A southwest Missouri asphalt contractor has found exclusive Hamm oscillation compaction is getting density numbers where conventional rollers can't.

Leo Journagan Construction Company, Inc. is a family owned and operated business based in Springfield, Missouri. The company performs, as either prime contractor or subcontractor, highway construction, site preparation, and the production of construction aggregates.

The company primarily operates in southwest Missouri and northwest Arkansas; although throughout it's history the company has performed work in 26 states for owners such as the US Army Corps of Engineers, Department of Energy, various public utility companies and many state highway departments.

Leo Journagan, Chairman of the Board, founded the company in 1948, and served as the President of the company for 50 years. Allen Journagan was named President and Chief Executive Officer in 1998. Since it's inception, Journagan has continued a steady and controlled growth. The company also maintains a wide variety of machinery in order to support its construction and manufacturing divisions.

Journagan considers their employees to be their greatest asset. They are well trained, highly motivated and focused on performance. Many of their employees have been with the company for more than 15 years.

In 2002, Leo Journagan Construction Company was recognized by the Missouri Department of Transportation as the highest rated contractor in the state of Missouri for Quality in Construction and Contract Compliance.

Journagan first learned of the benefits of Oscillation technology via two HD+ 140 VO "ozzie" rollers that the company is using on its main line paving projects. So when the new Compact Line HD 12 VO and HD 14 VO small oscillation rollers became available in North America. Journagan jumped at the chance to put them to work on smaller paving projects, such as commercial parking lots.

Journagan recently put the rollers to work while building a parking lot for a new condo expansion in Branson, Missouri/ The project included concrete curbs and gutters, placement of crusher run limestone base, and paving a 3-inch asphalt lift.

Rocking Versus Vibrating

The Hamm Compact Line 47-inch HD 12 VO and 54-inch HD 14 VO Oscillation Rollers are ideal for Journagan's commercial work. What sets these rollers apart from other small commercial rollers is oscillation compaction.

Traditional vibrating rollers are equipped with a circular vibrator in the drum. It works through a fast rotation, which begins to vibrate the drum and causes compaction forces to arrive into the soil. The two vibrating masses, moving in different directions, cause the directed oscillations.

The new oscillation drum masses, which turn in the same direction, produce one moment around the drum axle. The moment changes its effect direction during a turn of the mass (forward and backward), so that the oscillation drum movement is created. This action compacts the soil.

Instead of vibrating straight up and down, the Hamm oscillatory design gives the drum a horizontal or "rocking" force which keeps the drum in contact with the mat. Hamm oscillation technology attains very high compaction numbers with minimal passes and no shattering of aggregate. Some contractors have found it permits contractors to remove one or more rollers from a job.

"Oscillation has helped our compaction quite a bit," said Journagan Asphalt Superintendent Kevin McCann. "It brings our density points up one percent, to a percent-and-a-half. The other rollers might be on the borderline, but the different way oscillation compacts brings us up another couple of points."

On Missouri Department of Transportation (MoDOT) projects a minimum of 92 percent density, to 96 percent, is the target, McCann said. Now commercial work is adopting MoDOT specs so density requirements are the same everywhere.

Working with Mixes

While commercial mixes tend not to be Superpave designs, the agency work is.

"Because the Superpave mixes have to cool down to a certain temperature before you can gain another point or two, oscillation can get us to density before the mix cools too much," he said. "Other rollers were giving us a hard time getting there. Breakdown compaction will take place at close to 300 degrees Fahrenheit, we let it get to 200 degrees, and we then will gain another point, point and a half with oscillation."

 Some might say oscillation is fine for the big highway jobs, but overkill for smaller commercial work like in Branson. "I disagree 100 percent," McCann said. "If it's good for one application, it's good for all. With oscillation on parking lots, we've been able to get density quicker, and easier. With regular up-and-down vibration we would achieve a 91 or 92 percent, but with oscillation we are at 93 and 94 percent quicker and faster without having to beat on it when it gets cooler, and fracturing the aggregate. Oscillation in the small rollers has been, no doubt, a plus for us."