scholarly journals Laboratory Tests of Concrete Beams Reinforced with Recycled Steel Fibres and Steel Bars

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6752
Author(s):  
Małgorzata Pająk ◽  
Grzegorz Wandzik
Keyword(s):  
Tensile Tests ◽  
Image Correlation ◽  
Partial Replacement ◽  
Rc Beams ◽  
Bending Tests ◽  
Steel Fibres ◽  
Four Point Bending ◽  
Steel Bars ◽  
Cracking Pattern ◽  
Recycled Steel

This paper explores the possibility of the partial replacement of the longitudinal reinforcement in reinforced concrete (RC) beams with recycled steel fibres (RSF). Testing was focused on the contribution of two volume ratios of the RSF—0.5%, 1.0%. Basic compression and flexural tensile tests were performed to evaluate the effectiveness of the fibres following current standards. Additionally, the full-scale beams with and without conventional reinforcement were subjected to four-point bending tests. The results indicate that RSF improved the load-bearing capacity of the RC beams. Cooperation of RSF with the steel bars in carrying loads was proved. Findings from the Digital Image Correlation (DIC) revealed no impact on the cracking pattern of the RC beams.

scholarly journals OPTIMIZATION OF UHPFRC BEAMS SUBJECTED TO BENDING USING GENETIC ALGORITHMS

2014 ◽  
Vol 20 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Goran Ćirović ◽  
Vlastimir Radonjanin ◽  
Milan Trivunić ◽  
Milan Trivunić ◽  
Dragan Nikolić
Keyword(s):  
Mechanical Properties ◽  
Genetic Algorithms ◽  
High Performance ◽  
Experimental Studies ◽  
High Strength ◽  
Steel Fibres ◽  
Four Point Bending ◽  
Steel Bar ◽  
Steel Bars ◽  
Prestressed Reinforcement

Ultra high performance fibre reinforced concrete (UHPFRC) is cementitious composite with very high strength, and when compared with ordinary concrete it is a more superior material both in terms of its mechanical properties and its durability. In order to predict the behaviour of UHPFRC beams, first of all, experiments were carried out to investigate the mechanical properties of composites containing 2% and 4% of steel fibres. Following this, four beams of 2 m in length were tested by subjecting to four point bending. Two beams contained only micro steel fibres, while the remaining two contained conventional steel bar reinforcement. On the basis of experimental studies and recommendations by the AFGC for UHPC, the behaviour of the beams was modelled and optimization was carried out using genetic algorithms (GA) according to the criterion of minimum price. In this paper, the prices of individual UHPFRC beams are also shown in comparison with beams, which contain steel bars or prestressed reinforcement.

scholarly journals Recent advances in structural fibre-reinforced concrete focused on polyolefin-based macro-synthetic fibres

2020 ◽  
Vol 70 (337) ◽  
pp. 206 ◽  
Author(s):  
M. G. Alberti ◽  
A. Enfedaque ◽  
J. C. Gálvez ◽  
A. Picazo
Keyword(s):  
Reinforced Concrete ◽  
Reinforce Concrete ◽  
Tensile Tests ◽  
Environmental Benefits ◽  
Fibre Reinforced Concrete ◽  
Steel Fibres ◽  
Lower Weight ◽  
Steel Bars ◽  
Future Challenges ◽  
And Storage

Fibre-reinforced concrete (FRC) allows reduction in, or substitution of, steel-bars to reinforce concrete and led to the commonly named structural FRC, with steel fibres being the most widespread. Macro-polymer fibres are an alternative to steel fibres, being the main benefits: chemical stability and lower weight for analogous residual strengths of polyolefin-fibre-reinforced concrete (PFRC). Furthermore, polyolefin fibres offer additional advantages such as safe-handling, low pump-wear, light weight in transport and storage, and an absence of corrosion. Other studies have also revealed environmental benefits. After 30 years of research and practice, there remains a need to review the opportunities that such a type of fibre may provide for structural FRC. This study seeks to show the advances and future challenges of use of these polyolefin fibres and summarise the main properties obtained in both fresh and hardened states of PFRC, focussing on the residual strengths obtained from flexural tensile tests.

scholarly journals Shear strengthening of RC beams with thin panels of mortar reinforced with recycled steel fibres

2018 ◽  
Vol 194 ◽  
pp. 112-126 ◽  
Author(s):  
Lúcio Lourenço ◽  
Ziaaddin Zamanzadeh ◽  
Joaquim A.O. Barros ◽  
Mohammadali Rezazadeh
Keyword(s):  
Rc Beams ◽  
Shear Strengthening ◽  
Steel Fibres ◽  
Recycled Steel

scholarly journals APPLICATION OF STEEL FIBRES IN ALKALI-ACTIVATED MORTARS

2020 ◽  
Vol 27 ◽  
pp. 90-95
Author(s):  
Götz Hüsken ◽  
Lars-Christian Wagner ◽  
Gregor J. G. Gluth ◽  
Stephan Pirskawetz ◽  
Hans-Carsten Kühne
Keyword(s):  
Failure Modes ◽  
Tensile Tests ◽  
Single Fibre ◽  
Image Correlation ◽  
Destructive Testing ◽  
Steel Fibres ◽  
High Durability ◽  
Direct Tensile ◽  
Non Destructive ◽  
Alkali Activated

Alkali-activated materials are ideal for the repair of concrete structures in harsh environmental conditions due to their high durability in chemically aggressive environments. However, slag-based mortars, in particular, are prone to shrinkage and associated cracks. In this respect, the application of steel fibres is one solution to reduce the formation of shrinkage induced cracks and to improve post cracking behaviour of these mortars. This study investigated the influence of two different types of steel fibres on the tensile properties of two alkali-activated mortars. Direct tensile tests and single fibre pull-outs were performed to analyse the determining failure modes both on macro and micro scale. Mechanical testing was accompanied by non-destructive testing methods such as digital image correlation and acoustic emission for a detailed analysis of the fracture process.

