Pittsburgh, Pennsylvania - GMI Composites has worked with Bayer MaterialScience to create a customised formulation polyurethane to develop lightweight manhole covers.
A customised formulation of Baydur RTM 902 polyurethane, developed collaboratively by Bayer and GMI, is used to mould the composite manhole covers through GMI's liquid resin injection process.
GMI's composite covers weigh significantly less than traditional cast-iron manhole covers, with a 24-inch cover weighing only 25 lbs (11.3 kg) compared to a cast iron equivalent weighing more than 150 lbs, BMS said in a 30 Jan news release. The company added that the covers meet rigorous standards for cyclical fatigue, proof-load and durability.
"We were on site, providing hands-on support to the GMI team running tests to decide the best production process of composite covers," said Harry George, manager, New Applications, Polyurethanes, BMS. "It is always rewarding to work from start-to-finish on a product like manhole covers and see a concept turn into reality."
The covers are also corrosion-and slip-resistant and non-conductive, providing added safety to pedestrians and utility workers may come in contact with them, Bayer said. It also added that unlike cast-iron covers, GMI's manhole covers have zero scrap value and are therefore unattractive to thieves.
Bayer presented its composite solutions at Composites 2013 in Orlando, Florida, 29-31 Jan 2013.
