• Magazine of the Korea Concrete Institute
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• v.5 no.4
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• pp.156-166
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• 1993

The results of an experimental study on the manufacture and the mechanical properties of steel fiber reinforced polyester resin composites utilizing industrial waste products(fly ash) are presented in this paper. The composites using steel fiber, fly ash, unsaturated polyester resin, styrene monomer, catalyst (cobalt octate) and accelerator(methyl ethyl ketone peroxide), fine and coarse aggreates were prepared using various mixing conditions. As the test results show. the mechanical and physical properties, such as the compressive, tensile and flexural strengths, and the setting shrinkage of fly ash$\cdot$polyester resin composites were improved considerably by increasing the fly ash-binder ratio. And the workability of steel fiber reinforced fly ash$\cdot$polyester resin composites was reduced with increasing the fly ash-binder ratio and steel fiber content. Also, the compressive, flexural strength and toughness of the composites were remarkably increased by increasing steel fiber content.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.749-754
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• 2002

In this study, it is investigate to influence on tile dispersion of fiber and the flowability of matrix of type and amount of superplasticizer, velocity agent, mineral admixture and steel fiber to improve for construction performance of steel fiber reinforced cementitious composites. As for the test results, it was found that the dispersion of fiber and the flowability of matrix in steel fiber reinforced cementitious composites can improve by using of properly amount and combination of superplasticizer, velocity agent, mineral admixture. Furthermore, It show that the aspect ratio of steel fiber affect the construction performance of fiber reinforced cementitious composites, and the improvement for construction performance is the more effective the smaller aspect ration of steel fiber.

• Structural Engineering and Mechanics
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• v.83 no.5
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• pp.671-680
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• 2022

The shear capacity of beams is an essential parameter in designing beams carrying shear loads. Precise estimation of the ultimate shear capacity typically requires comprehensive calculation methods. For steel fiber reinforced concrete (SFRC) beams, traditional design methods may not accurately predict the interaction between different parameters affecting ultimate shear capacity. In this study, artificial neural network (ANN) modeling was utilized to predict the ultimate shear capacity of SFRC beams using ten input parameters. The results demonstrated that the ANN with 30 neurons had the best performance based on the values of root mean square error (RMSE) and coefficient of determination (R²) compared to other ANN models with different neurons. Analysis of the ANN model has shown that the clear shear span to depth ratio significantly affects the predicted ultimate shear capacity, followed by the reinforcement steel tensile strength and steel fiber tensile strength. Moreover, a Genetic Algorithm (GA) was used to optimize the ANN model's input parameters, resulting in the least cost for the SFRC beams. Results have shown that SFRC beams' cost increased with the clear span to depth ratio. Increasing the clear span to depth ratio has increased the depth, height, steel, and fiber ratio needed to support the SFRC beams against shear failures. This study approach is considered among the earliest in the field of SFRC.

• Magazine of the Korean Society of Agricultural Engineers
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• v.29 no.4
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• pp.124-131
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• 1987

The aims of this study was to determine the mechanical properties of steel-fiber reinforced concrete under direct tensile loading, and also to insestigate the mechanism fiber reinforcement in order to improve the possible applications of steel-fiber reinforced concrete. In this study the major variables of experimental investigation were fiber conntents, and the lengths and diameters of fibers. The major results obtained are summarized as follows : 1. The strength, elastic modulus and energy absorption capability of steel-fiber reinforced concrete under direct tensile loading were improved as increasing of fiber contents. 2. The direct tensile strength of steel-fiber reinforced concrete was not influenced by the lengths of fiber, but was decreased as increasing of fiber diameters. 3. The direct tensile strength of steel-fiber reinforced concrete was not influenced by the fiber aspect-ratio, but this was because the fiber contents were below the critical value of fiber content. 4. The correlation of direct tensile strength and combined parameter, Vf l/d, was not good. 5. Mutiple cracking and post-crack resistance were investigated at stress-strain curves in direct tensile test. 6. The effect of fiber reinforcement can be influenced by fiber orientation and the bond strength between fiber and matrix. 7. The improvement of mechanical properties of steel-fiber reinforced concrete under direct tensile loading can be theoretically explained by the concept of composite materials.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.209-217
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• 2021

