COLD IN-PLACE RECYCLING
Dennis McElroy - CIR Operations Manager
Specification & Research Papers
Overview
What is CIR?
When to use CIR and the Benefits
CIR Basics/Misc info
Order of Operations
Project Examples
“It is a beautiful thing when the Green Solution is also
the most cost effective one.”
Michael J. Murdter, P.E., Director County of Santa
Clara Roads and Airports Department
What is Cold In-Place Recyling (CIR)?
CIR is the processing and treatment with bitimious
and/or chemical additives of existing HMA
pavements without heating to produce a restored
pavement layer.
Wirtgen – 3800
“Single Unit Recycler”
CIR – Foamed Asphalt
“Welded or Bonded Product”
Oil Pump and Control Unit 12.5’ Down Cutting
Milling Drum
Microprocessor/Computer to
control Oil Percentage and
water delivery
Rear Tamping Screed
Or pickup machine
and paver
CIR – Depths
CIR – Foam
Depth: 3”minimum – 6” maximum
AC, AB, AC/AB blends
Eliminating the potential for reflective cracking = lowers costs in the long run on your Pavement Maintenance System
Typical AC/AB Section Typical AC/CIR/AB
Section
CIR (Foam) – How the mixing Chamber works
12.5’ (fixed)
Down Cutting
Drum
CIR Basics – How it Works
Bitumen (Oil)
PG 64-10 at 170 C
+ Water = Foam
Range 2% - 2.5%
Cement
Portland Type II
Range 1% - 1.5%
When to use it?
Bridging the gap between Maintenance Methods and Complete Reconstruction.
Alternate Method to:
Thick Overlays
Remove and Replace
Over 25% Digouts
Average Production Rates
Urban Environments:
50,000 SF – 70,000
SF per shift
Rural Environments:
65,000 – 130,000 SF
per shift
= 1 – 2 lane miles per shift
= Approximately 30 - 50% reduction in
construction times for the pavement rehabilitation
portion of the project
Benefit: Cost/Trucking/Emissions Savings
Reducing off haul costs/materials associated with conventional Remove and Replace
Emissions Savings from trucking, hot plants, and additional equipment needed during R&R – Environmentally Friendly
Benefit: Lowers User Delays
Immediate access for
pedestrians, vehicles,
driveway access, and
emergency personnel
safe and convenient.
Cold material, wont
pick up on car tires.
Benefit: Lowers User Delays
CIR- Foam (Night Work Acceptable)
Cost Savings (20% - 40%)
An example comparison between conventional rehabilitation with overlay and CIR with foamed asphalt for a project (Catamaran Street, Foster City with 149,600 ft2 paved surface area):
Conventional Rehabilitation:
32,000 ft2 of existing asphalt concrete repair= $176,000
3” asphalt concrete overlay= $252,824
Total = $428,824 (would’ve taken 5 days to complete).
CIR-foam:
4” CIR with foamed asphalt = $157,080
2” asphalt concrete overlay = $171,666
Total = $328,746 (took about 2 days to complete).
This project was bid using conventional methods and Value Engineered delivering a Net saving through using CIR-foam=$100,078 (~23%) while eliminating 3 days of traffic closures.
Where can you CIR?
Collector Roads County Rural Roads Major Arterials
Universities Residential
Order of Work
Preliminary Investigation:
(1) Conduct visual pavement inspection and coring
(2) Perform sampling of existing roadway materials to account for changes in the pavement, and
(3) perform mix design in the laboratory.
Order of Work
Public Notifications
Lower all existing utilities +/- 3” below CIR depth
Wedge Cut / Conforms/ Milling
Trim outside edge of roadway to make room for overlay or other surface treatment
Address Severe Base Failures at this time.
CIR - The Process
Cement spreading- The
cement spreader
is usually ahead of the
equipment train by
about 50 ft spreading
cement over a pre-
dampened pavement
surface, at an average
rate of about 1% by weight
of RAP.
