Composites in the building industry are getting a boost from a new national partnership of precast concrete manufacturers recently formed to market CarbonCast precast panels made with C-GRID carbon-fiber reinforcing grid. C-GRID is a carbon fiber/epoxy scrim fabricated by TechFab LLC (formerly Clark Schwebel TechFab Co., Anderson, S.C., U.S.A.), a joint venture of Hexcel (Dublin, Calif., U.S.A.) and Chomarat (Le Cheylard, France). Membership in the precast marketing group includes Oldcastle Precast Inc. (Edgewood, Md., U.S.A.), HIGH Concrete Structures Inc. (Lancaster, Pa., U.S.A.), Cretex Companies (Elk River, Minn., U.S.A.), Metromont Prestress Co. (Greenville, S.C., U.S.A.), and Rocky Mountain Prestress (Denver, Colo., U.S.A.).

The grid is produced in a proprietary process that lays down unidirectional warp and weft carbon fibers, then dips them in a fast-curing epoxy resin bath, to form a rectangular grid with openings anywhere from 0.25 to 3 inches square (depending on panel strength requirements). Carbon fiber is primarily supplied by Zoltek Corp. (St. Louis, Mo., U.S.A.). The carbon grid is used in combination with conventional steel reinforcement for secondary reinforcing and shear transfer. Carbon-reinforced panels can be fabricated thinner and up to 66 percent lighter than conventional precast elements, because the very thin, corrosion-resistant grid requires much less concrete cover and thus less overall panel thickness and weight. This reduces foundation, structural and seismic connection loads as well as shipping and erection costs. The stronger C-GRID-reinforced panels don't experience the rust staining and spalling caused by rebar and steel grids, as is sometimes seen with typical precast concrete walls. In addition, the panels are more energy efficient, with greater insulation values (see CT August 2002, p. 40.) William Dausch, chairman of the AltusGroup, maintains, "This is undoubtedly one of the most significant developments in the building products industry in the last 50 years."

Together the five companies have 25 manufacturing and sales locations in the U.S., staffed by more than 200 professionals, forming a network expected to generate more new product sales than any of the individual companies could have developed on its own, says Tom Holmes, chairman of the AltusGroup marketing committee.