Concrete chokes our landfill sites – but where else can it go?

Most concrete from demolished buildings is simply dumped, much of it illegally. But there’s a better way – and it involves lightning

At the Shenzhen dump, huge shards of dusty concrete lie in imposing piles. Once the very foundation of this Chinese city, these blocks now seem grotesque in their magnitude, and unsettling in their utter uselessness. Jumbled up with the other relics of modern construction – bricks, wood and steel – and dotted with plastic bags and bottles, it could take centuries, even millennia, for Shenzhen’s discarded concrete to disintegrate back into sand.
China produces more construction waste than any other country – around 2 billion tonnes per year (pdf), or around 4kg per person per day. Two million tonnes of this is concrete. In Shenzhen, which has grown from a town with 30,000 residents to a megacity with 11 million in just 35 years, a full 84% of that construction waste is unceremoniously dumped. It doesn’t even all make its way to official landfills, which don’t have the capacity to handle it, so almost half is disposed in unlicensed sites, or illegally tipped.

As our world urbanises at a pace never before seen, with buildings rising and falling in as little as 30 years, the crumbled debris of our cities often ends up in landfill. Around 10bn tonnes (pdf) of concrete are manufactured each year: a staggering one cubic metre for every person on Earth. Over the next 40 years the world is expected to build 230 billion square metres in new construction, adding the equivalent of Paris to the planet every single week.

Much of that new construction means knocking down old structures, and gradually engineers and policymakers are waking up to a question: what should we do with our concrete when we’re finished with it?

read the full artivel here

published on www.theguardian.com within the #GuardianConcreteWeek

Own note: I cannot support the type of reporting of “The Guardian”, but I think it is important to discuss the issue of recycled concrete in public.

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