Mix Design Summary
The project would be divided into two recycling depths:
– 2 miles (3.2 km) (both lanes from junction with Route 4) at a depth of 3“ (75 mm)
– remainder of project at a depth of 4“ (100 mm)
The emulsion content was calculated on a coarse gradation percentage as 2.25% to 3.75%.
Bid Specification Equipment Requirement
General Requirements: The following equipment requirements apply only to the CIR layer.
Milling Machine: Utilize a self-propelled cold milling machine that is capable of pulverizing the existing bituminous material in a single pass to the depth shown in the Contract documents and to a minimum width of not less than 10‘ (3,000 mm). The machine shall have automatic depth controls to maintain the cutting depth to within ± 1/4“ (6 mm) of that shown in the Contract documents, and shall have a positive means for controlling cross slope elevations. Do not use a heating device to soften the pavement. Do not use up-cutting machines unless secondary crushing is conducted inplace prior to mixing and the introduction of bituminous material. Equip the milling machine with a liquid metering device capable of adjusting the flow of asphalt emulsion to compensate for any variation in the speed of the machine and able to deliver the amount of asphalt emulsion to within ± 0.2% of the required design amount by weight of pulverized bituminous material. Utilize an asphalt emulsion pump of sufficient capacity to allow emulsion contents up to 3.5% by weight of pulverized bituminous material and containing automatic digital displays for both the flow rate and total amount of pulverized bituminous material and asphalt emulsion in appropriate units of weight and time.
Contractor & Equipment Selection
The contractor selected for the CIR section of the project was Dunn Co, Decatur, Illinois.
Dunn Co selected the Wirtgen recycler 2200 CR with 3.8 m working width for the project as described below.