Modular portable paving blocks made wholly or substantially of plastic for construction into relocatable roadways, and replacement parts therefor; connectable paving blocks made wholly or substantially of plastic for the surfacing of relocatable roadways, and replacement parts therefor; roadways of non-metallic materials, namely, temporary interconnected panels made wholly or substantially of plastic for supporting vehicles driving over the panels, and replacement parts therefor; ground reinforcement panels, namely, tiles made wholly or substantially of plastic for use in constructing portable roads, paths, tracks and helicopter landing pads, and replacement parts therefor; modular decking made wholly or substantially of plastic to serve as a ground cover; non-metallic building materials, namely, multilayer panels of plastic for use in building, and replacement parts therefor; modular non-metal interconnecting structures comprised wholly or substantially of plastic with flexible covers for agricultural, commercial or industrial storage; interlocking non-metal paving blocks, floor panels, tiles and paving blocks with shaped ramp or incline edges, all made wholly or substantially of plastic, for use in construction, and replacement parts therefor; polypropylene floorboards and replacement parts therefor; polypropylene vehicular surfacing materials, namely, modular portable polypropylene paving blocks for the surfacing of relocatable roadways, and replacement parts therefor; floor panels made of reinforced plastic; interlocking flooring made wholly or substantially of plastic, and replacement parts therefor; flooring of reinforced plastic and replacement parts therefor; roofing membranes made wholly or substantially of plastic for building purposes; interlocking non-metal paving blocks, floor panels, tiles, and paving blocks with shaped ramp or incline edges, all made wholly or substantially of plastic for use in ground reinforcement, and replacement parts therefor