In-Place Pavement Recycling
In-Place Pavement Recycling Southeast Pavement Preservation Partnership Louisville, Kentucky May 29, 2014 Brian Diefenderfer, PhD, PE
Overview • • • •
Why we should recycle In-place pavement recycling processes Ongoing research in Virginia Next steps
2
Why We Should Recycle our Pavements • Economic – Nevada DOT saved $600 million over 20 years – Other studies show 30-50 percent cost savings
• Environment – MTO (Ontario) estimated 50 percent less greenhouse gases emitted
• Construction – Fixes deterioration causes rather than symptoms
• FHWA recycled materials policy www.fhwa.dot.gov/legsregs/directives/policy/recmatpolicy.htm 3
In-Place Recycling Processes • Hot in-place recycling (HIR) • Cold recycling – Cold in-place recycling (CIR) – Cold central-plant recycling (CCPR)
Increasing depth and level of deterioration
• Full-depth reclamation (FDR)
4
Hot In-Place Recycling • All process – Scarify, rejuvenate, spread / pave, and compact
• Surface recycling – Top 1-2 inches prior to surfacing
• Surface remixing – Top 1-2 inches while adding additional materials prior to surfacing or as the wearing course
• Surface repaving – Top 1-2 inches along with an overlay to create a single thermally-bonded layer 5
Cold In-Place Recycling • CIR process – Pulverized in-place – Recycling agent is added – Layer is compacted • 2 to 5 inches • Within the bound layers (a.k.a. partial depth)
– Without addition of heat – Single-unit vs. multi-unit trains
• Recycling agents & additives – Foamed asphalt, emulsified asphalt – Cement, lime
6
Cold In-Place Recycling
7
Cold In-Place Recycling
Cold In-Place Recycling
8
Photo by Mike Marshall
Cold Central-Plant Recycling • Similar to CIR but the recycling agent is added at a mobile plant • Uses – Alternative to CIR – When access to deeper layers is needed • Mill, FDR, CCPR • Mill, CIR, CCPR
– When stockpiles of existing RAP are available • Lane addition, shoulder widening 9
Cold Central-Plant CCPR Recycling • Similar to CIR but the materials recycling agents are added at a mobile plant • Uses – When stockpiles of existing RAP are available • Lane addition, shoulder widening
– When access to deeper layers is needed • Mill, FDR, CCPR • Mill, CIR, CCPR
10
Photo by Wirtgen
CCPR with Existing RAP • Virginia has about 4.5 million tons of RAP
CCPR with Existing RAP • Could pave a 12-foot lane at 6 inches for about 2,000 miles
12
Charlottesville to Salt Lake City
Full-Depth Reclamation • FDR process – – – –
Pulverized in-place Recycling agent is added Layer is compacted Creates a stabilized base course • 4 to 12 inches • Includes unbound layers
– Without addition of heat
13
Full-Depth Reclamation • Mechanical stabilization – Additional aggregate or RAP
• Asphalt stabilization – Foamed asphalt – Emulsified asphalt
• Chemical stabilization – – – –
Cement Lime Fly ash (type C or F) Cement / lime kiln dust 14
Full-Depth Reclamation
FDR
• Mechanical stabilization – Additional aggregate or RAP
• Asphalt stabilization – Foamed asphalt – Emulsified asphalt
• Chemical stabilization – – – –
Cement Lime Fly ash (type C or F) Cement / lime kiln dust 15
Full-Depth Reclamation
16
Pavement Recycling & Preservation • Pavement Recycling – Can include treatments ranging from minor rehabilitation to full reconstruction
• Preservation – Cost-effective treatments to extend the service life of a pavement • Not reconstruction
– HIR & CIR • FDR & CCPR 17
Training Options • NCPP – Checklists – Regional workshops
• NHI – 131050 & 131050A • Asphalt Pavement In-Place Recycling Techniques • Instructor-led (fee) web-based (free)
