Recycled composite bridge installed in Europe

Axion International Holdings Inc. announced on Dec. 7, 2011, the completion of Europe’s first bridge made from recycled fiber-reinforced plastic.

Axion International Holdings Inc. (New Providence, N.J.) announced on Dec. 7, 2011, the completion of Europe’s first bridge made from recycled fiber-reinforced plastic. The materials for the bridge comprise extruded composite I-beams, deck boards and railing formed from Axion’s Recycled Structural Composite (RSC) technology, a combination of postconsumer high-density polyethylene (HDPE) and postindustrial fiber-reinforced polypropylene (PP).

The bridge components were prefabricated in the U.S. at Axion’s plant in Portland, Pa., and were transported in six sections to Scotland via container ship. It now spans the River Tweed at Easter Dawyck, near Edinburgh, Scotland, and forms part of the historic John Buchan Way. The bridge, approximately 12 ft wide by 90 ft long (3.6m by 27.4m), replaced an old bridge with a timber deck over steel beams. Still in good condition, the two masonry piers and abutments that supported the old bridge were kept in place to carry the new I-beam deck. The clear span is 28 ft/8.5m between piers, resulting in three effective spans at 30 ft/9.1m, representing the longest single spans yet constructed using this material. (Read more about Axion’s RSC bridge materials in “Tough I-beam bridge for tank traffic” at right.)

The entire construction project (including dismantling the old wood-and-steel bridge) was completed in less than two weeks. Thanks to its prefab design, installation of the new bridge itself took only four days and was completed on schedule, before Scotland’s winter season, by a team from Glendinning Groundworks Ltd., a Scottish contractor, and 10 Field Squadron (Air Support) Royal Engineers. The bridge has been designed to meet European standards, with a load rating of 45 metric tonnes (99,208 lb), thus allowing construction projects to be initiated in a similar manner throughout the continent.

With support from the Welsh Assembly Government, Axion made the project a reality in coordination with its U.K. partners Vertech Ltd. (Corwen, Clwyd, Wales) and Sicut Holding Ltd. (London), in addition to Dawyck Estates Ltd. (Peebles), specialist bridge designer Cass Hayward LLP (Chepstow, Monmouthshire), Cardiff University’s School of Engineering and Rutgers University’s AMIPP Advanced Polymer Center. AMIPP developed the extrusion process, now licensed to Axion and Sicut (each in different regions). The process combines the HDPE and fiber-reinforced PP by means of immiscible polymer blending, a method that can compound two or more polymers that are ordinarily incompatible in a melt blend to produce a composite. The extrusion process also tends to orient both fibers and polymer molecular chains in the axial direction, enhancing beam tensile strength and stiffness.

The process reportedly results in a composite in which the two matrices and the fiber form “three-dimensional networks” that combine the strength of HDPE with the stiffness of glass-reinforced PP. For bridge structural members, the extruder outputs T-beams that are then bolted together to make robust I-beams. On a weight-to-weight basis, the composite is said to be stronger than steel. Unlike steel, the RSC bridge components won’t rot, rust or corrode, and they don’t require painting or regular maintenance. In addition, the RSC composite is 100 percent recyclable at the end of its useful life. Axion uses the same extrusion process to produce Ecotrax railroad ties and a variety of building materials under the trade name Struxure.

“Axion couldn’t be more thrilled to be a part of this historic project in Scotland, producing Europe’s first plastic recycled bridge,” stated Steve Silverman, Axion’s president and CEO. “This project validates our strategy to deploy Axion’s building materials using our prefabrication concept to reduce onsite downtime and costs, creating a more value-added proposition for our customers. The remarkably fast erection time for a 90-ft bridge is a major benefit of our unique composite material, as it substantially reduces the complexity and cost of construction, and is good for the environment as well.”