This paper investigates the effect of high strength hooked-end steel fiber content and aspect ratio on the compressive and flexural performance of concrete. A total of ten mixtures were prepared and tested. Concretes with specific compressive strength of 30 MPa were reinforced with three different aspect ratios (l/d) of steel fibers 64, 67, and 80 and three different percentages of steel fibers 0.25, 0.50, and 0.75% by volume of concrete. Tensile strengths of steel fibers with l/d of 64, 67, and 80 are 2,000, 2,400, and 2,100 MPa, respectively. The compressive and flexural properties of plain and steel fiber-reinforced concrete (SFRC) mixtures were evaluated and compared. The experimental results indicated that the incorporation of high-strength hooked-end steel fibers had significant effects on the compressive and flexural performance of concrete. With the increase of steel fiber content, compressive performances, such as Poisson's ratio and toughness, of concrete were improved. The steel fibers with the least l/d of 67 resulted in a larger enhancement of compressive performances. The residual flexural strength, that is, post-cracking flexural resistance and toughness, of concrete is mainly depended on the dosage and aspect ratio of steel fibers. The residual flexural strength at serviceability (SLS) and ultimate limit state (ULS) defined in fib Model Code 2010 (MC2010) is increased as the fiber content and aspect ratio increase.

• Advances in concrete construction
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• v.10 no.6
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• pp.559-571
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• 2020

This study aimed to inspect the axial compression mechanical performance of basalt-fiber-reinforced recycled - concrete (BFRRC)-filled square steel tubular stub column. The replacement ratio of recycled coarse aggregate (RCA) and the basalt fiber (BF) dosage were used as variation parameters, and the axial compression performance tests of 15 BFRRC-filled square steel tubular stub column specimens were conducted. The failure mode and the load-displacement/strain curve of the specimen were measured. The working process of the BFRRC-filled square steel tubular stub column was divided into three stages, namely, elastic-elastoplasticity, sudden drawdown, and plasticity. The influence of the design parameters on the peak bearing capacity, energy dissipation performance, and other axial compression performance indexes was discussed. A mathematical model of segmental stiffness degradation was proposed on the basis of the degradation law of combined secant-stiffness under axial compression. The full-process curve equation of axial compressive stress-strain was proposed by introducing the influencing factors, including the RCA replacement ratio and the BF dosage, and the calculated curve agreed well with the test-measured curve.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.82-83
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• 2015

Recently, the research on steel fiber reinforced concrete has been actively conducted to compensate the defect of brittle fracture of concrete and to enhance toughness. Therefore, the effect of the mixture rate of straight steel fiber on flexural behavior of high strength steel fiber reinforced concrete was evaluated in this research. As a result, when 2% of steel fiber was mixed with concrete volume ratio, it showed the best flexural capacity.

• Journal of the Korea Institute of Building Construction
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• v.13 no.1
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• pp.20-28
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• 2013

Flexure toughness of Steel Fiber Reinforced Concrete (SFRC) shows a time-dependent characteristic due to the hydration process of the cement matrix in the SFRC system. The effect of two important factors, water/cement (w/c) ratio and fiber volume fraction, on the flexure toughness development of SFRC were investigated. Three different SFRC mixtures with hooked-end steel fibers were tested using a four-point bending testing configuration. Each mixture was tested at five different ages. The results showed that the post-peak toughness of SFRC developed at an earlier age than the first-crack toughness.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.44-45
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• 2018

In this study, water vapor pressure of high strength concrete reinforced with amorphous steel fiber(AF) was evaluated. Experimental results show that spalling occurs when the incorporation rate of amorphous steel fiber is 0.5 vol.% or more. This is because the ratio of AF increased per unit area influenced the formation of the water vapor pressure discharge passage by the polypropylene fiber(PPF) melting. Therefore, it is necessary to find the proper mixing ratio of AF and PPF to prevent spalling.

• Magazine of the Korea Concrete Institute
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• v.4 no.1
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• pp.81-87
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• 1992

In this thesis, the fatigue tests were performed on a series of SFRC(steel fiber reinforced concrete) to investigate the fatigue behavior of SFRC varying with the steel fiber contents and the steel fiber aspect ratios. The three point loading system is used in the fatigue tests. In tl1ese tests, relations between the repeated loading cycles and the mid-span deflections, number of repeated loadmg cycles when specimen was fractured were observed. On this basis, the mid-span deflections, the elastic strain energy and inelastic strain energy of SFRC were studied. A S - N curve \vas drawn to present the fatigue strength of SFRC beam. From che test results, by increasing the steel fiber content the energy lost on the permanent deformation decreases and the energy spent on crack growth increases. But in case of SFRC with the same steel fiber content the higher the steel fiber aspect ratio is, the less the elastic strain energy is. According to S - N curve drawn by the regression analysis on the fatugue test results, the fatigue strength with 2,000,000 repeated loading cycles in SFRC with the steel fiber content is 1.0% shows about 70% on the first crack static flexural strength.