Hooked End fibres have been in the market for over 25 years.
This shape is probably the most popular and successful in the history of SFRC. This is due to the fact, that over the last decade almost all fibre manufacturers have added the hooked end shape to their product range.
Hooked-End HE fibres can be used in almost any known application for SFRC. For example ArcelorMittal’s HE 55/35 and HE 75/35 are primarily used in shotcrete applications.
HE fibres do not perform as well as undulated fibres with regard to shrinkage control, but they provide excellent workability when using fibres with up to an aspect ratio of 60. Aspect ratios up to and including 80 provide satisfactory workability.
HE fibres can be used with any concrete mix and high concrete density is less mandatory then for undulated or for flat-end fibres. Load transfer in the crack is very good with this fibre shape. Thus after the appearance of the first crack the loss of load-bearing capacity occurs quickly, but then stabilizes and in some cases even begins to increase again after large cracks have developed.
ArcelorMittal HE fibres have lengths in the range of 35 to 60 mm. Diameters range from 0.55 to 1 mm. Tensile wire strengths range from 1100 to 1900 MPa.