Construction & Demolition Sources

Rubble, Aggregate and Ceramic

Asphalt - Asphalt pavement recycling is becoming more commonly practiced in Alberta and throughout North America. Asphalt may be stripped from a road surface, crushed and used as granular or hot mix on the same or future road construction projects. There can be several economic and environmental benefits in using this process. However, the biggest advantages result from reductions in the amount of virgin aggregate and oil used. The number of asphalt roads which are recycled is significantly larger than that of concrete roads, mainly because asphalt can be rejuvenated with oil additives and used in pavements, significantly reducing the cost of the finished road. On-site surface recycling involves removing and replacing the top layers of a pavement structure for the purpose of repairing a wide range of pavement distress (surface cracking, ravelling and rutting). Advanced pavement recycling equipment can be used to recycle the bottom lift and place virgin hot mix for the final lift.

Concrete - Crushed concrete from which reinforcing steel has been separated can be used as a replacement for natural aggregate (or blended with virgin aggregate) in foundation subgrades for building construction, road construction and other related applications such as embankment material or retaining walls for erosion control. One of the biggest benefits to using secondary sources of concrete is that it can be crushed and reused on the same site, eliminating the need for transportation, and thereby reducing costs. A major application for waste concrete is in the reconstruction and construction of roads and highways. Highway reconstruction applications have the most significant advantages as the use of recycled aggregate material offers cost savings in both the transportation of conventional aggregates to the site in the hauling and disposal of old concrete.

Metals

Sources of waste metals consist primarily of residential and commercially generated items such as steel and aluminum cans, white goods (fridges, stoves), small appliances and other miscellaneous items (metal furnishings, fasteners and fittings). Most sources of scrap metals are not considered part of the municipal solid waste stream, as they have traditionally been recovered for recycling due to their high value and are unlikely to end up in landfill. Steel made from recycled scrap uses only one-quarter of the energy it takes to make it from its primary resource, iron ore. Aluminum can be recycled at savings of up to 95 per cent of the energy used to manufacture it from aluminum ore. Close to 75 per cent of ferrous scrap (steel) and 45 per cent of non-ferrous scrap (aluminum, brass, copper) are recovered for recycling.

Wood

The largest source of wood wastes are generated from the construction and demolition industry. Within that industry, wood wastes are also typically the largest fraction of waste material generated, primarily from the following sources: pallets, building materials (lumber, plywood), and site excavation (trees and shrubs). Recovery of municipal sources of wood waste is minimal due to limited markets and low tipping fees at dry disposal sites. Nevertheless, a number of wood waste recyclers have established themselves in Alberta. Currently, the largest market for wood waste is feedstock for the production of roofing materials. Other markets include landscaping and livestock bedding applications.

Building Materials

These generally include potentially salvageable materials, such as tile, electrical materials, doors, windows, ceiling tiles, partitions, carpeting, insulation, plumbing fixtures, finishing materials, and roofing materials generated by building renovators, demolition companies and households. Through proper planning, salvaged building materials can be recovered as an integral part of the demolition process. A growing number of market outlets are purchasing these building components for resale.

Other Mixed

Other materials, each ranging about three per cent each in the construction and demolition waste composition profile, include cardboard, paper, gypsum, glass and plastic.