Road building pioneer takes on warm mix

Tracing its roots back more than 150 years, Barrett Paving Materials, Inc., Roseland, N.J., has seen and been a part of much innovation in the asphalt industry. In 1903, the company developed a roofing tar treatment product used to advance America’s burgeoning roadway system. Tarvia™ revolutionized the road industry by offering a cost-effective solution for building and maintaining higher quality roads.

In 1927, Barrett built its first stationary mix plant in Jamesville, N.Y. Ever since, this division of Colas, Inc. has been a part of the industry building America’s transportation infrastructure. Through innovation and acquisition, the vertically integrated company’s presence can be found in industry segments ranging from aggregate processing and binder manufacturing to asphalt production and paving.

This same Jamesville site is now home to both batch and counterflow drum mix plants. It is also home to innovation of a different nature: the production of warm mix asphalt with its Magnum 400-ton-per-hour counterflow drum mixer, using the first N. Y. State-approved water-injection foamed asphalt system from Terex Roadbuilding.

Transition to Foam

Several years ago, Barrett began experimenting with warm mix asphalt. Initially, the Jamesville site tested warm mix binder additives. These trials included both a wax additive blended with liquid AC and a proprietary binder with a goal of lowering mix temperatures at the plant.

These products were successful in allowing Barrett to meet target asphalt production temperatures. However, meeting this goal came at a price. “There is an additional cost per ton to use these products,” says William “Bill” Lallier, plant manager for Barrett Paving Materials, Inc.’s N.Y. Central Regional.  

With a vision to expand warm mix production, this additional cost per ton gave Barrett an incentive to look for other warm mix solutions. The producer looked at three different manufacturers offering warm mix asphalt systems based on water-injection foaming technology. At the end of the review process, Barrett chose the Terex^® warm mix system for three primary reasons. “It was easy to install, is compact and could be put on any drum mix plant we own,” comments Lallier.

Scott McMaster, district manager for Terex Roadbuilding, offered one additional explanation. “A Barrett plant in Ohio was ordering our warm mix system at the same time, so it gave the company an opportunity to use and compare the system in two different regions.”

The Terex^® warm mix asphalt system consists of two primary components. Installed directly into the plant’s existing liquid AC line, the system’s exclusive expansion chamber mixes water with hot binder to create a foaming action. Once exiting the chamber, the foamed asphalt binder is immediately injected into the drum via its existing AC line to thoroughly coat the aggregate.

A PLC/water skid package comprises the system’s second component. System operation is controlled by the plant’s existing controls package. The pump accurately meters a predetermined amount of water to the expansion chamber, based on a percentage of the binder’s mass weight. The system has enabled producers to lower mixing temperatures by 50 to 90° Fahrenheit.

Barrett installed the system on its existing Terex^® Magnum E400 counterflow plant and began experimenting with its capabilities for lowering mix temperatures. The plant reached target mixing temperatures with both virgin and RAP mix designs, and the water-injection foamed asphalt technology saved Barrett money when compared to the additives tested in the past.

The savings are not limited only to the price difference between using water vs. proprietary additives to lower mixing temperatures. “When mix temperatures are below 300° F, fewer emissions are produced,” explains Lallier. “With the Terex^® system, we were able to bump our maximum RAP content from 40 to 50 percent without blue smoke.” The system also gives Lallier more control over baghouse temperatures, so the company does not waste fuel. “Terex has estimated a 10 to 15 percent fuel savings. We are noticing lower fuel costs but a final number has not yet been determined,” he adds.