An Ontario construction industry coalition is calling for governments to mandate a minimum amount of recycled concrete and asphalt to be used in civil infrastructure projects, saying it will cut carbon emissions and costs.

Made up of nine industry associations across builders, suppliers and engineers, the initiative is urging municipalities to use more reclaimed asphalt and concrete (called recycled crushed aggregates or RCAs) when constructing roads, highways, bridges and tunnels – at least 20 per cent by volume.

If all Ontario municipalities adopted the recommended amount, approximately $260 million in savings per year and a reduction to greenhouse gas emissions equal to taking 15 million cars off the road would be realized, the coalition claims. Landfills will receive less waste and industry challenges with obtaining aggregate can be eased.

The coalition intends to raise awareness and “give municipalities the resources and the knowledge and the expertise so that they feel comfortable to use this material,” Raly Chakarova, the executive director of the Toronto and Area Road Builders Association told Sustainable Biz Canada in an interview.

The association is a member of the initiative, which does not have a formal name.

She laid out ways the provincial and municipal governments can boost RCA content, which has been used in the construction of Ontario's 400-series highways and at Pearson International Airport.

Why RCAs should be considered

Identified as high-performing, sustainable and cost effective, but underutilized, Chakarova said RCAs can tackle two major problems Ontario's construction industry is facing.

The first is obtaining primary aggregate – the sand, gravel and stone that is pulverized to make concrete and asphalt. Ontario needs more primary aggregate to build critical infrastructure, but developing sites to extract aggregate often encounters local opposition, squeezing supply. Recycled aggregate is an alternative source that does not require more quarries, instead relying on discarded materials.

Then there is the pressure on the construction industry to adopt greener practices. The sector is facing demands to lower the carbon from concrete production. Recycling means less new material has to be dug up and made in carbon-intensive processes, reducing the greenhouse gases from production called embodied carbon.

The carbon reduction for every 10,000 tonnes of aggregate that is recycled, Chakarova said, is equivalent to taking 137 gas-powered cars off the road for a month, or not burning 21,000 pounds of coal.

From a purely economic standpoint, RCA is also a winner, the coalition states. Its use can save tens of millions of dollars from aggregate production and transportation. Plus, it is just as reliable as primary aggregate, if not higher quality, Chakarova said.

Municipalities are struggling to fund and modernize infrastructure while balancing net-zero goals, she added. “Using this material, especially on major infrastructure projects, really hits both of those major goals.”

How governments can encourage RCA use

Despite the benefits, of the 170 to 180 million tonnes of aggregates used annually in Ontario, less than seven per cent are RCAs, the coalition said. Most of it is consumed by the Ministry of Transportation (MTO) for construction on the province's 400-series highways.

The construction industry coalition is recommending municipalities to lead on adoption. Municipalities are the largest aggregate consumers in Ontario; they also own and maintain more infrastructure than the federal and provincial governments combined, Chakarova said.

While recycled concrete is allowed as an aggregate in Ontario, it is only a guideline, not a mandate, Chakarova said. Municipalities also have their own unique standards, complicating matters for suppliers.

To undo these knots, the coalition is encouraging municipalities to require a minimum volume of RCA for its project tenders or to let contractors use recycled aggregate. The industry group is pitching 20 per cent for concrete because the MTO employs that proportion for 400-series highways. But even starting with 10 per cent is fine, Chakarova said.

“Anything would be an improvement as opposed to where we are now.”

Municipal specifications can be harmonized around a provincial standard. Aligning the rules “means that the producers know exactly what they’re putting out and can do so en masse rather than trying to create a whole bunch of different piles or materials for all these different municipalities,” Chakarova said.

Ontario’s government can incentivize RCAs as well. For example, funding for roads or transit projects could only be released if the municipality uses a certain amount of RCAs or bans project tenders that demand solely primary aggregates.

"We are pleased to see the launch of this campaign calling for the use of RCAs in Ontario's infrastructure projects,” Rachel Sutton, a senior analyst in the buildings program of the Pembina Institute, said in an emailed statement to Sustainable Biz Canada.

“This is an exciting push for the policy changes we need to reduce emissions in Ontario's buildings and infrastructure projects."