Converting Construction & Demolition (C&D) Waste to Resources
Urban construction is an important part of India’s GDP. Despite a slowdown in the past couple of years, it is expected to bounce back with a bang after the ascent of the new central government. A PwC report has predicted that the segment shall grow by 7 to 8 percent annually in the coming decade. Despite showing promise, the pitfall of this sector is the large quantity of construction and demolition waste generated. The waste is generated from the buildings that are torn down and residue of materials used in construction such as wood, cement, sand, and stone chips etc.
Most cities do not have correct means of disposing off these wastes. Dumping in landfills seems to be the immediate solution although its long term effects include imbalance of soil nutrition, contamination of ground water and other serious problems. Most city planners do not focus on recycling this waste by reusing it or converting its form. If the materials from landfills are segregated, ground and cleaned, they may be reused in some other constructions. For now, most of the C&D waste produced forms a part of solid waste and lies in landfills or along the sides of the road.
Importance of recycling construction waste
As per a report published by the TERI, sorting and restoring the C&D waste at their source is the best idea. The waste should be segregated into materials for structure building, materials for road work, building parts that could be salvaged and wastes from site clearances. Further segregation should be conducted among materials such as plastic, cables, glass, wood and plaster board. Materials that have been recycled from demolished masonry and concrete may be used profitably in numerous ways within the construction industry itself.
The materials could be used as fillers in the same site post completion of work or they may be used in stone, sand and gravel mines and road construction. Fancier usage of these materials includes construction of landscaped gardens and structural filling of areas that are low for assisting future development.
Recycled concrete blocks
Masonry and concrete make up more than fifty percent of generated wastes. These may be reused in the form of slabs or blocks. A lot of builders make use of the bricks that are unscathed post demolition of a house in the new building as it is cost effective. Reuse and recycling these materials have twin benefits on offer- conservation of landfill space and reduction of natural resource extraction meant for newer construction. These recycled materials may be used in bulk filling, as sub-base materials for road construction and lining of canals, filler materials for drainage projects etc.
Metal wastes generated through discarded cables and pipes can always be melted and remoulded into other items. There are waste pickers who deal in metals and they offer good rates for the metal sold to them by the kilo.
Recycle wood products
Solid and intact wood recovered after demolition may be fitted in window frames, beams, partitions and doors. Wood chips are highly valuable in the market for their reuses in flooring, cabinets and furniture. Low quality wood pieces may be incinerated for production of energy. Usually scrap wood pieces have to be sold to a centralised plant, where they are treated with chemicals to get rid of termites and other insects and make the pieces look as good as new. They may be used in animal bedding and for creating different press boards.
Coal wastes or Bituminous wastes
Bituminous wastes arise from construction of roads and their digging and breaking for maintenance utilities and services. These materials may be recycled through cold or hot mixing methods at a central or local asphalt mixing plant. It is highly beneficial as it saves energy, asphalt and reduces requirement for further projects.
Despite there being so many ways to recycle and reuse construction materials, the path isn’t easy. The best way to promote the use of these materials over new ones and marketing them on a mass basis are some of the issues plaguing reuse of C&D waste.
