A reinforcement system for concrete structures, comprising a first set of reinforcement elements configured to be connected to and co-functioning with a second set of reinforcement elements, each of said first and second set of reinforcement elements comprises each a number of more or less uniformly shaped units, intended to be tied together' the first and/or second set of reinforcement elements being made of basalt or carbon fibers, embedded in a suitable matrix. At least the units forming said first set of reinforcement elements are delivered to the construction site in a flat packed, compact state, each unit of said first reinforcement elements being configured to be stretched out into longer lengths when placed in situ and preferably being interconnected to at least several of the other units of said first reinforcement elements by means of at least one flexible or foldable, more or less continuous band.