19 Aggregate materials for use in concrete; barriers of plastic materials for civil engineering purposes; barriers of plastic materials for construction purposes; building elements of reinforced concrete, namely, walls, blocks, bricks, posts, slabs, panels; building products in the form of vents made from plastics; building products made by the extrusion of synthetic plastics, namely conduits for drainage and irrigation, tiles, wallboards; building products made by the moulding of synthetic plastics, namely, conduits for drainage and irrigation, tiles, wallboards; concrete; concrete panels for retaining earth; concrete prefabrications, namely, tombstones, statues, monuments, figurines, crash barriers, beams; concrete products for use in roadways; construction elements of plastic, namely, conduits for drainage and irrigation, tiles, wallboards; building materials, namely, corrugated sheets made of plastic building material; drains, other than of metal or plastic; expanded plastics for use in construction, namely, pipe fittings, decking; non-metallic building materials in the form of plastic extrusions, namely, pipe fittings, decking; plastic articles for use in civil engineering construction, namely, conduits for irrigation and drainage; plastic moulds for use with concrete, namely, for use forming cement posts, wall panels; rigid plastic pipes for water; polymer concrete; rainwater drainage apparatus of plastic materials; rainwater installations of plastic material, namely, conduits and rigid pipes; reinforced concrete for use in building foundations, road construction; rigid pipes of plastics other than parts of sanitary installations; sections of reinforced plastics for use in building, namely, for drainage and irrigation, constructing walls, barriers; storage tanks of concrete; tunnel lining segments made of concrete; water reservoirs of concrete