Knowledge CentreTechnical Resources SearchConference Papers“To recycle or not to recycle Asbestos-containing RAP: that is the question.”

“To recycle or not to recycle Asbestos-containing RAP: that is the question.”


In August 2008, as part of the City of Calgary‟s commitment to providing a safe work environment for its workers and contractors, The City requested that Golder Associates Ltd. (Golder) conduct an occupational hygiene assessment to determine the potential for worker exposure to asbestos during the various processes of The City Roads Business Unit that impact asbestos-containing asphalt and the use of recycled asphalt pavement (RAP). The final report, Asbestos in Asphalt, Calgary, Alberta, was submitted to the City of Calgary Roads Business Unit on November 27, 2008.1 Similar to other municipalities in North America, The City of Calgary incorporated chrysotile asbestos fibres (1-2 percent by weight) into their asphalt pavement to improve both durability and lifespan. From the mid-1960s to the mid-1980s, the asbestoscontaining asphalt pavement installed by The City was primarily used as a surfacing material on major arterial roads. The prevailing opinion was that asbestos in pavement presented a negligible exposure risk as the asbestos fibres were bound within the asphalt matrix. In the 1960s and 1970s, occupational and environmental air monitoring data supported this opinion. Occupational sampling conducted by The City in the 1980s found airborne asbestos concentrations below the allowable limits. However, due to concern for the health and safety of the workers handling bulk asbestos, the practice of adding raw asbestos to pavement was discontinued in 1984. Since the mid-1980s, as part of pavement resurfacing, these roadways have been planed and recycled asphalt pavement (RAP) has been incorporated into new asphalt to pave various roadways around Calgary. This recycling effort further diluted the concentration of asbestos in newly-laid asphalt. Asbestos was identified in 2007 when roadway core samples were put through destructive laboratory testing and sieved down to their finest constituents. Control measures were instituted in laboratories which effectively reduced the potential for worker exposure based on current legislation. Respecting The City of Calgary‟s „triple bottom line‟ of social, environmental and economic sustainability, the Roads business unit is committed to environmental protection and providing a safe workplace for employees, contractors and the citizens of Calgary. The City of Calgary‟s Roads Business Unit approached Golder in July 2008 to reassess the potential for asbestos exposure to workers during paving-related activities. The City also temporarily stopped using RAP until the outcome of this study was known. 

Conference Paper Details

Session title:
Joe Chyc-Cies
Ben G. Wineberger