ForConstructionPros.com

Dynapac demonstrated its most recent innovation which allows the simultaneous laying of the wearing and binder courses in a single pass at the National Center of Asphalt Technology (NCAT) Test Track at Auburn University. Over 50 spectators witnessed this new technology known as Kompact Asphalt Paving that allows "hot on hot" monolithic pavement to be laid simultaneously in a single pass.

The Dynapac F-300 C/S twin-paver, used during the demonstration, consists of two hoppers: the upper hopper that has a 25-ton capacity to hold the top course (wearing course) hot mix, and a lower hopper that has a 45-ton capacity to hold the binder course material, both courses of pavement are placed simultaneously "hot on hot." The paver also consists of two screeds that are fed by the two different hoppers. The first screed has the ability to place the binder course while compacting it to a density of up to 97 percent while the second screed places the top course directly over the freshly placed binder and compacting it to 92-percent density. The screeds can be adjusted to reduce or increase compaction as required.

The designed permeable mix, formulated by the Georgia DOT, will reduce water accumulation. This lowers the dangers of hydroplaning and truck back spray, which reduces the visibility of vehicular drivers on rainy days. In addition, this mix will assist in reducing noise pollution to residential living areas near designated highways.

The trial permeable mix pavement was placed at the assigned test section that is sponsored by research funding from the Georgia Department of Transportation, N-13, of the NCAT test track. The "hot on hot" mix consisted of an open-graded mix for both the binder and wearing course. The top course (wearing course) consisted of 3/8-inch minus material, and the binder course consisted of ½-inch minus material. The desirable void content of this mix would lay between 22 to 26 percent.

Observers who watched this first of a kind operation in the United States attentively endured the humidity and 100-degree temperature. The group consisted of state DOTs, contractors, and various paving and construction associations. The implementation of this unique and precise process was managed by Dynapac USA, headquartered in San Antonio, TX.