Geotextiles stabilise road embankme

Tag : PP Filament

The new Tamarins Road project - largest construction project everundertaken in the Indian Ocean zone, on the French island of LaRéunion, is using geotextiles to stabilise the roadembankments using metallocene polypropylene resin. The long-awaitedhighway will relieve congestion on the coastal road, which is nowsaturated with traffic.
The new highway will run from Saint Paul to L'Etang Salé, adistance of 33.7 kilometers, and will comprise two dualcarriageways on different levels. The whole project has beenplanned with an eye to sustainable development and preservation ofthe landscape along the route. The new road now under constructionbetween the sea and the coastal mountains will require 120 supportstructures, including 4 huge bridges as well as severalinterchanges and a number of roofed-over sunken stretches. Inaddition, within a few kilometers of its departure point, thehighway is being built on two huge embankments, 350 meters long and4-5 meters high, stabilised with geotextiles. These landscapedembankments, which provide a platform for the actual roadway, arebeing built by TenCate Geosynthetics France, which hasworld-renowned expertise in the construction ofgeotextile-reinforced structures. For the new road, projectengineers opted for a geotextile with elongation resistance of 95kN/meter. Between them, the two structures required severalthousand square meters of geotextile. The embankments are made fromlayers of landfill (crushed local basalt) interspersed with layersof geotextile. To avoid disfiguring the landscape, embankment wallsare getting cladded with volcanic stone that is typical of theisland landscape.
Stronger nonwovens mean higher-performance geotextile, and they canalso help reduce product weight while still meeting mechanicalrequirements. This downgauging reduces the environmental footprintof the nonwovens left in the ground as part of construction.Production processes are cleaner too: at TenCate's plant, the fumesthat are usually emitted by the high-temperature spunbond processare reduced by a factor of 4 to 5.

Metallocenes are the latest generation of catalyst used in thepolypropylene polymerisation process. This type of catalyst is alsocalled "single site" as opposed to the older"multiple sites" catalysts. Metallocenes achieve a verynarrow molecular weight distribution in a highly controlled way,resulting in polymer chains with very uniform length and nature.Total Petrochemicals metallocene grades are specially formulated tosuit the spunbond process used to produce nonwovens. Their narrowmolecular weight distribution results in low elongationalviscosity, which makes them ideal for the fast drawing ofcontinuous filaments forced by an airflow. Their low gel contentand high product consistency prevent fiber breaks, which tend todisrupt production and weaken nonwovens. Total Petrochemicalsmetallocene resins are an ideal choice for geotextile applicationsrequiring very strong nonwovens, because of the much higherfilament tenacity they allow. This fiber strength is directlytransmitted to the nonwovens through the bonding process used byTenCate in producing its Bidim geogrid.