The Influence of Steel Fiber Tensile Strengths and Aspect Ratios on the Fracture Properties of High-Strength Concrete

Choi, Wonchang; Jung, Kwon-Young; Jang, Seok–Myeong; Kim, Sun-Woo

doi:10.3390/ma12132105

Cited by 52 publications

(36 citation statements)

References 8 publications

(11 reference statements)

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“…The performance of concrete under tension can be substantially improved by the addition of steel fibers since SFRC exhibits increased tensile strength and mainly post-peak deformation capability showing pseudo-ductile behavior due to the gradual debonding failure of the fibers [ 78 ]. Various analytical stress versus strain expressions have been proposed to simulate the SFRC tensile behavior [ 79 , 80 , 81 ].…”

Section: Methodsmentioning

confidence: 99%

Effect of Steel Fibers on the Hysteretic Performance of Concrete Beams with Steel Reinforcement—Tests and Analysis

et al. 2020

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The use of fibers as mass reinforcement to delay cracking and to improve the strength and the post-cracking performance of reinforced concrete (RC) beams has been well documented. However, issues of common engineering practice about the beneficial effect of steel fibers to the seismic resistance of RC structural members in active earthquake zones have not yet been fully clarified. This study presents an experimental and a numerical approach to the aforementioned question. The hysteretic response of slender and deep steel fiber-reinforced concrete (SFRC) beams reinforced with steel reinforcement is investigated through tests of eleven beams subjected to reversal cyclic loading and numerical analysis using 3D finite element (FE) modeling. The experimental program includes flexural and shear-critical SFRC beams with different ratios of steel reinforcing bars (0.55% and 1.0%), closed stirrups (from 0 to 0.5%), and fibers with content from 0.5 to 3% per volume. The developed nonlinear FE numerical simulation considers well-established relationships for the compression and tensional behavior of SFRC that are based on test results. Specifically, a smeared crack model is proposed for the post-cracking behavior of SFRC under tension, which employs the fracture characteristics of the composite material using stress versus crack width curves with tension softening. Axial tension tests of prismatic SFRC specimens are also included in this study to support the experimental project and to verify the proposed model. Comparing the numerical results with the experimental ones it is revealed that the proposed model is efficient and accurately captures the crucial aspects of the response, such as the SFRC tension softening effect, the load versus deformation cyclic envelope and the influence of the fibers on the overall hysteretic performance. The findings of this study also reveal that SFRC beams showed enhanced cyclic behavior in terms of residual stiffness, load-bearing capacity, deformation, energy dissipation ability and cracking performance, maintaining their integrity through the imposed reversal cyclic tests.

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Section: Methodsmentioning

confidence: 99%

Effect of Steel Fibers on the Hysteretic Performance of Concrete Beams with Steel Reinforcement—Tests and Analysis

et al. 2020

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“…The macro fibers produced the best performance in most of the investigated parameters, under both tension and compression. This phenomenon could be explained through the highest aspect ratio of the macro fibers, equaling to 100, since the higher aspect ratio would produce the higher mechanical property of the composites [5,10,11]. In contrast, the micro fiber, having its lowest aspect ratio of 65, would produce the lowest mechanical property.…”

Section: Materials and Preparation Of Specimensmentioning

confidence: 99%

“…After demolding, the specimens were water-cured at 25 °C for 14 days. Next, the specimens were removed from the water tank and dried at 70 °C in a drying oven for at least 12 h. All the specimens were tested at the age of 18 On the other hand, the mechanical properties of SFCs have been reported to be dependent much on fiber characteristics, e.g., fiber aspect ratio (length/diameter ratio), fiber size and shape, fiber volume content, fiber material [4][5][6][7][8][9]. Also, in the process of making SFCs, the fiber type and fiber content greatly affected the probability of heterogeneous fiber distribution and fiber flocculation governing workability and viscosity of a concrete mixture [6].…”

Section: Introductionmentioning

confidence: 99%

Influence of fiber size on mechanical properties of strain-hardening fiber-reinforced concrete