– 134114 • Inspector Training for CIR • Web-based (free) • HIR and FDR available soon(ish) 18
Virginia In-Place Pavement Recycling Research • I-81 • NCAT test track • NCHRP 9-51
19
I-81 Pavement Recycling, 2011 • AADT = 23,000 (28 percent trucks) • 7.2 lane miles 4-inch New New AC AC 2-inch 5-inch CIR
4-inch New AC 6-inch New AC 8-inch CCPR
6-inch CCPR
Existing AC Existing Aggregate
12-inch FDR
Subgrade
Subgrade
Left Lane
Right Lane
Lane Closure
21
Rut Depth 0.5
Left lane
Average of 0.01 mile data Rut Depth, inches
0.4
Right lane
0.3
0.2
0.1
0.04 0.02
0.03
0.04 0.01
0.07
0.06
0.01
0.02
0.03
0.04
0.02
0.05
0.01
0 5
9
12 16 23 Months after construction
28
34
Ride Quality 120
Average of 0.01 mile data 1 standard deviation ~ 15 IRI
IRI, inches / mile
100
Left lane Right lane
80
60
56
52
46
42
55
54 45
55 46
56
54
46
45
44
40 20 0 5
9
12 16 23 Months after construction
28
34 23
FWD
Average Effective Structural Number
12.0 10.0
Right lane Left lane
9.9
9.9
9.0
8.0 5.5
6.0
5.8
5.7
4.0 2.0
0.0 6
15 Months After Construction
28
24
NCAT Recycled Sections
N4
N3
S12
25
NCAT Recycled Sections N3
N4
S12
6-inch AC
4-inch AC
4-inch AC
5-inch CCPR
5-inch CCPR
5-inch CCPR
6-inch Agg Base
6-inch Agg Base
8-inch FDR
Subgrade
Subgrade
Subgrade
26
27
28
Rutting 0.5
17%
Rut depth, inches
0.4
% of 10 million ESALs
41% 51%
0.3
75%
0.2
0.15 0.12
0.11
0.1
0.0
N3, 6 N3 inch AC
N4, 4 inch N4 AC
S12, 4 inch AC+FDR S1229
NCHRP 9-51 • Material Properties of CIR and FDR Asphalt Concrete for Pavement Design – Developing design inputs for Pavement-ME
• Partners – University of MD, VDOT, Colas Solutions, Wirtgen
• Looking for projects in Southeast US – Constructed in 2012 or 2013 – Asphalt emulsion or foamed asphalt 30
31
32
33
Next Steps 1. 2. 3. 4.
Think recycling Number of projects Design inputs for pavement designers Document long-term performance
34
Brian Diefenderfer, PhD, PE [email protected]
Overview • • • •
Why we should recycle In-place pavement recycling processes Ongoing research in Virginia Next steps
2
Why We Should Recycle our Pavements • Economic – Nevada DOT saved $600 million over 20 years – Other studies show 30-50 percent cost savings
• Environment – MTO (Ontario) estimated 50 percent less greenhouse gases emitted
• Construction – Fixes deterioration causes rather than symptoms
• FHWA recycled materials policy www.fhwa.dot.gov/legsregs/directives/policy/recmatpolicy.htm 3
In-Place Recycling Processes • Hot in-place recycling (HIR) • Cold recycling – Cold in-place recycling (CIR) – Cold central-plant recycling (CCPR)
Increasing depth and level of deterioration
• Full-depth reclamation (FDR)
4
Hot In-Place Recycling • All process – Scarify, rejuvenate, spread / pave, and compact
• Surface recycling – Top 1-2 inches prior to surfacing
• Surface remixing – Top 1-2 inches while adding additional materials prior to surfacing or as the wearing course
• Surface repaving – Top 1-2 inches along with an overlay to create a single thermally-bonded layer 5
Cold In-Place Recycling • CIR process – Pulverized in-place – Recycling agent is added – Layer is compacted • 2 to 5 inches • Within the bound layers (a.k.a. partial depth)
– Without addition of heat – Single-unit vs. multi-unit trains
• Recycling agents & additives – Foamed asphalt, emulsified asphalt – Cement, lime
6
Cold In-Place Recycling
7
Cold In-Place Recycling
Cold In-Place Recycling
8
Photo by Mike Marshall
Cold Central-Plant Recycling • Similar to CIR but the recycling agent is added at a mobile plant • Uses – Alternative to CIR – When access to deeper layers is needed • Mill, FDR, CCPR • Mill, CIR, CCPR
