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Rocky Mountain Asphalt

Conference February 24, 2011

Gary DeWitt, PE CDOT Region 4 Materials Engineer

Colorado Department of TransportationUse of Full Depth Reclamation

2011 CDOT Pavement Design Manual

• FULL DEPTH RECLAMATION:

a rehabilitation technique in which the full thickness of

asphalt pavement and a predetermined portion of the underlying materials (base, subbase, and/or subgrade) are, without heat, uniformly pulverized and blended to provide an upgraded, homogeneous material.

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2011 CDOT Pavement Design ManualFDR Layers

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CDOT Region 4 applicationsFirst project in year 2000

• Tired & fatigued pavement

• Rural & urban• 6 “ to 12 “ existing road

depth

• Low to moderate ADT

• Shoulders only & full width

• Striped pavements• Roadway vertical &

transverse profile changes

• Mostly 2 lane roadways & asphalt overlays

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CDOT Region 4 FDR enhanced applications

• 500 ft test section of cement treated base

• 500 ft test section of fly ash treated base

• 2 mile --emulsion treated base

• Concrete pavement placed

• Addition of granular material to clay base

• FDR surface used as a traffic detour for up to a week prior to paving

• Used where multi-layers of HMA from various vintages exist

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CDOT Region 4 –Pavement ManagementGood-Fair-Poor road conditions

43% good 33% good

2007 2010

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CDOT Region 4—2010 projectHwy 85—Wyoming South

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CDOT Region 4 –2010 projectHwy 85—Wyoming South

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CDOT Region 4—2010 projectHwy 85—Wyoming South

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CDOT Region 4—2010 projectHwy 85—Wyoming South

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CDOT Region 4—2010 projectHwy 85—Wyoming South

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CDOT Region 4-2010 projectHwy 85—Wyoming South

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CDOT Region 4 FDR project locations

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CDOT Region 4 FDR usage year 2000 to 2010

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CDOT Region 4 FDR at different depths

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CDOT Region 4 FDR costs & savings

• FDR costs 2006 thru 2010

• FDR 8 “ $2.25 / SY• FDR 8-12” $2.10 / SY

• FDR 12-16” $3.75 / SY

• FDR shoulders $2.83 / SY

• At 1 inch HMA saved, 140,000 Tons saved with use of FDR since 2000

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CDOT FDR Specifications (exerts)Item 310

• Particle size minimum of 99 % passing 1-1/2” sieve

• Uniformly distributing water with 2% of optimum• Final grade by a trimmer with a 30 ft ski

• Transverse slope trimmed to within 0.1 % of specified

• Payment FDR 0-8 “ by Square Yard

• FDR 8-12” by Square Yard• FDR 12-16” by Square Yard

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Conclusions from CDOT Region 4 FDR experiences

• Is a good technique to reconstruct roadways that are severely distressed

• Eliminates cracking from base and subbase issues when overlayed with sufficient depth

• Allows for correction of issues caused by overlaying of gutter pans via removing material during FDR

• Allows for detour traffic for a short duration

• Is passable during rain events

• Any excess material generated from the FDR process is generally acceptable as shouldering material

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Presentation acknowledgements

• Gary Strome—CDOT Region 4 Pavement

Manager (historic data)

Nicki Upright—CDOT Region 4 Project Manager

(pictures)

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