EP0861948A1 - Stahlfaser zur Armierung von Stahlbeton hoher Leistung - Google Patents

Stahlfaser zur Armierung von Stahlbeton hoher Leistung Download PDF

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Publication number
EP0861948A1
EP0861948A1 EP97200582A EP97200582A EP0861948A1 EP 0861948 A1 EP0861948 A1 EP 0861948A1 EP 97200582 A EP97200582 A EP 97200582A EP 97200582 A EP97200582 A EP 97200582A EP 0861948 A1 EP0861948 A1 EP 0861948A1
Authority
EP
European Patent Office
Prior art keywords
steel fibre
steel
anchorages
fibre
performance concrete
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97200582A
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English (en)
French (fr)
Inventor
Ann Lambrechts
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bekaert NV SA
Original Assignee
Bekaert NV SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bekaert NV SA filed Critical Bekaert NV SA
Priority to EP97200582A priority Critical patent/EP0861948A1/de
Priority to US09/355,975 priority patent/US6235108B1/en
Priority to CA002277971A priority patent/CA2277971A1/en
Priority to PCT/EP1998/001126 priority patent/WO1998038398A1/en
Priority to EP98913607A priority patent/EP0963494A1/de
Priority to JP53732298A priority patent/JP2001513157A/ja
Priority to AU68247/98A priority patent/AU728927B2/en
Priority to BR9807869-0A priority patent/BR9807869A/pt
Publication of EP0861948A1 publication Critical patent/EP0861948A1/de
Withdrawn legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/012—Discrete reinforcing elements, e.g. fibres

