BUSINESS
Advanced Polymer Composite Makers Look Toward Infrastructure Markets • As traditional aerospace uses stow, bridges and elevated highways are promising markets for fiher-polymer blends Marc S. Reisch C&EN Northeast News Bureau A dvanced polymer composite mak/ % ers are beginning to envision J L J L more down-to-earth uses for materials once destined for stealth military aircraft or commercial aerospace uses. In the past, these composites of carbon or aramid fibers and epoxy resins were so expensive that only military and commercial aerospace builders would think of using them. But now, along with fiberglass and resins, they may replace steel and concrete in the building of bridges and elevated highways. Advanced composites may make bridges and elevated highways more resistant to earthquake damage. Civil engineers could use them to extend the useful lives of deteriorating civil infrastructures, including bridges, that are years beyond their original design. Other engineers envision quickly assembled, low-maintenance, long-span advanced-composite bridges destined to last a century or more. But advanced composites face obstacles because they have no long-term track record of use for civil engineering structures. In comparison, concrete and steel have a long history of use in bridge and highway applications. And even in aerospace applications, where composites have been employed for 30 or more years, it has only been in the past decade or so that designers have trusted them in primary aircraft support structures, and then most often on expensive high-tech military planes. Composite makers will "have to make heroic development efforts" if 12
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Fiberglass composites frame 371-foot-long pedestrian bridge in Perthshire, Scotland. they hope to expand the market for use of composites in a civil infrastructure, says Composites Institute Marketing Director Douglas S. Barno. Barno, who works out of the Granville, Ohio, regional office for the New York City-based trade group, sees a potential $500 million market for composites use in earthquake-prone regions, where composites of glass, aramid, or carbon fiber and resins could reinforce
concrete highway support columns. The same composite technology could find its way into what Barno says could be a trillion-dollar market to upgrade and repair aging and deteriorating concrete highway and parkingdeck supports in areas where weather, instead of the threat of an earthquake, has begun to undermine structures. Composites offer a number of advantages in bridge construction, says Paul
W. Pendorf, president of American Materials & Technology Corp., Culver City, Calif. His company's Culver City Composites division manufactures aerospace composites and hopes to offer composites for civil infrastructure. "Composites have a 10-to-l weight advantage over steel and concrete," says Pendorf. And because concrete and steel are so heavy, "90% of a bridge's weight is there just to hold the structure up," he adds. That weight can be a problem in earthquakeprone areas, and lighter composites could more easily absorb an earthquake's energy. Plastics are widely used in the construction industry. According to Freedonia Group, industry consultants located in Cleveland, more than 14.4 billion lb of plastics went into the U.S. construction industry for products such as siding, plumbing, and insulation. Composites are also widely used in construction, though not necessarily for bridge and road repair. About 626.9 million lb of polymer composites were used in the construction industry in 1995, according to the Composites Institute. Much of that use was fiberglass composites for bathtubs, shower enclosures, and spas. Barno says perhaps 10% of construction composites find their way into civil infrastructure. Much of the civil infrastructure use is for fiberglass composites for sewer and water pipe repair. Manufacturers of advanced composites only recently have turned to civil infrastructure to develop new markets, says William H. Werst Jr., executive director of the Suppliers of Advanced Composite Materials Association (SACMA), Arlington, Va. The association values worldwide shipments of fibers such as carbon, aramid, glass, and ceramic preimpregnated with resins at $522.6 million in 1994, up 31% from the year before, largely because of the increased value of the Japanese yen. (Japan is a large producer of carbon fiber.) Shipments in 1994 were hardly changed from 1993 and totaled 19.9 million lb. Aerospace and sporting goods use largely accounted for the shipments, says Werst. High costs also may delay composites use. Carbon fiber exceeds $8 per lb and, depending on the grade, can be as high as $70 per lb. Aramid fiber exceeds $10, while high-performance fiberglass may cost $1.00 to $2.00 per lb. Costs of fabricating composites of these fibers with
