Steel fibre for reinforcing concrete or mortar having an anchorage end with at least three straight sections

Patent metadata

Field	Value
Publication number	US-9435122-B2
Application number	US-201113993509-A
Country	US
Kind code	B2
Filing date	Dec 14, 2011
Priority date	Dec 15, 2010
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

A steel fiber for reinforcing concrete or mortar has a middle portion and an anchorage end at one or both ends of the middle portion. The middle portion has a main axis. The anchorage end comprises at least a first straight section, a first bent section, a second straight section, a second bent section and a third straight section. The first straight section and the third straight section are bending away from the main axis of the middle portion in the same direction. The second straight section is substantially parallel with the main axis of said middle portion.

First claim

The invention claimed is:

1. A steel fibre configured to reinforce concrete or mortar, said steel fibre comprising:
a middle portion and anchorage ends at both ends of said middle portion,
said middle portion having a main axis,
each of said anchorage ends comprising at least a first straight section, a second straight section and a third straight section, said first straight section being connected to said middle portion by a first bent section, said second straight section being connected to said first straight section by a second bent section, said third straight section being connected to said second straight section by a third bent section,
each of said first, second and third straight sections having a main axis, wherein said first straight section is configured to bend away from the main axis of said middle portion thereby defining an included angle between the main axis of said middle portion and the main axis of said first straight section, said second straight section being substantially parallel with the main axis of said middle portion, and said third straight section is configured to bend away from the main axis of said middle portion in the same direction as said first straight section is configured to bend away from the main axis of said middle portion thereby defining an included angle between the main axis of said second straight section and the main axis of said third straight section, said included angle between the main axis of said middle portion and the main axis of said first straight section and said included angle included between the main axis of said second straight section and the main axis of said third straight section ranges between 100 and 160 degrees,
wherein said middle portion has a length greater than 25 mm and said first straight section, said second straight section, and said third straight section each has a length between 0.1 mm and 8 mm.

2. The steel fibre according to claim 1 , wherein said anchorage end further comprises a fourth straight section, said fourth straight section being connected to said third straight section by a fourth bent section.

3. The steel fibre according to claim 2 , wherein said fourth straight section has a main axis that is substantially parallel with said main axis of said middle portion.

4. The steel fibre according to claim 2 , wherein the angle between the main axis of the fourth straight section and said main axis of said middle portion ranges between −60 and +60 degrees.

5. The steel fibre according to claim 1 , wherein the included angle between the main axis of said middle portion and the main axis of said first straight section and the included angle between the main axis of said second straight section and the main axis of said third straight section are the same.

6. The steel fibre according to claim 1 , wherein said middle portion of said steel fibre has a tensile strength R m of at least 1000 MPa.

7. The steel fibre according to claim 1 , wherein said middle portion has an elongation at maximum load A g+e of at least 2.5%.

8. The steel fibre according to claim 1 , wherein said steel fibre is in a stress-relieved state.

9. The steel fibre according to claim 1 , wherein said middle portion of said steel fibre is provided with at least one flattened section.

10. The steel fibre according to claim 1 , wherein said middle portion of said steel fibre has a diameter D ranging from 0.1 mm to 1.20 mm.

11. The steel fibre according to claim 1 , wherein said steel fibre has a length to diameter ratio L/D ranging from 40 to 100.

12. A concrete structure reinforced with steel fibres according to claim 1 .

13. The concrete structure according to claim 12 , wherein the ratio residual flexural tensile strength f R,3 divided by residual flexural tensile strength f R,1 (f R,3 /f R,3 ) is higher than 1 with a dosage of said steel fibres of less than 1 vol %.

14. The concrete structure according to claim 12 , wherein the residual flexural tensile strength f R,3 is higher than 5 MPa with a dosage of said steel fibres of less than 1 vol %.

15. A method using the steel fibre according to claim 1 for a load carrying structure of concrete by placing the steel fibre in the load-carrying structure.

16. The steel fibre according to claim 1 , wherein said included angle between the main axis of said middle portion and the main axis of said first straight section and said included angle included between the main axis of said second straight section and the main axis of said third straight section are different.

17. The steel fibre according to claim 1 , wherein the anchorage ends bend in opposite directions from the main axis of the middle portion.

Assignees

• Lambrechts Ann
• Van Haeke Martin
• Bekaert Sa Nv

Inventors

• Lambrechts Ann
• Van Haeke Martin

Classifications

• E04C5/012 Primary

  Discrete reinforcing elements, e.g. fibres · CPC title

• Y10T428/2913

  Rod, strand, filament or fiber · CPC title

• Y10T29/49801

  Shaping fiber or fibered material · CPC title

• C04B20/0048

  Fibrous materials · CPC title

• Y10T428/249935

  Fiber is nonlinear [e.g., crimped, sinusoidal, etc.] · CPC title