Definitions

  • the invention relates to a steel fibre for reinforcement of high-performance concrete or mortar.
  • BE-A3-1005815 (N.V. BEKAERT S.A.) teaches that for conventional concretes with a compressive strength ranging from 30 MPa to 50 MPa, it makes no sense to increase the tensile strength of a steel fibre above 1300 MPa since an increase in tensile strength does not add any increase in flexural strength to the reinforced concrete.
  • BE 1005815 further teaches, however, that for concretes with an increased compressive strength, the tensile strength of the steel fibres should increase proportionally.
  • WO-A1-95/01316 (BOUYGUES) adapts the average length of metal fibres to the maximum size of granular elements which are present in high-performance concrete so that metal fibres act as conventional rebars in high-performance concrete.
  • the volume percentage of metal fibres in high-performance concrete is relatively high and ranges between 1.0 % and 4.0 % of the concrete volume after setting.
  • a steel fibre for reinforcement of high-performance concrete or mortar has a length ranging from 3 mm to 30 mm, a thickness ranging from 0.08 mm to 0.30 mm and a tensile strength greater than 2000 MPa, e.g. greater than 2500 MPa, or greater than 3000 MPa.
  • the steel fibre is provided with anchorages the dimension of which in a direction perpendicular to the longitudinal axis of the steel fibre is maximum 50 %, e.g. maximum 25 %, e.g. maximum 15 % of the thickness.
  • the compression strength is the strength as measured by ASTM-Standard N° C39-80 on a cube of concrete of 150 mm edge, where the cube is pressed between two parallel surfaces until rupture.
  • the term 'thickness' of a steel fibre refers to the smallest cross-sectional dimension of a straight steel fibre without the anchorages.
  • the term 'anchorage' refers to any deviation from a straight steel fibre with a uniform transversal cross-section where the deviation helps to improve the anchorage or staying of the steel fibre in the concrete.
  • the term 'anchorage' does not refer to small bendings, i.e. bendings with a high radius of curvature, in the steel fibre which are a result of the steel wire having been wound on a spool before the final drawing and/or cutting. Steel fibres with only such small bendings which are the result of the previous winding of the steel wire, are still considered as 'straight' steel fibres.
  • the advantage of the present invention may be explained as follows. Concretes have a so-called interfacial zone between the cement paste and aggregates added to the concrete. This interfacial zone can be studied by means of a scanning electronic microscope (SEM). It has been observed that due to an increased presence of water in the neighbourhood of the aggregates, cement hydration is accelerated in the interfacial zone, resulting in the presence of calcium hydroxide intermixed with calcium-silica-hydrates and ettringite in the interfacial zone. The consequence is an interfacial zone with a relatively high degree of porosity. This interfacial zone forms the weakest link of the concrete and determines to a large extent its strength which tends to be smaller than the strength of its cement paste.
  • SEM scanning electronic microscope
  • the thickness of the interfacial zone ranges from about 50 ⁇ m (micrometer) to about 100 ⁇ m around the aggregates.
  • a similar interfacial zone has been observed around steel fibres added to the concrete.
  • high-performance concretes are characterized by :
  • the anchorages are not limited to a particular form or way of manufacturing.
  • the anchorages may take the form of bendings or waves on condition that their dimension in a direction perpendicular to the longitudinal axis of the steel fibre is limited in size.
  • the anchorages may also take the form of micro-roughenings, e.g. obtained by means of a controlled oxidation or by means of a controlled etching operation.
  • the steel fibre according to the invention has no bendings or waves.
  • the absence of any bendings or waves increases the mixability of the fibre in the high-performance concrete. This is very important since the volume percentage of steel fibres in high-performance concrete is substantially higher than in conventional concretes, and the higher this volume percentage the greater the risk for mixing problems.
  • the anchorages are indentations which are distributed along the length of a straight steel fibre.
  • the depth of these indentations ranges from 5 % to 25 % of the thickness of the steel fibre without indentations.
  • the depth of these indentations ranges from 0.01 mm to 0.05 mm.
  • the indentations may be provided at regular distances along the length of the steel fibre.
  • the steel fibre is provided with flattenings at both ends of the steel fibre.
  • the thickness of the flattened ends may range from 50 % to 85 % of the thickness of the non-flattened steel fibre.
  • Such a steel fibre has preferably an elongation at fracture which is greater than 4 %.
