Special Issue "Steel Fibre Reinforced Concrete Behaviour"

A special issue of Fibers (ISSN 2079-6439).

Deadline for manuscript submissions: closed (30 September 2019).

Special Issue Editor

Prof. Dr. Constantin Chalioris
E-Mail Website
Guest Editor
Reinforced Concrete and Seismic Design of Structures Lab., Department of Civil Engineering, Structural Engineering Division, Democritus University of Thrace, University Campus, Kimmeria, 67100 Xanthi, Greece
Interests: design and analysis of reinforced/prestressed concrete and masonry structures; testing of reinforced concrete members under static and cyclic loading; repair and strengthening of concrete members and structures (resin injections, fiber-reinforced-polymer materials, reinforced cast-in-place concrete, self-compacting concrete, and shotcrete jacketing); in-situ testing and capacity assessment of reinforced concrete structures; torsion and shear of plain, fiber, reinforced and prestressed concrete members; steel fiber reinforced concrete behavior; damage detection and real-time structural integrity assessment of concrete members using piezoelectric sensors
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Special Issue Information

Dear Colleagues,

The addition of short discontinuous steel fibers in concrete has long been recognized as a non-conventional mass reinforcement that enhances the mechanical properties of concrete. Steel Fiber-Reinforced Concrete (SFRC) exhibits significant resistance to the formation and growth of cracks, increased post-cracking ductility and energy dissipation capacity. SFRC structural members under flexure, shear and torsion demonstrate a pseudo-ductile response in the tensile regime due to the gradual debonding procedure of the individual, randomly oriented steel fibers that bridge the developed cracks. Steel fibers were also found to be a promising non-conventional reinforcement in shear-critical beams due to the advantageous cracking performance of SFRC, which, under specific circumstances, alters the brittle shear failure to a ductile flexural one.

The existing design provisions for SFRC structural members, with or without bars and stirrups, under flexure/shear loading, are usually empirically formulated extensions of Reinforced Concrete (RC) rules. Further, strict guides to crucial questions about the minimum content and the type of the steel fibers required in a shear-critical SFRC element which will satisfy pre-set strength and ductility requirements are not included in the available code specifications and guidelines (such as CNR 2007, RILEM TC 162-TDF, 2003 and TR63, 2007).

Furthermore, thin and locally-applied concrete layers used as jacketing is a relatively recent development in the field of repair and rehabilitation of damaged or deficient RC members, which became possible with the development of high strength cementitious materials, shotcrete and Self-Compacting Concrete (SCC) reinforced with short steel fibers.

This Special Issue brings together experimental and analytical studies aiming to provide a comprehensive overview on the behaviour and the advancements of SFRC including aspects related, but not limited, to mechanical properties, cracking performance, synthesis, durability, bond behavior, fiber orientation/dispersion, repair/strengthening using traditional/innovative steel fibrous cement- based materials/techniques, structural applications and numerical simulation under various loading conditions (compression, tension, flexure, shear, torsion under monotonic, quasi-static, repeated, cyclic, seismic, impact and blast). Original research papers and authoritative review articles are invited for this Special Issue.

Papers selected for this Special Issue will be subject to a rigorous peer-review procedure with the aim of rapid and wide dissemination of research results, developments and applications.

Assoc. Prof. Dr. Constantin Chalioris
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Fibers is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Steel Fibre-Reinforced Concrete (SFRC)
  • Concrete
  • Reinforced Concrete (RC)
  • Shotcrete
  • Self-Compacting Concrete (SCC)
  • Steel fibrous cement-based materials
  • Mechanical properties
  • Fibre dispersion and orientation
  • Bond behaviour
  • Numerical Modeling
  • Flexural or/and Shear behaviour
  • Torsion
  • Compressive or/and Tensile response
  • Structural behaviour
  • Structural applications
  • Durability
  • Repair or/and strengthening

Published Papers (6 papers)

