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Circular Economy | Infrastructure's Role

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The circular economy aims to retain materials in use as long as possible. Can infrastructure play its part?

Here is some good news. Infrastructure is on its game when it comes to circular economy activity, well at entry level at least.

“It’s something infrastructure does without knowing it, and has always done,” says London Sustainable Development Commission commissioner and consultant Paul Toyne.

“As an industry, infrastructure always starts out thinking about how to reuse surplus material, which is one of the fundamental planks of any circular economy thinking,” he says.

The landfill tax has helped focus minds, but no contractor worth its salt has ever wanted to throw away valuable materials, and most designers pride themselves on using just what is needed and no more.

But according to circular economy standard bearer The Ellen MacArthur Foundation, the aim is now to push things much further. This involves decoupling economic activity from the consumption of finite resources, which are eventually thrown away when they are out of date only to be replaced by newer products using fresh material.

Circular economy thinking involves keeping products and materials in use for as long as possible

Circular economy thinking involves keeping products and materials in use for as long as possible and designing out waste altogether if possible.

“A circular economy is one that is restorative by design, and which aims to keep products, components and materials at their highest utility and value, at all times,” the Foundation says in its formal definition.

The commission Toyne sits on advises London mayor Sadiq Khan and the Greater London Authority, which in May produced London’s first integrated environment strategy.  The low carbon circular economy is a major part of that strategy. It commits the city to moving its investments away from using a linear approach to resources – take, make, use and dispose – to a circular economy approach, where as much economic value as possible is extracted from resources through their use and reuse, before they become waste.

More than just meeting the standard

In terms of infrastructure and the built environment, that involves a move away from just meeting the standard or targeting lowest cost when coming up with solutions.

Instead it will require a shift towards demonstrating whole life value and how the resources being poured into projects will be in place for a long time. There will also be a requirement for resources to be able to be repurposed and adapted for new uses in an unknown future almost ad infinitum.

It is a big challenge. Around 80% of the UK’s economy still relies on a “once through” process. The country uses 2.5 times more than a sustainable amount of resources each year with construction the largest consumer of these resources.

Over the next decades, and as competition for raw materials becomes more intense, there will be pressure not just to recycle material for a lower grade use but to design structures in a modular way so they can be dismantled and elements reused to keep the value in the products for as long as possible.  

Our contractors are coming up with ideas of using higher percentages of byproducts

“With a growing population, huge consumption and pressure on scarce resources, we are going to need to be smarter,” says Toyne.

Contractors are already starting to explore the future value of materials in their buildings and how they could be better used, for example by leasing the building to its occupier before it is later dismantled and re-leased to a new client in a new format, Toyne points out.

Early steps in understanding the potential of the circular economy are being taken by three of the country’s big infrastructure clients. Tideway – the promoter of London’s new super sewer, HS2 Ltd – promoter of the high speed railway to the Midlands and the North; and Highways England, which is in charge of the English strategic road network.

“Two years ago we included a circular economy commitment in our environmental policy and set out to explore circular economy opportunities,” says Tideway head of environmental sustainability Darren White.

“At its most basic, our project involves digging out 4M.t of material and putting in a lot of concrete. Once it’s gone in it’s never going to be deconstructed and we have a design life of 120 years with the idea that we won’t have to repair it in that time.”

If keeping high value materials in use for a long time is one of the planks of the circular economy, then Tideway is on the money. But that has involved the client demanding very high specification designs and construction standards.


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Tideway has a design life of 120 years with the idea that it will not have to be repaired in that time

“We have also designed Tideway so it can be expanded in hundreds of years, like the Bazalgette sewers that we have relied on since the Victorian era,” White explains.

Material excavated for the tunnels is being used to cap and regenerate landfills in Rainham and the Ingrebourne Valley in east London as you would expect. But Tideway is doing more. “Our contractors are coming up with ideas of using higher percentages of byproducts such as ground granulated blast furnace slag and PFA [pulverised fuel ash] in concrete and we are running a test on 100% cement free products to prove them in long term use.

