ForConstructionPros.com

Width and depth

Maximum width that can be handled in one path with this process depends on the amount of material put through the RT-500, which is designed for maximum throughput of about 600 tons per hour; as well as the paver production rate. A practical maximum width estimate would be 20 feet. A 13-foot 4-inch-wide cut was made on the Hwy. 93 portion of the project.

Coughlin "precut" a narrow path using a Roadtec RX-60 cold planer and had it deposit the material to one side. The RX-900 in the CIR train then walked over that material and incorporated it into the final milling pass.

Compaction specs are among the variables that influence the depth of cut. A typical depth of cut would be between 2 and 5 inches. Coughlin cut 3 inches deep on this project. The resultant 3-inch thickness of the CIR base layer provided sufficient stress-absorbing characteristics to keep any underlying reflective cracking from coming through to the top layer of HMA, according to Coughlin.

Following behind the cold planer was the Roadtec RT-500 cold recycler. The unit, which Roadtec says was being used on the job as part of the machine's prototyping program, can handle up to 600 tph of material. The RT-500 cold recycler is designed to crush and screen the RAP produced by the RX-900, while its pugmill mixes the emulsion with the recycled materials.

The RT-500's JCI brand double-deck screen received the milled material from the RX-900 conveyor. Any oversized material went through the RT-500's Telsmith 3048 impact crusher and back to the screen via a two-conveyor return circuit.