OUTSTANDING COMPACTION QUALITY AT “THE GREAT DIVIDE”

A&S CONSTRUCTION COMPACTS SCENIC U.S. HWY 160 WITH BOMAG PNEUMATIC TIRED ROLLER

 

Colorado’s A&S Construction is obsessive about quality. To ensure a superior finished product on every job, the longtime heavy highway construction contractor, based in Canyon City, mixes, hauls and lays all of its own asphalt. This uncompromising approach to quality control has led to statewide industry recognition for building better roads.

At the 2017 Colorado Asphalt Pavement Association (CAPA) “Best in Colorado” Awards, the Canon City-based contractor received “Smoothest Pavement” accolades for its work on the Colorado Department of Transportation (CDOT) State Highway 160 project.

A&S Construction was recently trusted to overhaul another significant Colorado roadway: U.S. Highway 160 in the southwestern part of the state. The CDOT awarded the contractor a U.S. $7.5 million job covering 14.3 miles (23.0 km) of the scenic highway between Pagosa Springs and Wolf Creek Pass, near the Continental Divide in the San Juan Mountains.

The resurfacing and safety-improvement project at “The Great Divide” would challenge A&S Construction, which specializes in Department of Transportation and federal construction projects. And it would test all the advantages of the company’s new BOMAG BW 28 RH pneumatic tired roller.

CONTRACTOR FACES PICKUP, CONTACT PRESSURE CHALLENGES

Scheduled to run from April to September 2018, the U.S. Highway 160 job called for a 2.5-inch (63.5-mm) surface treatment, including a 1-inch (25.4-mm) leveling course of asphalt mix to address imperfections, followed by a 1.5-inch (38.1-mm) overlay of new asphalt.

A&S Construction’s comprehensive commitment to quality includes careful selection of manufacturer partners and equipment. The contractor chose BOMAG Cedarapids pavers to lay the asphalt and BOMAG rollers for breakdown, intermediate and finish compaction.

To handle intermediate rolling, A&S Construction picked the BW 28 RH from BOMAG, which pioneered the pneumatic tired roller technology that combines conventional compaction with a hydrostatic drive for application versatility. In road-building applications, the BW 28 RH can compact anything from sub-base to surface lifts of asphalt.

Eddie Wheeler, an experienced A&S Construction operator, expected a challenge from the polymer-modified mix used for the base and surface layers of U.S. 160. “Tire pickup can be an issue with the material we were rolling on,” Wheeler says. Another obstacle to efficient compaction was ensuring proper contact pressure amid changing working conditions.

A&S Construction’s BW 28 RH pneumatic tired roller was equipped with optional Michelin E 20 Pilote XLC smooth radial tires. In an effort to meet the demands of the project, A&S Construction ballasted the pneumatic roller to 40,000 pounds (18,144 kg) and counted on the machine’s optional thermal aprons and standard tire-inflation system.

ROLLER’S TIRE INFLATION

FEATURE ENSURES

HIGH-QUALITY COMPACTION

To further prevent the roller’s high-quality tires from picking up material, Wheeler made certain that they stayed hot. The operator kept the heat retention curtains down and the upper flaps above the outer wheels closed. He also utilized a spray-on, heavy-duty degreaser on each tire and added a diluted release agent to the water tank.

The success of a compaction job depends heavily on the right contact pressure. Using the roller’s automatic tire-inflation system, Wheeler was able to quickly fine-tune tire pressure to changing working conditions. He had the capability to vary tire pressure, and automatically keep it constant, to ensure uniform contact of the tires with the ground.

The BW 28 RH achieved top compaction quality on U.S. 160 thanks to the kneading and rolling effect of the wheels. The weight at the rubber wheels generated contact pressure that produced uniform compaction and efficiently sealed the surface.

“The BOMAG tire-inflation system is a feature that’s really nice to have,” Wheeler says. “It helped me to keep the tires inflated at the desired pressure — 90 psi (6.2 bar) on this job while rolling the base layer — which helped with doing a quality job rolling.”

The tire-inflation system was just one of the BW 28 RH features that Wheeler appreci- ated. He liked the roller’s spacious platform, intuitive controls and the easily adjustable operator’s seat, which led to a comfortable operator experience that minimized fatigue. Excellent all-around visibility in forward and reverse helped him operate with safety and precision. Without the aprons the operator has a clear view to the top of the outside tires. This is accomplished via the innovative frame shape and design.

INCREASED DENSITIES PROVIDE PROOF OF PERFORMANCE

According to foreman and equipment manager Dave TaFoya, the installed ballast and pressure setting increased densities by up to 2 percent. TaFoya says A&S Construction also used the BW 28 RH as a “proof roller” to demonstrate that the finished surface would be capable of handling heavily loaded semi-trucks.

At “The Great Divide,” the ability of the     BW 28 RH to retain heat in the tire area, ballast flexibly, and adjust tire pressure on the fly has contributed to A&S Construction’s development of a smooth U.S. Highway 160 — another win for a do-it-all company totally dedicated to quality.