Lightweight composite bndge in Olympic National Park, Washington, assembles quickly. polymers can range from $5.00 per lb for civilian aircraft. The U.S. defense budget fiberglass and polyester resin to as much cuts of the past few years, along with a as $150 per lb for advanced aerospace slowdown in commercial aerospace, grades of carbon and epoxy composites. spurred industry interest in developing By comparison, the materials bridges are composites for infrastructure use. often made of—steel and concrete—cost However, Loud is no Pollyanna. He between 30 cents and $1.00 per lb. Still, points out that, from their introduction some industry observers think the po- into the automotive industry in the tential for advanced composites in 1950s, it took nearly 30 years for fiberbridge and road repair is huge. glass panels to garner a significant According to the Federal Highway share of the auto and truck body marAdministration, of the more than 576,000 ket. Civil infrastructure uses will take U.S. bridges, about 187,000 are either at least as long to make inroads, he bestructurally deficient or functionally ob- lieves. And questions about compossolete. Steve Loud, editor of the newslet- ites' durability will have to be anter Composites News: Infrastructure, Sola-swered before new bridges are consisna Beach, Calif., says U.S. state, local, tently built incorporating advanced and federal governments spend more composites. As a result, he maintains than $5 billion annually to build new the first big market for advanced combridges and maintain existing ones. De- posites will be in bridge repair. ferred bridge-building and maintenance Composites makers are eyeing repair projects have left the country with $91 markets in California, where the Loma billion in overdue repairs. Prieta earthquake near San Francisco in The civil infrastructure market is 1989 and the Northridge earthquake "the largest untapped market in the near Los Angeles in 1994 seriously country for composites," says Loud, a damaged bridges and elevated highcomposites expert who had a 20-year ways. Companies such as Xxsys, San career with fiberglass maker Owens Diego, developed carbon-fiber column Corning. He believes the market for wrap cured in place on concrete colcomposites looks as promising as, if umns. The advanced composite is not more promising than, military meant to preserve concrete that would aerospace markets did in the 1970s and otherwise turn to rubble in an earth'80s. During those years, growth in U.S. quake. Hardcore DuPont Composites, military spending funded a thriving a joint venture between DuPont and market for advanced composite uses in Hardcore Composites, New Castle, the latest generation of high-technolo- Del., offers a fiberglass composite sysgy, radar-transparent military aircraft. tem to do much the same thing. More recently, commercial aerospace Neither system has yet qualified for manufacturers such as Boeing have be- use, according to a spokesman for the gun to incorporate composites into their California Department of TransportaMARCH 25,1996 C&EN
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BUSINESS
tion. However, at least some composite systems should receive approval next month, say industry sources. But while composite systems wait for approval, welded steel jacket repairs of concrete columns have already captured between 50 and 75% of the 25,000 columns scheduled for seismic retrofits. Loud, though, says an additional $150 million will be spent in California for seismic repairs to elevated roads and bridges not included in the current projects, and he says composites may take a sizable piece of that expanded market. Ralph J. Nuismer, infrastructure programs manager of Alliant TechSystems Composite Structures, Magna, Utah, says carbon fiber and epoxy overlays applied like wallpaper to masonry and concrete may be an economic way to repair deteriorating highway support columns, and at the same time provide seismic reinforcement. Another company, Creative Pultrusions, Alum Bank, Pa., is working with the West Virginia Department of Highways, Bridges & Superstructures on a project to reinforce steel bridges with carbon-fiber laminates bonded to steel bridge stringers. The Composite Materials Center of Saint Jerome, Quebec, also has developed a number of advanced fiber composite road repair systems. According to the government-aided private center's general manager, Robert Guillemette, center engineers have developed a carbon epoxy system to repair a flaking concrete bridge. "[The system] is so simple to install, and [it] results in a completely