CIR - The Process
During CIR Activities
Single Lane Closure
Pulverize/Process/
Place/Compact
Existing Materials
12.5’ (fixed) Down
Cutting Drum
CIR – The Process
Water Truck with Paver
CIR – The Process
Material is compacted
to a minimum of 98%
using two (2) 12 – ton,
steel drum vibratory
rollers
A 12 – ton pneumatic
(rubber tire) roller is
used to finish the surface
and prepare it for
traffic.
CIR - The Process
Apply Fog Seal (SS1 cut 50/50), Temp Striping, Sand Blotter to treated Surface
Reconstructed Roadway is ready to surface in 2-3 days after initial cure period
No Deflection or Rutting, No Supplemental Compaction
OPEN TO TRAFFIC IMMEDIATELY
Fog Seal Sand Blotter
Example: Monterey Rd., San Jose (2011) Project Specifications
638,040 Sf
Conventional R&R
3” Mill
6” Digouts
Leveling Course / R-HMA Overlay
Total: $2,540,470.00
Cold In-Place Recycling
2” Wedge Cut
Minimal 6” Digouts (Areas
innaccessbible)
4” CIR – EAM (Foam)
2” RHMA Overlay
Total: $2,122,400.00
NET SAVINGS: 16% or $418,070.00
Monterey Rd., San Jose
Existing Pavement Conditions
Alligator Cracked Surface
Years of patching
Raveling/Potholes
Aged Oxidized Pavement
Type II Slurry Seal
Areas of Petro mat
Benefits
Elimination of costs for 780 truckloads of importing and off haul costs of over 15,600 tons of aggregates to and from landfill and/or asphalt plant or quarry.
Conventional R&R method would have taken approximately 18 days, whereas the CIR method took only 9 days.
BEFORE
FINAL CIR SURFACE
Monterey Rd., San Jose
Skid Marks on final CIR
Surface – No Raveling
Foamed CIR
Monterey Rd. Photos Taken on 3/22/2016
R-HMA Overlay was placed in the intersection (without an underlying CIR layer) and it is already showing signs of fatigue, cracking, early failures.
4” CIR – Foam w/ Leveling Course & R-
HMA Overlay Section
Holsclaw Rd – Santa Clara County
Constructed - Sept. 2011
Holsclaw Rd (Leavesley Rd – Gilman Rd, Gilroy CA)
Santa Clara County
6,000’ x 24’ = 144,000 SF Recycled using Foamed Asphalt
X2 Shifts (72,000 SF per Shift)
+/- 3” – 3.5” CIR layer using Foamed Asphalt
Chip Seal wearing course x1 (2’x2’) pothole/driveway scuffed
Pg. 10
x4 small locations chip seal worn, subgrade problems
Pg. 11
Holsclaw Rd – Before
May – 2011 Photo Taken off of
google Earth
Photo Taken 1-2-2013
Photo Taken 3-22-2016
Beginning of CIR Section at Leavesley Rd
3-22-2016
Beginning of CIR Section at Gilman Rd
3-22-2016
Skid marks – CIR layer still intact
Adjusted Utilities – No Settling
Consistent throughout the entire project
CIR Joint
CIR Layer
OLD AC Section, road was
reconstructed with (2) 12’
passes off of centerline.
No shoulder backing was
spec’d by the county
- No separation at the joint
Photo Taken 1-2-2013 Photo Taken 3-22-2016
Scuffed driveway entrance to farm
(1) HMA patched
pothole (2’ x 2’)
(1) location approx 30’
long in the SB lane with
4 small areas where the
chip seal has started to
wear and expose CIR
layer to elements. Soft
subgrade may also be
an issue here.
Note: Sharp Turn,
shaded by trees
Gilman Rd
(Chip Seal placed on top of existing pavement Sept 2011 – NO CIR)
Photo Taken 1-2-2013 Photo Taken 3-22-2016
Gilman Rd – Chip Seal Only
Final –Other Considerations
Work Hour Windows – Need to be
minimum 8 hrs. to be cost effective
Temperature: 50 degrees and rising
Widths outside of 12’ require a
supplemental milling machine
Recommend a discussion with a
contractor during the design
phase
Surface Layer is necessary
HMA / R-HMA Overlay
Chip Seals / Cape Seals in specific
areas
Questions and Answers
Dennis McElroy
CIR Operations Manager
Cell: 408-639-8063
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