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| Hünnebeck introduces new composite sandwich panels  Hünnebeck, one of the world's top suppliers of formwork and scaffolding, has just begun supplying concrete soffit formwork panels made by Quadrant Plastic Composites by sandwiching SymaLITE, a very light weight composite of polypropylene (PP) and glass fibres, between two skin layers of GMTex high performance glass reinforced thermoplastic (GMT). Hünnebeck says it will gradually phase out plywood panels in favour of the composite ones, in all of its formwork systems, including those for walls, starting with its TOPEC system for soffits. It introduced the new panels at Bauma, the international building and construction show in April.Quadrant Plastic Composites is marketing the panels, which are covered by patents, within the Quadrant product family. They are direct drop-in replacements for plywood, fitting together inside the metal frames usually used. Tests at Hünnebeck indicate that they can be used up to 200 times, they come away easily from the concrete after it has set to leave a near-perfect surface, they can be nailed just like wood, they are easy to maintain, humidity does not cause them to either swell or rot, they are highly damage resistant but also easy to repair and recycle. Plywood panels simply with plastic skins represent an improvement over traditional panels impregnated with phenolic resin, but they still have some disadvantages linked to the wooden core and to the different thermal expansion coefficients of the skin and the core. Humidity can still penetrate the core through nail holes or cuts in the plastic film, causing local swelling for example. An alternative composite solution uses a PP foam core bonded to aluminium skins covered with PP foil. Quadrant Plastic Composites solutions however, are metal-free, which makes them lighter, but they still have better mechanical properties, thanks to the very high performance GMTex skin. They are also easier to nail and to recycle. write your comments about the article :: © 2007 Construction News :: home page |