Abstract: The invention relates to reinforcing glass strands and the structures of such glass strands having an improved wet aging resistance and equipped with a coating composition, obtained from a solution and/or a suspension and/or an emulsion, that comprises (in % by weight of solids): 60 to 95% of at least one polymer 2 to 18% of nanoparticles. It also relates to a coating composition suitable for coating said strands and strand structures, its production method and the composites incorporating the strands and strand structures.