Executive Summary
Transportation agencies across the United States are under increasing pressure to rehabilitate aging roadway infrastructure while managing costs, improving resilience, and reducing environmental impacts. Traditional pavement reconstruction methods, while effective, are material‑ and energy‑intensive and often result in higher emissions, longer construction durations, and greater disruption to roadway users.
Cold recycling is a federally recognized pavement rehabilitation strategy that addresses these challenges by reusing existing roadway materials at or near ambient temperatures. Supported by the Federal Highway Administration (FHWA), state departments of transportation, and nationally recognized research institutions, cold recycling has demonstrated strong structural performance, cost effectiveness, and environmental benefits, particularly in cold‑climate regions such as Minnesota.
Roadways typically deteriorate due to traffic fatigue, asphalt aging, moisture damage, freeze–thaw cycles, and outdated structural design assumptions. Cold recycling directly addresses these mechanisms by restoring pavement structural capacity, improving moisture resistance, and reducing reflective cracking, thereby extending pavement service life. FHWA provides formal project‑selection guidance and application checklists to ensure cold recycling is used appropriately and performs as intended.
From a sustainability perspective, cold recycling significantly reduces fuel consumption, material hauling, and demand for virgin aggregates and asphalt binder. These reductions translate into measurable decreases in greenhouse gas emissions and align with FHWA’s national Sustainable Pavements Program and broader federal sustainability objectives.
Minnesota and other Midwest states have extensive experience implementing cold recycling. Guidance from the Minnesota Department of Transportation and field performance studies conducted through the Minnesota Local Road Research Board confirm the long‑term effectiveness and durability of recycled pavement structures under regional climatic conditions.
Given its strong public‑agency backing, proven field performance, and clear environmental advantages, cold recycling represents a defensible, scalable, and regionally appropriate rehabilitation strategy. These attributes make it well suited for infrastructure investment evaluations, sustainability initiatives, and pilot programs focused on resilience, cost efficiency, and emissions reduction.
Introduction
Transportation agencies across the United States face increasing challenges related to aging pavement infrastructure, higher traffic volumes, material cost escalation, and growing pressure to reduce environmental impacts. As a result, pavement rehabilitation strategies that extend service life while minimizing cost and emissions have gained prominence. One such strategy is cold recycling, which is widely supported by federal and state transportation agencies.
This paper provides a high-level overview of why roads fail, how they are traditionally reconstructed, and how cold recycling serves as a structurally sound and environmentally beneficial alternative. The discussion is grounded exclusively in publicly available guidance from federal agencies, state departments of transportation, and nationally recognized research institutions.
Why Roads Deteriorate
Roadways deteriorate due to a combination of mechanical loading, material aging, environmental exposure, and evolving traffic demands. The most common mechanisms include:
- Traffic fatigue: Repeated heavy truck loads cause progressive cracking in asphalt pavements.
- Asphalt aging: Over time, asphalt binder oxidizes, becoming stiffer and more prone to cracking.
- Moisture damage: Water intrusion weakens pavement layers and accelerates structural distress.
- Thermal effects: Freeze–thaw cycles contribute to cracking, potholes, and surface deformation.
Outdated design assumptions: Many pavements were designed decades ago and are no longer adequate for current traffic volumes and axle loads.
Traditional Pavement Rehabilitation
Conventional pavement reconstruction typically involves full removal of the existing pavement structure, followed by replacement with new materials. This process generally includes:
- Milling or excavation of existing pavement
- Hauling reclaimed materials offsite
- Importing virgin aggregates and asphalt binder
- Producing and placing new hot-mix asphalt at high temperatures
While effective, this approach is material-intensive, energy-intensive, and associated with higher fuel consumption, longer construction durations, and increased greenhouse gas emissions.
Cold Recycling as a Rehabilitation Strategy
Cold recycling is a pavement rehabilitation technique that reuses existing roadway materials at or near ambient temperatures. Common cold recycling methods include:
- Cold In-Place Recycling (CIR): Existing pavement is milled, processed, and reused directly on the roadway.
