Function and beauty: an artist casts her vision using integrally colored precast concrete - Western Gateway Project/Susan Ferrari Rowley design

Concrete Producer, The, Jan, 2004 by Sarah Fister Gale

Driving down the highway, most commuters put little thought into their daily trek. Who would, with looming sound barriers that are tall, bland, and unappealing? Engineers, as well as the public, believe concrete needs to be boring.

Thanks to an innovative producer's ability to recast a designer's approach to concrete, this is about to change in New York. On a long stretch of Interstate 490, design engineers from the New York State Department of Transportation (NYSDOT) have commissioned building a noise barrier structure that will be both visually stimulating and maintenance free.

The Western Gateway Project, a 5900-foot-long sound wall in Rochester, N.Y, will feature cinnamon brown-tinted concrete. And to further enhance the integrally colored concrete, seven of the 491 panels, which range from 11 to 13 feet across, will be elaborately decorated with three-dimensional artistic renderings of Rochester's waterways. Made from a variety of materials, the art will catch the light as the drivers pass by.

This artistic application of precast concrete is new for functional concrete structures. Producers can now use innovative mix design and process technology to create economical concrete structures--including sound walls--that are beautiful.

Pigment vs. stain

For Todd Clarke, executive vice president of Lakelands Concrete Products, a Lima, N.Y., producer of precast and pre-stressed concrete elements, the Western Gateway Project is a victory. Lakelands and NYSDOT, working together, found that by considering integrally colored precast concrete, they could save both time and costs. Lakelands was the successful bidder for the panels and posts and Sealand Contractors Corp., Rush, N.Y., is the contractor for the project.

The NYSDOT designers originally specified gray concrete panels and posts for the sound wall that would later be stained brown in the field. Engineers quickly saw the problems such a project would create, says Clarke. The design engineers thought, for quality and consistency, the concrete panels wouldn't be stained until they were erected along the highway. This would involve scaffolding and traffic delays, and would take longer to complete because of unpredictable weather.

Staining would be difficult, as the panels feature a heavily raked finish on one side and 3/4-inch ribs on the reverse side. The resulting three-dimensional surfaces would make staining almost impossible.

"It would have been a complete disaster for the contractor who did the staining," explains James Stacy, president of Lakelands Concrete.

Instead of a field-applied stain, "integrally colored concrete was a logical choice," Clarke says. "It's a more efficient and cost-effective way to do such a large project."

Integrally colored concrete is produced in the plant, not on the road, eliminating the need for additional labor in the field and enabling completion of the panels to continue through the winter. Also, since the pigment is mixed directly with the concrete, the color is all the way through the panel, so if a car hits it or there is other damage, the color remains consistent. Stain is only on the surface. "Once we set the panels, they will be maintenance-free," Clarke says. "That's a huge benefit."

Integrally colored concrete

By working with Dynamic Color Solutions (DCS), a Milwaukee-based supplier of pigments and coloration systems, Lakelands created sample color panels for the transportation staff to compare with the stained selections. "The precast elements looked a lot nicer than the stained samples," Clarke says. "The material cost was similar and the contractor liked the idea of not having to stain the panels in the field."

Once they saw the samples and considered the long-term maintenance issues, the NYSDOT agreed, says Kevin Miller, project landscape architect for the NYS-DOT. "A lot went into reviewing the two systems, and color pigment had a distinct advantage." They chose DCS Cinnamon Toast #45 because it most closely matched the stain color they had originally selected.

On past smaller projects, Lakelands had used dry color mix. But, to accommodate the scope and pace of this project they installed an automated liquid color dispensing system. It included five diaphragm pumps, a control panel, and a weigh vessel. "We got a more consistent color with liquid than with dry color mix," says Stacy.

With dry color, bags of pigment are poured into concrete batches. The liquid pigment dispensing is closely monitored with the automated system, so there is little variance between batches and the liquid also is enclosed in the equipment, unlike the dry mix in open bags. "When we originally started selling liquid color, we felt automation was the major benefit, but the most significant benefit is more consistently colored concrete," says Cathy Higgins, DCS vice president of sales and marketing.

"Batching with liquid color is working very well," Clarke says. "The color of the hardened surface looks great." Using the control panel, Lakelands selects the appropriate amount of liquid pigment for each panel. The liquid is automatically transported from storage drums into the weigh vessel to verify the quantity, then gravity-fed into the mixer where it is blended with the concrete, Higgins says.