2200 CR: Cold In-Place Recycling Highway 15, Mason County, Illinois

Mason County issued a bid document for the rehabilitation of Highway 15 in accordance with Section 324, Cold In-Place Recycled Bituminous Material.

General Requirements: Rework the existing asphalt structure per the depth shown on the plans utilizing the cold in-place recycling (CIR) process. Following completion of the CIR process, construct a structural course layer, as required in the Contract and as specified in Section 334, and construct a friction course layer, as required in the Contract and as specified in Section 337.

Asphalt Pavement Thickness

Coring and as-built data showed the existing asphalt pavement to be 5“ (125 mm) to 6“ (150 mm) in thickness.

Mix Design & Pavement Investigation

The mix design and pavement investigation were carried out by the emulsion supplier.

Operations caused only minimum disruption to traffic.

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.

Equipment Selection

Dunn Co selected the Wirtgen recycler 2200 CR with 3.8 m working width for the project as described below.

Optimal solution: the cold recycler 2200 CR with 3.8 m working width fully complied with equipment specifications.

  • Cold recycler 2200 CR with 3.80 m working width
  • Working width 12' 6" (3,800 mm)
  • Recycling depth 0 - 6" (0 - 150 mm)
  • Milling depth (counter rotation) 13 3/4" (350 mm)
  • Line spacing HT11 5/8" (15 mm)
  • Number of milling tools 294
  • Cutting direction counter-rotating or synchronous
  • For this purpose, the roller must be removed, turned by 180° and equipped with counter-rotating or co-rotating planetary gears.
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  • it mills the existing pavement (synchronously) to the required depth,
  • he adds the proportion of emulsion calculated according to the suitability test proportional to the working speed,
  • it adds precisely metered quantities of compaction water to meet the changing conditions on site (the water required for this is taken from the recycler's integrated tank),
  • he paves the recycled/stabilised material using an attached screed with the specified cross slope.
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Field Gradation Analysis

On this particular project the average working speed was 28‘/min (8.5 m/min) of recycled, pre-compacted, pavement with the average hourly tonnage being approx. 410 tons per hour.