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At first glance an $8 million, eight-kilometre-long rehabilitation of Leslie Street in York Region might seem like a run-of-the-mill undertaking.

But the recently completed project cements York Region’s commitment to conduct a High Reclaimed Asphalt Pavement (RAP) trial.

As two regional officials made clear at the Ontario Asphalt Pavement Council’s (OAPC) recent fall seminar the rehabilitation is anything but ordinary.

“It is the first in Canada that has implemented performance-based warm mix asphalt trials,” said transportation asset management director Mehran Farashah.

The purpose of the trial is to conduct long-term comparison monitoring and data analysis of a control section where standard asphalt pavement was used and trial sections consisting of various levels of RAP, he explained.

RAP is the process of milling/grinding old asphalt and reusing it in new mixes for road construction.

Along with regional project manager Kerolus Khalil and two National Research Council Canada officials, Farashah provided an overview of the project which is the culmination of months of planning, design and construction.

At its 2024 fall seminar the Ontario Road Builders’ Association and OAPC made a pitch for owners to pursue a High-RAP trial mix project in Ontario. The region took up the challenge.

In explaining the reasons why, Farashah cited York’s climate action plan and other environmental commitments, Canada’s net-zero plan and the savings that could be achieved through an increased use of RAP.

York Region maintains 4,200 kilometres of roads and assuming those roads have a 50-year service life, those savings could amount to $27 million a year over that 50-year span, he said.

In pursing that goal, the region worked with a host of partners/collaborators including ORBA/OAPC, the National Research Council Canada, Engtec Consultants Inc., Egis Canada, AtkinsRealis Canada Inc, Sripath Technologies LLC and contractor Viola Alliance.

In early November Markham-based Viola completed a seven-month reconstruction of Leslie Street from just south of Highway 7 north to just south of Elgin Mills Road East. Preliminary work started this past May with the paving phase commencing in early September.

Standard asphalt mixes for both the surface and base layers were used on the southbound lanes. On the northbound lanes, however, higher percentages of RAP were incorporated in the asphalt for four different road sections, Khalil told the audience.

Consisting of three lifts or layers, the base asphalt consisted of 30 per cent RAP in one section and 40 per cent in the other. As for the surface asphalt, it is comprised of 30 per cent RAP in one section and 20 per cent in the other, he said.

“Every project has it challenges and we were able to overcome the significant ones on this one,” said Khalil, citing issues such as the weather, RAP availability, mix designs that were not readily available and the need to conduct work at night to lessen the impact on the community. The contractor worked from 8 p.m. to 7 a.m.

A key partner in- and sponsor-of the project is the National Research Council which will conduct long-term monitoring of the pavement performance by way of five solar-powered (with battery backup) instrumentation panels along the route.

Electric wires extend from the boxes to sensors connected to both the trial and control sections.

The system components were designed in NRC’s facilities and then installed by its staff and Viola employees earlier this year, said senior research officer Omran Maadani.

As part of its participation in the project, the NRC also conducted a life cycle assessment, said research officer Jessica Achebe.