Engtec Consulting Principal Engineer, Dr. Salman Bhutta, delivered a keynote presentation [watch below] earlier this month to share findings from the firm’s 2024 research report demonstrating the gradation equivalency of recycled crushed aggregates to primary aggregates, and how their increased use can lower construction project costs and carbon emissions.
The May 8 presentation at the Ontario Society of Professional Engineers (OSPE) professional development series also demonstrated comparable performance for recycled crushed aggregates in terms of load-bearing support in pavement structures without compromise to the structural integrity of the pavement. Bhutta’s research concluded there is no need to increase layer thickness when using crushed concrete in pavement structures.
“Over the last 20-25 years, there has been significant improvement in these materials, including both their quality and quality control processes,” Bhutta announced.
Recycled crushed aggregates, or RCA, is reclaimed asphalt pavement and/or concrete, readily available from the millions of tonnes removed from construction sites across Ontario. It becomes available as roads are repaired, bridges are maintained, and other critical infrastructure is replaced and expanded.
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Raly Chakarova, executive director of the Toronto and Area Road Builders Association, (TARBA) shared with OSPE workshop attendees that the industry has long supported the use of RCA as a way to lower carbon emissions associated with long-haul trucking, reduce pollution and traffic congestion, extend the life of non-renewable resources, and promote a circular economy.
“Concrete and asphalt have already met performance specifications when originally used,” announced Chakarova. “When reclaimed, they undergo an additional rigorous process of crushing, screening, testing, and quality control to be repurposed for their application as construction material in new projects.”
TARBA estimates that RCA accounts for less than 7% of the 180 million tonnes of aggregates used annually in Ontario for projects involving roads, highways, bridges and subdivisions. Alongside an industry coalition, of which OSPE is a member, TARBA argues that increasing RCA use to a minimum of 20% would cut costs, reduce emissions, and promote sustainable construction, without compromising quality or durability.
TARBA and the coalition are also calling for:
- Aligning municipal standards with Ontario specification OPSS1010 to reduce administrative burden, ensure quality and compliance, and encourage wider adoption.
- Collaborating with industry to build capacity and confidence on quality control measures and a wide variety of applications for RCA.
- Including RCA use as part of the tenders for roads, bridges, sewer and watermains, subdivisions, and transit projects.