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Research

Article
U-Jacketing Applications of Fiber-Reinforced Polymers in Reinforced Concrete T-Beams against Shear—Tests and Design
Fibers 2020, 8(2), 13; https://0-doi-org.brum.beds.ac.uk/10.3390/fib8020013 - 17 Feb 2020
Cited by 30 | Viewed by 3250
Abstract
The application of externally bonded fiber-reinforced polymer (EB-FRP) as shear transverse reinforcement applied in vulnerable reinforced concrete (RC) beams has been proved to be a promising strengthening technique. However, past studies revealed that the effectiveness of this method depends on how well the [...] Read more.
The application of externally bonded fiber-reinforced polymer (EB-FRP) as shear transverse reinforcement applied in vulnerable reinforced concrete (RC) beams has been proved to be a promising strengthening technique. However, past studies revealed that the effectiveness of this method depends on how well the reinforcement is bonded to the concrete surface. Thus, although the application of EB-FRP wrapping around the perimeter of rectangular cross-sections leads to outstanding results, U-jacketing in shear-critical T-beams seems to undergo premature debonding failures resulting in significant reductions of the predictable strength. In this work, five shear-critical RC beams with T-shaped cross-section were constructed, strengthened and tested in four-point bending. Epoxy bonded carbon FRP (C-FRP) sheets were applied on the three sides and along the entire length of the shear-strengthened T-beams as external transverse reinforcement. Furthermore, the potential enhancement of the C-FRP sheets anchorage using bolted steel laminates has been examined. Test results indicated that although the C-FRP strengthened beams exhibited increased shear capacity, the brittle failure mode was not prevented due to the debonding of the FRP from the concrete surface. Nevertheless, the applied mechanical anchor of the C-FRP sheets delayed the debonding. Moreover, the design provisions of three different code standards (Greek Code of Interventions, Eurocode 8 and ACI Committee 440) concerning the shear capacity of T-shaped RC beams retrofitted with EB-FRP jackets or strips in U-jacketing configuration are investigated. The ability of these code standards to predict safe design estimations is checked against 165 test data from the current experimental project and data available in the literature. Full article
(This article belongs to the Special Issue Steel Fibre Reinforced Concrete Behaviour)
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Article
Influence of Fiber Content on Shear Capacity of Steel Fiber-Reinforced Concrete Beams
Fibers 2019, 7(12), 102; https://0-doi-org.brum.beds.ac.uk/10.3390/fib7120102 - 28 Nov 2019
Cited by 20 | Viewed by 3826
Abstract
For shear-critical structural elements where the use of stirrups is not desirable, such as slabs or beams with reinforcement congestion, steel fibers can be used as shear reinforcement. The contribution of the steel fibers to the shear capacity lies in the action of [...] Read more.
For shear-critical structural elements where the use of stirrups is not desirable, such as slabs or beams with reinforcement congestion, steel fibers can be used as shear reinforcement. The contribution of the steel fibers to the shear capacity lies in the action of the steel fibers bridging the shear crack, which increases the shear capacity and prevents a brittle failure mode. This study evaluates the effect of the amount of fibers in a concrete mix on the shear capacity of steel fiber-reinforced concrete beams with mild steel tension reinforcement and without stirrups. For this purpose, 10 beams were tested. Five different fiber volume fractions were studied: 0.0%, 0.3%, 0.6%, 0.9%, and 1.2%. For each different steel fiber concrete mix, the concrete compressive strength was determined on cylinders and the tensile strength was determined in a flexural test on beam specimens. Additionally, the influence of fibers on the shear capacity was analyzed based on results reported in the literature, as well as based on the expressions derived for estimating the shear capacity of steel fiber-reinforced concrete beams. The outcome of these experiments is that a fiber percentage of 1.2% or fiber factor of 0.96 can be used to replace minimum stirrups according to ACI 318-14 and a 0.6% fiber volume fraction or fiber factor of 0.48 to replace minimum stirrups according to Eurocode 2. A fiber percentage of 1.2% or fiber factor of 0.96 was observed to change the failure mode from shear failure to flexural failure. The results of this study support the inclusion of provisions for steel fiber-reinforced concrete in building codes and provides recommendations for inclusion in ACI 318-14 and Eurocode 2, so that a wider adoption of steel fiber reinforced concrete can be achieved in the construction industry. Full article
(This article belongs to the Special Issue Steel Fibre Reinforced Concrete Behaviour)
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Article
Effect of High Temperature on the Mechanical Properties of Steel Fiber-Reinforced Concrete
Fibers 2019, 7(12), 100; https://0-doi-org.brum.beds.ac.uk/10.3390/fib7120100 - 21 Nov 2019
Cited by 10 | Viewed by 4169
Abstract
The effect of high temperature on the mechanical properties of concrete reinforced by steel fibers with various aspect ratios has been investigated in this study. Concrete specimens were fabricated from four different concrete mixtures and cured for 28 days. After curing and natural [...] Read more.
The effect of high temperature on the mechanical properties of concrete reinforced by steel fibers with various aspect ratios has been investigated in this study. Concrete specimens were fabricated from four different concrete mixtures and cured for 28 days. After curing and natural drying, the specimens were annealed at a temperature of 500 °C for 3 h in an electric furnace. The compressive and tensile strengths as well as the elastic moduli of the produced specimens were determined. It was found that the mechanical properties (especially flexural toughness) of steel fiber-reinforced concrete were less affected by high temperature as compared to those of control concrete specimens. The flexural tensile strength of fiber-reinforced concrete measured after high-temperature treatment was almost equal to the value obtained for the reference concrete specimen at room temperature. It should be noted that the addition of steel fibers to concrete preserves its mechanical properties after exposure to a temperature of 500 °C due to fire for a period of up to 3 h, and thus is able to improve its high-temperature structural stability. The test results of this study indicate that the use of steel fibers in concrete-based materials significantly enhances their fire and hear-resistant characteristics. Full article