new bridge," he says. The center also has developed systems to repair deteriorated concrete bridge abutments with vinyl-ester and glassfiber envelopes. Guillemette expects these composite fixes to receive Canadian code approval in June. Gilbert A. Hegemier, professor of applied mechanics at the University of California, San Diego (UCSD), and director of the Powell Structural Research Laboratory, says much of the work to develop composites for infrastructure use is coming through the collective efforts of consortia and industry organizations such as the Composites Institute and the Construction Materials Council of the American Society of Civil Engineers, Washington, D.C. Hegemier heads the Advanced Composites Technology Transfer Consortium (ACTTC), a group of large fiber and composite makers who 14
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hope to develop inexpensive techniques to use advanced composites for infrastructure construction. They formed the consortium in 1992 at a time when high-margin aerospace markets were declining and low-margin sporting goods uses were rising. ACTTC members include Amoco, Hercules, DuPont, and aerospace manufacturer Carbon-fiber bndge deck is tested in laboratory. Lockheed Martin. More recent members include engineering companies Bechtel and Fluor costs will offset the high material costs Daniel. Drawing on ACTTC research, for composites compared with concrete Hegemier and his colleagues designed and steel. If bridge builders consider a hybrid traditional/advanced polymer long-term savings because the bridge may composite bridge. The design incorpo- require less maintenance and will not rates concrete-filled filament-wound flake, corrode, or rust, then bridges that carbon-fiber/epoxy tubes used to con- contain composites may have a long-term struct a proposed three-dimensional advantage over traditional construction, truss-beam bridge in Columbus, Ind. says Hegemier. The 200-foot span would carry four While someone may build a bridge lanes of traffic and two pedestrian walk- made entirely of advanced composites ways on a carbon-fiber-filled concrete someday, some engineers have already deck across a waterway to a new resi- built experimental bridges of fiberglass dential development. composites. A 371-foot polyester and Hegemier says the lab also has stud- fiberglass cable-stay footbridge spanied the development of a carbon shell ning the River Tay at a golf club in bridge with $1.6 million of Federal Aberfeldy in Perthshire, Scotland, went Highway Administration funds for a up in 1992. The bridge cables are made proposed 450-foot-long, 60-foot-wide ca- from polyethylene-coated aramid fible-stay bridge to be built over Interstate bers. Aerospace company Lockheed 5 on the campus of UCSD. Two other Martin has built a prototype bridge designs incorporating advanced poly- deck structure capable of supporting a mer composites are also under consider- 15-ton vehicle. Hardcore DuPont Comation for the UCSD bridge, which Hege- posites plans to build a fiberglass commier figures can be built for about posite superstructure for a single-lane, $6 million to $7 million. A conventional 70-foot-long maintenance yard bridge bridge might cost between $4.5 million for the Delaware River & Bay Authoriand $5 million, a figure the UCSD com- ty within the next few months. posite bridge could match if "this were As engineers increasingly consider not the first time out" with these new fiberglass and advanced composites for construction techniques, says Hegemier. use in bridges and elevated highway A decision on bridge design may come construction, UCSD professor Hegein May or June. mier says engineers will no longer Another $11 million from the Ad- think of composites as exotic building vanced Research Projects Agency's materials. "They will be an additional (ARPA) Technology Reinvestment Proj- option" for engineers to consider when ect contributed to the carbon shell bridge they repair or build new structures. design effort. UCSD used the ARPA Hybrid combinations of traditional magrant and matching funds from indus- terials with composites will come into try to form the ARPA Bridge Infrastruc- use first, he says. As engineers learn to ture Renewal Consortium to help in the use advanced composites, their designs development of civil engineering appli- will consider both the materials' percations of technologies developed orig- formance advantages and the initial inally for the military. These efforts lower cost of steel and concrete. Ulti"look like the beginning of a new in- mately, engineers may consider a heavydustry," says Hegemier, who believes traffic-bearing advanced composite • speed of assembly and lower labor bridge to be a realistic option.
