SEPTEMBER 2020, EDMONTON, AB: During Lafarge Canada’s collaboration with the University of Alberta’s PhD Sustainability Scholar program, PhD Student Md Mustafizur Rahman conducted a study to assess the lifecycle and CO2 of recycled aggregates versus natural aggregates in Edmonton, AB. He developed a Greenhouse Gas (GHG) calculator which accounted for the life cycle analysis for aggregates from production site to customer, including GHG generated associated with stripping, mining, de-watering (pumping water), crushing and screening, reclamation, and transportation.
Dr. Rahman’s study also completed the same analysis for recycled aggregates, which lack many manufacturing steps when compared to regular aggregates. One of our sources of recycled aggregates is the rubble from demolition of concrete structures and construction - another step in keeping non-recyclable waste out of our landfills.
In Edmonton, Lafarge stores recycled aggregates at our urban depots, so the transportation distances to the end user are even further reduced compared to facilities outside of the city limits. These factors alone significantly reduce the GHG emissions associated with transportation of aggregates to project sites, and Dr. Rahman’s calculator determines by just how much.
A detailed review of the GHG impact of supplying aggregates to the new Amazon warehouse in the Edmonton area considered haul distances and stripping depths. Lafarge Canada’s Northern Alberta team supplied recycled aggregates for the 1,000,000 ft2 facility - a total of 49,000 tonnes - from our Petroway depot. The recycled aggregate was also selected for its superior performance characteristics in this particular application.
The Sustainability Scholar calculations indicate that we reduced the amount of CO2 by 65% using recycled aggregates versus supplying new aggregate for this application. This is the equivalent of keeping 148 cars off the road for one year!