  • a steel fibre according to the present invention preferably has a carbon content above 0.40 %, e.g. above 0.82 %, or above 0.96 %.
  • FIGURE 1(a) shows a steel fibre 10 which is provided with indentations 12 which are regularly distributed along its length.
  • FIGURE 1(b) illustrates in more detail an indentation 12.
  • the steel fibre 10 has a length of 13 mm, and - apart from the indentations 12 - a round cross-section with a diameter of 0.20 mm.
  • the indentations 12 are provided both at the upper side and at the under side of the steel fibre 10.
  • the distance (pitch) between two indentations at the upper or at the under side is about 1.50 mm.
  • FIGURE 2 illustrates how a steel fibre 10 with indentations 12 can be manufactured.
  • a steel wire 14 is drawn by means of a winding drum 16 through a (final) reduction die 18. Having reached its final diameter the wire 14 is further guided to two wheels 20 which are both provided at their surface with protrusions 21 in order to bring the indentations 12 in the wire 14.
  • the two wheels 20 give the necessary pulling force to guide the wire 14 from the winding drum 16 to a cutting tool 22 where the steel wire 14 is cut in steel fibres 10 of the same lengths.
  • FIGUREs 3(a) and 3(b) illustrate a straight steel fibre 10 with flattened ends 24.
  • the flattened ends 24 provide the anchorage in the high-performance concrete.
  • the steel fibre 10 has no burrs since burrs could provoke concentrations of tensions in the concrete and these concentrations could lead to initiation of cracks.
  • the transition in the steel fibre 10 from the round transversal cross-section to the flattened ends 24 should not be abrupt but should be gradually and smooth.
  • the steel fibre 10 has following dimensions : a length of 13 mm, a diameter of a round cross-section of 0.20 mm, a thickness d of the flattened ends 24 of 0.15 mm and a length e of the flattened ends 24 - transition zone included - of 1.0 mm.
  • FIGURE 4 illustrates how a steel fibre 10 with flattened ends 24 can be manufactured by means of two rolls 26 which give flattenings to a steel wire 14 and simultaneously cut the steel wire into separate steel fibres.
  • a steel fibre 10 according to this second embodiment will be anchored in the high-performance concrete only at the ends 24 (and not along its length as in the first embodiment), it is preferable to increase the potential of plastic energy in the steel fibre by applying a suitable thermal treatment in order to increase the elongation at fracture of the steel fibre 10.
  • a suitable thermal treatment is known as such in the art.
  • the thermal treatment can be applied by passing the steel wire 14 through a high-frequency or mid-frequency induction coil of a length that is adapted to the speed of the steel wire and to heat the steel wire 14 to about more than 400 °C.
  • the steel wire will suffer from a certain decrease of its tensile strength (about 10 to 15 %) but at the same time will see its elongation at fracture increase. In this way the plastic elongation can be increased to more than 5% and even to 6%.
  • the composition of the steel fibre may vary to a large extent. Conventionally it comprises a minimum carbon content of 0.40 % (e.g. at least 0.80 %, e.g. 0.96 %), a manganese content ranging from 0.20 to 0.90 % and a silicon content ranging from 0.10 to 0.90 %.
  • the sulphur and phosphorous contents are each preferably kept below 0.03 %. Additional elements such as chromium (up to 0.2 à 0.4 %), boron, cobalt, nickel, vanadium ... may be added to the composition in order to reduce the degree of reduction required for obtaining a particularly tensile strength.
  • the steel fibre can be provided with a coating such as a metallic coating.
  • a coating such as a metallic coating.
  • it can be provided with a copper alloy coating in order to increase its drawability or it can be provided with a zinc or alluminium alloy coating in order to increase its corrosion resistance.
  • the steel fibre according to the present invention is not limited to particular tensile strengths of the steel fibre.
  • tensile strengths can be obtained ranging from moderate values of 2000 MPa to higher values of 3500 MPa, 4000 MPa and even higher. It is preferable, however, to adapt the tensile strength of the steel fibre both to the compression strength of the high-performance concrete and to the quality of the anchorage in the high-performance concrete. The higher the degree of anchorage in the concrete, the more useful it is to further increase the tensile strength of the steel fibre itself.
  • the steel fibres according to the invention may be glued together by means of a suitable binder which looses its binding ability when mixing with the other components of the high-performance concrete.
  • a suitable binder which looses its binding ability when mixing with the other components of the high-performance concrete.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Reinforcement Elements For Buildings (AREA)
EP97200582A 1997-02-28 1997-02-28 Stahlfaser zur Armierung von Stahlbeton hoher Leistung Withdrawn EP0861948A1 (de)

