A reinforced concrete structure has been patented. The structure is comprised of a composite having more than one longitudinally oriented fibers embedded in a matrix of a depolymerizable and repolymerizable. rigid thermoplastic polyurethane resin that has a glass transition temperature (Tg) of at least 50° C. There is also a hard segment content (defined as the proportion of the weight of the TPU that is made up of chain extender and polyisocyanate residues) of at least 75 percent, the composite having a maximum cross-sectional dimension of not more than 5 mm and an aspect ratio of at least 10, which is embedded in concrete for reinforcement.