 2011;Yoo, Yoon, & Banthia, 2015;Zhou & Uchida, 2017;Herrmann, Braunbrück, Tuisk, Goidyk, & Naar, 2019a;Eik, Puttonen, & Herrmann, 2016).…”

Section: Introductionmentioning

confidence: 99%

Initial results of local strength analysis of a fiber concrete plate by 4-point bending tests

Goidyk

Herrmann

2019

Modern Building Materials, Structures and Techniques (MBMST)

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The analysis of the post-cracking behavior of a large plate cast of fiber concrete shows a large variability due to the fiber alignment and dispersion. Therefore, one can expect, that the bending strength and other material parameters depend on the position in the plate. This means that the position the samples for testing are taken from may play a significant role in assessing the mechanical properties and strength of composite materials. Often, the investigation of fiber concrete properties have been performed by testing small size beams. The results can be influenced by the boundary restrictions, such as wall-effect, which influences the fiber distribution. In this study the four-point bending strength of beams cut out of a large plate was investigated, the results represent the local strength of the plate in this particular place. The fiber orientation and distribution have been evaluated by X-ray Computed Tomography and Image Analysis Method. The results of the experiments have shown that the position of the beam inside of a large-size plate has a strong influence on the mechanical properties and post-cracking behavior. The analysis of the obtained outcomes proposes the following conclusions: the beams that were located near the edges of the formwork have shown a strong, strain-hardening behavior, and the beams that were located on the way of the casting bucket (a zone of the high turbulence/perturbation/disturbance) have shown a weak, strain-softening behavior.

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Relationship between fiber orientation/distribution and post-cracking behaviour in ultra-high-performance fiber-reinforced concrete (UHPFRC)

Cited by 58 publications

References 17 publications

Biaxial bending of SFRC slabs: Is conventional reinforcement necessary?

Biaxial bending of SFRC slabs: Is conventional reinforcement necessary?

Microscopic Texture of Polypropylene Fiber‐Reinforced Concrete with X‐Ray Computed Tomography

Initial results of local strength analysis of a fiber concrete plate by 4-point bending tests

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