Priority Applications (8)

Application Number Priority Date Filing Date Title
EP97200582A EP0861948A1 (de) 1997-02-28 1997-02-28 Stahlfaser zur Armierung von Stahlbeton hoher Leistung
US09/355,975 US6235108B1 (en) 1997-02-28 1998-02-23 Steel fiber for reinforcement of high-performance concrete
CA002277971A CA2277971A1 (en) 1997-02-28 1998-02-23 Steel fibre for reinforcement of high-performance concrete
PCT/EP1998/001126 WO1998038398A1 (en) 1997-02-28 1998-02-23 Steel fibre for reinforcement of high-performance concrete
EP98913607A EP0963494A1 (de) 1997-02-28 1998-02-23 Stahlfaser zur armierung von stahlbeton hoher leistung
JP53732298A JP2001513157A (ja) 1997-02-28 1998-02-23 高性能コンクリート補強用鋼繊維
AU68247/98A AU728927B2 (en) 1997-02-28 1998-02-23 Steel fibre for reinforcement of high-performance concrete
BR9807869-0A BR9807869A (pt) 1997-02-28 1998-02-23 Fibra de aço para reforço de concreto de alta performance

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP97200582A EP0861948A1 (de) 1997-02-28 1997-02-28 Stahlfaser zur Armierung von Stahlbeton hoher Leistung
PCT/EP1998/001126 WO1998038398A1 (en) 1997-02-28 1998-02-23 Steel fibre for reinforcement of high-performance concrete

Publications (1)

Publication Number Publication Date
EP0861948A1 true EP0861948A1 (de) 1998-09-02

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Family Applications (2)

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EP97200582A Withdrawn EP0861948A1 (de) 1997-02-28 1997-02-28 Stahlfaser zur Armierung von Stahlbeton hoher Leistung
EP98913607A Withdrawn EP0963494A1 (de) 1997-02-28 1998-02-23 Stahlfaser zur armierung von stahlbeton hoher leistung

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Application Number Title Priority Date Filing Date
EP98913607A Withdrawn EP0963494A1 (de) 1997-02-28 1998-02-23 Stahlfaser zur armierung von stahlbeton hoher leistung

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EP (2) EP0861948A1 (de)
WO (1) WO1998038398A1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000046460A1 (de) * 1999-02-01 2000-08-10 Vulkan Harex Stahlfasertechnik Gmbh & Co. Kg Bewehrungsfaser zur bewehrung von stahlfaserbeton
EP1130184A3 (de) * 2000-02-29 2001-12-12 Horst Prof. Dr.-Ing. Falkner Stahlbeton-Stütze
GB2383368A (en) * 2001-12-24 2003-06-25 Univ Sheffield Fibre reinforced concrete
WO2011041995A1 (de) * 2009-10-08 2011-04-14 Karl-Hermann Stahl Metallfaser mit einer fase in der faserlängsrichtung verlaufenden faserkante
US9511413B2 (en) 2007-05-04 2016-12-06 Cent & Cent Gmbh & Co. Kg Method of making strip formed by web-connected wires
US9630226B2 (en) 2008-07-23 2017-04-25 Cent & Cent Gmbh & Co. Kg Method for producing steel fibers

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001513157A (ja) * 1997-02-28 2001-08-28 ナムローゼ・フェンノートシャップ・ベーカート・ソシエテ・アノニム 高性能コンクリート補強用鋼繊維
US20120261861A1 (en) * 2010-06-28 2012-10-18 Bracegirdle P E Nano-Steel Reinforcing Fibers in Concrete, Asphalt and Plastic Compositions and the Associated Method of Fabrication

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1941223A1 (de) * 1969-08-13 1971-02-25 Hendrix Hans Dr Baustoff mit hoher Schlagfestigkeit und Dauerschlagbestaendigkeit
DE2832495A1 (de) * 1978-07-25 1980-02-07 Thiel S Draadindustrie Thibodr Verankerungsfaser und matrize zur herstellung einer solchen verankerungsfaser
DE3024648A1 (de) * 1980-06-30 1982-01-21 Joachim Ing.(Grad.) 6380 Bad Homburg Hollatz Kunststeinbauelement sowie verfahren zu seiner herstellung
DE3032162A1 (de) * 1980-08-26 1982-04-08 Felix Schuh + Co Gmbh, 4300 Essen Flaechenheizvorrichtung fuer einen fussboden, sowie estrichwerkstoff hierfuer und verfahren zu dessen herstellung
DE3347675A1 (de) * 1983-12-31 1985-10-17 Gerd Dr. 7531 Neuhausen Lamprecht Kunststein-bauelement und verfahren zu dessen herstellung
DE8815120U1 (de) * 1988-12-05 1989-03-30 Hermann Gloerfeld -Metallwaren- GmbH & Co. KG, 5860 Iserlohn Armierungsfaser aus Metall, insbesondere aus Stahldraht, zur Armierung von Beton, insbesondere von Spritzbeton
DE4223804A1 (de) * 1992-07-20 1994-01-27 Gloerfeld Hermann Metallwaren Drahtfaser aus Metall zur Verwendung für die Verstärkung von insbesondere Beton

