Releases Anticipated Best Practice:
Road construction and maintenance can create large amounts of waste material often destined for overburdened landfills. This material can be efficiently reused and recycled through various techniques, making a modest, yet significant contribution to aggregate conservation and helping extend landfill life. Many landfills no longer accept road and utility construction materials, making their reuse and recycling essential. Those landfills that do accept them have greatly increased their fees and growing pressure has been encountered to keep all potentially reusable and recyclable materials from taking up limited landfill space.
While the need to reuse and recycle is most pressing in major urban centres, municipal, provincial, and federal agencies across Canada and internationally have adopted or are evaluating a broad range of applications for reuse and recycling of materials from road construction, maintenance, and utilities excavations. In addition to engineering and physical property considerations that are important for the end-use, there are also some environmental considerations involved in ensuring that contaminated materials are not placed back in the public right-of-way.
InfraGuide's newest Best Practice, Reuse and Recycling of Road Construction and Maintenance Materials, outlines these current state-of-the-art methods. InfraGuide the National Guide to Sustainable Municipal Infrastructure is a leader in creating best practices and outlining innovations for Canadian municipalities. InfraGuide has created over 50 best practices to date in disciplines including Decision Making and Investment Planning, Potable Water, Storm and Wastewater, Municipal Roads and Sidewalks, Environmental Protocols, and Transit.
Reuse and Recycling of Road Construction and Maintenance Materials provides descriptions of the current methods used by municipal agencies to reuse and recycle asphalt and concrete pavement materials recovered during road construction and maintenance work that are carried out within the public right-of-way. Evaluation protocols and reuse options for asphalt, earth, rock, concrete, and granular materials encountered during trench excavation for installation of underground services and during utility cut restorations are described in detail in this document.
Among asphalt pavement materials that are suitable for reuse and recycling are grindings, millings or pieces of asphalt pavements recovered during road reconstruction and maintenance/rehabilitation work, as well as rejected or waste materials from hot-mix asphalt production. In order to reuse and recycle these materials, this best practice describes techniques including: Central plant recycling (recycled hot mix); Hot in-place recycling; Cold in-place recycling; Cold central plant recycling; and Full depth rehabilitation (FDR). Recoverable concrete material from the right-of-way, including pavements, sidewalks, curbs, and gutters can be reused and recycled by: use as granular base coarse/subbase; as a concrete aggregate in recycled concrete mixtures; and through Rubblization.
The best practice also describes the current practices for the recycling of winter sand (also called street sand) that is spread to enhance road surface friction during winter maintenance activities and collected by road sweepers during the spring. The City of Edmonton's Pilot Study on winter sand recycling is described in detail in this best practice, including the engineering properties of winter sand and environmental challenges to successful winter sand recycling and reuse.
Case Studies describing specific, successful projects where various reuse and recycling techniques were employed are included in the best practice. These case studies include: Rubblization with Cold Central Plant and Cold In-Place Recycling; Full Depth Reclamation (FDR) with Foamed Asphalt Stabilization; City of Edmonton Winter Sand Recycling Pilot Project; and Hot In-Place Recycling. In addition, users of this best practice are directed to references and resources for more detailed technical information on asphalt and concrete reuse and recycling.
This InfraGuide best practice confirms that there is a broad range of technically proven, cost effective reuse and recycling options available to municipalities, engineers, and road managers that conserve natural resources and extend landfill life. The document will be available on our website this spring.
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