“The cement-free project was the result of a competition we ran last year through our innovation portal. Everyone needs evidence from cement-free concrete tests so we are going to provide it. We are going to use the three products on the market in some of our public realm areas and monitor the performance.”

For the rail systems, and electronics, we want to see recycling and reuse of components with value

Tideway has also partnered with charity Thames21 to collect waste plastic from the river Thames foreshore. “And the site teams have taken it on themselves to go out and litterpick as well.”

Tideway has also funded with Starbucks (raised from 5p charges on its paper coffee cups) construction of one of only two boats in the world made from 99% plastic waste. It was launched at Richmond last month.

Recycled plastic boat

The boat, called PET Project, was the brainchild of environmental charity Hubbub and is made from recycled single-use plastic called Plaswood. A tonne of plastic waste was sent from the Thames to the Plaswood factory in Dumfries, Scotland and returned as planks to be used as part of the 12 seater punt.

Over at HS2, the project started its journey to the circular economy by identifying three key principles to stick to, according to sustainability manager Andrea Charlson. These were to keep resources in use for as long a time as possible, to design for recovery and reuse in the future and to keep materials at high quality and in high value use.

“The circular economy puts the emphasis on whole life as you’d expect,” Charlson says. “For civil engineering that means high specification materials to suit a design life of 120 years as a minimum but with very low maintenance. We will be using the line at intensity so there will only be short windows for maintenance.

“But for the rail systems, and electronics, we want to see recycling and reuse of components with value. Likewise, our rolling stock will have to have 95% to 99% targets for recovery and recycling.”

Highways England’s challenge therefore is to be increasingly efficient in its resource use

In terms of keeping materials in high quality and high value use, HS2 is investigating reusing excavated material from its tunnels. Of the 128M.t that will be dug out, 90% is already earmarked for landscaping and the like. But for the other 10%, and in particular the London Clay from the London end of the project, the rail developer wants to build on work begun by Crossrail which was investigating how to reuse that material for actual construction products –  “uplifting it in value,” as Charlson says.

The Skanska, Costain, Strabag (SCS) joint venture working on the civils in Area South is keen to try out a couple of options and is bidding for funding from HS2’s innovation fund. This would be to explore turning the London Clay into lightweight aggregate or to use it in structural concrete.

Highways England priorities

Highways England has the circular economy as one of its five sustainable development priorities, taking the Ellen MacArthur Foundation definition as its starting point.

“It is concise, ambitious and aligns with our delivery plans,” says Highways England head of sustainable development and design Dean Kerwick-Chrisp.

“We are keen to ensure what we do in the future will further reduce the impact of our activities and will always be seeking a long term and sustainable benefit to the environment and the communities we serve.”

Kerwick-Chrisp highlights a significant way circular economy principles will be driven down through its activities, starting with design.

“Our circularity priority will be emphasised in a future Design Manual for Roads and Bridges (DMRB) introduction and general requirement to sustainable development and design,” Kerwick-Chrisp says.

Design lifecycle goals

“This will state that goals of sustainable development shall be delivered throughout the design lifecycle. And specifically it will state that the design shall aspire to be resource efficient and reflect a circular approach to the use of materials. DMRB requirements have to be followed by the company’s supply chain.”

Highways England believes that having the circular economy as a priority is recognition that road investment will require an increase in resources at a time when investment in other major infrastructure is also increasing.

 “Collectively, this will put pressure on the availability of, and increase competition for, the materials needed in construction,” Kerwick-Chrisp says.

“Highways England’s challenge therefore is to be increasingly efficient in its resource use and ensure recycled materials are reused for the highest value purpose.

 “The opportunities with the greatest potential for improving resource efficiency and contributing to the circular economy in construction projects occur during the feasibility and early design stage. Implementing these opportunities can provide significant reductions in cost, waste and carbon,” he stresses.

Expanded resource efficiency

“For our supply chain the DMRB will expand the resource efficiency and circular approach. It will require design solutions to seek to minimise the consumption of materials and the generation of waste,” he says.

