Sustainable material such as concrete should not end up in landfills, but rather re-used and recycled according to various construction needs.
Massive quantities of construction and demolition waste (C&DW) are being dumped in landfills without consideration for the potential value of recycling such valuable building material. This strong opinion is identified and highlighted by Bryan Perrie, MD of The Concrete Institute.
He goes on to say that significant volumes of C&DW – including large volumes of concrete – are ending up in municipal solid waste landfills in South Africa. “There is currently growing concern worldwide about this wastage of materials such as concrete, wood, gypsum, metals, bricks, glass, plastics and salvaged building components like doors, windows and plumbing fixtures,” he continues. “The waste debris, which usually originates from the demolition of buildings or civil infrastructure, could also contain hazardous materials such as lead, asbestos or even radioactive materials.”
This is perplexing, given the fact that there is tremendous potential to recycle several elements of demolition waste, particularly concrete, which can be crushed and re-used in construction projects.
Bryan says the European Union, for example, has identified C&DW as a priority waste stream, recognising the high potential for the recycling and re-use of such debris, particularly concrete. C&DW annually amounts to around 510 million tons (equivalent to 30% of all waste generated) in Europe.
“In the USA, C&DW totals about 325 million tons per year, and in Japan, 77 million,” says Bryan. “In Europe, the EU has decreed that aggregates derived from C&DW in roads, drainage and other construction projects must be recycled. In fact, the technology for the separation and recovery of construction and demolition waste is now well established in European countries, readily accessible and, generally, inexpensive.”
In addition, the USA’s Federal Highway Administration (FHWA) actively promotes the recycling of concrete from pavements and roads, and such recovery programmes are now in operation in just about every state in America.
According to Bryan, uncontaminated concrete pavements can serve as a substitute for most natural aggregates, with significant economic benefits. “In Anaheim in the USA, 700 000 tons of concrete was re-used on a freeway project, providing a cost saving of US$5-million. Similar economic benefits of concrete recycling have been experienced in Melbourne, Australia, where 15 000 cubic metres of concrete was recovered for the construction of the city’s Western Link, yielding cost savings of over Aus$4-million,” he asserts.
Bryan adds that controlled demolition, which incorporates a sorting system to separate re-usable elements on site – and also taking the quality and history of the concrete waste into account – is a vital component of sustainability.
“All concrete deemed suitable for recycling should be used for new concrete production,” Bryan concludes. “A properly structured demolition waste recycling programme would also create new employment opportunities and reduce the exploitation of natural resources.”
For these reasons, Bryan firmly believes that more attention should be paid to the re-use and recycling of building materials such as concrete at the design stage, which will more actively promote sustainability in the construction industry.
For more information visit www.theconcreteinstitute.org.za