Larry Hernandez with Caltrans provides the department's perspective on in-place recycling in a presentation delivered during the CalAPA Spring Asphalt Pavement Conference March 7-8, 2024 in Ontario, Calif.
3. WHY WE DO COLD RECYCLING
Proven technology backed up by
research
Uses all existing, paid for materials,
requiring limited new materials
Minimizes trucking operations
Shorter construction time, less traffic
disruption
3
Removes distresses instead of covering
them
Extended pavement life
Specifications are in place
Cost effective/ lower life-cycle cost
5. PARTIAL-DEPTH RECYCLING (PDR)
▪ Top-down distresses within the asphalt
layers
Oxidized asphalt,
Thermal cracks
Top-down cracking
Surface rutting
Fatigue cracking (from debonding, not weak
structure)
▪ Recycle top 0.25 to 0.5 ft with 0.15 to 0.2 ft.
of HMA or RHMA-G overlay
Milling teeth stay primarily in the AC layers
▪ 1 to 2 lane miles per day
▪ PDR-Emulsified Asphalt, PDR-Foamed
Asphalt
▪ New surfacing is required
6. ▪ Rehabilitation to address bottom-up distresses from the
underlying layers
Bottom-up cracking (alligator A & B, block,
shrinkage, etc.)
Base and/or subgrade rutting
Thermal cracks
Plus any top-down distresses usually addressed with
PDR
▪ Recycles top 0.7 to 1.0 ft.
Milling teeth go through AC layers into underlying
base
▪ 1 to 2 lane miles per day depending on recycle train
▪ FDR-No Stabilizer, FDR-Foamed Asphalt, FDR-Cement
▪ New surfacing is required
FULL DEPTH RECYCLING (FDR)
10. PAVEMENT
MATERIALS
PARTNERING
COMMITTEE
(PMPC)
Provides a forum for Caltrans to work with the
Construction Industry to develop and improve
Caltrans specifications, test methods, and
construction procedures
Improves construction contract standards by:
o Providing opportunity for Caltrans and
Industry to bring forward issues and/or
opportunities for improving current and
proposed construction contract standards.
o Exchanging information regarding new
technology, materials, and upcoming
initiatives.
o Providing transparency, stewardship,
efficiency, and sustainability.
11. PMPC TASK GROUPS
PMPC Task
Groups
Concrete
(CTG)
Asphalt (ATG)
Asphalt
Subtask Group
Preservation
Subtask Group
Recycling
Subtask Group
FDR-FA Working
Group
PDR Working
Group
14. SENATE BILL 1
Road Repair and Accountability Act
of 2017
“To the extent possible and cost effective,
and where feasible, the department and
cities and counties receiving funds under
the program shall use advanced
technologies and material recycling
techniques that reduce the cost of
maintaining and rehabilitating the streets
and highways, and that exhibit reduced
levels of greenhouse gas emissions through
material choice and construction method”
14
15. SENATE BILL 1
As part of the SB-1, the department is
required to report efficiencies on an
annual basis.
The definition of efficiencies, as
approved by the Caltrans Financial
Policy Board, is Caltrans will consider
efficiencies that result in cost
avoidance or a reduction in support or
capital costs.
The Office of Asphalt Pavements
began reporting Cold Recycling
efficiency savings starting in FY 19/20
15
16. SB-1 REPORTED COLD RECYCLING
COST SAVINGS
FY 19/20 FY 20/21 FY 21/22 FY 22/23 FY 23/24
No. Projects 6 9 5 5 6
Lane Miles
of Paving
86 205 75 99 95
CR Paved
(tons)
130,000 235,000 111,000 140,000 230,000
Cost Savings $2 million $7 million $1.2 million $5.0 million $14.8
17. NEXT STEPS FOR COLD RECYCLING
Continue monitoring pilot projects
30-3 Full Depth Recycling – Foamed
Asphalt Updates
30-4 Full Depth Recycling – Cement
30-5 Partial Depth Recycling
FY 23/24 SB-1 Efficiencies
Providing support for CR projects
Thank You !
18. Link:
https://maintenance.onramp.dot.ca.gov/asphaltp
aves/asphalt-pavement-recycling-pr-branch
Cold Recycling Resources
•2022/2023 In-Place Recycling Webinar Series
• Part I: Project Selection & Development of the In-Place Recycling (IPR) Industry (October 2022)
• Part II: Partial Depth Recycling (March 2023)
• Part III: Full Depth Recycling (June 2023)
• Part IV: Cold Central Plant Recycling (September 2023)
•2020 Introduction to Cold Recycling Webinar
•Site Investigation Guide
•Highway Design Manual: Chapter 630 Flexible Pavement
•Caltrans PaveM Portal Website
•Caltrans Cold Recycling Manual
•DES Website
•Office of Asphalt Pavement
•Wirtgen Cold Recycling Technology Manual (external link)
•Basic Asphalt Recycling Manual (BARM) (upon request)
•Road Resource Website (external link)
•Portland Cement Association Manual (external link)
Available Specifications
•Standard Specifications
• Section 30-2 Full Depth Recycling - No Stabilizer
• Section 30-3 Full Depth Recycling - Foamed Asphalt
• Section 30-4 Full Depth Recycling - Cement (Upcoming 2024 Updates)
•Non-Standard Specifications
• NSSPs require pre-approval by HQ Pavement
• NSSP-30-5 Partial Depth Recycling (11.09.2022)
• NSSP-30-7 Cold Central Plant Recycling (04.05.2022)
19. RECYCLING BRANCH
• RESEARCHING NEW INNOVATIVE RECYCLING
TECHNIQUES,
• PROMOTING BEST PAVEMENT RECYCLING
PRACTICES, AND
• ASSISTING DISTRICTS WITH DESIGN.
Contact Information
Christina Pang
Christina.Pang@dot.ca.gov
(916) 531-5418
Saeed Pourtahmasb
Saeed.Pourtahmasb@dot.ca.gov
(916) 639-5646
Larry Hernandez
Larry.Hernandez@dot.ca.gov
(916) 879-6723
19