scholarly journals Mechanical flexural properties of concrete with melt-extract stainless steel fibres

2021 ◽  
Vol 72 (12) ◽  
pp. 1155-1164
Author(s):  
Stjepan Lakusic
Keyword(s):  
Stainless Steel ◽  
Steel Fibre ◽  
Flexural Properties ◽  
Beam Specimen ◽  
Fatigue Load ◽  
Flexural Behaviour ◽  
Bending Tests ◽  
Steel Fibres ◽  
Steel Fibre Reinforced Concrete ◽  
Four Point Bending

An experimental study is performed to evaluate the effect of melt-extract stainless steel fibres on mechanical and flexural properties of concrete. A total of seventy-two specimens are used to determine an optimum fibre dosage and mechanical properties of plain and steel fibre reinforced concrete. Twelve full-scale beam specimens are then exposed to four-point bending tests. The effect of melt-extract stainless steel fibres on flexural behaviour of beams is quantified in this testing. A beam specimen is exposed to four-point bending, after being subjected to 15000 cycles of fatigue load. Pre- and post-fatigue flexural properties of beams with melt-extract steel fibres are compared and discussed.

Experimental Response of RC Beams Strengthened in Shear by FRP Sheets

2013 ◽  
Vol 7 (1) ◽  
pp. 127-135 ◽  
Author(s):  
E. Grande ◽  
M. Imbimbo ◽  
A. Rasulo
Keyword(s):  
Slenderness Ratio ◽  
Shear Capacity ◽  
Rc Beams ◽  
Fiber Reinforced Plastic ◽  
Frp Composites ◽  
Reinforced Plastic ◽  
Externally Bonded ◽  
Experimental Response ◽  
Transverse Steel ◽  
Cracking Pattern

The paper discusses the results of an experimental investigation carried out on reinforced concrete (RC) beams strengthened in shear by externally bonded fiber reinforced plastic (FRP) sheets. The study is devoted to analyze the role that the transverse steel reinforcement and the beam slenderness ratio could play on the resistant mechanism of RC beams strengthened in shear by FRP composites. The results are summarized and analyzed in detail in the paper in terms of shear capacity, cracking pattern and shear resisting contribution of FRP.

Effect of Steel Fibres on Flexural Toughness of Concrete and RC Beams

2021 ◽  
Author(s):  
Fuat Köksal ◽  
Kuppala Srinivasa Rao ◽  
Ziyafeddin Babayev ◽  
Mehmet Kaya
Keyword(s):  
Rc Beams ◽  
Steel Fibres ◽  
Flexural Toughness

scholarly journals Effect of Crystallographic Orientation and Grain Boundaries on Martensitic Transformation and Superelastic Response of Oligocrystalline Fe–Mn–Al–Ni Shape Memory Alloys

2021 ◽  
Author(s):  
A. Bauer ◽  
M. Vollmer ◽  
T. Niendorf
Keyword(s):  
Martensitic Transformation ◽  
Grain Boundary ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Grain Boundaries ◽  
Tensile Tests ◽  
Image Correlation ◽  
Stress Concentrations ◽  
Grain Orientations ◽  
High Degree

AbstractIn situ tensile tests employing digital image correlation were conducted to study the martensitic transformation of oligocrystalline Fe–Mn–Al–Ni shape memory alloys in depth. The influence of different grain orientations, i.e., near-〈001〉 and near-〈101〉, as well as the influence of different grain boundary misorientations are in focus of the present work. The results reveal that the reversibility of the martensite strongly depends on the type of martensitic evolving, i.e., twinned or detwinned. Furthermore, it is shown that grain boundaries lead to stress concentrations and, thus, to formation of unfavored martensite variants. Moreover, some martensite plates seem to penetrate the grain boundaries resulting in a high degree of irreversibility in this area. However, after a stable microstructural configuration is established in direct vicinity of the grain boundary, the transformation begins inside the neighboring grains eventually leading to a sequential transformation of all grains involved.

scholarly journals Strength Enhancement of Superduplex Stainless Steel Using Thermomechanical Processing

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1094
Author(s):  
M. A. Lakhdari ◽  
F. Krajcarz ◽  
J. D. Mithieux ◽  
H. P. Van Landeghem ◽  
M. Veron
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Thermomechanical Processing ◽  
Tensile Tests ◽  
Image Correlation ◽  
Strength Enhancement ◽  
Industrial Material ◽  
Superduplex Stainless Steel ◽  
The Impact ◽  
Strength Improvement

The impact of microstructure evolution on mechanical properties in superduplex stainless steel UNS S32750 (EN 1.4410) was investigated. To this end, different thermomechanical treatments were carried out in order to obtain clearly distinct duplex microstructures. Optical microscopy and scanning electron microscopy, together with texture measurements, were used to characterize the morphology and the preferred orientations of ferrite and austenite in all microstructures. Additionally, the mechanical properties were assessed by tensile tests with digital image correlation. Phase morphology was not found to significantly affect the mechanical properties and neither were phase volume fractions within 13% of the 50/50 ratio. Austenite texture was the same combined Goss/Brass texture regardless of thermomechanical processing, while ferrite texture was mainly described by α-fiber orientations. Ferrite texture and average phase spacing were found to have a notable effect on mechanical properties. One of the original microstructures of superduplex stainless steel obtained here shows a strength improvement by the order of 120 MPa over the industrial material.

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