FE is a straight fibre with flattened ends. It is sometimes referred to as fishtail. Through the flattening process, the ends become larger which significantly increases the anchorage of the fibre in the concrete matrix rather than relying solely on the friction between concrete and steel.
Today FE is almost exclusively used in shotcrete applications due to its low rebound ratio. This fibre can however also be used in other applications such as precast elements.
The workability of FE is excellent with aspect ratios up to 80. Flat-End fibre should not be used in applications where concrete shrinkage is a primary concern. In order to guarantee anchorage of the flattened ends, it is mandatory that a dense concrete mix with sufficient strength (minimum C 30/37) and fines content is used.