How to make roads with recycled waste and pave the way for a circular economy
by Salman Shooshtarian, Savindi Caldera, Tayyab Maqsood, Tim Ryley, The Conversation
It cost A $ 49 million to add an additional 12.5 kilometers of lane to the Kwinana Highway in Western Australia, south of Perth’s CBD. It is not unusual. On average, building a single lane of road costs around A $ 5 million per kilometer.
What is unusual about this additional stretch of motorway is not the money but the materials under the asphalt: two stabilizing layers made up of 25,000 tonnes of crushed recycled concrete, of which around 90% came from the demolition of Subiaco Oval (once Perth’s premier football ground).
Recycling of building materials remains the exception to the rule in Australia. The national waste policy agreed to by federal, state and territorial governments has a resource recovery target of 80% by 2030. It is currently around 40%.
Of the 74 million tonnes of waste generated in Australia in 2020, masonry materials accounted for around 22.9 million tonnes. Plastics, by comparison, accounted for around 2.5 million tonnes. Of the 61.5 million tonnes of “basic waste” managed by the waste and resource recovery sector, 44% (27 million tonnes) came from the construction and demolition sector, compared to 20% ( 12.6 million tonnes) of households and activities of local communities.
Most of this waste – concrete, brick, steel, wood, asphalt and plasterboard or cement – could be reused or recycled. It ends up in landfill for simple economic reasons. It is cheaper to buy new materials and throw them away than to reuse and recycle them.
Changing this equation and moving to a circular economy, in which materials are reused and recycled rather than landfilled, is a key objective to reduce the impact of building and construction on the environment, including its contribution to change. climate.
The economy of “externalities”
The fact that it is more “economical” to throw away materials than to reuse them is what economists call market failure, driven by the problem of “externalities”. That is, the social and environmental costs of producing, consuming and disposing of materials are not reflected in the prices charged. These costs are rather externalized, borne by others.
In such cases, governments have a legitimate – and necessary – role in intervening and correcting market failures. For an externality such as carbon emissions (imposing costs on future generations), the market-based solution favored by most economists is a carbon price.
For building material waste, governments have a few more policy levers to help create a viable market for more recycling.
Use of procurement policies
One way to make recycling more attractive to businesses would be to increase the cost of sending waste to landfill. But that would likely have unintended consequences, such as an illegal dumping.
The most obvious and effective approach is to help create more demand for recycled materials through public procurement, by adopting policies that require suppliers, for example, to use a minimum amount of recycled material.
With sufficient demand, recyclers will invest in further waste recovery, thereby reducing costs. Lower costs in turn create the possibility of greater demand, creating a virtuous circle that leads to a circular economy.
Australia’s federal, state and territorial governments all have sustainable procurement policies. The Federal Guide to Sustainable Procurement says the Australian government ‘is committed to turning Australian waste into a resource, where most goods and services can be continuously used, reused, recycled and reprocessed as part of a circular economy “.
But these policies lack some basic elements.
Three key market making reforms
Our research suggests that three important reforms could make a big difference in waste market operations. This is based on interviews with 27 stakeholders from the private sector and government on how to improve sustainable procurement.
First, government waste policies that set ambitious targets are not supported by procurement policies that set mandatory minimum recycled content targets. All contractors in government funded construction projects should be required to use a percentage of recycled waste.
Second, the nature of salvage building materials means that the quality can vary widely. Cement recycled from a demolition site, for example, could contain contaminants that reduce its durability.
Governments can help the market by regularly checking the quality of recycler processes, to increase buyer confidence and motivate suppliers to invest in production technologies.
Third, in some states (such as Western Australia) the testing regimes for recycled construction products are more complex than those for raw materials. More reasonable specifications would reduce compliance costs and therefore the cost of using recycled materials.
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