Construction World November 2021

are paying more attention to waste recycling as part of their sustainability agendas. “The crushing and screening of rubble at source would be a valuable contribution to these efforts, he concluded. 

due to poor enforcement contaminated C&D material is often dumped – illegally – with clean material, meaning it’s only useful as a cover material. With ongoing urbanisation, South Africa’s urban landfills are taking strain and recycling is becoming imperative. This is particularly the case in the metropolitan areas of Gauteng, which have dense populations and limited space for new landfill sites. “This waste material from construction can even be crushed and screened at the landfill sites themselves,” he says. “This will create a useful product that can actually be sold, while reducing the amount of space required for dumping at the landfill.” He also highlighted the importance of properly processing – or separating – construction and demolition waste, which would allow the various categories of waste to remain uncontaminated “Rubble cannot contain foreign material if it is to deliver a final product of high enough quality,” he says. “This will need separation at source as well as better enforcement on dumps – as a great deal of construction waste is not suitable for the production of general aggregate.” He notes that recyclers are losing out on large volumes of potential feed material of relatively high value, and are having to accept lower prices for fill material of poorer quality. There is also the problem of illegal sand mining is some areas, driving down the cost of sand and undermining the position of legitimate producers. “Most developed countries are in fact well ahead of South Africa on the recycling of construction and demolition material – with the necessary laws in place and the systems to implement these effectively,” says Abelho. “It is time that we updated our legislation accordingly, and facilitated the regular reporting of recycling performance.” The country’s reuse of construction and demolition waste is currently not well monitored or systematically recorded. Increasingly, however, responsible construction companies

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Concrete, construction and demolition waste being screened.

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27 CONSTRUCTION WORLD NOVEMBER 2021