As urban areas continue to grow, the demand for faster, more eco-friendly infrastructure solutions increases. One solution could be Cold In-Place recycling (CIR).
The method worked for the city of Kawartha Lakes and general contractors Brennan Paving & Construction and Miller Paving Limited of the Miller Group — the team behind the rehabilitation of County Road 49 in Bobcaygeon, Ontario, Canada.
Unlike traditional road resurfacing methods, CIR involves milling and reusing the existing pavement material on-site, reducing the need for new materials and minimizing environmental impact. The process begins with the removal of the top layer of the asphalt, which is then crushed, mixed with additives like asphalt cement or portland cement and reintroduced into the road structure.
This innovative approach earned the County Road 49 rehabilitation project the prestigious Cold In-Place Recycling Award from the Asphalt Recovery and Reclaiming Association (ARRA), recognizing its excellence in sustainable road construction.
To improve the 11-mile section of this two-lane, high-traffic arterial road, the project team took the CIR method a step further and included expanded asphalt, which refers to Full-Depth Reclamation with Expanded Asphalt Stabilization (FDREAS). Adding this to the project showed Kawartha Lakes’ dedication to the environment.
The team replaced 13 culverts and conducted cold in-place recycling (CIR) over a total area of 180,000 square meters. As part of the FDREAS approach, the road was topped with a 50 millimeter hot-mix asphalt overlay. The existing pavement had a 780 millimeter structure, made up of 55 millimeter of hot-mix asphalt and 720 millimeter of granular base.
The Cold In-Place Recycling Award from ARRA underscores the significance of this project as a model for innovation and sustainability in road construction.
Juan Rojas, director of engineering and corporate assets for the city of Kawartha Lakes emphasizes what the award means to the city.
“Winning this award is significant for the city as it recognizes our continued commitment to our Healthy Environment Objectives,” Rojas said. “As part of the city of Kawartha Lakes Strategic Plan, a healthy environment is one of our strategic priorities. Utilizing recycled material and methodology for our roads capital programs greatly aids in achieving this goal.”
By incorporating 0.5% portland cement into the mix, the curing process was accelerated, ensuring that the road was ready for traffic sooner than traditional methods would allow. This also helped reduce any delays in the construction schedule, allowing for a quicker return to full traffic flow.
The CIR process itself was completed in just 15 days. This expedited timeline was crucial for minimizing disruptions to the local community, which relied on this road for transportation. The use of the Wirtgen 380Cri Recycler, a milling and recycling machine, allowed for precise material efficiency tracking, speeding up production and further contributing to the project’s success.
Despite the complexity of the work, including the deep excavations required for the culvert replacements, the project team worked diligently to keep the construction process on track.
The machinery used on site, including the 3.8-meter milling recycling machine and the screening and crushing units, ensured that materials were processed quickly and accurately. The team mixed and reclaimed materials, which helped expedite the process while maintaining the high standards of quality required for the road’s rehabilitation.
Kawartha Lakes chose the CIR method in part for its proven reduction to impacts on traffic. Since County Road 49 is a major route, managing traffic during construction was critical. During work, lane closures and piloting allowed traffic to continue moving while the work was underway. The team opened up the road at the end of each workday, minimizing the overall disruption to drivers.
The road was rehabilitated in stages, with the work being done in one-mile stretches. This approach kept the impact on the public to a minimum.
In terms of environmental impact, the CIR process proved to be a sustainable choice. By reusing the existing materials, the need for new aggregates and asphalt was reduced, leading to lower emissions and a smaller carbon footprint. The inclusion of portland cement further improved the pavement structure, ensuring that the road would have a longer service life, well beyond the initial 20-year estimate, according to the Miller Group.
The combination of advanced recycling technology, careful planning and efficient execution made the project a success, proving that it is possible to carry out large-scale infrastructure projects while minimizing disruption and maintaining a focus on sustainability.
“It is encouraging to see a municipality the size of Kawartha Lakes growing their cold in-place recycling program year over year,” said Chris Maguire, surface treatment manager for Miller Paving Limited. “They are an example for neighboring municipalities, and even the province of Ontario, to cost-effectively rehabilitate their road networks, while prioritizing the impact we have on the environment.” RB