- Cold Central Plant Recycling (CCPR): Reclaimed materials are processed at a nearby facility and returned to the project.
- Full-Depth Reclamation (FDR): The entire pavement structure and a portion of the underlying base are reclaimed and stabilized.
Cold recycling restores structural capacity while significantly reducing the need for virgin materials and high-temperature asphalt production.
Engineering Performance Benefits
When properly designed and constructed, cold recycling provides several engineering benefits:
- Restoration of pavement structural capacity
- Reduction of reflective cracking
- Improved resistance to moisture damage
- Extension of pavement service life
Minnesota and Midwest Application
Cold recycling is particularly well suited to cold-climate regions such as Minnesota and the broader Midwest. Factors supporting its use include aggregate availability constraints, freeze–thaw durability requirements, and cost-effective rehabilitation needs for low- and medium-volume roads.
Environmental and Sustainability Benefits
Cold recycling reduces environmental impacts through several mechanisms:
- Lower fuel consumption due to elimination of high-temperature asphalt production
- Reduced material hauling and trucking distances.
- Decreased demand for virgin aggregates and asphalt binder
- Shorter construction durations and reduced traffic disruption
Relevance to Infrastructure Investment and Risk Management
From an infrastructure investment and risk management perspective, cold recycling offers:
- Proven performance supported by federal and state transportation agencies.
- Reduced lifecycle costs and construction disruption
- Measurable reductions in material use and emissions
- Scalability across multiple jurisdictions, particularly in the Midwest
These characteristics make cold recycling well suited for pilot programs and broader deployment where resilience, sustainability, and cost effectiveness are priorities.
Conclusion
Cold recycling is a federally recognized, state-validated pavement rehabilitation strategy that addresses both structural and environmental challenges associated with aging road infrastructure. Supported by extensive public-agency guidance and independent research, cold recycling provides a defensible, scalable solution for modern roadway rehabilitation.
Contributed By:
Chandra Akisetty, Ph.D., P.E.
Pavement Engineer, Global Emissionairy
Asphalt Technology Division Chief, Maryland State Highway Administration
References
- Federal Highway Administration. Pavement Recycling Overview. https://www.fhwa.dot.gov/pavement/recycling/
- Federal Highway Administration. Project Selection Guidelines for Cold In-Place and Cold Central Plant Recycling (FHWA-HIF-17-042). https://rosap.ntl.bts.gov/view/dot/38318
- Federal Highway Administration. Cold In-Place Recycling Application Checklist. https://pavementvideo.s3.amazonaws.com/FHWA%20Checklists/12%20-%20Cold%20In-Place%20Recycling%20Checklist.pdf
- National Center for Asphalt Technology. Material Selection Guidance for Sustainable Pavements (NCAT Report 18-01). https://eng.auburn.edu/research/centers/ncat/files/technical-reports/rep18-01.pdf
- Minnesota Department of Transportation. Increasing Cold In-Place Recycling Efficiency. https://mdl.mndot.gov/_flysystem/fedora/2023-01/202211ts.pdf
- Minnesota Local Road Research Board. Recycled Materials Performance Evaluation. https://www.lrrb.org/media/reports/TRS1604.pdf
- Federal Highway Administration. Sustainable Pavements Program. https://www.fhwa.dot.gov/environment/sustainability/pavements/
- Federal Highway Administration. Towards Sustainable Pavement Systems (FHWA-HIF-15-002). https://www.epa.gov/system/files/documents/2025-03/fhwa-hif-15-002-towards-sustainable-pavement-systems.pdf
About the Author
Dr. Chandra Akisetty, Ph.D., P.E., Senior Pavement Engineer Dr. Akisetty is a pavement engineer specializing in the design of foamed asphalt mixes and providing on-site installation support. After earning his Ph.D. with a focus on asphalt technology, he became a registered P.E. and has worked on numerous projects involving Cold Central Plant Recycling (CCPR) and Foamed Asphalt Stabilized Base (FASB) construction. He has more than 10 years of experience researching pavement evaluation and is a licensed radiation safety officer