(This article belongs to the Special Issue Steel Fibre Reinforced Concrete Behaviour)
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Article
ANN-Based Shear Capacity of Steel Fiber-Reinforced Concrete Beams without Stirrups
Fibers 2019, 7(10), 88; https://0-doi-org.brum.beds.ac.uk/10.3390/fib7100088 - 11 Oct 2019
Cited by 14 | Viewed by 3420
Abstract
Comparing experimental results of the shear capacity of steel fiber-reinforced concrete (SFRC) beams without stirrups to the capacity predicted using current design equations and other available formulations shows that predicting the shear capacity of SFRC beams without mild steel shear reinforcement is still [...] Read more.
Comparing experimental results of the shear capacity of steel fiber-reinforced concrete (SFRC) beams without stirrups to the capacity predicted using current design equations and other available formulations shows that predicting the shear capacity of SFRC beams without mild steel shear reinforcement is still difficult. The reason for this difficulty is the complex mechanics of the problem, where the steel fibers affect the different shear-carrying mechanisms. Since this problem is still not fully understood, we propose the use of artificial intelligence (AI) to derive an expression based on the available experimental data. We used a database of 430 datapoints obtained from the literature. The outcome is an artificial neural network-based expression to predict the shear capacity of SFRC beams without shear reinforcement. For this purpose, many thousands of artificial neural network (ANN) models were generated, based on 475 distinct combinations of 15 typical ANN features. The proposed “optimal” model results in maximum and mean relative errors of 0.0% for the 430 datapoints. The proposed model results in a better prediction (mean Vtest/VANN = 1.00 with a coefficient of variation 1 × 10−15) as compared to the existing code expressions and other available empirical expressions, with the model by Kwak et al. giving a mean value of Vtest/Vpred = 1.01 and a coefficient of variation of 27%. Until mechanics-based models are available for predicting the shear capacity of SFRC beams without shear reinforcement, the proposed model thus offers an attractive solution for estimating the shear capacity of SFRC beams without shear reinforcement. With this approach, designers who may be reluctant to use SFRC because of the large uncertainties and poor predictions of experiments, may feel more confident using the material for structural design. Full article
(This article belongs to the Special Issue Steel Fibre Reinforced Concrete Behaviour)
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Article
Enhancing the Punching Load Capacity of Reinforced Concrete Slabs Using an External Epoxy-Steel Wire Mesh Composite
Fibers 2019, 7(8), 68; https://0-doi-org.brum.beds.ac.uk/10.3390/fib7080068 - 24 Jul 2019
Cited by 1 | Viewed by 3613
Abstract
The present experimental work investigates the applicability and performance of a new strengthening method for concrete slabs, intended to increase their punching resistance using combination layers of steel wire mesh with epoxy attached to the concrete slabs’ tension face. Six simply supported square [...] Read more.
The present experimental work investigates the applicability and performance of a new strengthening method for concrete slabs, intended to increase their punching resistance using combination layers of steel wire mesh with epoxy attached to the concrete slabs’ tension face. Six simply supported square reinforced concrete slab specimens were tested up to failure under a central concentrated load. The main parameters in the study are the concrete compressive strength (30 MPa and 65 MPa) and the configuration of a bundle externally fixed to the tension side of the tested slabs. The experimental results appeared to greatly enhance the performance of the specimens, as they were externally strengthenined under this new method. When compared to the control slabs, the punching load and stiffness of the strengthened slabs increased up to 28% and 21%, respectively. Full article
(This article belongs to the Special Issue Steel Fibre Reinforced Concrete Behaviour)
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Article
Mechanical Effect of Steel Fiber on the Cement Replacement Materials of Self-Compacting Concrete
Fibers 2019, 7(4), 36; https://0-doi-org.brum.beds.ac.uk/10.3390/fib7040036 - 25 Apr 2019
Cited by 15 | Viewed by 3832
Abstract
The behaviors of the fresh and mechanical properties of self-compacting concrete (SCC) are different from those of normal concrete mix. Previous research has investigated the benefits of this concrete mix by incorporating different constituent materials. The current research aims to develop a steel [...] Read more.
The behaviors of the fresh and mechanical properties of self-compacting concrete (SCC) are different from those of normal concrete mix. Previous research has investigated the benefits of this concrete mix by incorporating different constituent materials. The current research aims to develop a steel fiber reinforcement (SFR)‒SCC mixture and to study the effectiveness of different cement replacement materials (CRMs) on the fresh and mechanical properties of the SFR‒SCC mixtures. CRMs have been used to replace cement content, and the use of different water/cement ratios may lower the cost of CRMs, which include microwave-incinerated rice husk ash, silica fume, and fly ash. Fresh behavior, such as flow and filling ability and capacity segregation, was examined by a special test in SCC on the basis of their specifications. Moreover, compressive and splitting tensile strength tests were determined to simulate the hardened behavior for the concrete specimens. Experimental findings showed that, the V-funnel and L-box were within the accepted range for SCC. Tensile and flexural strength increases upon the use of 10% silica fume were found when compared with other groups; the ideal percentage of steel fiber that should be combined in this hybrid was 2% of the total weight of the binder. Overall, steel fibers generated a heightened compressive and splitting tensile strength in the self-compacting concrete mixes. Full article
(This article belongs to the Special Issue Steel Fibre Reinforced Concrete Behaviour)
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