Nevada?s Department of Transportation initiated a second cold in-place recycling (CIR) project on its major east/west corridor - I-80 - and the agency is convinced the cost-effective approach bodes well for maintaining a high-quality road network.
The first CIR I-80 project was performed in Humboldt County at Golconda Summit three years ago. Nevada DOT has been successfully performing CIR road rehabilitation since the mid 1990s, and the Golconda project was the first real test of using the technique on its main east/west I-80 corridor, which supports heavy traffic volume. At the time of the project, the Annual Average Daily Traffic (AADT) volume was 6,620, with approximately 50 percent of that volume being truck traffic. The construction strategy consisted of CIR three inches of the existing asphalt surface and then placing four inches of NDOT?s Plant-mix Bituminous Surface overlay (a dense-graded mix) followed by a ¾-inch open-graded wearing course. The Golconda I-80 project has performed well over the past three years and the DOT expects it to continue to perform well as projected traffic volume increases puts additional demand on the road.
This past summer NDOT implemented the second I-80 CIR rehabilitation project east of Elko, an approximate 21-mile stretch of the divided four-lane interstate from 1.11 miles east of the Moor Interchange to 1.87 miles east of the Oasis Interchange. As with the first I-80 CIR project, this particular contract included traversing a high-elevation point - Pequop Summit - and completing work with minimal disruption to traffic flow.
Road and Highway Builders of Reno, NV was awarded the general $33-million contract, with Valentine Surfacing Co. of Vancouver, WA subcontracted to perform the CIR work. The project called for 215,662 tons of Nevada DOT Type 2C plant mix, 37,640 tons of open-graded plant mix, 859,590 square yards of existing asphalt to be recycled with 22,000 tons of quicklime and 2,200 tons of cationic medium-set (CMS-2S) emulsion.
The project is being constructed over two seasons, with approximately 60 percent completed in 2007. It was divided into one-third sections, with the east and west portions completed during the first year of construction and the center portion scheduled for completion in 2008.
The project required this approach due largely to the amount of drainage pipe work required in the center portion of the contract, which prohibited the CIR and overlay work to be completed during the 2007 construction season. Also, numerous traffic control limitations and limitations regarding how long the cold recycled material could remain without being overlaid proved to be a logistical challenge that could only be addressed by executing the project over two construction seasons.
The middle portion of the project also requires traversing the Pequop Summit, which consists of four to six percent grades on either side of the summit, and that in itself requires additional logistical and execution planning.
CIR, paving coordination