Reinforcement bar and method for manufacturing same

Reinforcement bar for concrete structures, comprising a large number of continuous, parallel fibers, slightly tensioned, preferably made of basalt, carbon, glass fiber, or the like, embedded in a cured matrix, the bars preferably having an average length in the range of 20 mm to 200 mm, and an average diameter in the range of 0.3 mm to 3 mm, each bar being made of at least one fiber bundle comprising a number of parallel, preferably straight fibers having a cylindrical cross section, the cross section preferably being more or less circular or oval, characterized in that at least a part of the surface of each bar being deformed prior to or during the curing stage of the matrix by means of:

• a) one or more strings of an elastic or inelastic, but tensioned material being helically wound around said at least one bundle of parallel, straight fibers prior to curing of the matrix in which the fibers are embedded, maintaining the fibers in an parallel state during curing and providing an uneven external surface with longitudinally arranged helical indents in a longitudinal direction on the surface of the matrixed fiber bundle(s) of the reinforcement bars, and/or
• b) that said bars being provided with a surface shape and/or texture which contributes to good bonding with the concrete thereby providing a roughened surface.