In-Place Recycling (IPR) for Asphalt Pavements
In-place recycling (IPR) techniques are powerful strategies to rehabilitate pavements. When properly applied, it has long term economic benefits—allowing owner agencies to stretch their available funds while providing the traveling public with a safe and reliable driving surface.
Why Recycle?
- Proven technology with a range of strategies to suit most rehabilitation challenges
- More sustainable if designed and constructed correctly
- Uses all existing, paid for materials
- Requires limited new materials
- Minimizes trucking operations
- Shorter construction time, less traffic disruption
- Cost effective / lower life-cycle cost
- Removes distresses instead of covering them
- Selected strategies enhance structural capacity
- Extended pavement life
- Recycled roads can be recycled again
- Specifications / nSSPs are already in place
- Experienced contractors are already working in California
In-Place Recycling Techniques
Typical flexible pavement recycling strategies used by Caltrans include:
- Partial Depth Recycling (PDR)
- Cold Central Plant Recycling (CCPR)
- Full Depth Recycling (FDR)
- Hot In-Place Recycling (HIR), not common in California
Although flexible pavement recycling strategies are capable of treating many different types of distress, not all rehabilitation projects are good candidates. Some strategies are better suited to treat certain distresses, and some projects are more suited to conventional rehabilitation methods. Review and assessment of pavement conditions, structural capacity, material properties, geometrics, traffic concerns, constructability, and cost effectiveness should be conducted as part of the project evaluation process.
Appropriate application of any rehabilitation strategy requires a comprehensive field review prior to design to evaluate the type, severity, and extent of the pavement distress (for more information, refer to the Pavement Evaluation Manual). The district Materials Engineer should be consulted during the initial project assessment. Other resources include as-built plans, the Photolog, Pavement Condition Report, and corresponding mapping available from Geographic Information Services (GIS).
Available Specifications
- Section 30-2 Pulverization (2018 Standard Specifications)
- Section 30-3 Full Depth Reclamation - Foamed Asphalt (2018 Standard Specifications)
- Section 30-4 Full Depth Reclamation - Cement (2018 Standard Specifications)
- RSS-30-4_2018 Full Depth Reclamation - Cement
- SSP-30-4_2018 Full Depth Reclamation - Cement
- NSSP-30-5 _2018 Partial Depth Recycling
In-Place Recycling Resources
- Highway Design Manual: Chapter 630 Flexible Pavement
- Caltrans In-Place Recycling Manual
- DES Website
- Office of Asphalt Pavement
- Wirtgen Cold Recycling Technology Manual (external link)
- Road Resource Website (external link)
- Portland Cement Association Manual (upon request)
Office of Asphalt Pavements Contacts
Office of Asphalt Pavements
2389 Gateway Oaks, Suite 200, MS-91
Sacramento, California 95833
Attn: Allen King
Email: Allen.King@dot.ca.gov
Partial Depth Recycling (PDR): PDR@dot.ca.gov
Full Depth Recycling (FDR): FDR@dot.ca.gov