 “Opportunities to reuse site-won materials or from on-site demolition, where available, should be identified, assessed and incorporated into design. A second requirement will be for safe design solutions that enable deconstruction, demounting and decommissioning to facilitate future high value recycling, re-manufacture or re-use at end of first life, to be identified and where feasible incorporated into design.”

Often the circular solution delivers not just savings in the future, but can deliver upfront savings too, Kerwick-Chrisp points out.

“Our Supplier Recognition Awards have recognised some of the best examples. For example, on the A160 upgrade our supply chain – in this case Costain, Jacobs and Tarmac – embodied circular economy principles through re-using and recycling materials to achieve value.

“For example, the project used around 70,000t of a low temperature asphalt product on a 5km stretch of road, over 90% of which was manufactured using secondary aggregates. Not only did this use resources efficiently, it also led to time savings during application an d carbon savings through the reduced temperature of the asphalt mix.” 


Circular thinking for China

Adopting circular economy principles at scale in China’s cities could reduce emissions of fine particulates by 50%, emissions of greenhouse gases by 23% and traffic congestion by 47% by 2040. This is the conclusion of new research produced by the Ellen MacArthur Foundation with Arup and McKinsey & Company.

Their report “The circular economy opportunity for urban and industrial innovation in China” launched in September reveals that it could save 16% of its GDP or 70 trillion Yuan (£7.8bn) by 2040.

China’s cities are already hubs of circular economy innovation, according to the Foundation.

Opportunities to scale up China’s circular economy in the built environment include designing for longevity (currently the average lifespan of a building in China is 20 to 30 years compared to 136 years in the UK), industrialising and modularising construction processes, improving the energy efficiency of buildings and scaling up re-use and recycling of construction and demolition waste.

China’s urban population is expected to double by 2040, creating substantial demand for new housing and infrastructure.

Nationwide in 2016, the built area under construction and completed reached 12.6bn.M2 and

4.2bn.M2 respectively – representing half of the world’s construction output in that year.

In 2013 China generated 1bn tonnes of construction and demolition waste.

“Applying circular economy principles throughout the value chain would help address these issues and provide economic, environment and societal benefits,” says the Foundation report.


Bringing in the circular economy

In June consultant WSP, supported by 15 organisations such as contractor Costain, supplier Tarmac and contractor Osborne, produced a report making 10 practical recommendations to speed up adoption of circular economy principals in the UK.

The report, Accelerating resource-efficient circular design in buildings and infrastructure targeted skills, strategy and policy, records and evidence, and finance and procurement.

On skills the recommendations were that:

  • Circular design principles should be included in all engineering, architecture and design degree courses from 2020
  • The construction and engineering industry training boards should deliver effective skills in modular, adaptable and flexible construction as part of their ongoing reform
  • Key is to give all staff in the sectors a strong grounding in practical, modular, adaptable and resource efficient design

In terms of standards and policy the report suggests:

  • Updating engineering and architecture design codes and standards so they do not inhibit adaptable, resource efficient design
  • Making “Module D” – the end of life element of Environmental Product Declarations – mandatory rather than voluntary. Currently product designers decide whether to say how a product might be reused, recycled or disposed of at the end of its life. Bolstering the standards to specifically consider end of life would reward clever design
  • Simplifying waste regulations as part of the UK’s emerging Resources and Waste Strategy. Today, waste regulations get in the way of reusing perfectly reliable building materials either directly or indirectly because of the stigma created by used resources being classified as “waste”. With Brexit, the Department for Environment Food and Rural Affairs should work to avoid classifying construction materials as waste unless no other safe use can be identified

For records and evidence the proposals are:

  • Store detailed design criteria and “as built” information securely and accessibly so both can be easily retrieved and used decades later
  • Launch a library of strong case studies showing examples of best practice resource-efficient designs

Finance and procurement aims should be:

  • Extend the first year capital allowance system to incentivise specification and installation of resource-efficient modular components
  • Learn from European best practice to incentivise resource efficiency in UK infrastructure procurement
  • Include adaptable, modular, flexible designs as evaluation criteria in international bank lending standards

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