– When stockpiles of existing RAP are available • Lane addition, shoulder widening 9
Cold Central-Plant CCPR Recycling • Similar to CIR but the materials recycling agents are added at a mobile plant • Uses – When stockpiles of existing RAP are available • Lane addition, shoulder widening
– When access to deeper layers is needed • Mill, FDR, CCPR • Mill, CIR, CCPR
10
Photo by Wirtgen
CCPR with Existing RAP • Virginia has about 4.5 million tons of RAP
CCPR with Existing RAP • Could pave a 12-foot lane at 6 inches for about 2,000 miles
12
Charlottesville to Salt Lake City
Full-Depth Reclamation • FDR process – – – –
Pulverized in-place Recycling agent is added Layer is compacted Creates a stabilized base course • 4 to 12 inches • Includes unbound layers
– Without addition of heat
13
Full-Depth Reclamation • Mechanical stabilization – Additional aggregate or RAP
• Asphalt stabilization – Foamed asphalt – Emulsified asphalt
• Chemical stabilization – – – –
Cement Lime Fly ash (type C or F) Cement / lime kiln dust 14
Full-Depth Reclamation
FDR
• Mechanical stabilization – Additional aggregate or RAP
• Asphalt stabilization – Foamed asphalt – Emulsified asphalt
• Chemical stabilization – – – –
Cement Lime Fly ash (type C or F) Cement / lime kiln dust 15
Full-Depth Reclamation
16
Pavement Recycling & Preservation • Pavement Recycling – Can include treatments ranging from minor rehabilitation to full reconstruction
• Preservation – Cost-effective treatments to extend the service life of a pavement • Not reconstruction
– HIR & CIR • FDR & CCPR 17
Training Options • NCPP – Checklists – Regional workshops
• NHI – 131050 & 131050A • Asphalt Pavement In-Place Recycling Techniques • Instructor-led (fee) web-based (free)
– 134114 • Inspector Training for CIR • Web-based (free) • HIR and FDR available soon(ish) 18
Virginia In-Place Pavement Recycling Research • I-81 • NCAT test track • NCHRP 9-51
19
I-81 Pavement Recycling, 2011 • AADT = 23,000 (28 percent trucks) • 7.2 lane miles 4-inch New New AC AC 2-inch 5-inch CIR
4-inch New AC 6-inch New AC 8-inch CCPR
6-inch CCPR
Existing AC Existing Aggregate
12-inch FDR
Subgrade
Subgrade
Left Lane
Right Lane
Lane Closure
21
Rut Depth 0.5
Left lane
Average of 0.01 mile data Rut Depth, inches
0.4
Right lane
0.3
0.2
0.1
0.04 0.02
0.03
0.04 0.01
0.07
0.06
0.01
0.02
0.03
0.04
0.02
0.05
0.01
0 5
9
12 16 23 Months after construction
28
34
Ride Quality 120
Average of 0.01 mile data 1 standard deviation ~ 15 IRI
IRI, inches / mile
100
Left lane Right lane
80
60
56
52
46
42
55
54 45
55 46
56
54
46
45
44
40 20 0 5
9
12 16 23 Months after construction
28
34 23
FWD
Average Effective Structural Number
12.0 10.0
Right lane Left lane
9.9
9.9
9.0
8.0 5.5
6.0
5.8
5.7
4.0 2.0
0.0 6
15 Months After Construction
28
24
NCAT Recycled Sections
N4
N3
S12
25
NCAT Recycled Sections N3
N4
S12
6-inch AC
4-inch AC
4-inch AC
5-inch CCPR
5-inch CCPR
5-inch CCPR
6-inch Agg Base
6-inch Agg Base
8-inch FDR
Subgrade
Subgrade
Subgrade
26
27
28
Rutting 0.5
17%
Rut depth, inches
0.4
% of 10 million ESALs
41% 51%
0.3
75%
0.2
0.15 0.12
0.11
0.1
0.0
N3, 6 N3 inch AC
N4, 4 inch N4 AC
S12, 4 inch AC+FDR S1229
NCHRP 9-51 • Material Properties of CIR and FDR Asphalt Concrete for Pavement Design – Developing design inputs for Pavement-ME
• Partners – University of MD, VDOT, Colas Solutions, Wirtgen
• Looking for projects in Southeast US – Constructed in 2012 or 2013 – Asphalt emulsion or foamed asphalt 30
31
32
33
Next Steps 1. 2. 3. 4.
Think recycling Number of projects Design inputs for pavement designers Document long-term performance
34
Brian Diefenderfer, PhD, PE [email protected]
