Constructions and construction elements not of metal; constructions and construction elements of concrete; prefabricated concrete elements for the building industry and for public or private works, civil engineering and agricultural engineering; transportable non-metallic constructions and construction elements; transportable concrete constructions and construction elements; non-metallic pipes and conduits for building and their parts; concrete pipes and conduits and their parts for the building industry and for public or private works, civil engineering and agricultural engineering