Fibre Reinforced Cementitious Composites

Zhu

Experimental Techniques

2011

Ultrashort steel fibers with small diameters are often used as reinforcements in concrete. Such fibers are cheap, easily dispersed, and do not unduly reduce the workability of concrete. In this study, cylindrical specimens are fabricated with three different volume fractions of 0.0, 1.5, and 3.0% ultrashort steel fibers (13.0 mm long and 0.2 mm in diameter). Then these concrete specimens are tested under repeated impacts in split Hopkinson pressure bar device. The effects of loading rate, fiber volume fraction, and impact times on the dynamic responses of concrete are respectively investigated. These experimental results show that addition of a small amount of steel fibers can significantly improve the impact resistance of concrete. In the fibrous concrete, the effect of strain‐rate hardening prevails against that of damage softening in the initial impact. Besides, the failure modes of plain and fibrous concretes are noticeably different.

“…In order to characterize the effect of repeated impacts on concrete, a strength decaying factor I n and a nominal damage D are calculated by the following 2,5,19 :…”

Section: Strength and Damage Deterioration Of Specimenmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Repeated-Impact Response of Ultrashort Steel Fiber Reinforced Concrete

Zhu

Experimental Techniques

2011

“…[21][22][23] The main contributions toward the addition of fibers to concretes regard the ability to control crack spreading and the increase of the toughness factor. 24 Polypropylene (PP), polyvinyl alcohol (PVA), and recycled polyester (POL) fibers are examples of reinforcements that have low hardness that aim to reduce shrinkage cracks that occur at initial ages of the mixture. In some cases, depending on the modulus of elasticity of the mixture, the reinforcement can have effect for 3 to 7 days.…”

mentioning

confidence: 99%

Experimental method for investigating the impact of the addition of polymer fibers on drying shrinkage and cracking of concretes

Ehrenbring

Quinino

Silva

et al. 2019

Structural Concrete

This study presents an investigation of a fiber‐reinforced concrete (FRC) with use of fibers of polypropylene, polyvinyl alcohol, and recycled polyester in the amount of 0.50%, seeking to analyze the impact of the fiber additions on mechanical properties, drying shrinkage, and cracking. Regarding flexural strength, a reduction of up to 25% of the value was observed for FRC. The residual strength of FRCs was increased values 20 times higher than the reference concrete. The addition of fibers also increased the void content of the matrices and, therefore, drying shrinkage of the reference matrix up to 74%. The fiber additions increased the internal tensile stresses of the FRC of up to 12.0 MPa. Besides the increase in resistance, the FRC presented formation cracks with openings 8 times smaller than the concrete.

“…2 When properly designed in terms of matrix composition, fiber dosage, and workability, SFRC can reduce concrete tensile brittleness, increase ductility, durability, energy absorption, fatigue, and toughness. [3][4][5] Discussion on this paper must be submitted within two months of the print publication. The discussion will then be published in print, along with the authors' closure, if any, approximately nine months after the print publication.…”

mentioning

confidence: 99%

Assessment of model error for reinforced concrete beams with steel fibers in bending

Foster

Parvez

2019

Structural Concrete

Numerous models have been developed to determine the strength contributions of steel fibers in reinforced concrete beams in flexure; however, little work has been undertaken on determining their reliability, particularly when combined with use of inverse analysis procedures for determining the postcracking residual tensile strength provided by the fibers. Recently, leading codes have accepted design guidelines for designing flexurally reinforced concrete structural elements that also contain steel fibers using rational principles that are compatible with conventional reinforced concrete design. To provide confidence to the designer, it is imperative to verify the design models against experimental results and test their reliability. Despite extensive studies, design models have not been validated against large amount of test data. In this paper, 50 flexurally reinforced steel fiber reinforced concrete beams from the literature are analyzed for flexural strength. Ultimate moment capacities are predicted using the design procedures of NZS 3101–2–2006, fib Model Code 2010, DAfStb Guideline‐2015 and AS3600–2018. The results of the analyses show that the models perform well, with the AS3600 being the most conservative of the models assessed, and the NZS 3101–2–2006 the least conservative. The model errors for each are determined, and model reliability is discussed.