Nguyen

2020

STCE

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This research deals with the influences of macro, meso and micro steel-smooth fibers on tensile and compressive properties of strain-hardening fiber-reinforced concretes (SFCs). The different sizes, indicated by length/diameter ratio, of steel-smooth fiber added in plain matrix (Pl) were as follows: 30/0.3 for the macro (Ma), 19/0.2 for the meso (Me) and 13/0.2 for the micro fiber (Mi). All SFCs were used the same fiber volume fraction of 1.5%. The compressive specimen was cylinder-shaped with diameter × height of 150 × 200 mm, the tensile specimen was bell-shaped with effective dimensions of 25 × 50 × 100 mm (thickness × width × gauge length). Although the adding fibers in plain matrix of SFCs produced the tensile strain-hardening behaviors accompanied by multiple micro-cracks, the significances in enhancing different mechanical properties of the SFCs were different. Firstly, under both tension and compression, the macro fibers produced the best performance in terms of strength, strain capacity and toughness whereas the micro produced the worst of them. Secondly, the adding fibers in plain matrix produced more favorable influences on tensile properties than compressive properties. Thirdly, the most sensitive parameter was observed to be the tensile toughness. Finally, the correlation between tensile strength and compressive strength of the studied SFCs were also reported. Keywords: aspect ratio; strain-hardening; post-cracking; ductility; fiber size.

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“…He found that by adding coconut fiber, compressive and flexural strengths were increased to 13% and 9%, respectively. However, in terms of durability, the chloride diffusion resistance was reduced [10] Previous studies have confirmed that fiber can improve the mechanical properties of concrete [11][12][13][14][15][16], but there are different opinions on the chloride diffusion resistance. Some researchers think that fiber can enhance the chloride diffusion resistance of concrete, but the other researchers hold the opposite opinion.…”

Section: Introductionmentioning

confidence: 99%

Influence of Combined Action of Steel Fiber and MgO on Chloride Diffusion Resistance of Concrete

Jiang

Deng

et al. 2020

Crystals

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To improve the chloride diffusion resistance and durability of concrete, a new kind of steel fiber reinforced MgO concrete (SFRMC) was made by adding steel fiber and MgO to concrete simultaneously. With steel fiber for load bearing and expansion limiting, MgO as the expander, SFRMC has both the advantages of fiber reinforced concrete and expansion concrete. The influence of steel fiber and MgO on the strength and chloride diffusion resistance of concrete was evaluated by splitting tensile test and chloride diffusion test. Mercury intrusion porosimeter (MIP) and scanning electron microscopy (SEM) were used to study the microstructure of SFRMC. The results showed that the combined action of steel fiber and MgO reduced the porosity of concrete and the chloride diffusion coefficient (CDC), which could not be achieved by steel fiber and MgO separately. In the free state, the expansion energy produced by the hydration of MgO made the concrete expand outwards. However, under the constraint of steel fiber, the expansion energy was used to tension the fiber, resulting in self-stress. In this way, compared to reference concrete RC, the tensile strength of SFRMC-1, SFRMC-2, and SFRMC-3 increased by 3.1%, 61.3%, and 64.5%, CDC decreased by 8.8%, 36.7%, and 33.1%, and the porosity decreased by 6.2%, 18.4%, and 20.6%, respectively. In addition, the SEM observations demonstrated that the interfacial transition zone (ITZ) between fiber and matrix was denser in SFRMC, which contributed to reduce the diffusion of chloride ions in the concrete.

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The Influence of Steel Fiber Tensile Strengths and Aspect Ratios on the Fracture Properties of High-Strength Concrete

Cited by 52 publications

References 8 publications

Effect of Steel Fibers on the Hysteretic Performance of Concrete Beams with Steel Reinforcement—Tests and Analysis

Effect of Steel Fibers on the Hysteretic Performance of Concrete Beams with Steel Reinforcement—Tests and Analysis

Influence of fiber size on mechanical properties of strain-hardening fiber-reinforced concrete

Influence of Combined Action of Steel Fiber and MgO on Chloride Diffusion Resistance of Concrete

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