GOMACO's revolutionary two-lift paving system draws from paving experience with two-lift applications from the past 25 years.
• GOMACO's design loads the second layer of concrete by a specially designed transfer system added to the front of the paver that places the material into a unique hopper located under the paver.
• A special paving system provides proper vibration and consolidation to the individual layers to give the surface a smooth GOMACO finish.
• GOMACO's patented mold incorporates two-layer paving into a single mold design. This system eliminates the use of more equipment for the job and eliminates having to extend the paver to great lengths between the front and back legs for second layer paving. This system has the ability to change the depth of the top layer without modifications to the machine with an adjustable leading strike-off. The single mold design features leading vibrators, spreading auger and an adjustable strike-off for the first layer of concrete.
• The second layer features a hopper design to be charged with a conveyor auger system, a spreading auger and a unique tamper bar for consolidation before the second strike-off.
The GOMACO two-lift system allows the incorporation of the In-The-Pan Dowel Bar Insertion (IDBI) System.
This four-track GP-4000 is equipped with the IDBI system, and on this project, the GOMACO operating system technology allows the machine to be controlled by a stringless 3-D machine-control system. This is a two-layer mainline paving project in the Czech Republic. Paving widths on this project range from 35 ft. (10.7 m) to 40 ft. (12.2 m). The total thickness of the two-layer slab is 12 in. (305 mm).
Two layers of concrete are visible during the demonstration of the two-lift slipforming process. One layer is fed through the hopper, and the other is placed in front of the machine. This test was conducted on the GHP-2800 four-track slipform paver.