Oct. 31, 2011
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CHAMPAIGN, Ill. — Two CERL teams received R&D Magazine’s prestigious R&D 100 Award, which recognizes the top 100 innovations worldwide each year. The teams accepted the awards at a ceremony in Orlando, Fla., in October.
All Thermoplastic Composite, I-Beam Design, High-Capacity Bridge System
Richard Lampo, James Wilcoski and Vincent Hock, ERDC-CERL, Henry Diaz-Alvarez, ERDC-GSL, Rutgers University, McLaren Engineering Group, and Axion International developed an all-thermoplastic composite bridge made of waste plastic and automotive bumper scraps which includes a novel I-beam design. Not only can the bridge stand up to a 70-ton Abrams tank, it suggests an economical way to rebuild the nation’s bridge infrastructure. The bridge eliminates material creep through an innovative I-beam design and patented mixture of composite materials.
The design demonstrates for the first time that thermoplastic composite lumber compares favorably to treated lumber on a first-cost basis. The designers estimate a 50-year life expectancy, thanks to the inherent resistance of the composite to moisture, rot, and insects. The result: a $300 per square foot lifecycle cost savings for the composite material compared to alternative materials.
The breakthrough 18-inch I-beam design, with its large moment of inertia, provides an increase in stiffness while eliminating material, reducing the bridge’s cost and weight. A non-linear strain energy equivalence model used for the bridge’s development predicted long-term creep strain—using short-term tests—would be negligible over the life of the structure by keeping the design stresses below 600 psi.
The patented thermoplastic composite material mixture combines post-consumer recycled high-density polyethylene with automotive bumper scraps (made of polypropylene and fiberglass). The immiscible polymer blending, extrusion, and molding process specifically orients the glass fibers.
The first bridge was installed at Fort Bragg, N.C., during summer 2009. This team also was presented the Editor’s Choice Award by R&D Magazine as one of the top three innovations.
Teslan Carbon Nanocoating
ERDC-CERL’s Susan Drozdz, with industry partner Todd Hawkins, Tesla NanoCoatings, Ltd., developed the first marketable corrosion-resistant coating for steel made with fullerene carbon nanotubes (CNTs). The product is an epoxy polyamide that features a low zinc content.
Traditional zinc-rich primers protect steel surfaces through the sacrificial action of the zinc dust. Zinc particles are anodic to steel, and the corrosion of the zinc particles protects the steel substrate from corrosion. The high volume of zinc dust pigment (up to 90% by weight) reduces the strength of the coating, increases permeability, and makes delamination of the paint film more likely.
Formulated at a much lower pigment volume content (PVC) than traditional zinc-rich primers, the Teslan Carbon Nanocoating has about 50% less zinc dust by weight. The addition of CNTs allows zinc particles to remain in electric contact, providing as much corrosion protection as before, but without the harmful effects of higher PVC formulations. In addition to elevated protection, the coating provides cost savings because it does not require an intermediate stabilization coating and it is compatible with a polyurethane topcoat.