In a quick entry to the commercial marketplace, Hardcore DuPont Composites LLC and Newport, Del., contractor James Julian Inc. replaced a 20-by-25-foot Maryland bridge in 15 hours Dec. 2.
Workers removed a timber structure in the morning and, using existing concrete abutments, installed a composite deck and guardrails in the afternoon and evening. Cecil County contracted with Hardcore DuPont for replacement of the bridge, which carries traffic near Elkton, Md.
``The county called up and asked for it'' in early November, Scott Hemphill, a Hardcore DuPont division manager, said in a telephone interview. ``This is the first composite bridge not underwritten by federal highway or DARPA [funds] or [as a] university research project.'' DARPA is the Defense Applied Research Projects Agency.
At its facility in New Castle, Del., Hardcore DuPont assembled the form during several weeks and infused resin into the single 16-inch-thick Cellcore structure in a half-hour process. The Seeman Composite Resin Infusion Molding Process, or Scrimp, is a low-cost way to manufacture large, high-glass-content, composite parts.
Brunswick Technologies Inc. of Brunswick, Maine, supplied standard quad-axial knitted glass fabrics; Dow Chemical Co. of Midland, Mich., Derakane PC100 vinyl ester; and Transpo Industries Inc. of New Rochelle, N.Y., T-48 epoxy polymer overlay for the wearing surface.
A downgrading of the bridge's capacity prompted Robert Campbell, Cecil County public works director, to explore alternate technologies for the urgent replacement.
Hemphill said the composite bridge's $40,000 cost is on par with prices for a steel or concrete bridge. The composite bridge's life expectancy of 75-100 years, however, is three to four times greater than that of other materials, he added.
DuPont Co. of Wilmington, Del., and New Castle-based Hardcore Composites Ltd. formed Hardcore DuPont as a joint venture in 1994.