Sustainable 

Asphalt 

Production

About the Project

Producing hot-mix asphalt requires significant energy to heat and dry aggregate, a process traditionally powered by fossil fuels. Our teams saw an opportunity to do it differently.

Working with Ottawa-based Harvest Green, Tomlinson integrated its BioPCP™ pyrolysis technology into our Research Asphalt Plant on Rideau Road. The system converts recovered construction and demolition wood into a renewable, waste-derived gas that can replace natural gas as the primary heat source for asphalt production.

The result connects two areas of our business in a new way: material recovered through Environmental Services becomes an energy source for Materials, creating a practical circular solution within our own operations.

What We Delivered

The project brought together expertise from across Tomlinson to take the technology from testing to full-scale asphalt production.

At the Tomlinson Waste Recovery Centre, construction and demolition wood is recovered from the waste stream and processed into an ISO 17225-4 compliant biofuel. That material feeds Harvest Green's pyrolysis system, where it is converted into gas and used to heat the asphalt plant's aggregate dryer.

Our teams integrated the system with the plant, updated controls to manage the new fuel source, tested the biomass and energy output, and completed quality-control testing of the finished asphalt.

On September 8, 2025, the first batches of asphalt produced using the system were successfully placed at our Rideau Quarry, demonstrating that the approach could move from research and development into real-world production.

Innovation

The innovation isn't only the technology. It's how the system connects waste recovery, energy production and asphalt manufacturing.

Instead of sending recovered wood to landfill and purchasing natural gas to generate heat, the process gives that wood another use. Harvest Green's BioPCP™ system converts it into a predictable pyrolysis gas that can directly heat the aggregate dryer.

During production trials, the plant operated with pyrolysis gas replacing natural gas as the heat source for the aggregate dryer while still producing asphalt that met required quality standards.

By bringing together the knowledge of our environmental, materials, technical and operations teams with Harvest Green's technology, we've demonstrated a different approach to one of the most energy-intensive parts of asphalt production.

Impact

The results show the potential of turning a waste stream into a resource.

Based on the project's preliminary lifecycle analysis, asphalt produced through the system achieved a 47.3% reduction in cradle-to-gate greenhouse gas emissions compared with the industry benchmark used in the study. That represents a reduction of 25.4 kg of CO₂e per tonne of asphalt produced.

At production scale, the system has the potential to avoid more than 1,000 tonnes of CO₂ emissions annually while also recovering construction and demolition wood that would otherwise take up landfill capacity.

More importantly, the project gives our teams a working model to continue developing. By combining capabilities that already exist across Tomlinson with new technology and new thinking, we're finding practical ways to recover more resources, reduce fossil fuel use and build the next generation of construction materials.