MARATHON, Wis. (August 8, 2002) – County Materials of Roberts, Wis., a leading producer of concrete prestress, precast and pipe products, has expanded its manufacturing facility to house a double 500' bridge girder bed system. The new prestress bridge beds are capable of handling up to 4 million pounds of prestress force.

The system is ready to produce high-strength concrete girders up to 81 inches high and in lengths of up to 150 feet. As a sign of what's to come, the system has the capacity for longer and taller girders.

"We like to be on the cutting edge of construction technology," says Dave Reneson, County Materials's Roberts Prestress division manager. "Before long, departments of transportation will be asking for 96 inch high girders with spans of 175-180 feet. The new designs are already on paper, and we'll be ready for them."

County Materials's girder bed project team worked with industry experts to develop two concrete mixes that would minimize thermal cracking and ensure the desired structural integrity. Cement supplier Holcim, Inc. of Naperville, Ill., concrete finisher Lewis Construction of Schofield, Wis. and admixture manufacturer, Master Builders, Inc. of Grayslake, Ill. provided the team with the knowledge necessary for executing each critical phase of the process.

The girder bed's nine-foot, three-inch base is a specialized mix of Portland cement, ground granulated blast furnace slag, sand, coarse aggregate, air-entraining agents, retarder and water reducers. For the nine-inch top layer, fly ash and steel fibers were incorporated into a mix of the same materials used for the base. For the entire concrete pour to set at once, admixture dosage rates were adjusted at predetermined intervals to alter settings times during placement. The result is 4,500 yards of ready-mixed concrete, poured in six layers over 13 hours.

"The 70% slag mixture contributes to the concrete's workability," says Reneson. "Crews handling 200 yards of ready-mix an hour can place and consolidate it without having to beat a clock. And we chose to pour overnight so we didn't interrupt our customers' demands."

Last summer County Materials completed a nearly 70,000 sq. ft. plant expansion with state-of-the-art equipment to produce Hollowcore Roof and Floor systems, concrete pipe and other specialty precast and prestress products, in addition to their production of concrete block and ready-mix. The expansion also allowed the company to begin manufacturing 21,000 concrete segments for the underground tunnels of Minnesota's first Light Rail Transit system.

The new facility helped County Concrete earn the St. Croix Economic Development Corporation "Business of the Year" title in 2001. "County Materials is a forward looking company that seeks out new markets and defines their niches. They've displayed staying power in achieving desired goals," William Rubin, SCEDC executive director, said.

For more information, call County Materials's Prestress, Precast & Pipe Division at 1-800-426-1126.

County Materials Corporation, producer of a full range of concrete products for over 55 years, has manufacturing facilities and HomeScape Studios located in 14 locations throughout Wisconsin and eastern Minnesota.