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Sustainability Case Study Review of Using Recycled Aggregate in Road Structure


Many transportation agencies are working towards more sustainable infrastructure management practices. One way in which agencies are being sustainable is by using recycled aggregates in road structures. It is important to evaluate the sustainability of these alternative road construction methods compared to the sustainability of traditional road construction methods. This paper reviewed the sustainability of rehabilitated road structures constructed using crushed reclaimed asphalt and cement concrete rubble. Four key aspects of sustainability were considered – economic, social, environmental and technical. A City of Saskatoon “Green Street” Infrastructure Program case study is presented in this paper. From an economic perspective, significant costs savings are observed compared to the use of traditional virgin road aggregate materials. From a social perspective, residents who use the rehabilitated road will see an equal or improved level of service compared to a traditional structure. This is observed through the use of non-destructive heavy weight deflection (HWD) measurements where the deflection measurements on the recycled structure were less or equal to a traditional structure. The cost savings with the use of recycled materials may also be reinvested into rehabilitating more roadways improving the overall performance of the roadway network for residents. Environmentally, because recycled materials are typically locally available and aggregate shortages are forcing justiditions to haul virging aggregates from futher away, fewer emissions are generated due to shorter distances for trucking and less energy is required to be consumed. Less virgin materials are required to be extracted from the earth and less waste material is also generated by recycling construction rubble. Technically, the mechanistic properties of the recycled materials were found to be equal or superior when compared to conventional road building materials. Laboratory and field measurements indicate that under higher applied stress state field conditions, the recycled materials exhibit performance measures that exceed that of conventional granular materials. This study illustrates that recycled materials can be used effectively in sustainable road construction when applied within a framework of applied engineering computational mechanics for design and analysis.

Conference Paper Details

Session title:
Marlis Foth
Rielle Haichert
Duane Guenther
Curtis Berthelot