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL173433C (de) 1973-04-16 Bekaert Sa Nv
BE1005815A3 (nl) 1992-05-08 1994-02-08 Bekaert Sa Nv Staalvezelbeton met hoge buigtreksterkte.
FR2708263B1 (fr) 1993-07-01 1995-10-20 Bouygues Sa Composition de béton de fibres métalliques pour mouler un élément en béton, éléments obtenus et procédé de cure thermique.

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1941223A1 (de) * 1969-08-13 1971-02-25 Hendrix Hans Dr Baustoff mit hoher Schlagfestigkeit und Dauerschlagbestaendigkeit
DE2832495A1 (de) * 1978-07-25 1980-02-07 Thiel S Draadindustrie Thibodr Verankerungsfaser und matrize zur herstellung einer solchen verankerungsfaser
DE3024648A1 (de) * 1980-06-30 1982-01-21 Joachim Ing.(Grad.) 6380 Bad Homburg Hollatz Kunststeinbauelement sowie verfahren zu seiner herstellung
DE3032162A1 (de) * 1980-08-26 1982-04-08 Felix Schuh + Co Gmbh, 4300 Essen Flaechenheizvorrichtung fuer einen fussboden, sowie estrichwerkstoff hierfuer und verfahren zu dessen herstellung
DE3347675A1 (de) * 1983-12-31 1985-10-17 Gerd Dr. 7531 Neuhausen Lamprecht Kunststein-bauelement und verfahren zu dessen herstellung
DE8815120U1 (de) * 1988-12-05 1989-03-30 Hermann Gloerfeld -Metallwaren- GmbH & Co. KG, 5860 Iserlohn Armierungsfaser aus Metall, insbesondere aus Stahldraht, zur Armierung von Beton, insbesondere von Spritzbeton
DE4223804A1 (de) * 1992-07-20 1994-01-27 Gloerfeld Hermann Metallwaren Drahtfaser aus Metall zur Verwendung für die Verstärkung von insbesondere Beton

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000046460A1 (de) * 1999-02-01 2000-08-10 Vulkan Harex Stahlfasertechnik Gmbh & Co. Kg Bewehrungsfaser zur bewehrung von stahlfaserbeton
EP1130184A3 (de) * 2000-02-29 2001-12-12 Horst Prof. Dr.-Ing. Falkner Stahlbeton-Stütze
GB2383368A (en) * 2001-12-24 2003-06-25 Univ Sheffield Fibre reinforced concrete
WO2003056112A1 (en) 2001-12-24 2003-07-10 University Of Sheffield Fibre reinforced concrete
GB2383368B (en) * 2001-12-24 2005-11-09 Univ Sheffield Fibre reinforced concrete
US7267873B2 (en) 2001-12-24 2007-09-11 Kypros Pilakoutas Fiber reinforced concrete
US9511413B2 (en) 2007-05-04 2016-12-06 Cent & Cent Gmbh & Co. Kg Method of making strip formed by web-connected wires
US9630226B2 (en) 2008-07-23 2017-04-25 Cent & Cent Gmbh & Co. Kg Method for producing steel fibers
WO2011041995A1 (de) * 2009-10-08 2011-04-14 Karl-Hermann Stahl Metallfaser mit einer fase in der faserlängsrichtung verlaufenden faserkante
EA023056B1 (ru) * 2009-10-08 2016-04-29 Цент Унд Цент Гмбх Унд Ко Кг Металлическое волокно с фаской на проходящей в продольном направлении волокна кромке

Also Published As

Publication number Publication date
EP0963494A1 (de) 1999-12-15
WO1998038398A1 (en) 1998-09-03

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