Reinforcement bar and method for manufacturing same

Reinforcement bar for concrete structures, comprising a plurality of parallel fibers, tensioned, comprising at least one of basalt, carbon, or glass fiber, embedded in a cured matrix, the bar having an average length in a range of 20 mm to 200 mm, and an average diameter in a range of 0.3 mm to 3 mm, the bar being made of at least one fiber bundle comprising the plurality of parallel fibers, characterized in that at least a part of a surface of the bar is deformed to provide a deformation of at least a part of the surface of the bar prior to or during a curing stage of the matrix such that the deformation is secured in the cured matrix, by means of:

• a) one or more strings of an elastic or inelastic, tensioned material being helically wound around said at least one fiber bundle comprising the plurality of parallel fibers prior to curing of the matrix in which the fibers are embedded, maintaining the fibers in a parallel state during curing and providing an uneven external surface with longitudinally arranged helical indents in a longitudinal direction on the surface of said at least one fiber bundle in the matrix of the reinforcement bar, and
• b) said bar being provided with a surface shape and/or texture which contributes to bonding with the concrete thereby providing a roughened surface,
• wherein a higher tension is applied to the one or more strings than the at least one fiber bundle, thereby providing a twist in the at least one fiber bundle.