Milling Out Asbestos in Canada
BY AsphaltPro Staff
“There are some roads in Quebec, usually those with very heavy truck traffic, where they’ve put asbestos in the roads.” — Denis Lussier
According to the International Agency for Research on Cancer, modern industrial use of asbestos dates back to 1880 when the Quebec chrysotile fields began to be exploited. In the following decades, the use of asbestos grew until new research on the safety of asbestos resulted in its rapid decline between 1970 and 1990. As a result, writes Quebec-based environmental services specialists Lab’eau-air-sol, “Quebec found itself with an abundance of chrysotile residues and no buyers.”
“After years of discussion and laboratory testing, the use of chrysotile in bitumen became common practice [in Quebec] in the ‘90s,” Lab’eau-air-sol continues, adding that chrysotile asbestos is a “highly resistant fibrous material, enabling significant reinforcement of bitumen matrix,” while the mixture’s non-friability makes its use in roads relatively safe for road users. However, Lab’eau-air-sol writes, there remains significant exposure risk when these roads are demolished, resulting in special measures to protect workers and increased removal costs than conventional asphalt.
According to Lussier, ACI has completed 50 asbestos-coated asphalt projects since 2010 and is one of a handful of companies in Quebec equipped to work with asbestos-coated asphalt. However, he added, “Asbestos projects represent a small percentage of annual planning and will continue to decrease because the Ministry of Transport removed asbestos-containing mixes from its standards in 2011.”
As companies like ACI are brought in to mill the remaining pavements containing asbestos–“usually those with very heavy truck traffic,” Lussier said–the company must follow all safety procedures and best practices. Lussier said there are two ways to handle these types of roads: stabilization and dry method. “When choosing the stabilization approach, a bitumen emulsion is introduced into the leveled layers of the surface, allowing asbestos particles to bind together,” Lussier said. “This process helps prevent the release of hazardous dust or fumes.” In the case of the dry method, he added, the pavement material is gathered, enclosed in large stitched bags, and then disposed of at a landfill site authorized by the Ministry of Sustainable Development, Environment, and the Fight Against Climate Change.
“The second method can be very expensive, so we prefer the first method, but ultimately the choice is up to the Transportation Ministry,” Lussier said. ACI has retrofitted one of its milling machines to handle the first method. When the company must utilize the second method, it would prefer to use its BOMAG milling machine in order to benefit from the ION DUST SHIELD, given that the asbestos particles are also quite fine. However, the machine isn’t quite large enough to make sense on the types of roads that contain asbestos. “If we had a larger BOMAG mill, we would definitely be using it on those jobs.”